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 thephonocardiogram to the negative peak of the first derivative (dA/dt) of the apex cardiogram, termed early apex cardiographic 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.In 100 normal subjects early apex cardiographic relaxation time averaged 3±12 (+1 SD) ms and total apex cardiographic relaxation time was 93±16 ms. In 11 patients with non-obstructive cardiomyopathy and decreased left ventricular function early and total apex cardiographic relaxation times were significantly (P<0*001) prolonged (52+23 ms and 152±23ms, respectively), whereas in 8 patients without or with only minimal left ventricular pressure or volume overload they were within normal limits (-1 ± 8 ms and 94±9 ms, respectively).Thefollowing significant correlations were observed between early apex cardiographic relaxation time and internally measured indices of left ventricular performance: maximal rate ofpressurefall (min dP/dt) in the left ventricle (r=-0 87), velocity of lengthening of the contractile elements at minimum dP/dt (r=-0.83), and ejection fraction (r=-0-80); significant correlations with several other values of left ventricularfunction (end-diastolic pressure, maximal dP/dt, and peak measured velocity of shortening of the contractile elements) were also observed. In the totalgroup ofsubjects total apex cardiographic relaxation time correlated significantly with early apex cardiographic relaxation time (r= + 0.67); further, in the catheterised patients total apex cardiographic relaxation time showed less close correlation with the internal indices.The early and total relaxation time intervals in the left apex cardiogram are two important noninvasive methods for assessing left ventricular performance in man.

In conclusion, this study using external and internal transducers with similar characteristics gives a new definition of the time relation between the externally recorded apex cardiogram and the haemodynamic events within the left heart in human subjects with normal left ventricular function.

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Background: Previous clinical studies using invasive and noninvasive methods have shown handgrip‐induced diastolic abnormalities in patients with coronary artery disease (CAD). Hypothesis: The study was undertaken to determine the utility of Doppler echo‐ and pressocardiography during handgrip in discriminating patients with coronary artery disease (CAD) and in those with normal coronary arteries. Methods: Both methods were obtained in 96 patients with suspected CAD within 24 h before coronary angiography. An abnormal handgrip‐Doppler was defined by an early (E) to late (A) transmittal flow velocities ratio (E/A) < 1 during handgrip and a positive handgrip pressocardiographic test (HAT) by an abnormal increase in the A wave/total excursion or prolongation of the absolute or relative (heart‐rate corrected) total relaxation time during isometric exercise. Results: Of the 96 patients studied, 23 had normal coronary arteries and 73 showed CAD. In patients with normal coronary arteries, handgrip‐Doppler showed an abnormal average E/A at rest and during handgrip, whereas all variables of HAT were within normal limits. In patients with CAD, handgrip‐Doppler showed only a moderate handgrip‐induced increase in average A (+ 19%, p < 0.001), whereas HAT showed a significant (p < 0.001) increase in mean A wave/total excursion (+ 60%) and decrease in the relative total relaxation time (‐17%). Furthermore, handgrip‐Doppler and HAT were abnormal in 15 of 23 (65%, specificity 35%) and the HAT in 5 of 23 (22%, specificity 78%) patients with normal coronary arteries, as well as in 57 of 73 (sensitivity 78%) and 69 of 73 (95%) patients with CAD. Conclusions: Our study demonstrates that these noninvasive stress tests can become a useful new diagnostic modality for detecting patients with unknown or suspected CAD.

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