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ȣ - 480677 170 |
| Tissue Doppler derived indices predict exercise capacity in patients with apical hypertrophic cardiomyopathy |
| Yonsei University College of Medicine |
| Jong-Won Ha, Namsik Chung, MD, PhD, Jeong-Ah Ahn, RN, Jin-Mi Kim, RN, Seok-Min Kang, MD, PhD, Se-Joong Rim, MD, PhD, Yangsoo Jang, MD, PhD, Won-Heum Shim, MD, PhD, Seung-Yun Cho, MD, PhD. |
BACKGROUND: Apical hypertrophic cardiomyopathy (ApHCM) is a unique form of hypertrophic cardiomyopathy, in which the hypertrophy of myocardium predominantly involves the apex of the left ventricle (LV). Although impaired LV diastolic function is a prominent feature of hypertrophic cardiomyopathy, diastolic function and its relation to exercise capacity in apHCM has not been explored previously. This study was sought to determine the relationship between diastolic annular velocities combined with conventional Doppler indices and exercise capacity in patients with ApHCM. METHODS: Twenty-nine patients with apHCM (24 male, mean age, 57+/-10) underwent supine bicycle exercise with simultaneous respiratory gas analysis and two-dimensional and Doppler echocardiographic study at the same time. The mitral inflow velocities were traced and the following variables were derived: peak velocity of early (E) and late (A) filling and deceleration time (DT) of E velocity. E' was measured at septal corner of mitral annulus by DTI from apical 4-chamber view. ProBNP was measured at the time of echocardiogram using a quantitative electrochemiluminescence immunoassay. RESULTS: E/E' correlated inversely with maximal oxygen uptake (VO2max) (r2 =0.22, p=0.011). There was significant positive correlation between E' and VO2max (r2 =0.17, p=0.024). However, no correlation was found between conventional two-dimensional, Doppler indices, and proBNP and exercise duration (E, r2 =0.03, p=0.4; E/A, r2 = 0.003, p=0.76; DT, r2 = 0.022, p=0.44; Left atrial volume index, r2 =0.004, p=0.75; proBNP, r2 =0.035, p=0.33). Of all the echo and clinical parameters assessed, E/E’ had the best correlation with exercise capacity (r2=0.22) and was the strongest independent predictor of VO2max by multivariate analysis (p=0.01). CONCLUSION: Conventional transmitral inflow Doppler, two-dimensional echocardiographic measures and proBNP are limited in predicting exercise capacity in patients with apHCM. DTI derived indices (E’, E/E’), an estimate of myocardial relaxation and LV filling pressures, correlate with exercise capacity in patients with apHCM, suggesting that abnormal diastolic function is an important factor limiting exercise capacity.
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