Ventricular Ejection Rate Research Articles

Effect of habitual exercise on left ventricular response to exercise.

To evaluate the effects of chronic physical exercise on left ventricular ejection fraction (LVEF) and ejection rate (LVER), radionuclide angiography was performed at rest and during upright-bicycle exercise in 45 healthy men. The subjects varied widely in exercise habits and working capacity. They were divided into three subgroups on the basis of habitual physical activity. Aerobic training was done more than 7, 2-4, and less than 1 h/wk by subgroups of athletes, trained, and untrained men, respectively. The results indicate marked differences in work capacity (298, 233, and 181 W in the athletes, trained, and untrained groups, respectively). Resting LVEF (72, 69, and 68%) and LVER (4.1, 3.4, and 3.6 s-1) were not significantly different among the groups. With maximal exercise, however, small but statistically significant differences in LVEF (75, 69, and 68%; P less than 0.05 athletes vs. trained and athletes vs. untrained) and in LVER (7.5, 6.3, and 5.2 s-1; P less than 0.05 among all groups) were observed. Work capacity was, however, poorly correlated with exercise LVEF (r = 0.18) and LVER (r = 0.47). The results of this study indicate that the enhanced working capacity observed secondary to increases in habitual physical activity can be attributed to differences in LVEF and LVER only in the most general terms. Accordingly the results agree with previous suggestions based primarily on echocardiographic data that the primary cardiac adaptation to exercise is dimensional rather than functional in character.

Left ventricular function at rest, peak exercise and postexercise.

To determine whether the temporal sequence of imaging could influence the results of exercise radionuclide angiography, 15 healthy volunteers were studied at rest, during peak bicycle exercise and immediately postexercise using first pass radionuclide angiography. Responses at rest, peak and postexercise included: heart rate (67 to 174 to 170 bpm), double product (7.4 to 31.5 to 27.5 mm Hg X bpm X 10(3)), left ventricular ejection fraction (68 to 69 to 80%) and mean normalized left ventricular ejection rate (3.63 to 6.56 to 8.56 s-1). The results indicate that left ventricular ejection fraction and mean normalized ejection rate were different during exercise and immediately postexercise although heart rate and double product were not. The results indicate that the temporal sequence of imaging is a significant procedural variable in the conduct of exercise radionuclide angiography.

Left ventricular ejection rate during the first third of systole in patients with aortic insufficiency

Left ventricular ejection rate during the first third of systole in patients with aortic insufficiency

Hemodynamic correlates of autonomic reflexes in patients with labile and fixed hypertension.

the autonomic sympathetic reflexes to sustained handgrip, upright tilt and the Valsalva maneuver, were tested in 26 patients with labile and 26 with fixed essential hypertension. Sustained handgrip increased systolic (SAP), diastolic (DAP) and mean arterial (MAP) pressure, heart rate (HR), cardiac index (CI), tension time index (TTI) (p less than .01), and had no effect on total peripheral resistance index (TPRI) and left ventricular ejection rate index (LVERI) in both groups of patients. However, the response to upright tilt and the Valsalva maneuver was different in the two groups. Upright tilt in labile hypertensives increased DAP, MAP, HR, and TPRI (p less than .001); decreased CI, stroke index (SI) and LVERI (p less than .01) and had no effect on SAP. In fixed hypertensives, it decreased SAP, MAP, CI, SI and LVERI (p less than .001); increased HR (p less than .01) and had no effect on DAP, and TPRI. The diastolic pressure overshoot of the Valsalva maneuver was attenuated in fixed hypertensives compared to labile (p less then .001). Additionally, when the percent changes from control in DAP, MAP, HR and TPRI to sustained handgrip and upright tilt between the two groups were compared, only differences to upright tilt between the two groups were observed. The results of this investigation suggest that upright tilt and the Valsalva maneuver might serve as better predictors of autonomic reflexes in hypertensive patients than the grip test.

