Left ventricular hypertrophy. Relation of structure to diastolic function in hypertension

Early diastolic time intervals during hypertensive pregnancy

Early diastolic time intervals have been assessed by means of the echopolycardiographic method in 17 pregnant women who developed hypertension during pregnancy (HP) and in 14 normal pregnant women (N). Systolic time intervals (STI), stroke volume (SV), ejection fraction (EF), and mean velocity of myocardial fiber shortening (VCF) were also evaluated. Recordings were performed in the left lateral decubitus (LLD) and then in the supine decubitus (SD). In LLD, isovolumic relaxation period (IRP) was prolonged in the hypertensive pregnant women compared with normal pregnant women (HP 51 +/- 12.5 ms, N 32.4 +/- 15 ms p less than 0.05), whereas time of the mitral valve maximum opening (DE) was not different in the groups. There was no difference in SV, EF, and mean VCF, whereas STI showed only a significant (p less than 0.05) lengthening of pre-ejection period (PEP) in HP. When the subjects shifted from the left lateral to the supine decubitus position, left ventricular ejection time index (LVETi) and SV decreased significantly (p less than 0.05) in both normotensive hypertensive pregnant women. IRP and PEP lengthened significantly (p less than 0.05) only in normals, whereas they were unchanged in HP. DE time did not vary in either group. In conclusion, hypertension superimposed on pregnancy induces lengthening of IRP, as well as of PEP, and minimizes the effects of the postural changes in preload on the above-mentioned time intervals.

Systemic and pulmonary hemodynamic responses to nicardipine during graded ergometric exercise in patients with moderate to severe essential hypertension

In 10 patients with moderate to severe hypertension, the hemodynamic effects of ergometric exercise and nicardipine, a dihydropyridine calcium channel antagonist, were characterized under basal conditions and after 1 week of therapy. The responses of plasma renin activity and catecholamines were also assessed. Nicardipine induced significant reductions of systolic, diastolic and mean blood pressure under conditions of rest and peak exercise (p less than 0.001), mediated by reversal of vasoconstriction (p less than 0.001). Overall, cardiac index and stroke volume index responses were not significantly altered by nicardipine. Although rest pulmonary wedge pressure was unchanged (6 +/- 3 to 5 +/- 4 mm Hg), peak exercise pulmonary wedge pressure decreased from 24 +/- 22 to 7 +/- 5 mm Hg (p less than 0.001) with nicardipine therapy. This effect of nicardipine on pulmonary wedge pressure was present across all work loads studied, and was accompanied by reduction of peak exercise pulmonary artery pressure from 43 +/- 10 to 25 +/- 7 mm Hg (p less than 0.001). Oxygen consumption was unchanged, associated with reduction of arteriovenous oxygen difference (p less than 0.02). Both plasma renin activity (p less than 0.05) and norepinephrine (p less than 0.005) were significantly increased with nicardipine therapy. Thus, nicardipine produced significant blood pressure reduction by reversal of vasoconstriction in patients with essential hypertension. The preservation of cardiac output, with markedly reduced pulmonary wedge pressure, indicated that nicardipine improved ventricular performance in response to reversal of vasoconstriction.

Respiratory modulation of cardiac time intervals

To determine the effect of respiration on systolic and diastolic time intervals, simultaneous phonocardiograms, carotid pulse tracings, M mode echocardiograms, and respiratory curve tracings were measured in 25 healthy subjects. The positioning of each cardiac cycle in relation to the phase of respiration was assessed and the dependency of heart rate and cardiac time intervals on respiration was examined. Heart rate clearly varied over the respiratory cycle. Where necessary the time intervals were corrected for heart rate or RR interval. The systolic time intervals showed a stronger dependency on respiratory group than the diastolic time intervals. The decrease in left ventricular ejection time and increase in pre-ejection period and isovolumic contraction time during inspiration support the idea that a relative increase in afterload in inspiration determines left ventricular systolic function. Isovolumic relaxation time also showed cyclic behaviour whereas the left ventricular filling time was affected by inspiration only. Filling time increased significantly when there was a transition from expiration to inspiration during left ventricular ejection. It seems that when isovolumic contraction takes place in expiration the diastolic intervals of this cycle take on an expiratory character. The increase in filling can be viewed as a compensatory effect that partly offsets the loss of stroke volume during inspiration.

Effects of intravenous verapamil administration on left ventricular diastolic function in systemic hypertension

The effects of intravenous verapamil administration (0.1 mg/kg as a bolus followed by an infusion of 0.007 mg/kg/min) were studied using high-temporal-resolution radionuclide angiography in 27 patients with hypertension. Verapamil administration increased heart rate from 69 +/- 11 to 75 +/- 12 beats/min (p less than 0.001) and decreased systolic, diastolic and mean blood pressures (BPs) from 155 +/- 21/102 +/- 12 mm Hg (mean 119 +/- 14) to 142 +/- 19/95 +/- 12 mm Hg (mean 109 +/- 13) (p less than 0.001 for all). Ejection fraction decreased significantly (from 65 +/- 10% to 60 +/- 11%, p less than 0.005); peak filling rate, however, increased significantly only in patients in whom it was subnormal in the basal study (from 2.2 +/- 0.4 to 3.0 +/- 0.6 end-diastolic counts/s, p less than 0.001). These latter patients had significantly higher values of left ventricular (LV) mass index than patients with normal or increased peak filling rate (129 +/- 22 vs 112 +/- 22 g/m2, respectively, p less than 0.05). The isovolumic relaxation period changes were inversely related to the baseline values (r = 0.83, p less than 0.001). In the subgroup of patients in whom isovolumic relaxation period lengthened, time to end systole decreased (from 360 +/- 31 to 329 +/- 30 ms, p less than 0.025) and time to onset of rapid filling increased (from 420 +/- 31 to 451 +/- 34 ms, p less than 0.025), whereas these 2 intervals had opposite patterns in patients in whom isovolumic relaxation period decreased or did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular filling in endurance-trained subjects

