Estratégia para Individualizar uma Dose Eficiente de Betabloqueador em Pacientes Idosos com Isquemia Miocárdica e Função Ventricular Esquerda Preservada

OBJECTIVE: To assess the strategy of titration for prescribing an efficient dosage of propranolol to reduce myocardial ischemia in the elderly. METHODS: The study comprised 14 elderly men (73.6 ± 5.3 years) with stable coronary heart disease documented on coronary cineangiography, ischemic response to exercise testing, and preserved left ventricular function. Titration was performed to identify the dosage of propranolol that would cause a 15% reduction in heart rate at the end of a 50 W load (corresponding to normal daily activities in the elderly) in weekly exercise tests. Synchronous scintigraphic study of the cardiac chambers was performed at rest and during exercise prior to and after propranolol use. RESULTS: The reductions in heart rate with the 50 W load and at rest were similar (21% vs 20%; P=0.5100). Propranolol improved the duration of exercise (12.2 ± 2.0 min vs 13.1 ± 1.8 min; P=0.0313) and abolished the changes in the ST segment induced by exercise in 8 (57%) patients. At rest, the ejection fraction was not modified by the beta-blocker. During maximum exercise, propranolol reduced the end-systolic volume index and increased ejection fraction. CONCLUSION: The strategy of using beta-blockers to reduce heart rate by 15% with a 50 W load is safe and beneficial in the elderly patient with myocardial ischemia and preserved ventricular function. The dose of beta-blocker used reduced myocardial ischemia and improved tolerance to exercise without hampering ventricular performance during maximum exercise.