Comparison of multigated radionuclide angiography with ultrasonic sonomicrometry over a wide range of ventricular function in the conscious dog

This study compared the noninvasive assessment of left ventricular function with radionuclide angiography with that obtained with ultrasonic sonomicrometry. Left ventricular ejection fraction and rate of ventricular ejection (dV/dt) were measured with both techniques over a wide range of ventricular function. Six dogs were prepared with epicardlal crystals across the major and minor axes of the left ventricle, paired transmural wall thickness crystals and a left ventricular catheter. The animals were studied while awake after they had recovered from operation. Left ventricular volume was calculated from the ultrasonic sonomicrometric dimension measurements and the equation for a prolate ellipsoid; dV/dt was calculated from the stroke volume and ejection time. Radionuclide angiograms were performed using technetium-99m-labeled red blood cells and an Anger camera with a converging collimator interfaced to a computer programmed for multigated acquisition. A wide range of ventricular function was produced with sequential infusion of isoproterenol, propranolol, phenylepnrine and sodium thiamylal. Ejection fraction and dV/dt were measured simultaneously during each intervention using the time-activity curves of the multigated radionuclide anglogram and ultrasonic sonomicrometric dimensions. Regression analyses demonstrated a close correlation between the simultaneous measurements of ejection fraction (r values ranged from 0.95 to 0.99) and dV/dt (r values ranged from 0.87 to 0.99). these data indicate that noninvasive multigated radionuclide angiography accurately assesses changes in ejection fraction and dV/dt over a wide range of ventricular function.

Abnormal left ventricular relaxation in hypertensive patients.

1. The maximum rates of left ventricular ejection and filling were derived (Fourier analysis) from the left ventricular volume curve (99m technetium-human serum albumin gated blood pool studies) in 12 normotensive subjects and 15 hypertensive patients of matched age groups. 2. Average values of cardiac output, ejection fraction, heart rate and left ventricular ejection rate were not significantly different in the two groups. 3. Hypertensive patients had a slower rate of left ventricular filling (P < 0.05), suggesting diminished left ventricular compliance in hypertension.

Inter-observer variation in estimates by nuclear angiography of left ventricular ejection fraction and ejection rate

The recent decline in the cost of computing has led to the introduction of data processing of gammacamera images in many medical centres, allowing the development and widespread use of radionuclide techniques for assessing left ventricular performance. Methods such as ECG-gated blood-pool imaging have the advantage of being much less invasive than contrast ventriculography and do not rely on geometrical assumptions about the shape of the ventricle. However, Walton et al. (1978) suggested that the analysis of these images is prone to considerable variability. This paper presents a study of the interobserver variation in estimates of ejection fraction (EF) and average and maximum systolic contraction rates using a micro-computer* to analyse gated blood-pool images of the left ventricle. Following an intravenous injection of 740 MBq (20 mCi) of technetium-labelled human serum albumin, patients were positioned under a gamma camera† in the 30° left anterior oblique position with a 10° caudal tilt. The patient'...

Nucleid-angiographic calculations of left ventricular end-diastolic pressure, pulmonary capillary pressure and diastolic pulmonary pressure (author's transl)

Proper of cardiac nucleid-angiography provides parameters which are comparable to those obtained by invasive procedures. Although various methods have been devised for determining left ventricular ejection rate and the geometric analysis of the left ventricle by isotope techniques (Adam 2-5), Ashburn (6, 7), Breuel (11, 12), Strauss/Bill, Strauss/Pitt (65, 66, 67), only a few comparative intra-cavitary pressure measurements are available. Of these, the method developed by de Vernejoul (73 to 76) is of particular importance for measurements during the bolus phase because of the large number of cases studied by simultaneous catheterisation (670 patients). The value of de Vernejoul's formula was confirmed by a study of 350 of our own cases. The disadvantage of the method lies in its susceptibility to variations in the bolus front. We have therefore attempted for some time to obtain pressure measurements by a pooling procedure.

