R. Lorenzoni et al., SYNCOPE AND VENTRICULAR ARRHYTHMIAS IN HYPERTROPHIC CARDIOMYOPATHY ARE NOT RELATED TO THE DERANGEMENT OF CORONARY MICROVASCULAR FUNCTION, European heart journal, 18(12), 1997, pp. 1946-1950
Non-sustained ventricular tachycardia on Holter and syncope have been
considered risk factors for sudden death in hypertrophic cardiomyopath
y. Aims In these patients the coronary vasodilator reserve is impaired
despite normal coronaries, so we evaluated the correlation between th
e severity of coronary vasodilator reserve impairment and the occurren
ce of syncope and non-sustained ventricular tachycardia. Methods and R
esults Eighty-four patients with hypertrophic cardiomyopathy (62 males
, age 43 +/- 12 years) had a two-dimensional echocardiographic study a
nd a 48-h Holter. Myocardial blood flow was measured by positron emiss
ion tomography, at baseline and after dipyridamole, and the coronary v
asodilator reserve was computed as dipyridamole myocardial blood flow/
baseline myocardial blood flow. In 27 patients, subendocardial and sub
epicardial myocardial blood flow was measured in the septum and the su
bendocardial/subepicardial ratio was computed. Twenty of 84 patients h
ad at least one syncopal episode, and 26 had at least one run of non-s
ustained ventricular tachycardia on Holter. Baseline and dipyridamole
myocardial blood flow, coronary vasodilator reserve, and baseline and
dipyridamole subendocardial/subepicardial myocardial blood flow ratio
were similar in patients with and without syncope and with and without
non-sustained ventricular tachycardia on Holter. However, patients wi
th nonsustained- ventricular tachycardia had larger left ventricular e
nd-diastolic (47+/-6 vs 44+/-5 mm, P<0.05) and end-systolic diameters
(30 +/- 6 vs 27 +/- 4 mm, P<0.05). Conclusions (1) Coronary vasodilati
on is not more severely impaired in patients with hypertrophic cardiom
yopathy and syncope or non-sustained ventricular tachycardia. (2) The
left ventricle is more dilated in hypertrophic cardiomyopathy with non
-sustained ventricular tachycardia.