Verapamil improves the pacing-induced vasodilatation in symptomatic patients with hypertrophic cardiomyopathy.
The purpose of the study was to assess the effect of verapamil on the response of diastolic coronary flow velocity and coronary vascular resistance to pacing in symptomatic patients with hypertrophic cardiomyopathy. In 14 patients with hypertrophic cardiomyopathy, the coronary flow velocity was detected in the left anterior descending coronary artery using transthoracic Doppler echocardiography. The peak diastolic coronary flow velocity and coronary vascular resistance was measured at baseline and during pacing. Changes of these parameters induced by the pacing (expressed as the percentage of baseline values) were compared on verapamil treatment and after verapamil withdrawal. The same measurements were obtained in ten control subjects. The results show that, in hypertrophic cardiomyopathy patients, increase in coronary flow velocity during pacing was significantly higher on than off verapamil therapy (64.8+/-32.5 vs. 41.1+/-21.3%, P<0.05). In control subjects, pacing-induced increase in coronary flow velocity was comparable to changes in coronary flow velocity in hypertrophic cardiomyopathy patients receiving verapamil (80.2+/-18.4 vs. 64.8+/-32.5%, P>0.05). After verapamil withdrawal in hypertrophic cardiomyopathy patients, coronary flow velocity increase during pacing was significantly lower than in control subjects (41.1+/-21.3 vs. 80.2+/-18.4%, P<0.05). During pacing the coronary vascular resistance decreased more on verapamil than after drug withdrawal (-34.7+/-11.7 vs. -24.6+/-12.9%, P<0.05). In control subjects the coronary vascular resistance decreased during pacing -38.6+/-6.3% to similar extent as in hypertrophic cardiomyopathy patients on verapamil. We can conclude that endothelium-dependent vasodilatation during pacing was impaired in symptomatic patients with hypertrophic cardiomyopathy. Verapamil treatment was able to restore adequate vasodilator response to pacing stress.
Dimitrow
Paweł Petkow
PP
Institute of Cardiology, Jagiellonian University School of Medicine, ul. Kopernika 17, 31-501 Kraków, Poland. dimitrow@mp.pl
Krzanowski
Marek
M
Grodecki
Janusz
J
Małecka
Barbara
B
Lelakowski
Jacek
J
Kawecka-Jaszcz
Kalina
K
Szczeklik
Andrzej
A
Dubiel
Jacek S
JS
D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects; D002304:Cardiac Pacing, Artificial; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications* / Q000188:drug therapy* / Q000503:physiopathology; D003326:Coronary Circulation / Q000187:drug effects* / Q000502:physiology; D003971:Diastole; D015150:Echocardiography, Doppler; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D013599:Systole; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology / Q000627:therapeutic use*; D014700:Verapamil / Q000494:pharmacology / Q000627:therapeutic use*
D014665:Vasodilator Agents; D014700:Verapamil