Pre- and postoperative hemodynamic and cineangiocardiographic assessment of left ventricular function in patients with aortic regurgitation

Hemodynamic and angiocardiographic analysis was performed prior to and 14 months on the average following valve replacement in 11 patients with severe, isolated, pure, chronic aortic regurgitation. The aortic diastolic pressure, reduced prior to surgery, reverted to normal as did the cardiac index. Left ventricular filling pressure, elevated prior to surgery, returned to normal while aortic systolic pressure did not vary substantially. The markedly increased stroke volume returned to normal as did the net left ventricular stroke work. Left ventricular end-diastolic and end-systolic volumes, also markedly elevated, decreased but did not return to normal levels. The shape of the left ventricle, which was more spherical than normal during end-systole prior to surgery, as evidenced by the decrease in the systolic axis ratio, reverted to normal. The ejection fraction, severely reduced before surgery, increased moderately (46 ± 13 vs 51 ± 19 per cent) as did the extent of circumferential fiber shortening (δD) (21 ± 8 vs 27 ± 12 per cent). The mean velocity of fiber shortening ( VCF ) increased significantly (0.68 ± 0.2 vs 1.03 ± 0.47 circ./sec.), as did the mean left ventricular ejection rate (1.32 ± 0.48 vs 1.91 ± 0.76). Comparative analysis of the evolution of left ventricular function indices and of extramyocardial factors (end-diastolic fiber stretching and impedance to ejection) showed that whereas in some cases myocardial damage appeared to be irreversible, in others dramatic improvement sometimes occurred following surgery. It was not possible, however, to determine the threshold below which the damage was irreversible. It may therefore be concluded that in some patients with severe regurgitation attended by profound myocardial insufficiency, correction of the valvular defect could produce not only clinical and hemodynamic improvement, but also improvement in myocardial contractile status.

Global and regional left ventricular response to bicycle exercise in coronary artery disease: Assessment by quantitative radionuclide angiocardiography

The left ventricular response to bicycle exercise was evaluated in 60 patients with coronary artery disease and in 13 normal control subjects. Left ventricular ejection fraction, mean normalized ejection rate and regional wall motion were determined using first-pass radionuclide angiocardiograms obtained at rest and again during peak graded bicycle exercise. All normal subjects demonstrated improved left ventricular function with exercise. Left ventricular ejection fraction increased significantly from 67 ± 3 per cent (mean ± SE) at rest to 82 ± 4 per cent with exercise (p < 0.001). Similarly, the left ventricular ejection rate increased significantly from 3.47 ± 0.31 sec −1 to 6.53 ± 0.42 sec −1(p < 0.001). In contrast, in 44 of 60 patients with coronary artery disease, the ejection fraction or ejection rate either decreased or remained the same with exercise. New or exaggerated regional wall motion abnormalities were detected in 28 of 60 patients with coronary artery disease. Over-all, global or regional evidence of compromised left ventricular reserve was found in 48 of 60 patients with coronary artery disease. The major determinant of an abnormal left ventricular response to exercise was the presence or absence of electrocardiographic evidence of myocardial ischemia. Left ventricular ejection fraction decreased or remained the same with exercise in all patients with coronary artery disease and electrocardiographic ischemia. New regional wall motion abnormalities were detected in 20 of these patients. In this group, the left ventricular ejection fraction decreased from 66 ± 2 per cent at rest to 58 ± 2 per cent with exercise (p < 0.001), whereas the ejection rate was unchanged by exercise (rest 3.33 ± 0.21 sec −1; exercise 3.34 ± 0.22 sec −1, p > 0.05). Of the 30 patients with coronary artery disease who exercised to symptom-limiting fatigue without electrocardiographic ischemia, 18 demonstrated compromised left ventricular reserve with exercise. Twelve of the remaining patients with coronary artery disease had normal left ventricular reserve, in eight of whom ventricular function was completely normal both at rest and during exercise. In this group exercised to fatigue, the left ventricular ejection fraction increased from 53 ± 4 per cent at rest to 58 ± 2 per cent with exercise (p < 0.001). The ejection rate also increased from 2.48 ± 0.24 sec −1 to 3.67 ± 0.39 sec −1 (p < 0.001). The direction and magnitude of the left ventricular responses to exercise were not affected by long-term oral propranolol administration in 22 patients. Based upon either abnormal exercise left ventricular reserve or abnormal global and regional left ventricular function at rest, the over-all sensitivity of this radionuclide technic for the detection of coronary artery disease was 87 per cent (52 of 60 patients). These data demonstrate that exercise ventricular performance studies provide important physiologic insights into left ventricular functional reserve as well as a sensitive noninvasive approach for the detection of coronary artery disease.

