A form of ventricular pre-excitation characterized by a normal PR interval and a long QRS interval with an initial slow deflection (delta wave). In this syndrome, the atrial impulse travel to the ventricle via the MAHAIM FIBERS which connect ATRIOVENTRICULAR NODE directly to the right ventricle wall (NODOVENTRICULAR ACCESSORY PATHWAY) or to the RIGHT BUNDLE BRANCH OF HIS (nodofascicular accessory pathway).
Abnormally rapid heartbeats with sudden onset and cessation.
Small band of specialized CARDIAC MUSCLE fibers that originates in the ATRIOVENTRICULAR NODE and extends into the membranous part of the interventricular septum. The bundle of His, consisting of the left and the right bundle branches, conducts the electrical impulses to the HEART VENTRICLES in generation of MYOCARDIAL CONTRACTION.
The valve consisting of three cusps situated between the right atrium and right ventricle of the heart.
Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.
Abnormally rapid heartbeats caused by reentry of atrial impulse into the dual (fast and slow) pathways of ATRIOVENTRICULAR NODE. The common type involves a blocked atrial impulse in the slow pathway which reenters the fast pathway in a retrograde direction and simultaneously conducts to the atria and the ventricles leading to rapid HEART RATE of 150-250 beats per minute.
An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
A form of heart block in which the electrical stimulation of HEART VENTRICLES is interrupted at either one of the branches of BUNDLE OF HIS thus preventing the simultaneous depolarization of the two ventricles.
Discrete concentrations of energy, apparently massless elementary particles, that move at the speed of light. They are the unit or quantum of electromagnetic radiation. Photons are emitted when electrons move from one energy state to another. (From Hawley's Condensed Chemical Dictionary, 11th ed)
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
The function of opposing or restraining the excitation of neurons or their target excitable cells.
Measurement of the intensity and quality of fluorescence.
Use of electric potential or currents to elicit biological responses.
Fluorescence microscopy utilizing multiple low-energy photons to produce the excitation event of the fluorophore. Multiphoton microscopes have a simplified optical path in the emission side due to the lack of an emission pinhole, which is necessary with normal confocal microscopes. Ultimately this allows spatial isolation of the excitation event, enabling deeper imaging into optically thick tissue, while restricting photobleaching and phototoxicity to the area being imaged.
The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.
The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.

Radiofrequency ablation of a right atriofascicular Mahaim fiber and two contralateral left free-wall accessory pathways. (1/12)

We report a rare combination of a right atriofascicular Mahaim fiber and two left-sided atrioventricular accessory pathways in a 57-year-old female presenting with an antidromic atrioventricular reciprocating tachycardia. Radiofrequency ablation was first targeted at the left lateral accessory pathway that served as the retrograde limb of the tachycardia. After elimination of the left lateral pathway, a bystander left posterolateral pathway was detected, and it too was successfully ablated. Although no tachycardia was reinducible, the Mahaim pathway was ablated because of its short effective refractory period. A discrete Mahaim potential recorded at the right atrial free-wall successfully guided the ablation.  (+info)

Catheter ablation of atriofascicular Mahaim fibers guided by the activation potential. (2/12)

OBJECTIVE: To determine whether recording of the activation potential may be used as an isolated criterion to guide catheter ablation of atriofascicular Mahaim fibers. METHODS: We studied 6 patients (5 females, mean age of 26 +/- 7.3 years) with paroxysmal tachycardias with a wide QRS complex, whose electrophysiological study diagnosed atriofascicular Mahaim fibers. Mapping and catheter ablation were performed in sinus rhythm, guided only by the recording of the activation potential of the fiber. RESULTS: Efficacy in ablation was achieved in all patients. The fibers were located in the right lateral region of the tricuspid ring in 3 patients, right posterolateral region in 2, and right anterolateral region in 1. A mean of 5.3 +/- 3 radiofrequency applications was performed. The mean fluoroscopy time was 46.6 +/- 25 minutes, and the mean duration of the procedure was 178.6 +/- 108 minutes. No complication occurred. In a mean 20-month follow-up, all patients were asymptomatic and receiving no antiarrhythmic drugs. CONCLUSION: Catheter ablation of Mahaim fibers may be performed with good safety and efficacy by mapping the activation potential of the tricuspid ring in sinus rhythm.  (+info)

The electrocardiogram during sinus rhythm and tachycardia in patients with Mahaim fibers: the importance of an "rS" pattern in lead III. (3/12)

OBJECTIVES: The purpose of the study was to identify the electrocardiographic (ECG) characteristics of the Mahaim fiber. BACKGROUND: Mahaim fibers are slowly conducting accessory pathways reaching into the right ventricle. They often play a role in tachycardias. METHODS: We retrospectively analyzed 40 patients with Mahaim fibers. Five patients had associated Wolff-Parkinson-White syndrome and were excluded from the study. Two patients had a short atrioventricular decremental accessory pathway and were also excluded. The remaining 33 patients had a tachycardia with anterograde conduction over a Mahaim fiber. Twenty were female. Their mean age was 24 +/- 10 years. RESULTS: The most common pattern of minimal preexcitation during sinus rhythm was an rS pattern in lead III. This was found in 20 patients. There was a match between the presence of rS in lead III during sinus rhythm and left axis deviation during tachycardia with anterograde conduction over the Mahaim fiber. After ablation, a different QRS pattern emerged in lead III, indicating the absence of conduction over the Mahaim fiber. To obtain information on the prevalence of an rS pattern in lead III in age-matched controls with palpitations and without structural heart disease, the 12-lead ECG of 200 young individuals were examined. An rS pattern in lead III was found in 6%. CONCLUSIONS: A narrow QRS with an rS pattern in lead III during sinus rhythm in a patient with a history of palpitations should alert the physician to the possibility of a Mahaim fiber. During tachycardia, these patients typically show a left bundle branch block-like QRS complex with left axis deviation.  (+info)

The automaticity of Mahaim fibre and its response to effective ablation. (4/12)

