Artifacts recorded through failing bipolar polyurethane insulated permanent pacing leads.
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Pacing failure in bipolar systems using polyurethane insulated leads may be frequent depending on the type of polyurethane and can cause oversensing and or failure to capture. The reason for this failure is often breakage in the inner insulation. The aim of this study was to evaluate the signals created by such a short circuit. Thirty-seven patients were included in the study, 13 with failing leads with polyurethane 80A insulation, 14 with old but normally functioning leads and 10 patients with new leads. Artifacts in the form of spikes were recorded, during surgical revision, from 11 patients with failing leads (84.6%). In patients with normally functioning leads and newly implanted leads no artifacts were recorded. A significant decrease in impedance of 373.4 Ohms (99% confidence intervals 286.4-460.4, P<0.05) was noted in the failing leads compared with a decrease of only 113.0 Ohms (99%, confidence intervals 6.5-219.6, P<0.01) in the control leads. The difference between the groups was highly significant. In 10 newly implanted and five normally functioning bipolar ventricular leads similar artifacts could be created by making intermittent contact between the proximal lead connections. Thus, artifacts could be recorded from failing leads and from intact leads with artificial intermittent connection at the proximal end. Our results suggest that the failure is caused by a short circuit in the lead. This finding may have important clinical applications in the follow-up of bipolar pacing and defibrillation leads. (+info)
Pregnancy with an ICD and a documented ICD discharge.
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We report a successful pregnancy in a patient affected by idiopathic ventricular fibrillation 3 years after insertion of an ICD, with a documented defibrillator discharge. (+info)
First worldwide clinical experience with a new dual chamber implantable cardioverter defibrillator. Advantages and complications. The Ventak AV II DR investigators.
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AIMS: The need for physiological pacing and for improving the ability to discriminate atrial from ventricular tachyarrhythmias has prompted the development of dual chamber implantable cardioverter/defibrillators (ICDs). METHODS: Fifty-two patients were implanted with a newly developed dual-chamber ICD providing rate-responsive physiological pacing (Ventak AV II DR). The device possesses two new arrhythmia detection algorithms ('atrial fibrillation rate threshold' and 'ventricular to atrial rate relationship') in addition to commonly used features such as 'onset' and 'stability'. During implantation, the atrial and ventricular lead impedances and pacing thresholds were determined together with the defibrillation threshold. Prior to discharge, attempts were made to induce both atrial and ventricular tachyarrhythmias in order to test those new detection criteria. All patients were followed for at least 3 months. RESULTS: The device was successfully implanted in all 52 patients. Placement of the atrial lead was successful in 50/52 patients (96%; P-wave 3.2 +/- 1.4 mV; impedance 576 +/- 123 omega; atrial pacing threshold 1.2 +/- 0.9 V). Prior to discharge, 32 episodes of atrial fibrillation (AF) alone, 38 episodes of AF with ventricular fibrillation and 10 episodes of AF with monomorphic ventricular tachycardia were induced in 33/50 patients (66%) and all were appropriately classified by the detection algorithm. During the 3 months follow-up, 12 patients (23%) had appropriate and successful therapies for ventricular arrhythmias, while four patients (8%) experienced inappropriate ICD therapies. Although all these episodes were detected correctly as supraventricular arrhythmias by the device, therapy was delivered because of incorrect or incomplete programming. In all cases reprogramming of the device resolved the problem. CONCLUSION: Implantation of dual chamber ICDs is feasible and appears to improve discrimination of supraventricular from ventricular tachyarrhythmias. In addition, patients with tachyarrhythmias and concomitant bradyarrhythmias may benefit from simultaneous physiological pacing. However, implantation and follow-up of such patients should be performed at experienced centres since both surgical handling and programming of these devices is more difficult and complex than conventional ICDs. (+info)
The management of peripheral vascular complications associated with the use of percutaneous suture-mediated closure devices.