Radionuclide assessment of ventricular performance during propranolol withdrawal prior to aortocoronary bypass surgery

The effects of oral propranolol upon left ventricular performance were assessed in 18 patients with angiographically documented coronary artery disease in whom propranolol was tapered prior to elective aortocoronary bypass surgery. Left ventricular ejection fraction, ejection rate, and regional wall motion were obtained on three occasions with first-pass radionuclide angiocardiographic techniques. Patients were studied at peak propranolol dose (±SEM) 224±29 mg./day; serum propranolol level, 85±22 ng./ml.), intermediate dose (99±9 mg./day; serum propranolol, 30±6 ng./ml.), and 24 hours following discontinuation of propranolol therapy. Heart rate increased significantly (62±2.3 vs 67±3.0 vs 73±2.3 beats/minute, p<0.001) during propranolol withdrawal, while systolic blood pressure did not change significantly (114.7±4.3 vs 110.3±3.0 vs 113±3.0 mm. Hg, p>0.05). There was no significant change in ejection fraction (59.1±2.4 vs 60.4±2.0 vs 59.2±2.5 per cent) or ejection rate 2.80±0.18 vs 2.87±0.18 vs 2.92±0.20 sec. −1) as propranolol was tapered (p>0.05). No patient demonstrated a change in regional wall motion in response to propranolol withdrawal. The results of this study suggest that oral proparanolol in commonly used clinical dosages does not significantly affect radionuclide measures of left ventricular performance in the basal state.

Effects of aminophylline upon right and left ventricular performance in chronic obstructive pulmonary disease: Noninvasive assessment by radionuclide angiocardiography

Although aminophylline is a widely used bronchodilator in chronic obstructive pulmonary disease (COPD), its effects upon cardiac performance have not been fully established. The effect of aminophylline upon right ventricular and left ventricular ejection fraction and the left ventricular ejection rate was evaluated by first-pass quantitative radionuclide angiocardiography in 15 patients with COPD, including four with cor pulmonale, and in five control subjects without cardiopulmonary disease. Aminophylline infusion (9 mg/kg) significantly increased the right ventricular ejection fraction (45 to 52 per cent), left ventricular ejection fraction (60 to 67 per cent) and left ventricular ejection rate (3.4 to 4.1 sec −1) in patients with COPD (all parameters, p < 0.001). In six of eight patients with depressed control right ventricular performance, right ventricular ejection fraction normalized and in two of five patients with depressed control left ventricular performance, the left ventricular ejection fraction and left ventricular ejection rate normalized. In control subjects, comparable increases were noted in the right ventricular ejection fraction (50 to 56 per cent), left ventricular ejection fraction (62 to 71 per cent) and left ventricular ejection rate (3.2 to 4.6 sec −1) (p < 0.001). One-second forced expiratory volume (FEV 1) and forced vital capacity (FVC) increased significantly in patients with COPD but not in control subjects. Arterial carbon dioxide tension decreased significantly in both groups (p < 0.05), whereas arterial oxygen tension did not change. Theophylline blood levels did not correlate with absolute increases in right ventricular or left ventricular ejection fraction. These data indicate that aminophylline acutely enhances biventricular performance in COPD. Since comparable cardiovascular changes are induced in normal subjects in whom ventilatory function was not altered, the beneficial effects of aminophylline upon global ventricular performance appear to be independent of the degree of pulmonary compromise.

Assessment of cardiac performance with quantitative radionuclide angiocardiography. Effects of oral propranolol on global and regional left ventricular function in coronary artery disease.

The effect of incremental dosages of oral propranolol (mean peak dose of 165 +/- 13 mg/day) of left ventricular ejection fraction, ejection rate and regional wall motion was studied sequentially in 22 stable, resting patients with coronary artery disease using a geometry-independent first-pass radionuclide angiocardiographic technique. All patients improved clinically, in association with a fall in heart rate and therapeutic serum propranolol levels. No significant changes were noted in ejection fraction, ejection rate or regional wall motion. No patient developed a new regional wall motion disturbance. Thus, oral propranolol administered at clinically effective antianginal dosages in patients with stable coronary artery disease does not appear to have significant deleterious effects on resting left ventricular performance.

