Isovolumic relaxation period in hypertrophic cardiomyopathy.

Previous reports have demonstrated that patients with hypertrophic cardiomyopathy have a prolonged isovolumic relaxation period as a result of a delay in mitral valve opening, reflecting a reduced rate of fall of left ventricular pressure. This period as measured from the aortic closure sound (A2 on phonocardiogram) to the opening of the mitral valve (on echocardiogram) was determined in 84 patients with hypertrophic cardiomyopathy and compared with findings in 31 normal volunteers. The duration of the isovolumic relaxation period in the 84 patients had a wide range from 0 to 160 ms (mean 71 +/- 32) that was not significantly different from that in normal subjects (63 +/- 11 ms). However, it was possible to identify a group of 15 patients with an extremely short isovolumic relaxation period, 2 standard deviations below the normal range. This shortening was due to a marked delay in aortic closure sound (A2) due to late left ventricular-aortic pressure crossover, as well as early opening of the mitral valve secondary to elevated left atrial pressure, which was confirmed by hemodynamic correlations and digitized echocardiographic data. In this subset of patients, A2 is a poor marker of the onset of rapid left ventricular pressure decline and, thus, the interval from A2 to mitral valve opening is not a valid reflection of left ventricular relaxation. It is concluded that in hypertrophic cardiomyopathy, both the timing and sequence of relaxation are abnormal, as is the rate of relaxation. Furthermore, the isovolumic relaxation period is multifactorially determined and depends not only on the rate of left ventricular pressure decline, but also on the magnitude of the pressure drop from A2 to mitral valve opening. All of these determinants must be kept in mind when the isovolumic relaxation period is used as a measure of left ventricular relaxation.

Echophonocardiographic estimates of pulmonary artery wedge pressure in mitral stenosis.

The efficacy of noninvasive indexes for predicting pulmonary artery wedge (PAW) pressure was reviewed in 77 patients with mitral stenosis. M-mode echocardiography and phonocardiography were used to measure the aortic valve closure-mitral valve E-point interval (A2-E) and the electrocardiographic Q wave-mitral valve closure interval (Q-C) close to the time of diagnostic cardiac catheterization. During catheterization, in 65 patients PAW pressure was measured and in 12 left atrial (LA) pressure was measured. The A2-E and Q-C intervals taken alone had only modest correlation with PAW pressure (r = -0.54 and r = 0.46, respectively). The correlation was weakest in patients with atrial fibrillation and best in sinus rhythm when heart rate variation between invasive and noninvasive studies was within +/- 5 beats. Substitution of V-wave pressure for mean PAW pressure and correction for variation in blood pressure improved the A2-E correlation (r = -0.64), as did combining the A2-E and Q-C intervals into a ratio [(Q-C)/(A2-E)] (r = 0.62). However, the best results were obtained in patients where LA pressure was measured directly (r = -0.91 for A2-E), suggesting the PAW pressure is not always an accurate reflection of LA pressure. In conclusion, many factors in addition to LA pressure affect the Q-C and A2-E intervals which, in many situations, decrease their predictive value. However, if used appropriately, these intervals may allow an estimation of PAW pressure.

The noninvasive assessment of pulmonary capillary wedge pressure in mitral regurgitation.

The interval between the aortic closure sound and the mitral opening snap (A2-OS) has been shown to have a significant inverse correlation with pulmonary capillary wedge pressure (PCW) in mitral stenosis. The present study critically examines the relationship of several noninvasively determined diastolic intervals to PCW in patients with relatively pure mitral regurgitation (MR). Fifty-seven patients with MR of diverse etiologies were studied with echocardiograms and phonocardiograms in addition to right and left heart catheterization. Noninvasive determination of the time intervals of aortic closure sound to mitral valve opening (A2-MO), mitral D point to E point (D-E), aortic closure sound to mitral E point (A2-E), the interval from the onset of the QRS to mitral closure (Q-C), and the ratio Q-C/A2-E were compared to invasive measurements of mean PCW, the height of the V wave of PCW (PCW-V), and the ratio of PCW-V to left ventricular (LV) peak systolic pressure (PCW-V/LV). Correlation between each of the five noninvasive intervals and each of the three invasive pressure measurements was then determined. Of the noninvasive intervals studied, A2-MO had the best inverse correlation with all measures of PCW. All 18 patients having a short A2-MO (less than 40 msec) had a PCW-V of greater than or equal to 40 mm Hg and all seven patients having a long A2-MO (greater than 85 msec) had a PCW-V of less than 22 mm Hg. A2-E also had a strong inverse correlation with PCW.(ABSTRACT TRUNCATED AT 250 WORDS)