Effect of the second-generation calcium channel blocking drug nisoldipine on diastolic left ventricular dysfunction in heart failure

Long-term effects of angiotensin-converting enzyme inhibitors and calcium antagonists on the right and left ventricles in essential hypertension

To compare the effects of chronic antihypertensive treatment on left and right ventricular structure and function, 24 patients with mild to moderate, never-treated hypertension were randomized to receive fosinopril (20 mg daily) or amlodipine (10 mg daily) for 12 months. At baseline and subsequently at the end of third, sixth, and twelfth months, each patient underwent an integrated echocardiographic study and noninvasive ambulatory blood pressure monitoring. Both drugs significantly reduced blood pressure, casual or monitored (p < 0.01), and left ventricular mass index (from 125 +/- 32 to 100 +/- 12 gm/m2 [p < 0.02] with amlodipine and from 106 +/- 18 to 89 +/- 10 gm/m2 [p < 0.02] with fosinopril). The decrease in left ventricular mass was essentially caused by a reduction of ventricular thickness. Free right ventricular wall thickness was also lowered in both groups, more consistently with amlodipine (from 8.0 +/- 2.1 to 6.4 +/- 0.8 mm; p < 0.01), without an increase in plasma natriuretic peptide and insulin concentrations or heart rate. With both treatments, the decrease in ventricular mass was not associated with impairment of systolic function, whereas a trend toward an improvement of Doppler echocardiographic indexes of biventricular diastolic function was observed. In conclusion, both amlodipine and fosinopril induced similar qualitative effects on anatomy and function of both ventricles. The clinical meaning of these observations must be defined further by means of adequately sized prospective trials.

Acute effects of intravenous nisoldipine on left ventricular function after acute myocardial infarction

Nisoldipine is a calcium antagonist with potent coronary vasodilating effects in patients with chronic stable angina pectoris. In an initial study we showed that intravenous nisoldipine, given 24-72 hours after uncomplicated myocardial infarction, was a safe and feasible intervention that had beneficial effects on global and regional myocardial function. We subsequently studied the acute effects of nisoldipine in six patients within 24 hours (mean 14 +/- 4 hours) after the onset of myocardial infarction. Nisoldipine was administered as a 4.5 micrograms/kg intravenous bolus over 3 minutes, followed by intravenous infusion of 0.2 microgram/kg over 60 minutes. Radionuclide angiography, cardiac output, and intraarterial blood pressure measurements were performed before and during nisoldipine. Left ventricular ejection fraction increased from 48.3 +/- 10.3% to 55.3 +/- 11.8% (p = 0.034) during nisoldipine infusion. Regional wall motion score changed during nisoldipine infusion from 3.3 +/- 2.5 to 1.8 +/- 2.6 (p = 0.027). Cardiac output increased from 5.5 +/- 1.0 to 7.3 +/- 1.3 l/min (p = 0.0001). Heart rate increased from 78 +/- 12 to 88 +/- 11 min-1 (p = 0.004). Mean arterial blood pressure decreased from 92 +/- 20 to 79 +/- 13 mmHg (p = 0.038). The rate-pressure product did not change significantly during nisoldipine infusion. It is concluded that nisoldipine improves global and regional left ventricular function in patients with acute myocardial infarction within the first 24 hours.

Normal right ventricular systolic and diastolic function assessed by krypton-81m equilibrium ventriculography

Krypton-81m equilibrium ventriculography was used to study right ventricular function in 23 healthy male volunteers. Technetium-99m lung perfusion scintigraphy was employed to subtract radionuclide activity within lung during image analysis thereby enhancing image quality. The imaging technique was used to generate a time-activity curve for the right ventricle allowing the definition of indices of normal systolic and diastolic function for the right ventricle. At rest, indices of systolic ejection and diastolic filling were comparable to those previously reported for the left ventricle. Using the imaging technique, movement artifact during exercise reduces image quality and limits accurate measurement of these indices to resting studies.

