Relation between apex cardiographic and internal indices of left ventricular relaxation in man.

Abstract

In 19 patients the left apex cardiogram was recorded by a transducer with infinite time constant; at the same time left ventricular (tip manometer) and aortic pressures were recorded during cardiac catheterisation. The relation between two relaxation time intervals in the apex cardiogram and haemodynamic as well as angiocardiographic indices ofleft ventricular performance were studied. These apex cardiographic time intervals were: (1) the timefrom the onset of the aortic component of the second heart sound (S2) in thephonocardio- gram to the negative peak of the first derivative (dA/dt) of the apex cardiogram, termed early apex cardio- graphic relaxation time, and (2) the timefrom S2 to the point where dA/dt after having reached its negative peak ascends to the zero line, termed total apex cardiographic relaxation time.