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Effect of propranolol and disopyramide on left ventricular function at rest and during exercise in hypertrophic
1Department of Cardiology, Johann Wolfgang Goethe-University, Medical School, Frankfurt, FRG.
Insights
Disopyramide negatively impacts left ventricular function in hypertrophic cardiomyopathy patients, reducing ejection fraction and peak ejection rate. Propranolol, however, effectively lowers heart rate during rest and exercise.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Hypertrophic cardiomyopathy (HCM) is a complex cardiac condition.
- Intraventricular pressure gradients are common in HCM patients.
- Assessing left ventricular function is crucial for managing HCM.
Purpose of the Study:
- To evaluate the effects of disopyramide and propranolol on left ventricular function in patients with hypertrophic cardiomyopathy.
- To compare acute and long-term treatment effects of these drugs.
Main Methods:
- Nineteen patients with hypertrophic cardiomyopathy underwent radionuclide ventriculography.
- Left ventricular function was assessed at rest and during exercise.
- Patients received acute and chronic treatment with disopyramide or propranolol in a crossover design.
Main Results:
- Disopyramide significantly decreased resting ejection fraction and peak ejection rate after long-term treatment.
- Disopyramide also reduced the peak filling rate at rest.
- Propranolol significantly reduced heart rate at rest and during exercise, both acutely and long-term.
Conclusions:
- Disopyramide may impair left ventricular systolic and diastolic function in HCM patients.
- Propranolol effectively controls heart rate in HCM.
- Further research is needed to fully understand the long-term implications of disopyramide therapy in HCM.
Abstract:
In 19 patients with hypertrophic cardiomyopathy (15 males, 4 females, mean age 49.2 +/- 10.8 years) left ventricular function was studied with radionuclide ventriculography at rest and during exercise in a crossover design without intervention and after disopyramide and propranolol treatment. 15 of the 19 patients had a resting or latent intraventricular gradient of more than 30 mm Hg. Left ventricular function at rest and during exercise was evaluated before medication, 90 min after oral administration of 200 mg disopyramide or 160 mg propranolol and after 3 weeks of oral therapy with disopyramide 200 mg 2 times a day or propranolol 80 mg 4 times a day. After long-term treatment with disopyramide, resting ejection fraction decreased from 72 +/- 12 to 69 +/- 14% (p less than 0.01) and peak ejection rate (PER) decreased from 3.46 +/- 135 to 3.24 +/- 65 end-diastolic volume (EDV).s-1 (p less than 0.01). Peak filling rate (PFR) at rest decreased from 3.01 +/- 0.8 to 2.77 +/- 0.63 EDV.s-1 (p less than 0.05). Time to peak filling rate (TPFR) at rest and during exercise after acute and chronic therapy did not change compared to control values. Acute and long-term administration of propranolol lead to a significant reduction in heart rate at rest and during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)