title: Clinical value of calibrated and differentiated displacement apexcardiography in ischemic heart disease.
abstract: The calibrated left apexcardiogram with time constant 4 s and its first derivative (dA/dt) has been evaluated in 62 patients with ischemic heart disease and in 50 normal subjects. The normalized positive peak of dA/dt (max dA/dt/Ad), the peak velocity of contractile element shortening (Vpm), the normalized negative peak of dA/dt (min dA/dt/Ar), and the time constant of myocardial relaxation T as well as the time interval from R wave of the electrocardiogram to the peak positive dA/dt (R-max dA/dt) and the total apexcardiographic relaxation time interval divided to mean arterial pressure (TRI) were measured. In patients with ischemic heart disease we found a decrease of max dA/dt/Ad, Vpm, min dA/dt/Ar and an elongation of T, R-max dA/dt, and TRI, when compared to controls. Various indexes for myocardial contraction and relaxation were calculated in 21 of the patients who underwent left ventricular catheterization and biplane angiography. These parameters were used as dependent variables in the multiple regression analysis. Apexcardiographic indexes were used as independent variables. The indexes Vpm, max dA/dt/Ad, min dA/dt/Ar, and T were significantly correlated with all analogous invasive indexes. It is concluded that calibrated and differentiated apexcardiography provides useful information on left ventricular contraction and relaxation.
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D002138:Calibration; D003327:Coronary Disease / Q000503:physiopathology*; D004285:Dogs; D005260:Female; D006334:Heart Function Tests; D006801:Humans; D007702:Kinetocardiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D005082:Physical Exertion