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Biomedical subjects

P Samet

Publications and source records attributed to P Samet.

At least 19 recordsLinked to original sources

Skeletal muscle ventricles for total heart replacement.

Skeletal muscle ventricles (SMV) were constructed from canine left latissimus dorsi muscle. The animals were divided into three groups: group A (n = 5), SMVs rested 4 weeks without electrical conditioning; group B (n = 6), SMVs rested 4 weeks and then electrically conditioned for 6 weeks; group C (n = 5), SMVs rested 18 weeks without electrical conditioning. At the end of each protocol, the SMVs were acutely tested by connecting them to a mock-circulation device. The SMVs in group C developed stroke work at physiologic preloads superior to any previously reported, as high as 194% of left ventricular stroke work at afterloads of 80 mmHg. The SMVs in group B developed work outputs equivalent to 53% of the left ventricle, which is still more than four times that of the right ventricle. The results show that it is possible to harvest sufficient work from skeletal muscle ventricles to fully replace cardiac function at physiologic preloads.

Adaptation, Physiological

The significance of increased left ventricular outflow tract velocities in the elderly measured by continuous wave Doppler.

Forty-four elderly patients (mean age 80 +/- 7 years) with elevated left ventricular outflow tract velocities and corresponding outflow tract gradients documented by continuous wave Doppler are reported (mean peak gradient 50 +/- 28). They had severe left ventricular hypertrophy, small left ventricular end-diastolic dimensions, and supernormal ejection fractions. Thirty-nine percent had a history of hypertension. They were predominantly female, had uniform concentric left ventricular hypertrophy, and had a high incidence of congestive heart failure. Diastolic function was found to be reduced in the elderly group compared to young patients with hypertrophic cardiomyopathy and to age- and sex-matched normal controls. It is concluded that most elderly patients with increased left ventricular outflow tract velocities are etiologically distinct from young patients with hypertrophic cardiomyopathy.

Adult

The postcardiotomy syndrome following transvenous pacemaker insertion.

We describe a syndrome of fever, pericarditis, and symptomatic pericardial effusion beginning 2 months after transvenous insertion of a permanent pacemaker in a 75-year-old woman. The syndrome improved dramatically following pericardiocentesis and resolved after subsequent administration of indomethacin. Although right ventricular perforation during pacemaker insertion was not recognized, inadvertent perforation leading to the postcardiotomy syndrome is postulated.

Aged

New principles for optimum left ventriculography.

Left ventriculography has become the single most important procedure in the evaluation of cardiac function. This study reevaluated the refinements of catheter and power injector technology to assess recommendations of past years and establish new principles for optimum ventriculography. Ventriculograms from 102 patients undergoing left heart catheterization and coronary arteriography for coronary, valvular, and myocardial heart disease served as the test sample. Three styles of #7F high-flow 110-cm pigtail catheters were utilized. One had 12 sideholes while the other two had six sideholes positioned nearer the base of the curl. Analysis of ventriculographic quality of each angiogram was performed by three of the authors independently and subsequently together. Five variables were analyzed for their effect on the diagnostic quality of the angiogram: 6-hole catheters, 12-hole catheters, volume of contrast, flow rate, and location of injection. Once these analyses were complete, the effect of combinations of these variables was tested to determine their effect on angiographic quality. The first combination included contrast volume and flow rate. The second combination compared contrast volume and flow rate when utilized with 6- or 12-hole catheters. The third combination tested the 6- and 12-hole catheters in the apex or inflow locations. A multivariate contingency analysis was used to define relationships between the variables and the quality of the angiogram obtained. As independent variables, catheter style, volume of contrast, flow rate, and location of injection did not influence angiographic quality. However, the apex as a location of injection was the single most consistently important determinant of ventricular angiographic quality.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization

Regression of severe alcoholic cardiomyopathy after abstinence of 10 weeks.

