Noninvasive detection of coronary artery disease by assessing diastolic abnormalities during low isometric exercise

The handgrip-apexcardiographic test (HAT) is a simple low-level (40% of maximal voluntary handgrip during 2 min) stress test which can detect left ventricular (LV) diastolic abnormalities. To determine whether it contributes to the diagnosis of coronary artery disease (CAD), HAT was obtained in 68 patients--47 with and 21 without angina pectoris--who prospectively underwent coronary arteriography. According to the highest or lowest individual values of diastolic apexcardiographic indices in 255 healthy volunteers, a pathologic or positive HAT was defined by the presence of at least one of the following new criteria: (1) A wave relative to total height of apexcardiogram during and/or after handgrip > 21%, (2) total apexcardiographic relaxation time (TART) during handgrip > TART at rest > 143 ms and/or TART corrected for the duration of diastole (TARTI) during handgrip < 0.14, or (3) diastolic amplitude time index (DATI), given by dividing TARTI and A wave relative to total diastolic amplitude of apex tracing during handgrip < 0.27. HAT was positive in 20 of 21 patients with single-vessel disease (sensitivity 95%), 21 of 24 patients with double-vessel disease (sensitivity 88%), and in 22 of 23 patients with triple-vessel disease (sensitivity 96%). Furthermore, HAT was positive in 20 of 21 (95%) patients without symptoms. Thus, the overall sensitivity of HAT for detecting CAD was 93%. This study is the first to demonstrate the high sensitivity of HAT in identifying patients with CAD with or without symptoms by assessing diastolic apexcardiographic abnormalities during low-level isometric stress. Thus, HAT potentially could become an additional simple diagnostic tool for noninvasive detection of patients with CAD.