To assess the effects of intravenous isradipine (0.5 mg) on left ventricular function in patients pretreated with the β-blocker propranolol (0.1 mg/kg i.v.), 10 patients were studied during cardiac catheterization for suspected coronary artery disease (confirmed in 6). All patients had normal ejection fractions at rest. Following propranolol, isradipine significantly reduced mean aortic pressure (base-line: 112 mm Hg: propranolol: 107 mm Hg; isradipine: 92 mm Hg) and left ventricular systolic pressure (149 vs. 144 vs. 117 mm Hg, respectively). Propranolol alone significantly decreased heart rate, which then increased after isradipine (75 vs. 66 vs. 70 heats/min, respectively). Cardiac index was depressed with propranolol but normalized with isradipine (3.8 vs. 3.0 vs. 3.7 L/min/m2, respectively) as was mean pulmonary artery pressure (16 vs. 18 vs. 16 mm Hg, respectively). Left ventricular contractility decreased significantly during β-blocker infusion and reached baseline values with isradipine (2,270 vs. 2,080 vs. 2,320 mm Hg/s, respectively). Parallel to dP/dlmax, systolic wall tension de-creased as a consequence of the reduction of left ventricular volume and afterload (1,223 vs. 1,332 vs. 905 units, respectively). It is concluded that isradipine effectively reduces cardiac afterload with no sign of intrinsic cardiodepression.
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