The relation of heart rate and shortening fraction to echocardiographic indexes of left ventricular relaxation in normal subjects.

To determine the relation of heart rate and systolic function to echocardiographically derived indexes of left ventricular relaxation, M-mode echocardiograms of the left ventricle and mitral valve with a simultaneous phonocardiogram were recorded at rest from 28 normal men. The effects of altering the inotropic state and ventricular loading conditions were examined during isometric handgrip exercise and the Valsalva maneuver in a subset of 15 men. The left ventricular endocardial echocardiograms were digitized to provide a display of left ventricular internal dimension and its first derivative (dD/dt). The time course of relaxation, defined as the interval from left ventricular minimal systolic dimension to the point when the rate of change of dimension (dD/dt) decreased to 50% of peak, was directly related to the RR interval (r = 0.64, p less than 0.0001) in the entire group, and this relation remained throughout the interventions. The slopes of the regression lines of relaxation time (RT) and electromechanical systole (QS2) on the RR interval were similar. Diastolic time decreased proportionately more than relaxation time as the RR interval decreased, so that the proportion of diastole occupied by the relaxation time varied with cycle length. Peak diastolic dD/dt, normalized for variations in end-diastolic dimensions [( dD/dt]/D), was directly related to left ventricular shortening fraction (r = 0.71 p less than 0.0001) and this relation remained during isometric grip. There was no correlation between the heart rate at rest and (dD/dt)/D over the range of 44 to 99 beats/min.(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.

Prognostic value of dobutamine stress echocardiography in patients referred because of suspected coronary artery disease.

To determine whether dobutamine stress echocardiography (DSE) provides prognostic information beyond that available from routine clinical data, we reviewed the outcome of 210 consecutive patients referred for DSE to evaluate chest pain, perioperative risk, and myocardial viability. Dobutamine was infused in increments of 10 micrograms/kg/min in 5-minute stages to a maximum of 40 micrograms/kg/min. The dobutamine stress echocardiogram was considered abnormal only if dobutamine induced a new wall motion abnormality as determined by review of the digitized echocardiographic images in a quad screen format and on videotape. Thirty percent of tests were abnormal. An abnormal test was more common (p < or = 0.02) in men and patients with angina pectoris, in patients taking nitrate therapy, or those with prior myocardial infarction or abnormal left ventricular wall motion at rest. Twenty-two deaths, 17 of which were cardiac, occurred over a median follow-up of 240 days (range 30 to 760). Sixteen cardiac deaths occurred in the 63 patients with versus 1 cardiac death among the 147 without a new wall motion abnormality (p < or = 0.0001). Other variables associated with cardiac death (p < or = 0.05) were age > 65 years, nitrate therapy, ventricular ectopy during DSE, suspected angina pectoris, and hospitalization at the time of DSE. When cardiac death, myocardial infarction, and revascularization procedures were all considered as adverse outcomes, a new wall motion abnormality continued to be the most powerful predictor of an adverse cardiac event.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic sinotubular junction calcium as a marker of severe aortic atherosclerosis.

Because the significance of calcification of the sinotubular junction is poorly understood, we retrospectively investigated its association with aortic atherosclerosis in 101 patients who underwent transesophageal echocardiography. Such calcification was found to be a marker of more severe aortic atherosclerosis and, specifically, aortic arch disease.

Factors leading to progression of valvular aortic stenosis.

The rate of progression of aortic stenosis (AS) in adults is variable. To determine whether clinical or echocardiographic variables are associated with more rapid hemodynamic progression, we identified 91 AS patients (initial valve area < or = 2.0 cm2) with 2 technically adequate studies separated by > or = 6 months. From the first study, left ventricular dimensions and AS severity were measured by standard Doppler-echocardiographic methods. Each aortic valve was graded for severity of calcification and degree of restricted leaflet motion; the sum of these grades provided a severity index reflecting leaflet pathology. Clinical and electrocardiographic variables were abstracted from medical records. Mean age was 68 years (range 29 to 89) and 61 were women. Initial AS severity ranged from an aortic valve area of 0.6 to 2.0 cm2 (median 1.3 cm2). During a mean follow-up of 1.8 years the aortic valve area decreased 0.04 cm2/year. The patient group with more rapid progression (decrease in aortic valve area > or = 0.1 cm2/year) had a larger proportion of men (p <0.01) and patients with an elevated serum creatinine (p = 0.04), a higher left ventricular mass index (p = 0.01), and a higher severity index (p <0.001). Multivariable regression analysis identified the severity index (direct relation) and the initial aortic valve area (inverse relation) as the only independent variables associated with more rapid progression. In conclusion, the rate of AS progression, although highly variable, is more rapid when leaflet calcification is more marked.

