Joe M. Moody

Recently diagnosed idiopathic dilated cardiomyopathy: Incidence of myocarditis and efficacy of prednisone therapy

Fifty-two patients with recently diagnosed idiopathic dilated cardiomyopathy were studied to determine the incidence of myocarditis; patients were randomly assigned to receive either conventional therapy alone or conventional therapy plus prednisone to assess possible therapeutic efficacy with regard to survival. Inflammatory criteria were present in 23% of the population studied with 13% having overt myocarditis according to the Dallas criteria. The addition of prednisone to conventional therapy did not improve survival in a homogeneous population with new-onset dilated cardiomyopathy. Furthermore, the diagnosis of myocarditis by endomyocardial biopsy did not influence 2-year survival once dilated cardiomyopathy had developed. Biopsy-documented myocarditis resolved in all patients, according to results of 3-month follow-up endomyocardial biopsies, regardless of treatment group. There was a trend for patients with a left ventricular ejection fraction less than 20% to show reduced survival at 2 years compared to the group with a higher ejection fraction (p = 0.07). Right ventricular dysfunction determined at catheterization was present in 20 of 52 patients and was the most significant predictor of survival. Patients with preserved right ventricular function had a 95% 24-month survival rate compared to 47% for patients with right ventricular diastolic dysfunction (right ventricular end-diastolic pressure greater than or equal to 11 mm Hg) (p = 0.005).

Left ventricular performance of the athletic heart during upright exercise: a heart rate-controlled study.

This study compares the left ventricular performance of chronically conditioned pentathletes (N = 10) with less-conditioned subjects (N = 10) during dynamic upright exercise. The pentathletes were found to have a superior treadmill performance [24 +/- 4 vs 17 +/- 2 min (SD), P less than 0.01], reduced resting heart rate (41 +/- 13 vs 62 +/- 6 bpm, P less than 0.01), and increased left ventricular mass (254 +/- 85 vs 179 +/- 35 g, P less than 0.05) compared to the control group. Radionuclide ventriculography and heart rate controlled-bicycle ergometry were employed to examine changes in left ventricular ejection fraction, end-diastolic volume, end-systolic volume, and stroke volume. Heart rate was controlled by adjusting the resistance of the ergometer until stable heart rates of 90, 110, 130, and 150 bpm were achieved. Following heart rate stabilization, 99mTc images were acquired during 3-min stages at each target heart rate level. In the pentathletes, left ventricular ejection fraction, end-diastolic volume, and stroke volume increased (P less than 0.01) during exercise, and end-systolic volume tended to decrease. No difference was noted in left ventricular ejection fraction between groups when heart rates were matched. However, the exercise-induced changes in end-diastolic volume and stroke volume were greater (P less than 0.01) in the pentathletes. In conclusion, the athletes studied relied on the same mechanism as the less-conditioned subjects for improving pump performance during exercise stress, but the athletes ability to mobilize a greater end-diastolic volume accounts for their larger stroke output during each stage of heart rate-matched exercise.

Limitations of the cardiokymograph for assessing left ventricular wall motion

In order to evaluate the reliability and reproducibility of the CKG we studied four groups of patients. In 27 patients with a prior myocardial infarction the CKG recordings were compared to simultaneous wall motion videotracking. Identical wall motion was recorded in 75% of left ventricular sites and most of the discordant sites were false abnormal posterior wall motion recorded by the CKG. The second group consisted of 21 normal subjects studied by CKG only and 35% displayed anterior dyskinesis during expiration. The third group consisted of nine stable patients who were studied on two separate days by CKG and identical wall motion was recorded in only 55% of the sites on the two recordings. The final group consisted of seven patients with mitral regurgitation and all had late systolic outward movement posteriorly. Systolic wall motion was normal postoperatively in the three patients who underwent valve replacement. We conclude that: (1) the usefulness of the CKG is limited by the frequent recording of false wall motion abnormalities in normal subjects, (2) false anterior wall motion abnormalities can be reduced by recording during inspiration, (3) false posterior wall motion abnormalities may be due to systolic left atrial expansion, and (4) cardioxymography recordings are often not reproducible.

Comparison of binomial, ZAM and minimum cross-entropy time-frequency distributions of intracardiac heart sounds

One reason why automated heart sound analysis remains unfeasible may be the inadequacy of conventional spectral techniques in representing the nonstationary, multicomponent characteristics of phonocardiograms. This study compares several generalized time-frequency distributions (GTFDs) applied to intracardiac phonocardiograms (ICP) obtained at rest in six patients using catheter-mounted transducers. ICPs were bandpass filtered (50-500 Hz) and digitized at 4 kHz. The TFDs employed in this study were the binomial transform (BT), Zhao-Atlas-Marks (ZAM) distribution, minimum cross-entropy (MCE) distributions and the spectrogram. The BT and MCE representations in particular show improved concentration of ICP energy in time-frequency vs. the spectrogram. These findings suggest that several GTFDs may prove useful in the design of automated auscultation systems.<<ETX>>

Percutaneous Mechanical Reperfusion During Acute Myocardial Infarction

The treatment of acute myocardial infarction has progressed from bedrest to mechanical, catheter-based reperfusion. The authors review the use of percutaneous coronary intervention (PCI) as a primary treatment for acute myocardial infarction and the use of adjunctive agents. The most recent American College of Cardiology/ American Heart Association (ACC/AHA) guidelines for the use of PCI in ST segment elevation myocardial infarction (MI) advocate the use of PCI as primary therapy at those centers in which the procedure can be performed within accepted standards. Because a majority of hospitals (80%) do not have the capability of performing primary PCI, most patients are treated with thrombolytic therapy. PCI should be considered in those patients treated with thrombolytic therapy who have persistent or recurrent ischemia and/or cardiogenic shock. For patients with non-ST elevation MI, the use of an invasive strategy (early angiography and PCI if needed) has recently shown to be beneficial. Although revascularization is the basis of the acute therapy of MI, additional pharmacologic therapy in the acute setting is now recognized as a key to favorable long-term outcome.