Diverticulum of the left ventricle in hypertrophic cardiomyopathy.

An unusual case of diverticulum of the left ventricle is presented. The most distinctive feature was the presence of a circumferential mid-ventricular contraction ring with histologic abnormalities similar to those described in patients with asymmetric septal hypertrophy. This abnormal ring of tissue obstructed emptying of the ventricular apex and isolated it from the rest of the ventricle. The obstructed apex assumed the appearance of a muscular diverticulum, and the residual portion of the ventricle was markedly diminished in volume. In addition, the abnormal mid-ventricular hypertrophy interfered with papillary muscle function, producing mitral valve prolapse and mitral regurgitation. The patient's age was equally unusual; she was 65 at the time of diagnosis, probably the oldest known patient with ventricular diverticulum. She was treated surgically by transapical myotomy and myectomy of the mid-ventricular contraction ring, in order to increase effective ventricular volume. The relationship of this entity to other types of ventricular deiverticula and aneurysms, and to hypertrophic cardiomyopathy, is discussed.

A new method for quantifying ventricular regularization during atrial fibrillation.

Atrial fibrillation (AF) characteristically results in random variation of the intervals between successive ventricular depolarizations. However, when a patient with AF is treated with excessive amounts of digitalis, regular junctional rhythms may occur. The detection of "regularization" of the ventricular rhythm in patients with AF may signal early digitalis toxicity. In this paper, we describe a new method for quantifying the extent of ventricular regularization by the statistical analysis of the intervals between successive ventricular depolarizations (R-R intervals). This method yields a single index (Z score) which reflects the degree to which a sequence of R-R intervals deviates from a random distribution. Simulation studies demonstrate that our method is sensitive to "regularization" of as little as two to four percent of R-R intervals, even when equal intervals occur in small groups that might easily escape detection by visual electrocardiographic interpretation. Analysis of records from six nondigitalized subjects in AF shows that the sequence of R-R intervals is usually random, or very nearly so. Records obtained from the same patients when digitalized often demonstrate more regularized activity, reflected by an index (Z score) which is higher than expected from chance deviation if a random process is assumed. Preliminary data also suggeest that exercise is associated with substantial regularization of ventricular depolarization.

Afterload reduction in the management of postinfarction ventricular septal defect.

The primary goal in the medical management of ventricular septal defect complicating myocardial infarction is to support cardiac function and control symptoms, if possible, for a period of 4 to 6 weeks. If the patient survives this period, surgical correction of the defect is technically easier and safer. In many cases, However, cardiac function is severly compromised, intractable biventricular failure develops,early operation is necessary and the likelihood of successful repair is diminished.

Echocardiographic evaluation of the stent mounted aortic bioprosthetic valve in the mitral position. In vitro and in vivo studies.

Echocardiograms were performed on 20 clinically stable patients following mitral valve replacement with glutaraldehyde-preserved porcine aortic heterografts and three patients with antibiotic sterilized aortic homografts mounted in the mitral position. Such valves were evaluated in a test chamber at varied flow rates resulting in improved understanding of movements seen with the echocardiogram in vivo. The technique for recording the valvular stent and leaflets is described and a method for measuring several parameters is demonstrated. Initial diastolic slope averaged 2.4 +/- 0.5 cm/sec (range 1.9 to 3.3 cm/sec). Left ventricular outflow tract measured from the anterior portion of the stent to the interventricular septum averaged 1.5 +/- 0.5 cm at end-diastole and 1.3 +/- 0.6 cm at end-systole. Leaflet excursion averaged 1.5 +/- 0.3 cm (with a range from 1.0 to 2.1 cm). The ratio of internal to external stent diameters averaged 0.66 +/- 0.05 (with a range from 0.56 to 0.74).

Changes in survival and symptom relief in a longitudinal study of patients after bypass surgery.

The first 350 patients having coronary surgery at Stanford Medical Center (excluding patients with aneurysmectomy or valve replacement) have been followed sequentially utilizing a computer-based information system. Our experience spans 72 months (900 patient-years), with an average follow-up of 30 months. Hospital mortality was 4.9%. Actuarial analysis revealed survival of 91% at 1 year and 80% at 6 years. Forty patients (11.5%) had 43 late myocardial infarctions, of which 5 were fatal. Analyses of selected patient subgroups revealed significantly poorer survival in patients with prior myocardial infarction (P less than 0.05), significant congestive heart failure, or mitral regurgitation (P less than 0.01). Survival in multigrafted (and multivessel) patients was not significantly different from survival in single-grafted (predominantly single-vessel) patients. Actuarial studies suggest improved survival in patients with multivessel disease after coronary artery surgery. Between an initial evaluation at 9 months postoperatively (range: 2 to 40 months) and the most recent evaluation after 30 months (range: 6 to 72 months), 13% of patients showed further clinical improvement, 47% were unchanged, while 40% deteriorated with respect to chest pain. We conclude that initial symptomatic benefits may not be maintained in late follow-up studies owing to progression of underlying vascular disease.