BACKGROUND: Typical accessory pathways (APs) of Wolf-Parkinson-White syndrome have been widely discussed in recent decades. However, the characteristics of the special AP, Mahaim fibre, are not so clear. It is known that these fibres have antegrade conduction only, long conduction time, decremental node-like conduction and automaticity properties. This study was to elucidate the automaticity of Mahaim fibre and its response to effective ablation. METHODS: Thirteen patients with Mahaim fibre (ten atrioventricular and three atriofascicular accessory pathways) were subjected to electrophysiological study and radiofrequency ablation via catheter. The incidence and characteristics of anautomatic rhythm originating from Mahaim fibre were observed during the whole procedure, especially during radiofrequency current delivery. RESULTS: Repetitive and short-run automatic rhythm (rate: 65-72 beats per minute), with a QRS morphology similar to that of clinical pre-excited atrioventricular re-entrant tachycardia (AVRT), occurred in two patients during sinus rhythm. Conduction via Mahaim fibre was successfully eliminated by radiofrequency current. Fourteen applications of RF were associated with irregularly accelerated automatic tachycardia of Mahaim fibre (with a sensitivity of 78%), lasting for 1.2-14 seconds. However, such automatic tachycardia of Mahaim fibre did not occur during 54 failed applications of radiofrequency current. CONCLUSIONS: Mahaim fibre has the function of automaticity. The accelerated automatic tachycardia of Mahaim fibre occur red during radiofrequency catheter ablation can be used as a predictor for successful procedure.  (+info)

Is the activation potential of Mahaim pathway always a fast potential? Implication for radiofrequency catheter ablation. (5/12)

INTRODUCTION: Accessory pathways (AP) exhibiting Mahaim physiology are amenable to radiofrequency (RF) catheter ablation. The recording of an AP potential is an excellent guide for selection of ablation site. The purpose of this study is to determine whether the pathway potential is always a fast potential. METHODS: Ten patients (six females, mean age, 30 +/- 12 years) with preexcited tachycardias involving a Mahaim pathway underwent electrophysiological study and subsequent attempts at RF ablation. Mahaim potentials (M-potential) recorded at the site of successful ablation were reviewed and classified by at least two reviewers. RESULTS: In all patients, Mahaim pathways were characterized as atriofascicular types. The M-potential was fast in seven patients (group one), and slow in the remaining patients (group two). All group two patients had a history of prior failed ablation. Atrial electrograms were recorded closer to the QRS onset in group one. Atrium to fast M-potential (42 +/- 15 ms) was shorter than atrium to slow M-potential (83 +/- 12 ms, P = 0.03) but M-potentials were recorded with similar distance before local ventricular electrogram (P = NS). Ablation was successful in all patients with mean of 2.9 +/- 1.4 RF applications per patient. Ablation data were similar between the two groups (P = NS). No complications occurred. During 12 months of follow-up, no recurrence was observed. CONCLUSION: Our results illustrated that the activation potential of Mahaim pathways is not always a fast potential. One-third of Mahaim pathways can be mapped and ablated when the slow type of M-potential was used as a target for ablation. We also confirmed high efficacy of catheter ablation of Mahaim pathways guided by activation potentials.  (+info)

The clinical course and risk in patients with pseudo-Mahaim fibers. (6/12)

BACKGROUND: Pseudo-Mahaim (AP-M) fibers are a rare variant of atrioventricular (AV) accessory pathways. Atriofascicular and atrioventricular accessory connections are characterized by slow conduction and decremental properties. Dual physiological AV node pathways, slow and fast, are observed in a large number of patients with AP-M. Therefore, there is substrate for AV nodal reentrant tachycardia (AVNRT) in addition to antidromic AV reentrant tachycardia (AVRT) with left bundle branch block (LBBB)-like morphology. Other arrhythmia such as atrial fibrillation (AF) or atrial flutter (AFL) and ventricular fibrillation (VF) are also observed. We analysed the occurrence of arrhythmias in a group of patients with AP-M treated in our department. METHODS: We evaluated 27 patients (12 women) aged 14-53 years (mean age 25.6 years) with AP-M. The clinical course in these patients, in particular with regard to the occurrence of arrhythmias, was analysed. Patients with dual AV node properties were compared to patients without such findings. RESULTS: We found dual AV node properties in 18 patients (Group 1), while 9 patients had fast pathway only (Group 2). Twenty-six patients presented with AVRT, 2 patients with AVNRT, 3 patients with AF, 1 patient with AT, 2 patients with AFL, and 3 patients with VF. In 2 patients, AP-M were seen in an atypical area. In one patient, the pathway connected the right atrium with the left ventricle (septal region), and in the other patient it connected the left atrium with the left ventricle (left anterior region). CONCLUSIONS: The majority of AP-M was right-sided. Two thirds of patients with AP-M had anatomical substrate for AVNRT (fast/slow pathway AV node). VF or asystole occurred in 10% of patients.  (+info)

Electrophysiology study and radiofrequency catheter ablation of atriofascicular tracts with decremental properties (Mahaim fibre) at the tricuspid annulus. (7/12)

 (+info)

Wide-QRS tachycardia inducible by both atrial and ventricular pacing. (8/12)

We describe an interesting case of an atriofascicular re-entrant tachycardia due to a Mahaim pathway. The differential diagnosis is discussed and a review of the relevant literature is presented.  (+info)

"Pre-excitation, Mahaim-type" is a medical term used to describe a specific electrical conduction pattern in the heart that can lead to an abnormal heart rhythm (arrhythmia). This condition involves an accessory pathway, also known as a "Mahaim fiber," which connects the atria (the upper chambers of the heart) to the ventricles (the lower chambers) in a way that bypasses the normal conduction system.

In this type of pre-excitation, the electrical impulses travel through the accessory pathway and reach the ventricles earlier than they would via the normal conduction system, resulting in a characteristic pattern on an electrocardiogram (ECG) known as a "delta wave." This pre-excitation can lead to tachyarrhythmias such as atrioventricular reentrant tachycardia (AVRT), which can cause symptoms like palpitations, dizziness, or even syncope (fainting).

