Miyai Nobuyuki, Kawasaki Tatsuya, Taniguchi Takuya, Kamitani Tadaaki, Kawasaki Shingo, Sugihara Hiroki
Department of Cardiology, Matsushita Memorial Hospital, Osaka.
J Cardiol. 2005 Oct;46(4):141-7.
Patients with hypertrophic cardiomyopathy (HCM) sometimes develop myocardial ischemia during exercise in the absence of coronary lesions. The relationship between myocardial ischemia and ST-segment depression was investigated during exercise testing in patients with HCM.
Regional hypoperfusion and/or transient left ventricular cavity dilation, a parameter of subendocardial hypoperfusion, were assessed on exercise 99mTc-tetrofosmin myocardial scintigraphy in 42 patients with non-obstructive HCM. The scintigraphic results were further correlated with the ST-segment responses to exercise.
Regional hypoperfusion or transient left ventricular cavity dilation were observed in 19 (45%) or 16(38%)patients with HCM, respectively. The incidence of ST-segment depression > or = 0.1 mV during exercise testing was similar in HCM patients with regional hypoperfusion, with transient left ventricular cavity dilation, and without hypoperfusion (42%, 38%, 38%, p = 0.95). Furthermore, exercise-induced ST-segment depression > or = 0.1 mV occurred similarly irrespective of symptoms, exercise tolerance, the degree or the site of hypertrophy, or the presence or absence of resting ST-segment depression.
ST-segment depression during exercise testing was common in patients with HCM, but seems to be an unreliable marker of myocardial ischemia as assessed by exercise scintigraphy.
