Chronic Amlodipine Treatment During the Development of Heart Failure

Background—This study examined the effects of chronic amlodipine treatment on left ventricular (LV) pump function, systemic hemodynamics, neurohormonal status, and regional blood flow distribution in an animal model of congestive heart failure (CHF) both at rest and with treadmill exercise. In an additional series of in vitro studies, LV myocyte contractile function was examined. Methods and Results—Sixteen pigs were studied under normal control conditions and after the development of chronic pacing–induced CHF (240 bpm, 3 weeks, n=8) or chronic pacing and amlodipine (1.5 mg · kg−1 · d−1, n=8). Under ambient resting conditions, LV stroke volume (mL) was reduced with CHF compared with the normal control state (16±2 versus 31±2, P<0.05) and increased with concomitant amlodipine treatment (29±2, P<0.05). At rest, systemic and pulmonary vascular resistance (dyne · s−1 · cm−5) increased with CHF compared with the normal control state (3102±251 versus 2156±66 and 1066±140 versus 253±24, respectively, both P<0.0...