It's important to note that not all individuals with Mahaim-type pre-excitation will develop arrhythmias, but some may require treatment if they experience symptoms or have a high risk of complications. Treatment options include medications, catheter ablation, or surgical intervention.

Paroxysmal Tachycardia is a type of arrhythmia (abnormal heart rhythm) characterized by rapid and abrupt onset and offset of episodes of tachycardia, which are faster than normal heart rates. The term "paroxysmal" refers to the sudden and recurring nature of these episodes.

Paroxysmal Tachycardia can occur in various parts of the heart, including the atria (small upper chambers) or ventricles (larger lower chambers). The two most common types are Atrial Paroxysmal Tachycardia (APT) and Ventricular Paroxysmal Tachycardia (VPT).

APT is more common and typically results in a rapid heart rate of 100-250 beats per minute. It usually begins and ends suddenly, lasting for seconds to hours. APT can cause symptoms such as palpitations, lightheadedness, shortness of breath, chest discomfort, or anxiety.

VPT is less common but more serious because it involves the ventricles, which are responsible for pumping blood to the rest of the body. VPT can lead to decreased cardiac output and potentially life-threatening conditions such as syncope (fainting) or even cardiac arrest.

Treatment options for Paroxysmal Tachycardia depend on the underlying cause, severity, and frequency of symptoms. These may include lifestyle modifications, medications, cardioversion (electrical shock to restore normal rhythm), catheter ablation (destroying problematic heart tissue), or implantable devices such as pacemakers or defibrillators.

The Bundle of His is a bundle of specialized cardiac muscle fibers that conduct electrical impulses to the Purkinje fibers, which then stimulate contraction of the ventricles in the heart. It is named after Wilhelm His, Jr., who first described it in 1893.

The Bundle of His is a part of the electrical conduction system of the heart that helps coordinate the contraction of the atria and ventricles to ensure efficient pumping of blood. The bundle originates from the atrioventricular node, which receives electrical impulses from the sinoatrial node (the heart's natural pacemaker) and transmits them through the Bundle of His to the Purkinje fibers.

The Bundle of His is divided into two main branches, known as the right and left bundle branches, which further divide into smaller fascicles that spread throughout the ventricular myocardium. This ensures a coordinated contraction of the ventricles, allowing for efficient pumping of blood to the rest of the body.

The tricuspid valve is the heart valve that separates the right atrium and the right ventricle in the human heart. It is called "tricuspid" because it has three leaflets or cusps, which are also referred to as flaps or segments. These cusps are named anterior, posterior, and septal. The tricuspid valve's function is to prevent the backflow of blood from the ventricle into the atrium during systole, ensuring unidirectional flow of blood through the heart.

Catheter ablation is a medical procedure in which specific areas of heart tissue that are causing arrhythmias (irregular heartbeats) are destroyed or ablated using heat energy (radiofrequency ablation), cold energy (cryoablation), or other methods. The procedure involves threading one or more catheters through the blood vessels to the heart, where the tip of the catheter can be used to selectively destroy the problematic tissue. Catheter ablation is often used to treat atrial fibrillation, atrial flutter, and other types of arrhythmias that originate in the heart's upper chambers (atria). It may also be used to treat certain types of arrhythmias that originate in the heart's lower chambers (ventricles), such as ventricular tachycardia.

The goal of catheter ablation is to eliminate or reduce the frequency and severity of arrhythmias, thereby improving symptoms and quality of life. In some cases, it may also help to reduce the risk of stroke and other complications associated with arrhythmias. Catheter ablation is typically performed by a specialist in heart rhythm disorders (electrophysiologist) in a hospital or outpatient setting under local anesthesia and sedation. The procedure can take several hours to complete, depending on the complexity of the arrhythmia being treated.

It's important to note that while catheter ablation is generally safe and effective, it does carry some risks, such as bleeding, infection, damage to nearby structures, and the possibility of recurrent arrhythmias. Patients should discuss the potential benefits and risks of the procedure with their healthcare provider before making a decision about treatment.

Atrioventricular (AV) nodal reentrant tachycardia (AVNRT) is a type of supraventricular tachycardia (SVT), which is a rapid heart rhythm originating at or above the atrioventricular node. In AVNRT, an abnormal electrical circuit in or near the AV node creates a reentry pathway that allows for rapid heart rates, typically greater than 150-250 beats per minute.

In normal conduction, the electrical impulse travels from the atria to the ventricles through the AV node and then continues down the bundle branches to the Purkinje fibers, resulting in a coordinated contraction of the heart. In AVNRT, an extra electrical pathway exists that allows for the reentry of the electrical impulse back into the atria, creating a rapid and abnormal circuit.

AVNRT is classified based on the direction of the reentry circuit:

1. Typical or common AVNRT: The most common form, accounting for 90% of cases. In this type, the reentry circuit involves an "anterior" and a "posterior" loop in or near the AV node. The anterior loop has slower conduction velocity than the posterior loop, creating a "short" reentry circuit that is responsible for the rapid heart rate.
2. Atypical AVNRT: Less common, accounting for 10% of cases. In this type, the reentry circuit involves an "outer" and an "inner" loop around the AV node. The outer loop has slower conduction velocity than the inner loop, creating a "long" reentry circuit that is responsible for the rapid heart rate.

AVNRT can present with symptoms such as palpitations, dizziness, lightheadedness, shortness of breath, chest discomfort, or syncope (fainting). Treatment options include observation, vagal maneuvers, medications, and catheter ablation. Catheter ablation is a curative treatment that involves the destruction of the abnormal electrical pathway using radiofrequency energy or cryotherapy.

