Chordal force distribution determines systolic mitral leaflet configuration and severity of functional mitral regurgitation. (1/2148)

OBJECTIVES: The purpose of this study was to investigate the impact of the chordae tendineae force distribution on systolic mitral leaflet geometry and mitral valve competence in vitro. BACKGROUND: Functional mitral regurgitation is caused by changes in several elements of the valve apparatus. Interaction among these have to comply with the chordal force distribution defined by the chordal coapting forces (F(c)) created by the transmitral pressure difference, which close the leaflets and the chordal tethering forces (FT) pulling the leaflets apart. METHODS: Porcine mitral valves (n = 5) were mounted in a left ventricular model where leading edge chordal forces measured by dedicated miniature force transducers were controlled by changing left ventricular pressure and papillary muscle position. Chordae geometry and occlusional leaflet area (OLA) needed to cover the leaflet orifice for a given leaflet configuration were determined by two-dimensional echo and reconstructed three-dimensionally. Occlusional leaflet area was used as expression for incomplete leaflet coaptation. Regurgitant fraction (RF) was measured with an electromagnetic flowmeter. RESULTS: Mixed procedure statistics revealed a linear correlation between the sum of the chordal net forces, sigma[Fc - FT]S, and OLA with regression coefficient (minimum - maximum) beta = -115 to -65 [mm2/N]; p < 0.001 and RF (beta = -0.06 to -0.01 [%/N]; p < 0.001). Increasing FT by papillary muscle malalignment restricted leaflet mobility, resulting in a tented leaflet configuration due to an apical and posterior shift of the coaptation line. Anterior leaflet coapting forces increased due to mitral leaflet remodeling, which generated a nonuniform regurgitant orifice area. CONCLUSIONS: Altered chordal force distribution caused functional mitral regurgitation based on tented leaflet configuration as observed clinically.  (+info)

Changes in porcine transmitral flow velocity pattern and its diastolic determinants during partial coronary occlusion. (2/2148)

OBJECTIVES: To define the mechanical determinants of transmitral flow and the effect of heart rate during regional ischemia. BACKGROUND: Myocardial ischemia changes the transmitral flow velocity pattern due to disease-induced changes in the heart's diastolic properties. METHODS: Regional ischemia was produced in 12 pigs by partially occluding the left anterior descending coronary artery until segment-length shortening in the ischemic region fell by 20%. Transmitral flow velocity patterns and their determinants were measured under two conditions, baseline and ischemia, at two heart rates, 70 and 90 beats/min. RESULTS: Regional ischemia had a significant effect on two determinants of filling: relaxation, which was slower, and chamber stiffness, which increased. These changes were associated with reduced contractility and increased myocardial stiffness, resulting in an early transmitral flow pattern that was flatter and narrower, but no change in the late flow pattern. Moderate increases in heart rate accelerated relaxation and decreased atrioventricular pressure gradient but had no effect on contractility or myocardial or chamber stiffness, resulting in an early transmitral flow pattern that was flatter and narrower and an increased late flow velocity. CONCLUSIONS: This model of regional ischemia leads to a flatter and narrower early transmitral flow velocity pattern and no change in late flow due to a combination of slowed left ventricular relaxation and increased chamber stiffness. Reflex increases in heart rate that accompany ischemia tend to mask this effect.  (+info)

Effects of permanent dual-chamber pacing on mitral regurgitation in hypertrophic obstructive cardiomyopathy. (3/2148)

AIMS: To assess the effects of chronic dual-chamber pacing on mitral regurgitation in hypertrophic obstructive cardiomyopathy. METHODS AND RESULTS: Twenty-three patients with hypertrophic obstructive cardiomyopathy and mitral regurgitation. treated with DDD pacing for 16 +/- 14 months, were included in the study. Mitral regurgitation was assessed by Doppler-echocardiography using semi-quantitative analysis (grades I-IV) and by measuring the maximum regurgitant jet area/left atrial area ratio. At the end of follow-up, DDD pacing reduced the outflow gradient from 93 +/- 37 mmHg to 31 +/- 30 mmHg (P<0.0001). Nine of the 14 patients who initially had > or =grade II mitral regurgitation improved by at least one grade, two of them exhibiting dramatic improvement (from grade IV and III to grade I). The regurgitant jet area/left atrial area ratio was reduced with DDD pacing from 20 +/- 13% to 11 +/- 6% (P<0.0001). Patients who had significant mitral regurgitation despite pacing were those whose outflow gradient remained high or those with mitral valve organic abnormalities (mitral annulus calcification or mitral valve prolapse). In the absence of organic abnormalities other than leaflet elongation, there was a significant correlation between the gradient value achieved with DDD pacing and the extent of mitral regurgitation (P<0.05). CONCLUSION: In the absence of organic mitral valve abnormalities, DDD pacing reduces in parallel mitral regurgitation and left ventricular outflow gradient. In such patients therefore, significant mitral regurgitation is not a contraindication to pacing.  (+info)

Perivalvular abscesses associated with endocarditis; clinical features and prognostic factors of overall survival in a series of 233 cases. Perivalvular Abscesses French Multicentre Study. (4/2148)

