摘要
背景:典型的心电图(ECG)劳损图形[V5和(或)V6导联劳损改变]与左室肥厚(LVH)和左室(LV)舒张功能障碍有关,但其是否与左室舒张功能障碍独立相关尚不明确。方法:LIFE研究纳入心电图提示有LVH的高血压患者,其中10%进行了多普勒超声心动图检查。检查左室舒张功能的指标包括:二尖瓣E波、A波峰流速及E/A比值;E波减速时间(EDT);心房充盈分数(AFF);等容舒张时间(IVRT)。
BACKGROUND: Whether the typical electrocardiographic(ECG) strain pattern(Strain, in leads V5 and/or V6), which is associated with left ventricular hypertrophy(LVH) and LV systolic dysfunction, is independently associated with LV diastolic dysfunction is unknown. METHODS: The Losartan Intervention For Endpoint reduction in hypertension(LIFE)study enrolled hypertensive patients with ECG-LVH, of whom 10%underwent Doppler echocardiography. LV diastolic function measures included peak mitral E and A wave velocities and their ratio(E/A); E wave deceleration time(EDT); atrial filling fraction(AFF); and isovolumic relaxation time(IVRT). Normal filling pattern was defined by E/A< 1 with EDT ≥150 and ≤250 ms and IVRT ≤100 and ≥60 ms; abnormal relaxation by E/A<1 with EDT>250 ms or IVRT >100 ms; pseudonormal filling pattern by E/A≥1 associated with IVRT >100 ms or EDT >250 ms; restrictive pattern by E/A ≥1 with IVRT< 100 ms and EDT< 250 ms. A combined index of LV systolicdiastolic function was also computed(isovolumic time/ejection time, modified myocardial performance index). Of LIFE echo substudy participants with all needed ECG and Doppler data(n=791), 110(14%) had Strain. RESULTS: Strain was associated with male gender, African-American race, diabetes, history of coronary heart disease(CHD), higher systolic blood pressure(BP), LV mass and relative wall thickness, and higher prevalences of echo-LV hypertrophy and wall motion abnormalities, and with slower heart rate(all P< 0.05). Age, diastolic BP and LV ejection fraction were similar in patients with or without Strain. Diastolic parameters, and prevalences of different LV filling patterns, did not differ significantly between patients with versus those without Strain(all P >0.1), but modified myocardial performance index was higher with Strain(P< 0.05). Findings were consistent in multivariate analyses. The association of Strain with higher modified myocardial performance index was no longer statistically significant after accounting for LV systolic function and wall motion abnormalities. CONCLUSIONS: In hypertensive patients with ECG-LVH, the ECG Strain pattern did not identify independently those with more severe LV diastolic abnormalities.