The heart conduction system is a group of specialized cardiac muscle cells that generate and conduct electrical impulses to coordinate the contraction of the heart chambers. The main components of the heart conduction system include:

1. Sinoatrial (SA) node: Also known as the sinus node, it is located in the right atrium near the entrance of the superior vena cava and functions as the primary pacemaker of the heart. It sets the heart rate by generating electrical impulses at regular intervals.
2. Atrioventricular (AV) node: Located in the interatrial septum, near the opening of the coronary sinus, it serves as a relay station for electrical signals between the atria and ventricles. The AV node delays the transmission of impulses to allow the atria to contract before the ventricles.
3. Bundle of His: A bundle of specialized cardiac muscle fibers that conducts electrical impulses from the AV node to the ventricles. It divides into two main branches, the right and left bundle branches, which further divide into smaller Purkinje fibers.
4. Right and left bundle branches: These are extensions of the Bundle of His that transmit electrical impulses to the respective right and left ventricular myocardium. They consist of specialized conducting tissue with large diameters and minimal resistance, allowing for rapid conduction of electrical signals.
5. Purkinje fibers: Fine, branching fibers that arise from the bundle branches and spread throughout the ventricular myocardium. They are responsible for transmitting electrical impulses to the working cardiac muscle cells, triggering coordinated ventricular contraction.

In summary, the heart conduction system is a complex network of specialized muscle cells responsible for generating and conducting electrical signals that coordinate the contraction of the atria and ventricles, ensuring efficient blood flow throughout the body.

Electrocardiography (ECG or EKG) is a medical procedure that records the electrical activity of the heart. It provides a graphic representation of the electrical changes that occur during each heartbeat. The resulting tracing, called an electrocardiogram, can reveal information about the heart's rate and rhythm, as well as any damage to its cells or abnormalities in its conduction system.

During an ECG, small electrodes are placed on the skin of the chest, arms, and legs. These electrodes detect the electrical signals produced by the heart and transmit them to a machine that amplifies and records them. The procedure is non-invasive, painless, and quick, usually taking only a few minutes.

ECGs are commonly used to diagnose and monitor various heart conditions, including arrhythmias, coronary artery disease, heart attacks, and electrolyte imbalances. They can also be used to evaluate the effectiveness of certain medications or treatments.

Bundle-branch block (BBB) is a type of conduction delay or block in the heart's electrical system that affects the way electrical impulses travel through the ventricles (the lower chambers of the heart). In BBB, one of the two main bundle branches that conduct electrical impulses to the ventricles is partially or completely blocked, causing a delay in the contraction of one of the ventricles.

There are two types of bundle-branch block: right bundle-branch block (RBBB) and left bundle-branch block (LBBB). In RBBB, the right bundle branch is affected, while in LBBB, the left bundle branch is affected. The symptoms and severity of BBB can vary depending on the underlying cause and the presence of other heart conditions.

In some cases, BBB may not cause any noticeable symptoms and may only be detected during a routine electrocardiogram (ECG). However, if BBB occurs along with other heart conditions such as coronary artery disease, heart failure, or cardiomyopathy, it can increase the risk of serious complications such as arrhythmias, syncope, and even sudden cardiac death.

Treatment for bundle-branch block depends on the underlying cause and the severity of the condition. In some cases, no treatment may be necessary, while in others, medications, pacemakers, or other treatments may be recommended to manage symptoms and prevent complications.

A photon is not a term that has a specific medical definition, as it is a fundamental concept in physics. Photons are elementary particles that carry electromagnetic energy, such as light. They have no mass or electric charge and exhibit both particle-like and wave-like properties. In the context of medicine, photons are often discussed in relation to various medical imaging techniques (e.g., X-ray imaging, CT scans, and PET scans) and therapeutic interventions like laser therapy and radiation therapy, where photons are used to diagnose or treat medical conditions.

An action potential is a brief electrical signal that travels along the membrane of a nerve cell (neuron) or muscle cell. It is initiated by a rapid, localized change in the permeability of the cell membrane to specific ions, such as sodium and potassium, resulting in a rapid influx of sodium ions and a subsequent efflux of potassium ions. This ion movement causes a brief reversal of the electrical potential across the membrane, which is known as depolarization. The action potential then propagates along the cell membrane as a wave, allowing the electrical signal to be transmitted over long distances within the body. Action potentials play a crucial role in the communication and functioning of the nervous system and muscle tissue.

Neural inhibition is a process in the nervous system that decreases or prevents the activity of neurons (nerve cells) in order to regulate and control communication within the nervous system. It is a fundamental mechanism that allows for the balance of excitation and inhibition necessary for normal neural function. Inhibitory neurotransmitters, such as GABA (gamma-aminobutyric acid) and glycine, are released from the presynaptic neuron and bind to receptors on the postsynaptic neuron, reducing its likelihood of firing an action potential. This results in a decrease in neural activity and can have various effects depending on the specific neurons and brain regions involved. Neural inhibition is crucial for many functions including motor control, sensory processing, attention, memory, and emotional regulation.

Fluorescence spectrometry is a type of analytical technique used to investigate the fluorescent properties of a sample. It involves the measurement of the intensity of light emitted by a substance when it absorbs light at a specific wavelength and then re-emits it at a longer wavelength. This process, known as fluorescence, occurs because the absorbed energy excites electrons in the molecules of the substance to higher energy states, and when these electrons return to their ground state, they release the excess energy as light.

Fluorescence spectrometry typically measures the emission spectrum of a sample, which is a plot of the intensity of emitted light versus the wavelength of emission. This technique can be used to identify and quantify the presence of specific fluorescent molecules in a sample, as well as to study their photophysical properties.

Fluorescence spectrometry has many applications in fields such as biochemistry, environmental science, and materials science. For example, it can be used to detect and measure the concentration of pollutants in water samples, to analyze the composition of complex biological mixtures, or to study the properties of fluorescent nanomaterials.

Electric stimulation, also known as electrical nerve stimulation or neuromuscular electrical stimulation, is a therapeutic treatment that uses low-voltage electrical currents to stimulate nerves and muscles. It is often used to help manage pain, promote healing, and improve muscle strength and mobility. The electrical impulses can be delivered through electrodes placed on the skin or directly implanted into the body.