Clinical impact of second harmonic imaging and left heart contrast in echocardiographic stress testing.

Second harmonic imaging and left heart contrast agents are recent echocardiographic advancements that enhance the assessment of wall motion. Because little information exists concerning their clinical impact on echocardiographic stress testing in daily practice, this was determined for 9-month periods before (1997) and after (1998) their introduction. Harmonic imaging was used in all patients after its introduction. A second generation intravenous left heart contrast agent (Optison) was used at the discretion of the sonographer and physician team. Both exercise and dobutamine stress tests were included. At the time of study interpretation, diagnostic confidence was assigned as high, medium, or low. For all patients who underwent coronary angiography < or = 6 months after stress testing, the diagnostic accuracy was determined (true positive plus true negative/total studies). There were 574 studies before and 746 studies after implementation. Optison was used in 28% of the harmonic imaging studies. Study cancellations due to uninterpretable images fell from 6.4% to 1.2% (p <0.001) despite a more obese population completing testing (body mass index: 29 +/- 7 to 31 +/- 8 kg/m2, p = 0.02), whereas high diagnostic confidence increased from 55% to 64% (p <0.001). For the 7% of patients who underwent cardiac catheterization, the diagnostic accuracy remained unchanged (74 vs 73%) although a prior negative stress test was less common (40% to 20% p = 0.04). Thus, these new technologies had a favorable clinical impact.

Left axis deviation: diagnostic contribution of stress testing and post-exercise systolic time intervals.

The response to graded submaximal upright bicycle ergometry combined with resting and postexercise systolic time intervals (STIs) was investigated in ten ambulatory subjects (study group) with normal electrocardiograms except for a frontal plane axis of greater than or equal to -30 degrees, or left axis deviation (LAD) mean -40 degrees); and eight age-matched volunteers (control group) with a normal ECG and frontal plane axis (mean +35 degrees). Following a 12-lead resting ECG, supine STIs were measured. The subjects then exercised on a bicycle ergometer at progressive workloads with ECG and blood pressure monitoring until a heart rate based on 85 percent of tha age-predicted maximum was attained or an abnormal end point was noted. STIs were repeated immediately postexercise. Prolongation of left ventricular ejection time corrected for heart rate (LVETc) of 8 msecs or more from rest to post-exercise. (deltaLVETc) was considered an abnormal STI response. The deltaLVETc can elicit left ventricular dysfunction and possible latent organic heart disease in patients with isolated left axis deviation.

Prolapsed mitral valve associated with the Holt-Oram syndrome.

The association of hypoplastic thumb and atrial septal defect, (Holt-Oram syndrome) with a prolapsed mitrial valve is described. Recognition of this association adds further support to the concept that the prolapsed mitrial valve syndrome is not necessarily an isolated cardiac disorder but may be part of a more generalized heritable disorder of connective tissue.

Multidisciplinary treatment of chronic pulmonary insufficiency. 3. The effect of physical training on cardiopulmonary performance in patients with chronic obstructive pulmonary disease.

We examined the effect of physical training on cardiopulmonary function in 21 patients with chronic obstructive pulmonary disease and compared the results with similar observations in eight untrained patients. The training consisted of daily walking on a treadmill at increasing speeds and grades and other graded physical exercises. Evaluation of pulmonary function, including spirometric studies, lung volumes, and arterial blood gas levels, showed no significant change after training. Hemodynamic functions, including heart rate, cardiac index, stroke index, pulmonary vascular resistance, and arteriovenous oxygen content difference, were similarly unchanged at comparable submaximal loads. Pulmonary arterial wedge pressure increased after training in the treated group at rest and during exercise, but this may be related to changes in respiratory mechanics. Consumption of oxygen and minute ventilation decreased in the treated group during treadmill exercise, suggesting improved neuromuscular coordination and efficiency of walking on the treadmill. Total work performed on the treadmill increased significantly in the trained group. This increase was unexplained by physiologic observations but was thought to be due in part to increased efficiency of walking and increased motivation. We conclude that improvement in the capacity for exercise following physical training for four weeks is not associated with improvement in cardiopulmonary function at submaximal exercise.