Hemodynamic correlates of saralasin-induced arterial pressure changes.

Angiotensin antagonists have proved useful in elucidating the clinical role of the renin-angiotensin system; and their diagnostic and therapeutic efficacy in hypertension has been the subject of many reports but the hemodynamic effects remain unknown. Therefore, saralasin was infused intravenously (1.3 mg/min for 30 min) in 26 sodium-depleted patients with hypertension. Systemic hemodynamic alterations were determined before, during, and after infusion. On the basis of mean arterial pressure (MAP) changes, patients were classified as responders, nonresponders, or pressorresponders (MAP changes greater than or equal to 10 mm Hg). MAP fall in responders was achieved through reduced cardiac output and/or total peripheral resistance, with minimal or absent reflexive heart rate increase. In nonresponders, despite no change in MAP, output fell in parallel with stroke index and left ventricular ejection rate, In pressorresponders, saralasin increased vascular resistance. Thus, in addition to variable effects on vascular receptors, saralasin produced inhibitory cardiac effects either through altered venous return or inhibition of contractility.

Hemodynamic, reflexive, and metabolic alterations induced by acute and chronic timolol therapy in hypertensive man.

The hemodynamic, cardiovascular, and metabolic effects of acute (intravenous) and prolonged (four weeks oral) timolol treatment were assessed in 16 patients with mild or moderate essential hypertension. Fifteen patients completed the outpatient study and ten showed a fall in mean arterial pressure of at least 10 mm Hg. They also demonstrated a significant fall in supine systolic (7%), diastolic (9%), and mean arterial pressure. Hemodynamic evaluation was performed in 13 patients and cardiac index was found to be reduced with both intravenous (20%) and oral timolol (13%). There was no correlation between the decrease in cardiac index and arterial pressure. Calculated total peripheral resistance rose with intravenous timolol and returned toward, but not below, pretreatment values with the oral therapy. Left ventricular ejection rate also fell significantly with intravenous timolol but returned toward pretreatment levels with oral therapy. Plasma renin activity was reduced similarly with both modes of administration and its reduction also did not correlate with the fall in arterial pressure. Plasma volume fell in eight of 13 patients. Reflexive responses to the Valsalva maneuver were considerably modified by both intravenous and oral timolol but responses to 50 degrees upright tilt and handgrip were not. Timolol is an effective oral antihypertensive agent with similar hemodynamic and metabolic effects to propranolol.

Assessment of cardiac performance with quantitative radionuclide angiocardiography: sequential left ventricular ejection fraction, normalized left ventricular ejection rate, and regional wall motion.

Sequential quantitative first pass radionuclide angiocardiograms (RA) were used to measure left ventricular ejection fraction (LVEF) and left ventricular ejection rate (LVER), and to assess regional wall motion (RWM) in the anterior (ANT) and left anterior oblique (LAO) positions. Studies were obtained with a computerized multicrystal scintillation camera suitable for acquiring high count-rate data. Background was determined in a new fashion by selecting frames temporally from the left ventricular region of interest time-activity curve. A ''representative'' cardiac cycle was formed by summing together counts over three to six cardiac cycles. From this background corrected, high count-rate ''representative''cardiac cycle, LVEF, LVER, and RWM were determined. In 22 patients with normal sinus rhythm in the absence of significant valvular regurgitation, RA LVEF correlated well with that measured by contrast angiography (r = 0.95). LVER correlated well with LVEF measured at contrast angiography (r = 0.90) and allowed complete separation of those with normal (LVER = 3.4 +- 0.17 sec/sup -1/) and abnormal (LVER = 1.22 +- 0.11 sec/sup -1/) (P < 0.001) left ventricular performance. This separation was independent of background. Isoproterenol infusion in five normal subjects caused LVER to increase by 81 +- 17% while LVEF increased by 10 +- 2.0%.more » RWM was correctly defined in 21/22 patients and 89% of left ventricular segments with abnormal wall motion.« less

