INFLUENCE OF LEFT-VENTRICULAR HYPERTROPHY ON DETECTION OF CORONARY-ARTERY DISEASE USING EXERCISE ECHOCARDIOGRAPHY

Objectives. This study examined the influence of left ventricular hype rtrophy on the accuracy of exercise electrocardiography and echocardio graphy for detection of coronary artery disease. Background. Electroca rdiographic repolarization abnormalities caused by left ventricular hy pertrophy compromise the diagnostic accuracy of exercise electrocardio graphy but not of exercise echocardiography. The relative merits of th ese investigations are less well defined in patients with hypertrophy but without electrocardiographic (EGG) changes. Methods. We prospectiv ely evaluated 147 consecutive patients without prior myocardial infarc tion undergoing both exercise echocardiography and coronary arteriogra phy. Coronary stenoses >50% diameter were present in 62 patients (42%) . Positive test results were defined by a new or worsening nail motion abnormality or >0.1 mV of ST depression. Echocardiographic left ventr icular hypertrophy (mass >131 g/m(2) in men, >100 g/m(2) in women) was identified in 68 patients. A subgroup with clinically suspected hyper trophy was defined according to the presence of ECG evidence of hypert rophy, hypertension or aortic stenosis. Results. The overall sensitivi ty of exercise echocardiography exceeded that of exercise electrocardi ography (71% vs. 54%, p = 0.06). Echocardiographic hypertrophy had no significant effect on the sensitivity of either test. The specificity of exercise echo cardiography exceeded that of exercise electrocardiog raphy (91 vs. 74%, p = 0.01). In patients with hypertrophy, the specif icity of exercise echocardiography exceeded that of exercise electroca rdiography (95% vs. 69%, p < 0.01), whereas among patients without hyp ertrophy, the specificities (respectively, 87% and 78%) were more comp arable. The accuracy of exercise echocardiography exceeded that of the exercise ECG in the overall group (82% vs. 65%, p = 0.002) and in pat ients with hypertrophy (85% vs. 60%, p = 0.004), but this difference w as less prominent in patients without hypertrophy (80% vs. 69%, p = NS ). In patients with clinically suspected hypertrophy, exercise echocar diography demonstrated a higher sensitivity, specificity and accuracy than exercise electrocardiography. The cost incurred in the identifica tion of coronary disease was least with a strategy involving use of th e exercise echocardiogram instead of routine exercise testing in patie nts with known or clinically suspected left ventricular hypertrophy. C onclusions. Exercise echocardiography is more accurate than exercise e lectrocardiography for the detection of coronary artery disease in pat ients with known or clinically suspected left ventricular hypertrophy.