Hitoshi Yokozuka

Effectiveness of carvedilol alone versus carvedilol + pimobendan for severe congestive heart failure ∗

Pimobendan is a new inotropic agent with phosphodiesterase-inhibiting and calcium-sensitizing effects that increase contractility with minimal increase in oxygen consumption.1‐5 We hypothesized that short-term administration of pimobendan in the early phase of b-blocker therapy would be beneficial in alleviating exacerbation of congestive heart failure (CHF) resulting in withdrawal for patients with severe CHF. The present study investigated the effects of short-term coadministration of pimobendan during introduction of carvedilol therapy on the clinical outcome, left ventricular contractile function, and neurohormone and cytokine levels compared with conventional carvedilol therapy in a randomized fashion in patients with severe CHF. ••• For the present study patients with New York Heart Association (NYHA) class III/IV symptomatic CHF who had multiple episodes of decompensated heart failure and a left ventricular ejection fraction of ,40% on radionuclide ventriculography or contrast ventriculography were enrolled. They were treated with conventional medical treatment including digitalis glycosides, diuretics, and angiotensin-converting enzyme (ACE) inhibitors. Exclusion criteria included a heart rate of ,50 beats/min, systolic blood pressure of ,90 mm Hg, significant bradyarrhythmias or atrioventricular block, serum creatinine of .3.0 mg/dl, and the presence of stenotic valvular heart disease, alcohol abuse, active myocarditis, or hypertrophic obstructive cardiomyopathy. Plasma creatinine phosphokinase level determination and scintigraphic assessment were performed to exclude myocarditis in the absence of biopsy samples. The study protocol was approved by an institutional review committee, and informed consent was obtained from all patients who participated in the study.

Long-standing bidirectional tachycardia in a patient with hypokalemic periodic paralysis

Bidirectional tachycardia is an uncommon arrhythmia that usually occurs in aged persons with severe myocardial disease or digitalis intoxication, and carries a poor prognosis. This is a report of a young woman with familial hypokalemic periodic paralysis, who has a 13-year history of asymptomatic bidirectional tachycardia in the absence of organic heart disease or digitalis intoxication. Association of periodic paralysis and bidirectional tachycardia in this case and four previously reported cases suggests a strong relationship between this arrhythmia and potassium.

Rapid Growth of Left Ventricular Thrombus Leading to Fatal Heart Failure in Six Hours

A left ventricular (LV) thrombus grew rapidly over chronic endocarditis 2 months after anterior myocardial infarction. Echocardiograms demonstrated a rapidly growing LV thrombus an eventual obstruction. Despite anticoagulant/thrombolytic therapy, the patient died of acute LV failure. Histopathologically, a fresh thrombus overlay thickened endocardium with massive T lymphocyte infiltration over healed infarction.

Variations in myocardial contraction sequence under various hypoxic conditions

SummaryHypokinetic myocardial segment motion is observed in various pathophysiologic conditions. The aim of this study was to clarify the mechanisms involved in differences in segment motion of hypokinesis. Nineteen open-chest dogs were studied with regard to myocardial segment length, left ventricular pressure, and internal minor-axis diameter. Sequential instantaneous myocardial elastance [α(t) curve] was calculated under 4 different hypoxic conditions: complete coronary occlusion and reperfusion, partial coronary occlusion, coronary microembolization, and anoxic perfusion. The α(t) curve peaked at end-systole in the case of normal contraction; but it was almost totally flat when complete bulging occurred. The hypokinesis which occurred during development of the complete systolic bulgc immediately after complete coronary occlusion had an earlier α(t) peak curve than the hypokinesis resulting from partial coronary stenosis (209.5 ± 35.6 ms after end-diastole vs. 261.9 ± 18.2 ms; p < 0.02), microsphere injection into the coronary artery (243.2 ± 24.5 ms vs. 289.3 ± 15.4 ms; p < 0.05), or anoxic perfusion (213.4 ± 40.2 vs. 275.6 ± 28.3 ms; p < 0.05). The early a(t) peak resulted in a late-systolic bulge in segment length motion. In conclusion, hypokinetic segment motion differed depending on whether the coronary blood flow was present or not. A late-systolic bulge only developed immediately after complete coronary occlusion, and resulted from an abrupt decrease in myocardial stiffness during the cardiac cycle, which is closely related to the abrupt cessation of coronary blood flow.