Alcoholic cardiomyopathy usually has a poor prognosis, but the case presented here documents a dramatic regression of left ventricular dysfunction in a patient with alcoholic cardiomyopathy. Ejection fraction determined by echocardiography increased from 12% at the time of presentation to 45% 10 weeks later. This was associated with clinical resolution of congestive heart failure and a decrease in cardiac and left ventricular size documented by chest x-ray and echocardiography.

Cardiac Catheterization

Doppler diagnosis of valvular aortic stenosis in patients over 60 years of age.

Twenty-five consecutive elderly patients with suspected aortic stenosis underwent continuous-wave Doppler echocardiography followed by cardiac catheterization. Doppler-derived calculations of peak and mean aortic valve gradients were compared with catheterization-derived values of peak-to-peak, peak and mean gradients. The best correlation was found between Doppler- and catheterization-derived mean gradients (r = 0.89). A Doppler-derived measure of the timing of peak aortic flow velocity (modified time-to-peak velocity/modified left ventricular ejection time) successfully separated those with gradients above or below 50 mm Hg and also helped to avoid over- or underestimation of aortic valve gradients by Doppler.

Aged

Resolution of congestive failure, mitral regurgitation, and angina after percutaneous transluminal coronary angioplasty of triple vessel disease.

Congestive heart failure, unstable angina, and moderate mitral regurgitation improved after double-vessel angioplasty in a 41-year-old woman who was considered inoperable because of high risk of bypass surgery. With the concomitant use of balloon counterpulsation, angioplasty reduced the cross-sectional stenosis in the left anterior descending coronary artery from 98 to 20% and in the left circumflex coronary artery from 90 to 0%. The right coronary artery was completely occluded and angioplasty was not attempted. The ejection fraction was 17% prior to angioplasty and 50% 2 months later at follow-up.

Adult

Pacer-induced tachycardia associated with an atrial synchronous ventricular inhibited (ASVIP) pulse generator.

A 68-year-old white male underwent permanent pacemaker implantation with an atrial synchronous ventricular inhibited pulse generator (Medtronic model 2409) because of syncope and abnormal H-V interval of 70 ms. Paroxysmal bouts of pacemaker associated tachycardia were subsequently recorded on several occasions, initiated and terminated by spontaneous ventricular premature beats. The mechanism for the occurrence of the tachyarrhythmia is discussed in detail and the functional characteristics of the pulse generator are described. Replacement of the unit with a different pacer device prevented further occurrence of the arrhythmia.

Aged

Coronary sinus pacer lead simulating left atrial mass.

M-mode and two-dimensional echocardiographic evaluation of a patient with rheumatic heart disease and an atrioventricular sequential pacemaker with a coronary sinus lead showed an echo-producing mass in the left atrium. A repeat study after the coronary sinus lead was replaced by a right atrial screw-in lead revealed the disappearance of the echo-producing mass.

Diagnosis, Differential

Cardiac-pulmonary edema and low pulmonary capillary wedge pressure.

We describe a patient who presented with acute massive pulmonary edema, clinically and on chest roentgenogram. Two hours later the patient became hypotensive and was found to have a low pulmonary capillary wedge pressure (PCWP). The blood pressure returned to normal after administration of fluids. Acute pulmonary edema develops if PCWP rises higher than 25 to 30 mm Hg. In our patient, the elevated PCWP fell to low normal within two hours, when chest roentgenogram and clinical examination still suggested severe pulmonary edema. A phase lag existed between lowering of the pulmonary capillary wedge pressure and clearing of fluid from the alveolar and interstitial spaces in the lungs. At least three different pathogenetic mechanisms in patients with coronary artery disease can produce this phase lag. Transient global ischemia of the left ventricle was thought to be the responsible mechanism in our patient.

Blood Pressure

Electrophysiologic evaluation of elderly patients with sinus bradycardia: a long-term follow-up study.