Multidisciplinary treatment of chronic pulmonary insufficiency. 4. The influence of intrathoracic pressure variations on increases in pulmonary vascular pressure during exercise in patients with chronic obstructive pulmonary disease.

In the present era of direct monitoring of pressure in patients with chronic obstructive pulmonary disease (COPD), an appreciation of all factors that may influence the observed pulmonary vascular pressures is essential. Our study examines the impact of respiratory variations in intrathoracic pressure on the recorded pulmonary vascular pressures in 28 patients with COPD. Althouth pulmonary hypertension was present in only nine subjects at rest, all had an abnormal increase in the mean pulmonary arterial pressure during supine exercise. In 15 subjects, this abnormal response was, in part, related to an increase in pulmonary arterial wedge pressure to 15 mm Hg or more. The increase in pulmonary arterial wedge pressure was directly related to the amplitude of the peak-to-peak respiratory variation of such wedge pressure. This variation correlated with the specific airway resistance but was not related to the arterial oxygen pressure or pulmonary vascular resistance. These findings indicate the important influence of exaggerated respiratory effort on the measurement of pulmonary arterial wedge pressure and mean pulmonary arterial pressure in patients with chronic obstructive pulmonary disease.

Vectorcardiographic detection of early hemodynamic abnormalities in chronic obstructive pulmonary disease.

The ability of the vectorcardiogram to detect mild circulatory abnormalities in patients with chronic obstructive pulmonary disease (COPD) is unclear. Therefore, vectorcardiographic changes were correlated with hemodynamic measurements made at rest and during supine exercise in 32 patients with COPD and no clinical or electrocardiographic evidence of right ventricular hypertrophy. Twelve patients had normal hemodynamic data (group 1), nine had abnormal hemodynamic data only during exercise (group 2), and 11 had abnormal hemodynamic data at rest and during exercise (group 3). The extent of rightward terminal QRS forces noted on the vectorcardiogram was significantly less in group 1 (5.5 +/- 8.7 percent) than in either group 2 (19.0 +/- 10.7 percent) or group 3 (17.8 +/- 14.8 percent). Sixty-five percent (13) of the 20 patients with hemodynamic abnormalities had rightward terminal QRS forces of 15 percent or more, whereas only 8 percent (one) of the 12 patients with normal hemodynamic data had such forces of 15 percent or more. The mean of the rightward terminal QRS forces in 27 age-matched normal subjects was 5.0 +/- 5.4 percent, and only one subject had forces of 15 percent or more. We conclude that hemodynamic abnormalities are frequent in patients with COPD and no clinical evidence of right ventricular hypertrophy and that the vectorcardiogram provides an indirect method of detecting these abnormalities.

Predicting left heart failure after a myocardial infarction: a preliminary study of the value of echocardiographic measures of left ventricular filling and wall motion.

Heart failure occurs from both systolic and diastolic dysfunction. To determine whether simple Doppler echocardiographic measures of left ventricular filling could improve upon the ability of systolic function to predict heart failure after infarction, patients with acute myocardial infarction were studied within the first 36 hours by Doppler and two-dimensional echocardiography. Forty-eight patients who did not have heart failure before the Doppler echocardiographic study and who did not have myocardial revascularization, moderate or severe mitral regurgitation, or other complications during recovery were monitored for 6 months or to the onset of heart failure (n = 10). The univariate predictors of heart failure were age (p less than 0.05), anterior infarction (p less than 0.05), early diastolic peak filling velocity (p = 0.05), filling velocity with atrial systole (p less than 0.05), the ratio of these velocities (p less than 0.001), the percentage of filling with atrial systole (p less than 0.001), and the wall motion score index (p less than 0.001). However, the only independent predictors of heart failure by use of multivariant stepwise logistic regression analysis were the wall motion score index (p less than 0.05) and either the ratio of early and late peak filling velocities (p less than 0.001) or the percentage of filling with atrial systole (p less than 0.001). The combined use of a measure of systolic function and measures of the relative contribution of atrial systole to ventricular filling were useful predictors in identifying patients likely to develop subsequent heart failure after myocardial infarction.