Whether exercise-induced increases in left ventricular mass can alter left ventricular diastolic function was evaluated by measuring transmitral flow velocities at rest by Doppler echocardiography in 15 amateur endurance-trained runners and 15 age- and sex-matched sedentary control subjects. Ventricular mass index, end-diastolic volume index and stroke volume index were derived from measurements of M-mode echocardiograms recorded under two-dimensional guidance. All three variables were increased in the runners (p less than 0.01). These findings, plus the lower heart rate at rest (p less than 0.001), were consistent with endurance training. Although the runners had an almost twofold greater myocardial mass index, their peak early diastolic filling velocity and time to peak filling velocity did not differ from those of the sedentary subjects. In runners, the peak filling velocity with atrial systole tended to be lower (p = 0.12), the ratio of peak filling velocity with atrial systole to that of early diastole was less (p less than 0.05) and the percent of stroke volume contributed by atrial systole was less (p less than 0.001). These differences in atrial filling may be related to the lower heart rates at rest in runners. In summary, significant increases in left ventricular mass, when associated with endurance training, do not alter the early diastolic filling of the left ventricle.

Noninvasive evaluation of systolic and diastolic function in severe congestive heart failure secondary to coronary artery disease or idiopathic dilated cardiomyopathy

The usefulness of systolic time intervals, diastolic time intervals and echocardiography in evaluating left ventricular (LV) function was determined in 69 patients with severe congestive heart failure. All systolic time intervals were markedly abnormal (preejection period/LV ejection time 0.59 +/- 0.18 vs 0.30 +/- 0.04, preejection period index 170 +/- 37 vs 117 +/- 11, LV ejection time index 372 +/- 26 vs 410 +/- 17; patients vs control subjects, p less than 0.05). Diastolic time intervals in patients were not different from those in control subjects. Echocardiographic measurements were all markedly abnormal (LV end-diastolic dimension 6.9 +/- 1.0 vs 4.8 +/- 0.4 cm, patients vs control subjects, p less than 0.05). No pattern of abnormalities distinguished ischemic cardiomyopathies from idiopathic dilated cardiomyopathies. The presence of LV conduction delay did not substantially alter results, except that exclusion of patients with LV conduction delay normalized the total time of systole (QA2) index (from 542 +/- 40 to 531 +/- 31 ms) and reduced but did not normalize prolongation in the preejection period index (from 170 +/- 37 to 162 +/- 29 ms). No systolic or diastolic interval strongly correlated with any hemodynamic or other independent measure of LV performance. Twenty-four patients were given inotropic or unloading agents, which significantly improved hemodynamic values. Systolic and diastolic intervals were measured at baseline and at maximal hemodynamic effect. The correlation of changes in hemodynamics with changes in systolic and diastolic intervals was only modest. Thus, although systolic time intervals and associated echocardiographic measurements can detect abnormal LV function, they cannot reliably detect a change in LV function or distinguish gradations of abnormality.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular diastolic function in elite athletes with physiologic cardiac hypertrophy

Left ventricular hypertrophy due to aortic stenosis, hypertension and other forms of heart disease is associated with abnormalities of diastolic function. It is uncertain whether these changes are an inherent consequence of the hypertrophic process or represent additional pathologic factors. To investigate this issue, echocardiographic indexes of left ventricular early diastolic function in highly trained athletes were compared with those in age-matched normal control subjects. Athletes were equally classified into two groups: 11 swimmers who had a pattern of myocardial hypertrophy with normal wall thickness to dimension ratio and 11 power lifters whose wall thickness to dimension ratio was increased. The peak rates of left ventricular dimension increase and wall thinning in swimmers and power lifters were greater than in control subjects despite significantly higher left ventricular wall thickness and left ventricular mass index in the athletes. This increase in diastolic function indexes was associated with greater ventricular size and systolic performance. Normalization of the peak rate of dimension increase for end-diastolic dimension and adjustment of the peak rate of wall thinning for the fractional systolic thickening resolved any differences between groups. Thus, after the effects of ventricular size and systolic function were taken into consideration, diastolic function was normal in these subjects with considerable physiologic hypertrophy. This is in contrast to the findings in patients with hypertrophy associated with left ventricular pressure or volume overload, and suggests that abnormalities of diastolic function seen in pathologic hypertrophy are due to factors other than cardiac hypertrophy itself.

Athletic dysrhythmias. A case report and review of the phenomenon of the 'athlete's heart'

A 36-year-old athlete was anaesthetised for a minor surgical procedure. His heart rate fell to 30 beats/minute during the operation, the electrocardiogram showed A-V junctional rhythm. Sinus rhythm of 58 beats/minute was restored by atropine 1.2 mg. His resting 12-lead electrocardiogram showed sinus bradycardia and features consistent with a diagnosis of 'athlete's heart'. A review is presented of the physiological and electrocardiographical features of this phenomenon. The current popularity of running as a leisure pursuit makes it important that anaesthetists recognise the peculiarities of the trained athletic heart.