One hundred three patients with persistent sinus bradycardia were evaluated electrophysiologically and followed prospectively for a mean of 4.6 years. The 5-year survival rate was 74.8%, not significantly different from the 72% rate in the general population with similar age and sex distribution. Forty-one patients had abnormal corrected sinus-node recovery time. Overall accuracy of abnormal corrected sinus-node recovery time in predicting serious sinus node disease in symptomatic and asymptomatic patients was 90% (37 of 41 patients) and 100% in patients with syncope (18 of 18 patients). The sensitivity of the test was 66%. Abnormal corrected sinus-node recovery time in patients with sinus bradycardia appears to be a valuable specific, predictive index of serious sinus node disease and therefore a useful test in selecting patients for pacemaker therapy, especially if symptoms such as dizziness or syncope are present.

Aged

Syncope and aortic stenosis: significance of conduction abnormalities.

22 patients with syncope and significant aortic stenosis underwent electrophysiological evaluation in addition to the hemodynamic study. Abnormalities of impulse formation or conduction were present in 12 patients. 6 patients demonstrated HV times greater than or equal to 55 msec. There was no correlation between the aortic valve gradient and the HV interval, between the enddiastolic volume of the ventricle and the HV time and between aortic valve calcification and the HV time. Syncopal attacks were corrected with aortic valve replacement even in patients with prolonged HV times.

Adult

Optimal enzyme test combination for diagnosis of acute myocardial infarction.

One hundred consecutive patients admitted to our cardiology service with the suspected diagnosis of acute myocardial infarction were evaluated with serical enzyme and isoenzyme determinations in an attempt to develop the medically and financially optimal combination of enzyme tests. In patients with onset of chest pain less than 24 hours before admission, creatine phosphokinase MB determination on admission and after 12 hours was sufficient to diagnose of exclude myocardial infarction. One serum LDH isoenzyme determination 24 hours after admission confirmed the diagnosis in 74% of patients.

Acute Disease

Conduction disturbances in patients with mitral valve prolapse.

The electrocardiograms (ECGs) of 55 patients with mitral valve prolapse were analyzed. Twelve of these demonstrated conduction abnormalities. Five patients had first degree heart block. Three had the classic ECG changes of the Wolff-Parkinson-White syndrome. Two patients had left anterior hemiblock, one of whom also had incomplete right bundle branch block. One patient had episodes of advanced atrioventricular block and periods of sinus arrest, which resulted in recurrent syncopal attacks. One patient had incomplete left bundle branch block. The presence of conduction disturbances points to the diffuse nature of the myocardial abnormality in mitral valve prolapse.

Adolescent

Echocardiographic assessment of left ventricular function in coronary arterial disease.

This investigation was designed to determine the role of echocardiography in the assessment of left ventricular function in patients with significant coronary arterial disease. Satisfactory echocardiograms were obtained in 43 patients with coronary arterial disease. The ventriculographic ejection fraction was determined by the area length method. The echocardiographic left ventricular end-diastolic dimension was increased to more than 5-4 cm in 17 patients. Fifteen of these patients had an ejection fraction of 0-45 or less. Three patients had a normal left ventricular end-diastolic dimension but an ejection fraction of less than 0-45. Twenty-three patients had an ejection fraction of more than 0-45 and a normal left ventricular end-diastolic dimension. The left ventricular end-diastolic dimension index was increased (greater than 3 cm/m2) in 15 patients, all of whom had ejection fraction of less than 0-45. Three patients had a normal left ventricular end-diastolic dimension index and an ejection fraction of less than 0-45. Twenty-five patients had a left ventricular end-diastolic dimension index of less than 3 cm/m2 or less and an ejection fraction of more than 0-45. The percentage fractional shortening of the echocardiographic left ventricular dimension was reduced in 25 patients. In 18 of these the ejection fraction was 0-45 or less. The percentage fractional shortening of the left ventricle was normal in 18 patients. In 2 of them the ejection fraction was less than 0-45. In summary, increase of the left ventricular end-diastolic dimension or left ventricular end-diastolic dimension index is usually associated with a critical reduction of the ejection fraction as determined by ventriculography. Since the ejection fraction is an important determinant of mortality related to bypass graft surgery, echocardiography should be useful in the detection of patients with a poor prognosis.

Adult