In a medical context, electric stimulation may be used for various purposes such as:

1. Pain management: Electric stimulation can help to block pain signals from reaching the brain and promote the release of endorphins, which are natural painkillers produced by the body.
2. Muscle rehabilitation: Electric stimulation can help to strengthen muscles that have become weak due to injury, illness, or surgery. It can also help to prevent muscle atrophy and improve range of motion.
3. Wound healing: Electric stimulation can promote tissue growth and help to speed up the healing process in wounds, ulcers, and other types of injuries.
4. Urinary incontinence: Electric stimulation can be used to strengthen the muscles that control urination and reduce symptoms of urinary incontinence.
5. Migraine prevention: Electric stimulation can be used as a preventive treatment for migraines by applying electrical impulses to specific nerves in the head and neck.

It is important to note that electric stimulation should only be administered under the guidance of a qualified healthcare professional, as improper use can cause harm or discomfort.

Fluorescence microscopy is a type of optical microscopy that uses fluorescent probes to highlight and visualize specific components or structures within a sample. When these probes are excited by light of a specific wavelength, they emit light at longer wavelengths, creating a bright contrast against the dark background. This allows for high-resolution imaging of cells, tissues, and subcellular structures.

Multiphoton microscopy is a type of fluorescence microscopy that uses multiple photons of lower energy to excite the fluorophores, rather than a single high-energy photon. This technique offers several advantages over traditional fluorescence microscopy, including reduced photodamage and improved depth penetration in thick samples. Additionally, multiphoton microscopy can be used for techniques such as second harmonic generation (SHG) and third harmonic generation (THG), which provide additional contrast mechanisms for imaging.

In summary, fluorescence multiphoton microscopy is a powerful tool for high-resolution imaging of biological samples, offering improved depth penetration, reduced photodamage, and additional contrast mechanisms compared to traditional fluorescence microscopy.

"Energy transfer" is a general term used in the field of physics and physiology, including medical sciences, to describe the process by which energy is passed from one system, entity, or location to another. In the context of medicine, energy transfer often refers to the ways in which cells and organ systems exchange and utilize various forms of energy for proper functioning and maintenance of life.

In a more specific sense, "energy transfer" may refer to:

1. Bioenergetics: This is the study of energy flow through living organisms, including the conversion, storage, and utilization of energy in biological systems. Key processes include cellular respiration, photosynthesis, and metabolic pathways that transform energy into forms useful for growth, maintenance, and reproduction.
2. Electron transfer: In biochemistry, electrons are transferred between molecules during redox reactions, which play a crucial role in energy production and consumption within cells. Examples include the electron transport chain (ETC) in mitochondria, where high-energy electrons from NADH and FADH2 are passed along a series of protein complexes to generate an electrochemical gradient that drives ATP synthesis.
3. Heat transfer: This is the exchange of thermal energy between systems or objects due to temperature differences. In medicine, heat transfer can be relevant in understanding how body temperature is regulated and maintained, as well as in therapeutic interventions such as hyperthermia or cryotherapy.
4. Mechanical energy transfer: This refers to the transmission of mechanical force or motion from one part of the body to another. For instance, muscle contractions generate forces that are transmitted through tendons and bones to produce movement and maintain posture.
5. Radiation therapy: In oncology, ionizing radiation is used to treat cancer by transferring energy to malignant cells, causing damage to their DNA and leading to cell death or impaired function.
6. Magnetic resonance imaging (MRI): This non-invasive diagnostic technique uses magnetic fields and radio waves to excite hydrogen nuclei in the body, which then release energy as they return to their ground state. The resulting signals are used to generate detailed images of internal structures and tissues.

In summary, "energy transfer" is a broad term that encompasses various processes by which different forms of energy (thermal, mechanical, electromagnetic, etc.) are exchanged or transmitted between systems or objects in the context of medicine and healthcare.

Treatment outcome is a term used to describe the result or effect of medical treatment on a patient's health status. It can be measured in various ways, such as through symptoms improvement, disease remission, reduced disability, improved quality of life, or survival rates. The treatment outcome helps healthcare providers evaluate the effectiveness of a particular treatment plan and make informed decisions about future care. It is also used in clinical research to compare the efficacy of different treatments and improve patient care.

Neurons, also known as nerve cells or neurocytes, are specialized cells that constitute the basic unit of the nervous system. They are responsible for receiving, processing, and transmitting information and signals within the body. Neurons have three main parts: the dendrites, the cell body (soma), and the axon. The dendrites receive signals from other neurons or sensory receptors, while the axon transmits these signals to other neurons, muscles, or glands. The junction between two neurons is called a synapse, where neurotransmitters are released to transmit the signal across the gap (synaptic cleft) to the next neuron. Neurons vary in size, shape, and structure depending on their function and location within the nervous system.

A laser is not a medical term per se, but a physical concept that has important applications in medicine. The term "LASER" stands for "Light Amplification by Stimulated Emission of Radiation." It refers to a device that produces and amplifies light with specific characteristics, such as monochromaticity (single wavelength), coherence (all waves moving in the same direction), and high intensity.

In medicine, lasers are used for various therapeutic and diagnostic purposes, including surgery, dermatology, ophthalmology, and dentistry. They can be used to cut, coagulate, or vaporize tissues with great precision, minimizing damage to surrounding structures. Additionally, lasers can be used to detect and measure physiological parameters, such as blood flow and oxygen saturation.

It's important to note that while lasers are powerful tools in medicine, they must be used by trained professionals to ensure safe and effective treatment.

Fluorescence is not a medical term per se, but it is widely used in the medical field, particularly in diagnostic tests, medical devices, and research. Fluorescence is a physical phenomenon where a substance absorbs light at a specific wavelength and then emits light at a longer wavelength. This process, often referred to as fluorescing, results in the emission of visible light that can be detected and measured.

In medical terms, fluorescence is used in various applications such as:

1. In-vivo imaging: Fluorescent dyes or probes are introduced into the body to highlight specific structures, cells, or molecules during imaging procedures. This technique can help doctors detect and diagnose diseases such as cancer, inflammation, or infection.
2. Microscopy: Fluorescence microscopy is a powerful tool for visualizing biological samples at the cellular and molecular level. By labeling specific proteins, nucleic acids, or other molecules with fluorescent dyes, researchers can observe their distribution, interactions, and dynamics within cells and tissues.
3. Surgical guidance: Fluorescence-guided surgery is a technique where surgeons use fluorescent markers to identify critical structures such as blood vessels, nerves, or tumors during surgical procedures. This helps ensure precise and safe surgical interventions.
4. Diagnostic tests: Fluorescence-based assays are used in various diagnostic tests to detect and quantify specific biomarkers or analytes. These assays can be performed using techniques such as enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction (PCR), or flow cytometry.

