Once-daily pravastatin in patients with primary hypercholesterolemia: a dose-response study.

This multicenter, double-blind, placebo-controlled study was conducted to evaluate dose-response effects and safety of once-daily administration of pravastatin, a new inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. Pravastatin 5, 10, 20, 40 mg or placebo was administered at bedtime to 150 patients with primary hypercholesterolemia inadequately controlled on a low-fat, low-cholesterol (AHA Phase I) diet. After 8 weeks of treatment, pravastatin produced dose-dependent reductions in low-density lipoprotein (LDL) cholesterol of 19.2 to 34.1% (p less than or equal to .001 vs. baseline and placebo) and reductions in total cholesterol of 14.3 to 25.1% (p less than or equal to .01 to p less than or equal to .001 vs. placebo and p less than or equal to .001 vs. baseline). The relationship between the loge dose of pravastatin and decrease in LDL cholesterol was linear (p less than 0.002). High-density-lipoprotein cholesterol increased up to 11.7% and triglycerides decreased by as much as 23.9%. Pravastatin was well tolerated; no patient withdrew from the study as a consequence of treatment-related adverse events. Despite its relatively short serum half-life of approximately 2 h, once-daily administration of pravastatin provides a safe and effective means of reducing elevated LDL and total cholesterol.

Lyme carditis. Electrophysiologic and histopathologic study.

To further define the nature of Lyme carditis, electrophysiologic study and endomyocardial biopsy were performed in a patient with Lyme disease, whose principal cardiac manifestation was high-degree atrioventricular block. Intracardiac recording demonstrated supra-Hisian block and complete absence of an escape mechanism. Gallium 67 scanning demonstrated myocardial uptake, and right ventricular endomyocardial biopsy revealed active lymphocytic myocarditis. A structure compatible with a spirochetal organism was demonstrated in one biopsy specimen. It is concluded that Lyme disease can produce active myocarditis, as suggested by gallium 67 imaging and confirmed by endomyocardial biopsy. Furthermore, the presence of high-grade atrioventricular block in this disease requires aggressive management with temporary pacemaker and corticosteroid therapy.

Sustained postischemic cardiodepression following magnesium-diltiazem cardioplegia.

Magnesium-diltiazem cardioplegia was evaluated in the intact, perfused rat heart to determine whether the joint administration of these agents would adversely affect myocardial contractile and high-energy phosphate recovery following intermittent, normothermic global ischemic arrest. Sequential metabolic and functional analyses were performed on isolated perfused rat hearts during each phase of the experimental protocol: control (10 min), normoxic cardioplegia (10 min), intermittent global ischemic arrest (two 15-min periods separated by 2 min infusion of the normoxic cardioplegic perfusate), and normoxic postischemic control reperfusion (60 min). Four different cardioplegic solutions were evaluated: 30 mM KCl, 30 mM KCl with 2 mg diltiazem/liter, 20 mM MgCl2, and 20 mM MgCl2 with 2 mg diltiazem/liter. Myocardial phosphatic metabolite levels and intracellular pH were analyzed nondestructively in the intact hearts by phosphorus-31 NMR spectroscopy. Corresponding measurements of peak left intraventricular pressure, rate of peak pressure development (dP/dt), and contraction frequency were performed at the midpoint during each 5-min interval of 31P NMR signal averaging. Magnesium plus diltiazem-treated hearts were distinguished from all other groups by a marked delay in postischemic functional recovery consisting of a prolonged depression in contractility (34% of control, P less than 0.01) that persisted throughout the first 50 min of postischemic reperfusion. Diltiazem in combination with magnesium cardioplegia was detrimental to postischemic functional recovery, despite a rapid restoration of high-energy phosphate stores. The apparent adverse interactive effects of excess magnesium and diltiazem suggest that elective ischemic arrest with magnesium cardioplegia in combination with diltiazem may be contraindicated clinically. The mechanistic basis and drug specificity of this response require further clarification. The present findings appear to exclude ATP and PCr production, and structural causes as the basis for the observed aberrant functional recovery from global ischemia of magnesium plus diltiazem-arrested hearts.

Infective endocarditis: a current review.

Infective endocarditis is a dynamic disease for which various infective organisms may be responsible in different patient populations. Antimicrobial therapy should be directed against the specific organism after it has been identified by blood culture. An agent with a spectrum that includes the enterococci should be given in the meantime. Prophylactic use of a bactericidal agent is necessary for patients with valvular or congenital heart disease. Recent advances in microbiologic and cardiac diagnostic procedures offer the clinician various methods of following the activity of the disease, and immunobiology has provided new insights into its pathogenesis.

Demonstration of Ebstein's anomaly by simultaneous catheter-tip localization of the tricuspid valve visualization: A new method.

The diagnosis of Ebstein's anomaly has traditionally been made by angiocardiography and confirmed by simultaneous intracardiac electrocardiographic and pressure recordings. These techniques may result in false positive or negative tests. A new method is proposed, whereby the right coronary artery is used an an angiographic marker for the tricuspid annulus and a pressure catheter simultaneously marks the position of the tricuspid valve. In the right anterior oblique position the tip of the pressure catheter should be just under the right coronary artery as the tricuspid leaflets close in systole, indicating the normal relationship of the tricuspid leaflets and annulus. In Ebstein's anomaly the tip of the catheter extends well past the coronary artery in systole, demonstrating the characteristic displacement of the attachments of the tricuspid valve downward toward the right ventricular apex.