Beta-adrenergic blocking agents in heart failure.

Cardiac dysfunction in heart failure is widely recognized as a progressive process, regardless of the clinical signs and symptoms. An increase in cardiac sympathetic drive is one of the earliest neurohormonal responses occurring in patients with heart failure and may be one of the major causes of the progressive remodeling leading to the decline in myocardial function, and responsible for the poor prognosis of patients with heart failure. Therefore, recent data provided by several appropriately designed clinical trials clearly indicate the benefits of beta-adrenoceptor blocking agents, combined with diuretics, ACE inhibitors, and digoxin in chronic heart failure class II to IV due to systolic ventricular dysfunction. The benefits are related to symptoms, functional capacity, remodeling, and improvement in left ventricular function, reduction in cardiovascular hospitalization, a decrease in the overall and sudden cardiac death rate, and are similar in patients with ischemic or nonischemic cardiomyopathy, independent of age, gender, or functional class. In this review we describe the cardiovascular effects of the increase in sympathetic drive, the pharmacological properties of the beta-blockers most evaluated in heart failure therapy (metoprolol, bisoprolol, and carvedilol), the major clinical trials related to these agents in heart failure, the recommendations for their appropriate use in clinical practice, the precautions to be adopted, and how to handle the more common adverse reactions.

[Acute myocardial infarct in a patient with dextrorotation]. / Infarto agudo do miocárdio em paciente com dextro-rotção.

A 79-year-old woman developed myocardial infarction associated with acute pulmonary edema. The electrocardiogram recorded QRS complex of QS type in V1 with upper ST extending from V3R to V6R. The polarity of the P wave in bipolar leads was positive, so compatible with dextrorotation complicated by myocardial infarction. The dextrorotation was confirmed with chest roentgenogram and echocardiogram.

[Familial complete atrioventricular block in patients with hypertrophic cardiomyopathy]. / Bloqueio atrioventricular total familiar em pacientes com cardiomiopatia hipertrófica.

The association of spontaneous complete heart block and hypertrophic cardiomyopathy is rare. We have studied three patients of the same family, two brothers and one nephew, ages 19-41 years, with hypertrophic cardiomyopathy confirmed by hemodynamic and angiographic studies. All patients were treated with permanent cardiac pacemaker implant. They are asymptomatic, aging 33 to 55 years, with follow-up of 157 to 176 months after the onset of the heart block.

Long-term antianginal and antiischemic effects of mibefradil, the novel T-type calcium channel blocker: a multicenter, double-blind, placebo-controlled, randomized comparison with sustained-release diltiazem.

This study compared the efficacy, safety, and tolerability of mibefradil to sustained-release diltiazem in patients with chronic stable angina pectoris. At week 12, statistically equivalent mean increases in exercise tolerance test (ETT) duration of > 1 minute were observed in both groups. Similar improvements in time to onset of angina and time to persistent 1 mm ST-segment depression were also observed with both drugs. Large reductions in heart rate, blood pressure, and rate-pressure product were observed at each stage of the ETT among patients treated with mibefradil. Each drug was associated with at least a 70% reduction from baseline in anginal frequency and nitroglycerin consumption. Patients maintained on mibefradil during the withdrawal period had significant increases in all three ETT variables at week 16 compared with placebo. The effectiveness of mibefradil is comparable with sustained-release diltiazem in treating chronic stable angina pectoris, although mibefradil provides greater reductions in heart rate and cardiac workload.

Infarto antero-septal com eixo eletrico normal e com desvio para a esquerda. / Anteroseptal infarction with normal electric axis and with left axis deviation

Sao estudados 110 casos de infarto anteroseptal (IAS), sendo que 55 tinham seus ECG sem desvio do eixo eletrico no plano frontal (AQRS normal) e 55 com AQRS desviado para a esquerda. Destes, 24 nao apresentavam aspectos de disturbios da conducao ventricular e 31 tinham criterio para o diagnostico do bloqueio divisional esquerdo anterior (BDEA). A cinecoronariografia de 59 casos revelou oclusao total ou lesoes graves na descendente anteior, nao se encontrando relacao entre esta ocorrencia e o BDEA, ja que todos tinham IAS, mas somente 28% apresentavam bloqueio