AIMS: The purposes of this study were to determine the clinical features and to identify prognostic factors of abscesses associated with infective endocarditis. METHODS AND RESULTS: During a 5-year period from January 1989, 233 patients with perivalvular abscesses associated with infective endocarditis were enrolled in a retrospective multicentre study. Of the patients, 213 received medical surgical therapy and 20 medical therapy alone. No causative microorganism could be identified in 31% of cases. Sensitivity for the detection of abscesses was 36 and 80%, respectively using transthoracic and transoesophageal echocardiography. Surgical treatment consisted of primary suture of the abscess (38%), insertion of a felt aortic or mitral ring using Teflon or pericardium (42%), or debridment of the abscess cavity (20%). The 1 month operative mortality was 16%. Actuarial rates for overall survival at 3 and 27 months in operated patients were 75 +/- 10% and 59 +/- 11%, respectively. Increasing patient age, staphylococcal infection, and fistulization of the abscess were found to be independent risk factors in both 1 month and overall operative mortality. Renal failure was a risk factor predictive of operative mortality at 1 month, whereas uncontrolled infection and circumferential abscess were regarded as risk factors predictive of overall operative mortality. CONCLUSION: The data determined prognostic factors of abscesses associated with infective endocarditis.  (+info)

Intraoperative left ventricular perforation with false aneurysm formation. (5/2148)

Two cases of perforation of the left ventricle during mitral valve replacement are described. In the first case there was perforation at the site of papillary muscle excision and this was recognized and successfully treated. However, a true ventricular aneurysm developed at the repair site. One month after operation rupture of the left ventricle occurred at a second and separate site on the posterior aspect of the atrioventricular ring. This resulted in a false aneurysm which produced a pansystolic murmur mimicking mitral regurgitation. Both the true and the false aneurysm were successfully repaired. In the second case perforation occurred on the posterior aspect of the atrioventricular ring and was successfully repaired. However, a false ventricular aneurysm developed and ruptured into the left atrium producing severe, but silent, mitral regurgitation. This was recognized and successfully repaired. The implications of these cases are discussed.  (+info)

Echocardiographic diagnosis of large fungal verruca attached to mitral valve. (6/2148)

In a patient with endocarditis due to Candida tropicalis echocardiograms from mitral valve vegetations were found to mimic the typical pattern of a left atrial myxoma. A mass was shown occupying the mitral orifice posterior to the anterior mitral leaflet; densities also appeared in the left atrium. Though these echocardiographic findings were consistent with the diagnosis of a left atrial myxoma, there were other distinctive differential diagnostic features. Other diagnostic possibilities must, therefore, be considered in the interpretation of echocardiograms which suggest left atrial tumour.  (+info)

Long-term clinical and echocardiographic follow-up after percutaneous mitral valvuloplasty with the Inoue balloon. (7/2148)

BACKGROUND: The objective of this study was to assess the long-term clinical outcome and valvular changes (area and regurgitation) after percutaneous mitral valvuloplasty (PMV). METHODS AND RESULTS: After PMV, 561 patients were followed up for 39 (+/-23) months and clinical/echocardiographic data obtained yearly. Kaplan-Meier and Cox regression analyses were performed to estimate event-free survival, its predictors, and the relative risks of several patient subgroups. There were several nonexclusive events: 19 (3.3%) cardiac deaths, 55 (9.8%) mitral replacements, 6 (1%) repeated PMVs, 56 (10%) cases of restenosis, and 108 (19%) cases of clinical impairment. Survival free of major events (cardiac death, mitral surgery, repeat PMV, or functional impairment) was 69% at 7 years, ranging from 88% to 40% in different subgroups of patients. Wilkins score was the best preprocedural predictor of mitral opening, but the procedural result (mitral area and regurgitation) was the only independent predictor of major event-free survival. Mitral area loss, though mild [0.13 (+/-0.21)cm2], increased with time and was >/=0.3 cm2 in 12%, 22%, and 27% of patients at 3, 5, and 7 years, respectively. Regurgitation did not progress in 81% of patients, and when it occurred it was usually by 1 grade. CONCLUSIONS: Seven years after PMV, more than two thirds of patients were in good clinical condition and free of any major event. The procedural result was the main determinant of long-term outcome, although a high score had also negative implications. Mitral area decreased progressively over time, whereas regurgitation did not tend to progress.  (+info)

Mobile echoes on prosthetic valves are not reproducible. Results and clinical implications of a multicentre study. (8/2148)

AIMS: To test the hypothesis that inter-observer variability accounts for the wide variation in reported prevalences of fibrin strands on prosthetic heart valves and to develop criteria for their identification and reporting. METHODS AND RESULTS: A videotape with 30 sequences of prosthetic heart valves imaged by transoesophageal echocardiography and showing abnormalities such as strands, microbubbles, and spontaneous echocardiographic contrast, was assessed in 13 European and three American centres. There were three duplicated examples, unbeknown to the observers. Definitions and reported prevalence rates of the abnormalities were analysed, and inter- and intra-observer agreement estimated with the kappa statistic. Mobile echoes were identified in 40 to 80% of the sequences on the tape. The reported prevalence of mobile echoes correlated with the time spent reporting the tape. There was moderate inter-observer agreement for the identification of any mobile echoes (kappa = 0.38), but no agreement for their labelling (kappa = 0.22), in spite of similar definitions. Intra-observer reproducibility was good (agreement in 76% of the reduplicated sequences). CONCLUSIONS: The true prevalence and potential significance of mobile echoes on prosthetic heart valves cannot be assessed unless inter-observer consensus on echocardiographic criteria for identifying such echoes is reached.  (+info)