Ventricular Activation Time as a Marker for Diastolic Dysfunction in Early Hypertension

Abstract

A standard 12-lead electrocardiogram (ECG) is performed in all hypertensive patients, primarily to detect left ventricular hypertrophy. Echocardiographic assessment of hypertensive subjects reveals that abnormalities in diastolic function occur more commonly and earlier than increased left ventricular mass. However, ECG changes associated with diastolic dysfunction (DD) remain poorly defined; we assessed the ventricular activation time (VAT) (i.e., the time for the ventricle to depolarize) as a potential marker for DD in early hypertension. Ninety subjects (aged 46 +/- 1.3 years; 43 men) with newly diagnosed, untreated hypertension underwent ECG and comprehensive two-dimensional echocardiography. Left ventricular DD was echocardiographically assessed using Canadian Consensus Guidelines. We compared VAT, which corresponds to the QR interval in the 12-lead ECG, with echocardiographic parameters of DD. VAT was prolonged in subjects with DD (46.3 +/- 0.4 vs. 39.6 +/- 0.3 ms, P < 0.01). There was a significant correlation between VAT and tissue Doppler imaging (TDI) (early diastolic velocity) e' (r = -0.53, P < 0.0001), (ratio of early and late diastolic velocities) e'/a' (r = -0.53, P < 0.0001), transmitral Doppler (TMD) (early peak filling rate, and early deceleration peak) E/A (r = -0.32, P = 0.001), and (ratio of early diastolic mitral inflow and early diastolic velocities) E/e' (r = 0.44, P < 0.0001). Prolongation of the VAT is associated with DD in patients with newly diagnosed untreated hypertension.