The American journal of cardiology
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Biography Historical Article
Leslie David Hillis, MD: a conversation with the editor. [interview by William Clifford Roberts].
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Randomized Controlled Trial Clinical Trial
Effects of propranolol on recovery of heart rate variability following acute myocardial infarction and relation to outcome in the Beta-Blocker Heart Attack Trial.
This study evaluated the effects of propranolol on recovery of heart rate variability (HRV) after acute myocardial infarction and its relation to outcome in the Beta-blocker Heart Attack Trial (BHAT). Beta blockers improve mortality after acute myocardial infarction, but through an unknown mechanism. Depressed HRV, a measure of autonomic tone, predicts mortality after acute myocardial infarction. ⋯ Recovery of HF, the strongest HRV predictor of outcome, and propranolol therapy independently predicted outcome. In summary, after acute myocardial infarction, propranolol therapy improves recovery of parasympathetic tone, which correlates with improved outcome, and decreases morning sympathetic predominance. These findings may elucidate the mechanisms by which beta blockers decrease mortality and reduce the early morning risk of sudden death after acute myocardial infarction.
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Comparative Study
Acute blood pressure effects at the onset of supraventricular and ventricular tachycardia.
This study was designed to assess the effects of tachycardia origin, the significance of atrial contribution, and the effects of left ventricular ejection fraction on hemodynamically tolerated ventricular tachycardia (VT) and supraventricular tachycardia (SVT). Forty-one subjects with inducible hemodynamically tolerated VT (n = 24) or SVT (n = 17) with mean ages of 60 +/- 13 and 40 +/- 16 years and mean ejection fractions of 32 +/- 15% and 59 +/- 5%, respectively, were studied. VT and SVT were induced by standard techniques, and femoral arterial blood pressure (BP) was recorded for 30 seconds. ⋯ However, AV pacing at the tachycardia cycle length was associated with improved BP response over RV pacing alone. Increased age and lower ejection fraction adversely influenced BP response in the VT group and longer cycle length, and higher preinduction BP favorably influenced BP response in the SVT group. The determinants of BP response after tachycardia onset are complex and differ in patients with SVT and VT.