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PURPOSE: The purpose of this study is to identify the peripheral vascular complications associated with the use of percutaneous suture-mediated closure (PSMC) devices and compare them with postcatheterization femoral artery complications not associated with PSMC devices. METHODS: This is a retrospective review of all patients admitted to the vascular surgery service at the Chattanooga Unit of the University of Tennessee Department of Surgery with a peripheral vascular complication after percutaneous femoral arteriotomy between July 1, 1998, and December 1, 1999. The complications followed the use of PSMC devices (group I, n = 11) and traditional compression therapy (group II, n = 14) to achieve arterial hemostasis. Group II was subdivided into patients who required operative intervention (group IIA, n = 8), and those who were treated without operation (group IIB, n = 6). RESULTS: No significant difference was found between groups I and II with regard to age (P =.227), time to vascular surgery consultation (P =.987), or diagnostic versus therapeutic catheterization (P =.897). A significant difference was found with regard to mean pseudoaneurysm size (group I = 5.9 cm, group II 2.9 cm; P =.003). Ultrasound compression was successfully performed in 66.6% of group II patients, but no (0.0%) patient in group I responded to this therapy (P =.016). Groups I and IIA had a significant difference for mean estimated blood loss (group I = 377.2 mL, group II = 121.8 mL; P =.017) and requirement for transfusion (P =.013). More patients in group I required extensive surgical treatment (P =.007), with six of these patients requiring vein patch angioplasty during their treatment. More patients in group I also had infectious complications (n = 3) compared with group IIA (n = 1). CONCLUSION: In comparison with complications that follow percutaneous arteriotomy when PSMC devices are not used for hemostasis: (1) pseudoaneurysms after the use of PSMC devices are larger and do not respond to ultrasound compression, (2) complications associated with PSMC devices result in more blood loss and increased need for transfusion and are more likely to require extensive operative procedures, and (3) arterial infections after the use of PSMC devices are more common and require aggressive surgical management. (+info)
The effect of micro-etching on the retention of orthodontic molar bands: a clinical trial.
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Failure of orthodontic bands occurs most frequently at the band-cement interface, when conventional glass ionomer cements are used. Modification of the band surface may improve clinical performance by increasing the mechanical interlock at this junction. The aim of this prospective study was to compare the retention of micro-etched and untreated first molar orthodontic bands in a randomized, half-mouth trial. Seventy-nine patients had 304 bands cemented as part of routine fixed appliance therapy. The effect of micro-etching, patient age and gender, operator, molar crossbite, treatment mechanics, and arch on band failure was investigated. Failure rates and survival times were compared for each variable assessed. Micro-etched molar bands showed a significant reduction in clinical failure rate over untreated molar bands and an increase in mean survival time (P < 0.001). Of the other variables examined, only the presence of a molar crossbite had any significant effect on band failure (P = 0.004). (+info)
Recurrence of myocarditis presenting as pacing and sensing failure after implantation of a permanent pacemaker at first onset.
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A 31-year-old woman was admitted to hospital with loss of consciousness and generalized convulsions. Electrocardiography (ECG) showed complete atrioventricular block (AV block) with a pulse rate of 30 beats/min. Endomyocardial biopsy from the right ventricle showed massive necrosis and degeneration of myocardial cells with extensive infiltration of lymphocytes into the interstitial space. These pathological findings suggested fulminant myocarditis. Following glucocorticoid therapy, the patient became asymptomatic, but the AV block did not resolve completely and a bifocal pacemaker was implanted. However, similar symptoms recurred 7 years later. An ECG showed pacing and sensing failure linked to an increase in the pacing threshold and a decrease in the sensing threshold. Endomyocardial biopsy from the right ventricle again showed interstitial infiltration with lymphocytes and eosinophils. After glucocorticoid therapy, she became asymptomatic once more, and the improvement in the pacing and sensing failure, and cardiomegaly, was satisfactory. This patient represents a very rare case of recurrence of acute myocarditis without progression, as much as 7 years after its first occurrence. Glucocorticoid therapy was still effective in treating the recurrent myocarditis presenting with pacing and sensing failure. (+info)
Laparoscopic forceps--a useful tool in revision hip arthroplasty.
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During revision hip arthroplasty, distal cement plugs and broken instrument tips in the femoral canal pose quite a challenge. We report the use of laparoscopic forceps to facilitate their removal thereby avoiding complications associated with other methods previously described. (+info)
Technical results of falloposcopy for infertility diagnosis in a large multicentre study.
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Despite increasing evidence of its potential clinical value, falloposcopy has not yet found widespread use. In a large prospective international multicentre study we investigated the hypothesis that limited technical reproducibility may be of crucial significance in this regard. From 1994 to 1998, data on 367 patients with 639 tubes were recorded from 18 centres (median number of falloposcopies 22). Falloposcopy was performed using hysteroscopic ostium access, coaxial tubal cannulation and retrograde visualization under laparoscopic control. The procedure was successful in 69.6% of the tubes. Failures occurred in 6.1% during hysteroscopy, in 10.6% during the cannulation step and in 16.4% during visualization. While predominantly intracavitary pathology or thick endometrium were found to interfere with hysteroscopic ostium access, technical insufficiencies resulting in catheter damage or vision disturbing light reflexions were identified to be responsible for most cannulation and visualization failures, confirming the importance of these factors. The number of patients who received a complete falloposcopic evaluation did not exceed 57%. Additionally, 23.7% of patients may have profited from unilateral success depending on the individual indication. As a consequence of these technically limited results it was concluded that the method currently qualifies for selected indications rather than for routine clinical application. (+info)