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Effect of verapamil on absolute myocardial blood flow in hypertrophic cardiomyopathy
R Gistri1, F Cecchi, L Choudhury
1Consiglio Nazionale delle Ricerche (CNR) Institute of Clinical Physiology, Florence, Italy.
Insights
Verapamil did not significantly improve myocardial blood flow or flow reserve in patients with hypertrophic cardiomyopathy (HC). This study found no significant difference between verapamil and placebo in measures of blood flow in the interventricular septum or left ventricular free wall.
Area of Science:
- Cardiology
- Cardiovascular Imaging
- Pharmacology
Background:
- Angina is common in hypertrophic cardiomyopathy (HC) patients, even with normal coronary arteries.
- Verapamil may improve silent myocardial perfusion defects in HC patients.
Purpose of the Study:
- To assess verapamil's effect on absolute regional myocardial blood flow and flow reserve in HC patients.
- Utilized positron emission tomography (PET) for precise blood flow measurements.
Main Methods:
- 20 HC patients underwent PET scans at rest and after dipyridamole infusion.
- Patients were randomized to slow-release verapamil (240 mg daily) or placebo for 8 weeks.
- Echocardiography and exercise stress testing were also performed.
Main Results:
- No significant differences in resting or post-dipyridamole myocardial blood flow were observed between the verapamil and placebo groups.
- Resting and stress blood flow in the interventricular septum and left ventricular free wall showed no significant changes from baseline or between groups.
- p-values indicated no statistically significant differences for any measured blood flow parameters.
Conclusions:
- Verapamil, at the tested dosage and duration, did not significantly alter absolute regional myocardial blood flow or flow reserve in patients with hypertrophic cardiomyopathy.
- Further research may be needed to explore other therapeutic strategies or dosages for managing myocardial perfusion abnormalities in HC.
Abstract:
Angina, despite angiographically normal coronary arteries, is a common symptom in patients with hypertrophic cardiomyopathy (HC). Verapamil has been shown to ameliorate silent myocardial perfusion defects documented by thallium-201 in patients with HC. The aim of this study was to investigate the effects of verapamil on absolute regional myocardial blood flow and flow reserve, measured by positron emission tomography (PET) in patients with HC. Echocardiography, exercise stress testing, and measurements of myocardial blood flow at rest and after administration of intravenous dipyridamole (0.56 mg/kg) were undertaken in 20 patients with HC at baseline study and 8 +/- 2 weeks after double-blind randomization to either slow-release verapamil 240 mg or placebo once daily. During treatment, resting myocardial blood flow in the interventricular septum was 0.81 +/- 0.23 versus 0.96 +/- 0.42 ml/min/g in the placebo and verapamil group, respectively (p = NS between groups and when compared with respective baseline study); resting myocardial blood flow in the left ventricular free wall was 0.67 +/- 0.17 versus 0.74 +/- 0.45 ml/min/g, respectively (p = NS). After dipyridamole infusion, myocardial blood flow in the interventricular septum was 1.42 +/- 0.52 versus 1.92 +/- 1.23 ml/min/g (p = NS between groups and when compared with respective baseline study); myocardial blood flow in the left ventricular free wall was 1.25 +/- 0.41 versus 1.68 +/- 1.37 ml/min/g, respectively (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)