Systemic and renal hemodynamic effects of bupicomide: A new vasodilator

The systemic and renal hemodyanmic effects of bupicomide were studied in 10 male patients with uncomplicated essential hypertension of moderate severity. Bupicomide significantly reduced systolic, diastolic, and mean arterial pressure and peripheral vascular resistance and this hypotensive effect was associated with a reflexive increase in heart rate, left ventricular ejection rate, and cardiac index; it had no effect upon other reflexive sympathetic adjustments induced by upright tilt and the Valsalva maneuver. Bupicomide also increased renal blood flow and decreased renal vascular resistance, but it had no effect upon the glomerular filtration rate. The hypotensive mechanism of bupicomide therefore is mediated by peripheral arteriolar dilation, through vascular smooth muscle relaxation. The more immediate clinical side effects of bupicomide are related to its strong vasodialting action and include headaches, cutaneous flushing, and tachycardia.

Measurement of left ventricular mean circumferential fiber shortening velocity and systolic ejection rate by computerized radionuclide angiocardiography

Recently attention has focused on ejection phase indexes as clinically relevant measures of left ventricular contractility. Using an Anger camera interfaced to a dedicated computer with injection of radionuclide (technetium 99m) into a wedged pulmonary arterial catheter we have developed a method for measuring left ventricular mean circumferential fiber shortening velocity and mean systolic ejection rate. For determination of mean fiber shortening velocity an area of interest coincident with the left ventricular minor axis is constructed and a time-activity curve obtained. In 31 patients radionuclide-determined values for mean fiber shortening velocity and mean systolic ejection rate correlated ( r = 0.90, P < 0.001 and r = 0.98, P < 0.001, respectively) with values for these indexes obtained from left cineventriculography. Left ventricular ejection fraction correlated with mean fiber shortening velocity and systolic ejection rate ( r = 0.60, P < 0.001 and r = 0.92, P < 0.001, respectively). No patient with a normal mean fiber shortening velocity or systolic ejection rate had a diminished ejection fraction. Because these radionuclide measurements do not require left heart catheterization, they can be frequently repeated.

Systolic hypertension: Nonhomogeneous diseases

Prospective studies have shown that systolic hypertension is associated with increased cardiovascular risk, but few physiologic studies have characterized the problem. Therefore, two groups of men (older and younger than 35 years) with systolic hypertension (systolic pressure 150 mm Hg or greater and diastolic pressure 95 mm Hg or less) were studied hemodynamically. The 13 younger patients demonstrated a hyperkinetic circulation manifested by a significantly increased heart rate, elevated left ventricular ejection rate and cardiac indexes and normal vascular resistance. The 13 older patients had a normal heart rate, significantly reduced cardiac and left ventricular ejection rate indexes, and increased vascular resistance with respect to the younger men with systolic hypertension and normotensive control subjects. Plasma volume was reduced only in the older patients ( P < 0.05). These data demonstrate that systolic hypertension should not be considered a homogeneous disease entity clinically or physiologically. The physiologic differences between the younger and older patients suggest that different mechanisms may be operative.

Angiographic Determination of the Left Vetricular Ejection Rate in Man with Heart Disease

Eighty-two adults with various chronic heart diseases were studied by cardiac catheterization and quantitative biplane left ventriculography with filming at 12 per second. Mean left ventricular ejection rate (dVe/dt), which is the change in chamber volume with respect to time, was calculated from the films. The patient series included those with left ventricular volume overload, pressure overload, myocardial disease, idiopathic hypertrophic subaortic stenosis, and one patient with a ventricular septal defect. dVe/dt correlated significantly with stroke volume and both parameters varied over nearly a ten-fold range of values. dVe/dt correlated poorly with the ejection fraction, whereas dVe/dt divided by end-diastolic volume correlated significantly with the ejection fraction. dVe/dt alone bas minimal value in assessing left ventricular function but when dVe/dt is normalized for end-diastolic volume, it may reflect the contractile function of the left ventricle. Therefore, ventricular ejection rate is similar to other assessments of ventricular pump function (ie, stroke volume, strokework, and power) and only has significance in evaluating left ventricular myocardial function when preload is considered.