Alterations in cardiac diastolic function in patients with ankylosing spondylitis.

Ankylosing spondylitis is associated with a decreased survival that appears attributable to cardiovascular causes. To determine whether alterations in systolic or diastolic cardiac function precede overt cardiac disease, 20 ankylosing spondylitis patients without clinical evidence of cardiovascular disease and 25 healthy age and gender matched controls were studied by cross-sectional and Doppler echocardiography. Systolic function was assessed by wall motion analysis and ejection velocities. Diastolic function was measured by the peak velocity of early ventricular inflow, peak velocity in late diastole during atrial systole, the ratio of these velocities and the diastolic filling time. Atrial, ventricular and aortic dimensions were similar in patients and controls. Ejection indexes and systolic wall motion were normal in both groups. Diastolic function differed in patients as evidenced by a shorter diastolic filling period [405 +/- 68 ms vs 548 +/- 136 ms, p = 0.0001], a reduced velocity of early mitral inflow [0.55 +/- 0.09 m/s vs 0.63 +/- 0.11 m/s (p = 0.005)], and lower ratios of early/late inflow velocities [1.21 +/- 0.33 vs 1.60 +/- 0.35 (p = 0.0005) for mitral and 1.36 +/- 0.34 vs 1.71 +/- 0.42 (p = 0.016) for tricuspid]. These changes are consistent with impaired ventricular relaxation in some patients with ankylosing spondylitis.

Exercise performance in patients with hypertension. Relation to electrocardiographic criteria for left ventricular hypertrophy.

The influence of the electrocardiographic diagnosis of left ventricular hypertrophy on exercise performance was assessed in 101 hypertensive patients and 37 control subjects referred to an exercise testing laboratory. Maximal exercise capacity was measured by the duration of a symptom-limited, treadmill test using the modified Bruce protocol. The Romhilt-Estes point score system, as modified by Murphy, was used to define left ventricular hypertrophy by electrocardiographic criteria. After adjusting for age differences between hypertensive and control subjects, the hypertensive group without left ventricular hypertrophy had a shorter exercise duration than the control group (13.0 +/- 3.0 vs. 15.3 +/- 2.5 min, respectively; p less than 0.01). The 16 hypertensive patients with electrocardiographic evidence of hypertrophy had a shorter exercise duration than those without (10.9 +/- 2.0 vs. 13.0 +/- 3.0 min, respectively; p less than 0.01). Multivariate regression analysis indicated that age, gender, systolic blood pressure, and electrocardiographic point score were all significant independent variables in predicting exercise duration (R2 = 0.48, p less than 0.0001). Exercise duration was unrelated to QRS amplitude. The authors conclude that electrocardiographic evidence of left ventricular hypertrophy, as manifested by P wave and T wave abnormalities, is associated with an impaired exercise capacity in a hypertensive population without prior myocardial infarction.

Postexercise systolic time intervals in the midsystolic click syndrome.

Postexercise systolic time intervals (STI) were measured in ten patients (PMV group) with auscultatory evidence of the midsystolic click syndrome (i.e. one or more systolic nonejection clicks alone or in association with the late systolic murmur), and compared to eight age-matched volunteers (control group) with no evidence of heart disease. Following measurement of supine STIs, the subjects pedalled an upright bicycle ergometer at progressive work loads until a target heart rate (HR) representing 85% of the age-adjusted maximum was attained, or an abnormal end point was noted. Immediately postexercise, a repeat measurement of STIs, was obtained. A shortened or unchanged postexercise left ventricular ejection time corrected for HR (deltaLVETc) and a marked shortening of total electromechanical systole after exercise (deltaQS2c) constituted a normal STI response to stress testing and was noted in all control subjects. All of the PMV group exhibited evidence of left ventricular dysfunction characterized by a prolonged deltaLVETc. It is concluded that an abnormal STI response to exercise consistent with left ventricular dysfunction can be demonstrated in patients with prolapse of the mitral valve by the response of the STI.