In summary, fluorescence is a physical process where a substance absorbs and emits light at different wavelengths. In the medical field, this phenomenon is harnessed for various applications such as in-vivo imaging, microscopy, surgical guidance, and diagnostic tests.

... pre-excitation, mahaim-type MeSH C14.280.067.780.977 - Wolff-Parkinson-White syndrome MeSH C14.280.067.829 - sick sinus ... pre-excitation syndromes MeSH C14.280.067.780.560 - Lown-Ganong-Levine syndrome MeSH C14.280.067.780.770 - ... glycogen storage disease type iib MeSH C14.280.238.510 - Kearns-Sayre syndrome MeSH C14.280.238.615 - myocardial reperfusion ...
LGL is usually categorized in a class of preexcitation syndromes that includes the Wolff-Parkinson-White syndrome (WPW), LGL, ... and Mahaim-type preexcitation. [2] Investigations into WPW have revealed that an accessory pathway for conduction, called a ... Pre-excitation revisited. Am J Cardiol. 1970 Jun. 25(6):690-7. [QxMD MEDLINE Link]. ... 20] Mahaim fibers, [21] Brechenmacher-type fibers, [7] and an anatomically underdeveloped (hypoplastic) [22] or small AV node. ...
... pre-excitation, mahaim-type MeSH C14.280.067.780.977 - Wolff-Parkinson-White syndrome MeSH C14.280.067.829 - sick sinus ... pre-excitation syndromes MeSH C14.280.067.780.560 - Lown-Ganong-Levine syndrome MeSH C14.280.067.780.770 - ... glycogen storage disease type iib MeSH C14.280.238.510 - Kearns-Sayre syndrome MeSH C14.280.238.615 - myocardial reperfusion ...
PRE-EXCITATION SYNDROMES] 73. ՆԱՏՐԻՈՒՄԻ ՖՏՈՐԻԴ [SODIUM FLUORIDE] 24. ՆԱԽԱԴՐԴՈՒՄ ԸՍՏ ՄԱՆԱԻՄ ՏԻՊԻ [PRE-EXCITATION,MAHAIM TYPE] 74 ...
Preexcitation can be surgically created, as in certain types of Bjork modifications of the Fontan procedure, if atrial tissue ... Pre-excitation revisited. Am J Cardiol. 1970 Jun. 25(6):690-7. [QxMD MEDLINE Link]. ... AV nodal blocking medications in adult patients to slow AV nodal conduction in certain situations (ie, Mahaim or ... Electrophysiological evaluation of asymptomatic ventricular pre-excitation in children and adolescents. Int J Cardiol. 2005 Feb ...
Preexcitation can be created surgically, such as in certain types of Bjork modifications of the Fontan procedure, if atrial ... The preexcitation associated with atriofascicular APs (so-called Mahaim) is associated with a normal PR interval. Patients with ... Figure 3. Normal conduction and origin of pre-excitation. A, activation originating from the sinoatrial node and normally ... The different patterns of preexcitation have produced various classification systems. Classification by type is largely ...
Pre-Excitation Syndromes. *Lown-Ganong-Levine Syndrome. *Pre-Excitation, Mahaim-Type. *Wolff-Parkinson-White Syndrome ... A form of ventricular pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave. In this ...
Pre-Excitation Syndromes. *Lown-Ganong-Levine Syndrome. *Pre-Excitation, Mahaim-Type. *Wolff-Parkinson-White Syndrome ... A form of ventricular pre-excitation characterized by a short PR interval and a normal QRS complex. In this syndrome, the ...
Pre-excitation Syndromes • Wolff-Parkinson-White Syndrome • Lown Ganong Levine Syndrome • Mahaim Type Preexcitation ... Types of Pacemakers. Three leads can be seen in this example of a cardiac resynchronization device: a right atrial lead (solid ... Two types of leads are available; pill electrode with flexible wire that can be swallowed and a flexible catheter that is ... Different types of temporary pacing techniques (based upon the approach used to consign the leads to the heart chambers) have ...
Pre-excitation Syndromes • Wolff-Parkinson-White Syndrome • Lown Ganong Levine Syndrome • Mahaim Type Preexcitation ...
Pre-excitation Syndromes • Wolff-Parkinson-White Syndrome • Lown Ganong Levine Syndrome • Mahaim Type Preexcitation ...
Pre-excitation Syndromes • Wolff-Parkinson-White Syndrome • Lown Ganong Levine Syndrome • Mahaim Type Preexcitation ...
Pre-excitation Syndromes • Wolff-Parkinson-White Syndrome • Lown Ganong Levine Syndrome • Mahaim Type Preexcitation ...
Pre-Excitation, Mahaim-Type [C14.280.067.780.770] Pre-Excitation, Mahaim-Type * Wolff-Parkinson-White Syndrome [C14.280.067.780 ... Ventricular Pre-Excitation with Arrhythmia WPW Syndrome Wolf Parkinson White Syndrome Wolf-Parkinson-White Syndrome Wolff ... A form of ventricular pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave. In this ... A form of ventricular pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave. In this ...
Mahaim Type Pre Excitation use Pre-Excitation, Mahaim-Type Mahaim Type Pre Excitation, Nodofascicular use Pre-Excitation, ... Mahaim-Type Pre-Excitation use Pre-Excitation, Mahaim-Type Mahaim-Type Pre-Excitation, Nodofascicular use Pre-Excitation, ... Mahaim Type Pre Excitation, Nodoventricular use Pre-Excitation, Mahaim-Type Mahaim Type Preexcitation use Pre-Excitation, ... Mahaim-Type Pre-Excitation, Nodoventricular use Pre-Excitation, Mahaim-Type Mahaim-Type Preexcitation use Pre-Excitation, ...
