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Afterload reduction by nifedipine—the acute haemodynamic response to exercise in hypertensive subjects

1985; Oxford University Press; Volume: 6; Issue: 4 Linguagem: Inglês

10.1093/oxfordjournals.eurheartj.a061863

1522-9645

C G Wathen, W. J. Hannan, Lindsay W. Turnbull, Alexander Muir,

Heart Failure Treatment and Management

In 16 people with essential hypertension, heart rate (HR), blood pressure (BP) and relative cardiac volumes were measured at rest and during submaximal upright exercise before and after 10 mg of sublingual nifedipine using radionuclide ventriculography. In 10 patients who had had no previous therapy (BP 152/103±5/3 mmHg) nifedipine produced a fall in BP of 6/12±3/3 mmHg (SEM) and a rise in HR of 15±5 bpm (P<0.001). This was associated with a rise in LVEF of 0.07±0.02 (P<0.005) and in cardiac output of 44±9%, presumably as a result of ventricular offloading. The cardiac response to exercise given the different starting values, was unchanged by nifedipine. Thus the HR was 101±6 bpm at rest after nifedipine and on exercise rose to 124±6 bpm (P<0.001): stroke volume was +22±8% at rest after nifedipine and rose to +43±12% on exercise. Thus cardiac output which had increased by 44±9% after nifedipine increased by 100±10% from the initial value. In 6 patients pre-treated with atenolol (100 mg) and with similar resting BP (158/101±5/4 mmHg) there was a fall in BP of 32/15±3/2 mmHg after nifedipine which was greater than in the previously untreated group (P<0.01). In this group HR increased by 8±3 bpm (P<0.05). Following nifedipine the exercise response was similar given the different starting values. The combination of nifedipine and a beta adrenoceptor antagonist can depress myocardial function and the difference between pressure–volume ratios in the two groups supports this view but there was no important depressant effect. We conclude that the combination of beta blocker and nifedipine therapy is effective and safe in hypertensive subjects without significant myocardial dysfunction.