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Left ventricular diastolic function in patients with left ventricular systolic dysfunction due to coronary artery
C N Aroney1, M J Semigran, G W Dec
1Department of Medicine, Massachusetts General Hospital, Boston 02114.
Insights
Nicardipine did not significantly alter left ventricular (LV) diastolic function in patients with systolic dysfunction, unlike nitroprusside. This study assessed the impact of these drugs on diastolic pressure-volume relations in heart failure patients.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Patients with left ventricular (LV) systolic dysfunction often experience impaired diastolic function.
- Understanding drug effects on diastolic function independent of loading conditions is crucial for managing heart failure.
Purpose of the Study:
- To evaluate the effect of nicardipine on LV diastolic function in patients with systolic dysfunction.
- To compare nicardipine's effects with nitroprusside, controlling for blood pressure changes.
Main Methods:
- 12 patients with heart failure (LV ejection fraction < 0.40) received intravenous nitroprusside and nicardipine at equihypotensive doses.
- LV micromanometer pressure and radionuclide volumes were measured at baseline and during infusions.
- Diastolic pressure-volume relations were analyzed during common volume ranges.
Main Results:
- Both nitroprusside and nicardipine reduced mean systemic arterial pressure.
- Nitroprusside caused a greater decrease in LV end-diastolic pressure and reduced the time constant of relaxation.
- Nicardipine did not significantly alter the LV diastolic pressure-volume relation, while nitroprusside did in some patients.
Conclusions:
- Nicardipine does not appear to impair LV diastolic function in patients with systolic dysfunction.
- Nitroprusside, however, may negatively affect LV diastolic relaxation and pressure-volume relations.
- These findings suggest differential effects of these vasodilators on diastolic mechanics in heart failure.
Abstract:
To assess the effect of nicardipine on left ventricular (LV) diastolic function independent of concurrent effects on loading conditions in patients with LV systolic dysfunction due to coronary artery disease, equihypotensive doses of intravenous nitroprusside and nicardipine were administered to 12 patients with congestive heart failure due to previous myocardial infarction (LV ejection fraction less than 0.40). LV micromanometer pressure and simultaneous radionuclide volume were obtained during a baseline period, during nitroprusside infusion, during a second baseline period and during nicardipine infusion. Mean systemic arterial pressure decreased an average of 21 mm Hg with nitroprusside and 19 mm Hg with nicardipine. A greater decrease in LV end-diastolic pressure was observed with nitroprusside (29 +/- 2 to 15 +/- 2 mm Hg, p less than 0.01) than with nicardipine (29 +/- 2 to 25 +/- 3 mm Hg, p less than 0.05). There was a decrease in the time constant of relaxation during nitroprusside but not during nicardipine infusion. There was enough overlap in LV volumes in the baseline and nitroprusside periods to compare diastolic pressure-volume relations over a common range of volumes in 4 patients, and enough overlap in the baseline and nicardipine periods in 11 patients. The relation was shifted downward in 3 of 4 patients taking nitroprusside and in 6 of 11 patients taking nicardipine. The relation between end-diastolic pressure and volume was not shifted with nicardipine.(ABSTRACT TRUNCATED AT 250 WORDS)