Mahaim Type Pre Excitation use Pre-Excitation, Mahaim-Type Mahaim Type Pre Excitation, Nodofascicular use Pre-Excitation, ... Mahaim-Type Pre-Excitation use Pre-Excitation, Mahaim-Type Mahaim-Type Pre-Excitation, Nodofascicular use Pre-Excitation, ... Mahaim Type Pre Excitation, Nodoventricular use Pre-Excitation, Mahaim-Type Mahaim Type Preexcitation use Pre-Excitation, ... Mahaim-Type Pre-Excitation, Nodoventricular use Pre-Excitation, Mahaim-Type Mahaim-Type Preexcitation use Pre-Excitation, ...
Mahaim Type Pre Excitation use Pre-Excitation, Mahaim-Type Mahaim Type Pre Excitation, Nodofascicular use Pre-Excitation, ... Mahaim-Type Pre-Excitation use Pre-Excitation, Mahaim-Type Mahaim-Type Pre-Excitation, Nodofascicular use Pre-Excitation, ... Mahaim Type Pre Excitation, Nodoventricular use Pre-Excitation, Mahaim-Type Mahaim Type Preexcitation use Pre-Excitation, ... Mahaim-Type Pre-Excitation, Nodoventricular use Pre-Excitation, Mahaim-Type Mahaim-Type Preexcitation use Pre-Excitation, ...
Mahaim Type Pre Excitation use Pre-Excitation, Mahaim-Type Mahaim Type Pre Excitation, Nodofascicular use Pre-Excitation, ... Mahaim-Type Pre-Excitation use Pre-Excitation, Mahaim-Type Mahaim-Type Pre-Excitation, Nodofascicular use Pre-Excitation, ... Mahaim Type Pre Excitation, Nodoventricular use Pre-Excitation, Mahaim-Type Mahaim Type Preexcitation use Pre-Excitation, ... Mahaim-Type Pre-Excitation, Nodoventricular use Pre-Excitation, Mahaim-Type Mahaim-Type Preexcitation use Pre-Excitation, ...
However, when such a condition occurs, it will be hard to manage since pre-excitation will be induced as long as the aneurysm ... Unlike the acquired type, congenital LQTS has a genetic inheritance and it may be diagnosed by syncope, stress in activity, ... One of the APs was a Mahaim pathway. Ablation localisations were right anterior and right anterolateral in 8/11 and 3/11 ... and a pre-excitation pattern was then observed on the surface electrocardiogram. An initial electrophysiological study revealed ...
LGL is usually categorized in a class of preexcitation syndromes that includes the Wolff-Parkinson-White syndrome (WPW), LGL, ... and Mahaim-type preexcitation. ... Pre-excitation revisited. Am J Cardiol. 1970 Jun. 25(6):690-7. ... Mahaim I. Kents fibers and the A-V paraspecific conduction through the upper connections of the bundle of His-Tawara. Am Heart ... Electrocardiogram demonstrating ventricular preexcitation. A delta wave, which corresponds to initial myocardial depolarization ...
LGL is usually categorized in a class of preexcitation syndromes that includes the Wolff-Parkinson-White syndrome (WPW), LGL, ... and Mahaim-type preexcitation. ... Pre-excitation revisited. Am J Cardiol. 1970 Jun. 25(6):690-7. ... Mahaim I. Kents fibers and the A-V paraspecific conduction through the upper connections of the bundle of His-Tawara. Am Heart ... Electrocardiogram demonstrating ventricular preexcitation. A delta wave, which corresponds to initial myocardial depolarization ...
Mahaim Type Pre Excitation Mahaim Type Preexcitation Mahaim-Type Pre-Excitation Mahaim-Type Preexcitation Pre Excitation, ... Mahaim Type Preexcitation. Mahaim-Type Pre-Excitation. Mahaim-Type Pre-Excitation, Nodofascicular. Mahaim-Type Pre-Excitation, ... Nodoventricular Mahaim Type Pre Excitation. Nodoventricular Mahaim-Type Pre-Excitation. Pre Excitation, Mahaim Type. Pre- ... Nodofascicular Mahaim-Type Pre-Excitation Entry term(s). Mahaim Type Pre Excitation, Nodofascicular Mahaim-Type Pre-Excitation ...
Mahaim-Type Pre-Excitation Mahaim-Type Pre-Excitation, Nodofascicular Mahaim-Type Pre-Excitation, Nodoventricular Mahaim-Type ... use PRE-EXCITATION, MAHAIM-TYPE to search PRE-EXCITATION, MAHAIM TYPE 1986-91. History Note. 92; was PRE-EXCITATION, MAHAIM ... Nodofascicular Mahaim-Type Pre-Excitation Nodoventricular Mahaim-Type Pre-Excitation Public MeSH Note. 92; was PRE-EXCITATION, ... Nodoventricular Mahaim-Type Pre-Excitation Narrower Concept UI. M0501921. Terms. Nodoventricular Mahaim-Type Pre-Excitation ...
Mahaim-Type Pre-Excitation Mahaim-Type Pre-Excitation, Nodofascicular Mahaim-Type Pre-Excitation, Nodoventricular Mahaim-Type ... use PRE-EXCITATION, MAHAIM-TYPE to search PRE-EXCITATION, MAHAIM TYPE 1986-91. History Note. 92; was PRE-EXCITATION, MAHAIM ... Nodofascicular Mahaim-Type Pre-Excitation Nodoventricular Mahaim-Type Pre-Excitation Public MeSH Note. 92; was PRE-EXCITATION, ... Nodoventricular Mahaim-Type Pre-Excitation Narrower Concept UI. M0501921. Terms. Nodoventricular Mahaim-Type Pre-Excitation ...
Pre-Excitation, Mahaim-Type. A form of ventricular pre-excitation characterized by a normal PR interval and a long QRS interval ... Pre-excitation, Mahaim-type, also known as Mahaim fiber or Mahaims phenomenon, is a condition in which an accessory pathway, ... Mahaim-type pre-excitation is a rare condition characterized by abnormal electrical pathways in the heart that can cause an ... There are several types of pre-excitation syndromes, including WPW syndrome, Lown-Ganong-Levine syndrome, and Mahaim syndrome. ...
Pre-excitation Syndromes • Wolff-Parkinson-White Syndrome • Lown Ganong Levine Syndrome • Mahaim Type Preexcitation ...
