mall Q waves in the left lateral leads are often termed as septal q waves, which are considered to reflect the rightward-directed depolarization through the ventricular septum. 1,2 The response of the septal q wave to exercise has been reported to be a reliable sign of septal ischemia in patients with coronary artery disease. 3,4 Patients with hypertrophic cardiomyopathy (HCM) sometimes develop septal ischemia in the absence of coronary stenosis, but little data are available concerning the

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... ciation of the septal q wave response with septal ischemia. 5-7 Thus, we examined the response of the septal q wave to septal ischemia on a short-and long-term basis in patients with HCM. Methods This retrospective study consisted of 29 HCM patients with asymmetric septal hypertrophy referred to the Matsushita Memorial Hospital (22 men and 7 women; age 56±10 years). The diagnosis of HCM was based on echocardiographic demonstration of ventricular septal hypertrophy with an end-diastolic thickness ≥15 mm and a nondilated left ventricle with an end-diastolic diameter ≤55 mm Background Small Q waves in the left lateral leads are termed septal q waves, and their response to exercise has been reported to be a marker of septal ischemia in coronary artery disease. Patients with hypertrophic cardiomyopathy (HCM) sometimes develop septal ischemia in the absence of coronary stenosis, but little data are available concerning the association of the septal q wave response with septal ischemia. Methods and Results Exercise electrocardiography and Tc-99m-tetrofosmin myocardial scintigraphy were recorded to detect myocardial ischemia in 29 HCM patients with asymmetric septal hypertrophy. The septal q wave amplitude was summed up in V5 and V6 during exercise testing, and the results were correlated with septal ischemia defined as a regional septal ischemia or a part of diffuse subendocardial ischemia. A decrease in the sum of the septal q wave amplitude during exercise testing yielded a sensitivity of 100% and specificity 33% for regional septal ischemia, and a sensitivity of 100% and specificity of 43% for diffuse subendocardial ischemia, although an absent septal q wave at rest provided a low sensitivity for the detection of regional septal ischemia (43%) and diffuse subendocardial ischemia (33%). Conclusions The septal q wave response to exercise is a useful marker of septal ischemia in HCM with asymmetric septal hypertrophy. (Circ J 2008; 72: 953 -957)