Postextrasystolic changes in systolic time intervals in the assessment of hypertrophic cardiomyopathy.

To determine if postextrasystolic changes in systolic time intervals can be used to estimate the severity of resting or provocable left ventricular outflow pressure gradient, we studied the cardiac catheterisation records of 42 patients with hypertrophic cardiomyopathy looking for instances of a single premature beat preceded by a control sinus beat and followed by a postpremature sinus beat. There were 75 such instances in 25 patients. In comparison to the control beat, the pre-ejection period in the postpremature beat was shorter by deltaPEP = -20 +/- 11 ms in 73 of 75 instances, and remained unchanged in two. The ejection time in the postpremature beat was invariably longer by deltaET = 37 +/- 20 ms (range: 10 to 85 ms) and the pre-ejection period/ejection time ratio lower than control by delta(PEP/ET) = -0 . 10 +/- 0 . 05 (range: -0 . 01 to -0 . 25). Total electromechanical systole in the postpremature beat was shorter (11/75), the same (10/75), or longer (53/75) than in the control beat, the overall change being deltaEMS = -18 +/- 22 ms. Both deltaPEP and delta(PEP/ET) correlated poorly with the systolic peak left ventricular-aortic pressure gradient in either the control beat (Gc) or the postpremature beat (Gx), and also with the change in gradient (delta G) from the control to the postpremature beat. In contrast, significant linear correlations were found between delta EMS and either Gc, Gx, or delta G; and also between deltaET and either Gc, Gx, or deltaG. Since internal and external measurements of ejection time are known to be almost identical, the regression equation (deltaG = 1 . 65 delgaET -9) relating deltaET and deltaG should be useful for the non-invasive assessment of the magnitude of provocable left ventricular outflow pressure gradient in patients with hypertrophic cardiomyopathy with spontaneous or externally-induced premature beats.

End-diastolic amplitude of mitral valve echogram in mitral stenosis.

By using simultaneous recordings of the mitral valve echogram and apex cardiogram, the mitral echogram amplitude was measured at the onset of left ventricular isovolumic contraction (MAIC). Twenty normal subjects and 68 patients with a reduced diastolic closure rate in the mitral valve echogram were studied. Of these patients, 53 had mitral stenosis, 6 aortic valvar stenosis, and 9 hypertrophic obstructive cardiomyopathy. In the normal subjects the MAIC ranged between 2 and 4 mm, average 2-7 mm, in the patients with aortic valvar stenosis or hypertrophic obstructive cardiomyopathy between 2 and 4 mm, average 2-9 mm, and in the patients with mitral stenosis between 6 and 17 mm, average 11-3 mm. The DE/MAIC ratio, where DE represents the opening amplitude of the mitral valve in early diastole, was between 3-3 and 6-5, average 5-1, in normal subjects; in the patients with aortic stenosis or hypertrophic obstructive cardiomyopathy the DE/MAIC ratio was between 2-7 and 6-5, average 4-2, and in the patients with mitral stenosis between 0-7 and 1-5, average 1-1. An excellent correlation was found between the DE/MAIC ratio and mitral valve area in the patients with mitral stenosis (r = 0-84, P less than 0-01) while the correlation between the diastolic closure rate and valve area was less satisfactory (4 = 0-62, P less than 0-01). These findings suggest that in cases with a reduced diastolic closure rate for reasons other than mitral stenosis, error can be avoided by using the DE/MAIC ratio.