Pre-excitation Syndromes • Wolff-Parkinson-White Syndrome • Lown Ganong Levine Syndrome • Mahaim Type Preexcitation ... based on pre-test probability. Pre-test probability is the assessment of a patient and their likelihood of CAD based on ... Its main values lies in excluding CAD in patients with a low pre-test probability of CAD based on gender and age. ... 5] Given the fact that the majority of children have no probable cardiac risk factors, their pre-test probability is already ...
Jervell-Lange Nielsen SyndromeRomano-Ward SyndromeParasystolePre-Excitation SyndromesLown-Ganong-Levine SyndromePre-Excitation ... Mahaim-TypeWolff-Parkinson-White SyndromeTachycardiaTachycardia, ParoxysmalTachycardia, Reciprocating +Tachycardia, ...
Pre-excitation Syndromes • Wolff-Parkinson-White Syndrome • Lown Ganong Levine Syndrome • Mahaim Type Preexcitation ...
Preexcitation can be surgically created, as in certain types of Bjork modifications of the Fontan procedure, if atrial tissue ... Pre-excitation revisited. Am J Cardiol. 1970 Jun. 25(6):690-7. [QxMD MEDLINE Link]. ... AV nodal blocking medications in adult patients to slow AV nodal conduction in certain situations (ie, Mahaim or ... Electrophysiological evaluation of asymptomatic ventricular pre-excitation in children and adolescents. Int J Cardiol. 2005 Feb ...
Pravastatin Prazepam Praziquantel Prazosin Pre-B Cell Receptors Pre-Eclampsia Pre-Excitation Syndromes Pre-Excitation, Mahaim- ... Type I Collagen Type II Collagen Type III Collagen Type IV Collagen Type IX Collagen Type V Collagen Type VI Collagen Type VII ... Type 5 Receptor, Galanin, Type 1 Receptor, Galanin, Type 2 Receptor, Galanin, Type 3 Receptor, IGF Type 1 Receptor, IGF Type 2 ... Collagen Type VIII Collagen Type X Collagen Type XI Collagen Type XII Collagen Type XIII Collagen Type XVIII Collagenases ...
Risk Stratification for Arrhythmic Events in Patients With Asymptomatic Pre-Excitation: A Systematic Review for the 2015 ACC/ ... "Atriofascicular ("Mahaim") pathway tachycardia".). Exercise uncommonly causes an abrupt loss of preexcitation as the sinus ... The two major forms of this type of arrhythmia in WPW syndrome are orthodromic AVRT (ie, antegrade conduction via the AV node ... 54 : Risk Stratification for Arrhythmic Events in Patients With Asymptomatic Pre-Excitation: A Systematic Review for the 2015 ...
  • LGL is usually categorized in a class of preexcitation syndromes that includes the Wolff-Parkinson-White syndrome (WPW), LGL, and Mahaim-type preexcitation. (medscape.com)
  • The clinical manifestations of WPW syndrome reflect the associated tachyarrhythmia episodes-rather than the anomalous ventricular excitation per se. (medscape.com)
  • A form of ventricular pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave. (rush.edu)
  • A form of ventricular pre-excitation characterized by a short PR interval and a normal QRS complex. (sdsu.edu)
  • Forma de pre-excitación ventricular caracterizada por un intervalo PR corto y un intervalo QRS largo con una onda delta. (bvsalud.org)
  • Arrhythmogenic right ventricular cardiomyopa- thy, another hereditary arrhythmia type, also shows high genetic heterogeneity and variable expressivity. (bvsalud.org)
  • WPW syndrome is not the only form of preexcitation, but it is the most common. (rjmatthewsmd.com)
  • F. The most common form of paroxysmal supraventricular tachycardia (PSVT) is AV nodal reentry due to dual pathways of excitation in the region of the AV node (see Figure 1). (rjmatthewsmd.com)
  • However, when such a condition occurs, it will be hard to manage since pre-excitation will be induced as long as the aneurysm persists. (bvsalud.org)
  • En este síndrome, el impulso auricular viaja hasta el ventrículo por las fibras de Mahaim que conectan el NÓDULO AURICULOVENTRICULAR directamente con la pared ventricular derecha (vía nodoventricular) o con la RAMA DERECHA DEL HAZ DE HIS (vía nodofascicular). (bvsalud.org)
  • In this syndrome, the atrial impulse travel to the ventricle via the MAHAIM FIBERS which connect ATRIOVENTRICULAR NODE directly to the right ventricle wall ( NODOVENTRICULAR ACCESSORY PATHWAY ) or to the RIGHT BUNDLE BRANCH OF HIS (nodofascicular accessory pathway). (bvsalud.org)
  • See 'Electrocardiographic findings' below and "Lown-Ganong-Levine syndrome and enhanced atrioventricular nodal conduction" and "Atriofascicular ("Mahaim") pathway tachycardia" . (medilib.ir)
  • Mahaim I. Kent's fibers and the A-V paraspecific conduction through the upper connections of the bundle of His-Tawara. (medscape.com)
  • In 1943, the ECG features of preexcitation were correlated with anatomic evidence for the existence of anomalous bundles of conducting tissue that bypassed all or part of the normal atrioventricular (AV) conduction system. (medilib.ir)
  • In some patients with left free wall accessory pathways, pacing the left atrium via the coronary sinus, in an area closer to the accessory pathway, may be necessary to bring out antegrade accessory pathway conduction and overt preexcitation. (medilib.ir)
  • The common type involves a blocked atrial impulse in the slow pathway which reenters the fast pathway in a retrograde direction and simultaneously conducts to the atria and the ventricles leading to rapid HEART RATE of 150-250 beats per minute. (lookformedical.com)