Nifedipine inhibits responses to alpha-adrenoceptor stimulation in canine blood vessels: impact of heart failure

The effects of nifedipine (10(-8) and 10(-7) M) on alpha-adrenergic responses of the dorsal pedal artery and saphenous vein were examined from dogs with pacing-induced heart failure. Two groups of dogs had their right ventricles paced at 250 beats/min: group (1) 1 week of pacing (mild heart failure) and group (2) paced for a mean period of 25.8 days (peak heart failure). Nifedipine non-competitively antagonised 6-allyl-2-amino-5,6,7,8-tetrahydro-4H- thiazolo[4,5-d]azepin dihydrochloride (BHT 920)-induced contractions to the same extent (i.e. at control, mild heart failure and peak heart failure) and IC50 values were as follows: for dorsal pedal artery 3.9 (1.8-6.1) nM, 4.4 (1.2-8.4) nM and 8.5 (2.9-38.9) nM, respectively; for saphenous vein 13.0 (4.6-26.0) nM, 13.0 (7.3-18.6) nM and 19.0 (9.3-32.8) nM, respectively). Before the onset of pacing, nifedipine did not affect concentration-effect curves generated to noradrenaline or phenylephrine in either the artery or the vein. After 1 week of pacing, nifedipine (10(-7) M) inhibited contractions to noradrenaline in the artery and the vein (70 +/- 5% for the artery and 51 +/- 4% for the vein). Nifedipine had no effect on phenylephrine-induced contractions. At peak heart failure, nifedipine inhibited both noradrenaline and phenylephrine contractions. These results indicate that nifedipine is useful in differentiating contractile activity of vascular smooth muscle with respect to alpha-adrenoceptor agonism.

Acute and chronic effects of the dihydropyridine calcium antagonist nisoldipine on the resting and exercise hemodynamics, neurohumoral parameters, and functional capacity of patients with chronic heart failure

The acute and chronic effects of the dihydropyridine calcium antagonist nisoldipine were studied in patients with chronic heart failure (LV EF < .35; peak VO2 < 25 ml/kg/min) caused by idiopathic or postinfarction cardiomyopathy. The study group initially consisted of 16 patients; two patients were excluded from the acute study due to side effects of the drug and two more patients were excluded during the chronic part of the study because of excessive tachycardia or worsening heart failure, respectively; therefore, the final study group consisted of 12 patients. Each patient was evaluated at rest, in the supine and sitting positions, and during maximal bicycle exercise, before and after acute and chronic (2-3 months) oral nisoldipine therapy (20 mg bid). Plasma levels of renin activity, aldosterone, norepinephrine, and epinephrine were measured before and 1 hour after nisoldipine in 10 patients. Concomitant therapy with digitalis and diuretics was kept constant throughout the study. At rest, in the supine position, nisoldipine (20 mg orally) induced an acute increase of cardiac index from 2.87 +/- 0.52 to 3.93 +/- 1.52 l/min/m2, with a reduction of mean arterial pressure from 97 +/- 7 to 85 +/- 9 mmHg and systemic vascular resistance from 1417 +/- 201 to 968 +/- 257 dynes sec/sec cm5 without significant changes of right atrial and pulmonary pressures. Hemodynamic effects peaked 1 hour after its administration and persisted for 6 hours. Similar changes were observed in the resting sitting position.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of postural changes and isometric exercise on Doppler-derived measurements of diastolic function in normal subjects

To determine if simple maneuvers that occur in daily life, such as changes in body position and isometric handgrip exercise, affect Doppler-derived measurements of diastolic function, we studied 22 normal male subjects in the supine position at rest and during several postural manipulations and during handgrip exercise. Comparison of values obtained in the 80 degrees upright tilt position with those obtained in the standard supine position revealed significant decreases in early diastolic flow velocity (peak E) (-25 +/- 3 percent; p less than 0.001), late diastolic flow velocity (peak A) (-9 +/- 3 percent; p less than 0.01), and the ratio of early to late flow velocities (E/A ratio) (-17 +/- 4 percent; significant increases in deceleration time (+55 +/- 10 percent; p less than 0.001) and isovolumic relaxation time (+38 +/- 4 percent; p less than 0.001). Comparison of values obtained with supine isometric exercise with those obtained during the preceding supine resting state revealed significant decreases in peak E (-12 +/- 3 percent; p less than 0.001) and the E/A ratio (-21 +/- 4 percent; p less than 0.001) and significant increases in peak A (+15 +/- 4 percent; p less than 0.001) and isovolumic relaxation time (+16 +/- 3 percent; p less than 0.001). The response of Doppler-derived measurements of diastolic function to postural changes and isometric exercise is complex and multifactorial. Interpretation of these measurements must take into account changes in loading conditions.