Septal Q wave as a marker of septal ischemia in hypertrophic cardiomyopathy.
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.


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 V(5) and V(6) 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.
Akakabe
Yoshiki
Y
Department of Cardiology, Matsushita Memorial Hospital, 5-55 Sotojima, Moriguchi 570-8540, Japan. akakabe.yoshiki@panasonic.com
Kawasaki
Tatsuya
T
Yamano
Michiyo
M
Miki
Shigeyuki
S
Kamitani
Tadaaki
T
Kuribayashi
Toshiro
T
Matsubara
Hiroaki
H
Sugihara
Hiroki
H
D000368:Aged; D015415:Biomarkers; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis*; D004562:Electrocardiography / Q000379:methods*; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006346:Heart Septum; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D015415:Biomarkers