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[Functional aortic systolic murmurs in the elderly].

The authors report a clinical and phonocardiographic study of functional aortic systolic murmurs in 26 elderly patients, in 19 of which the lesion was confirmed pathologically. Systolic murmurs radiating across the chest in elderly have the same clinical characteristics as aortic stenosis from which they may, however, be distinguished owing to the: absence of a thrill during systole. The brief duration and the proto-meso-systolic position of the murmur with early inscription of maximal oscillations on the phonocardiogram. Conversion of the second aortic sound. Almost constant absence of a diastolic murmur. Normal carotid arteriogram, including normal ejection time after correction and time of half rise. "Innocent" systolic murmurs are due to calcification of the aortic valve without stenosis, and/or dilatation of the ascending aorta. There is no systolic pressure gradient between the left ventricle and the aorta during cardiac catheterisation. No lesions were found in the mitral valve suggesting mitral incompetence, therefore, we consider the term mitro-aortic murmur used by Huchard should be dropped; Radiation of the murmur from the apex of the heart up into the neck may be explained by the simultaneous occurrence of anatomical changes due to age and/or hypertension and by the vibratory nature of the murmurs which become propagated above and below their origin, as shown by the intracardiac recordings.

Age Factors↗

[Various etiologies of systolic murmurs radiating from the apex of the heart to the neck].

The authors studied systolic murmurs in 89 cases, 50 of aortic stenosis, 14 cases of obstructive cardiomyopathy and 20 cases of mitral incompetence. This systolic murmur is characterised by its exceptional intensity, its raspy character at the base, becoming softer at the apex and in the axilla, the presence of a thrill and irradiation into the neck in 50 to 75% of cases. The etiological diagnosis was ensured precisely by 1) pharmaco-dynamic tests: amyl nitrite accentuates the systolic ejection murmurs and attenuates murmurs due to mitral regurgitation. 2) careful analysis of diastole: a systolic murmur extending into early diastole, a third sound or an opening snap and a low-pitched diastolic murmur, suggest mitral incompetence. A high-pitched diastolic murmur is in favour of aortic stenosis. 3) the carotid arteriogram and catheterisation show the characteristic abnormalities of the carotid arteriogram found in aortic valve disease and the existence of a trans-aortic or intra-ventricular pressure gradient, when there is an obstruction to left ventricular jection. The F wave of the apex cardiogram or left atrial reflux of the contrast medium during cineangiocardiography, confirm mitral incompetence. The main phono-hemodynamic and phono-anatomical correlations have been emphasized: 1. The intensity of the systolic murmur is directly proportional to the degree of obstructive cardiomyopathy or mitral incompetence, but does not parallel the degree of the sub-valvular apparatus. 3. The maximum intensity of the murmur occurs all the later when the stenosis is tight, whilst it is earlier in severe obstructive cardio-myopathy. 4. The lozange shape of the murmur of mitral incompetence on phono-cardiography is, above all, due to those cases with lesions of the sub-valvular apparatus. Finally, a study of the sound recorded by the Allard-Laurens micromanometer permitted us to determine the mechanism of this irradiating systolic murmur.

Aortic Valve↗

Reproducibility of systolic and diastolic time intervals in normal humans: an important issue in clinical cardiovascular pharmacology.

The purpose of this study was to evaluate the long-term variability and reproducibility of systolic and diastolic time intervals in human subjects. Ten healthy volunteers underwent serial determinations of systolic and diastolic time intervals and, as internal physiologic standards, heart rate (HR), systemic blood pressures, and resting oxygen consumption (VO2). The protocol lasted 1 month and measurements were made on days 1, 2, and 30. No statistically significant differences were found in the various systolic time interval parameters, percentage of diastolic time, heart rate, systolic blood pressure (SBP) and resting oxygen consumption for the 3 study days. Diastolic blood pressure tended to rise slightly (p = 0.07) from day 1 to day 30. The average coefficients of variation for systolic and diastolic time interval parameters in individual study subjects ranged from 1.2 to 7.0%, whereas those for resting physiologic data ranged from 5.3 to 8.5%. In normal human subjects, systolic and diastolic time intervals are highly reproducible, with acceptable variation over time; these measurements should be thought of as possessing reproducibility equal to or greater than the resting physiologic parameters of HR, systemic blood pressure and oxygen consumption.

Adult↗

Systolic blood pressure: arterial compliance and early wave reflection, and their modification by antihypertensive therapy.

Arterial stiffness (the inverse of compliance) is the major determinant of left ventricular and central aortic peak systolic pressure. Recent prospective epidemiological studies (MRFIT, Framingham) have confirmed the importance of systolic (rather than diastolic) pressure in the development of cardiac failure and stroke, and in all-cause mortality. Arteries stiffen in hypertension and with increasing age. Arterial stiffening increases systolic pressure by two mechanisms. The first is by causing a higher pressure to be generated at the peak of ventricular ejection (through increase in aortic characteristic impedance), and the second is by causing a secondary rise attributable to early return of wave reflection from peripheral sites (through an increase in arterial pulse wave velocity). ACE inhibitors, and also nitrates, decrease arterial stiffness. They also dilate peripheral conduit arteries; this reduces wave reflection. These drugs thus reduce systolic pressure in central arteries not only by reducing arterial stiffness but also by reducing inappropriately early wave reflection. Quantitatively, the latter action seems to be more important than the former. Neither action is seen with beta-blocking agents. These beneficial actions on central systolic pressure are not always apparent when pressure is measured in a peripheral artery such as the brachial or radial. This is because the reflected wave constitutes the peak of the pressure wave in central arteries but is usually just an undulation on the downstroke of the wave in peripheral arteries. Hence sphygmomanometric recordings underestimate reduction in central systolic pressure and in left ventricular load brought about by ACE inhibitors and by nitrates.

Antihypertensive Agents↗

[Systolic stress in mitral stenosis].

Left ventricular systolic stress was studied in nineteen patients with mitral stenosis, twelve in sinus rhythm and seven in atrial fibrillation. Left ventricular dimensions and volumes and septal and posterior wall thickness were measured by means of M and two bidimensional echocardiography at rest and during isometric exercise. Expulsive indices: fractional shortening, ejection fraction and mean circumferential shortening rate were calculated. Ventricular mass, meridional stress and several end-systolic stress or pressure/volume relationships were estimated. Patients with atrial fibrillation were older and had systolic dysfunction: greater end-systolic volumes and depression of both expulsive fractions and some of the end-systolic indices. Preload and wall thickness were normal. Patients with atrial fibrillation showed higher ventricular stress as a consequence of greater ventricular dimensions. Ejection fraction correlates directly with mitral valve area and inversely with inotropic state and heart rate. It is concluded that systolic dysfunction in mitral stenosis is multifactorial. The most important determinants of the abnormality are heart rate and inotropic state. The study did not show any primary abnormality of afterload or hypotrophy of the left ventricle.

Adult↗

Stability of systolic blood pressure reactivity to exercise in young children.

Blood pressure reactivity to stress in childhood has predicted development of hypertension 45 years later, so it is important to understand the characteristics of blood pressure reactivity in childhood. The present study assessed the 1-week and 6-month stability of systolic blood pressure reactivity to a 40-meter run stressor in preschool children. Sixty-three low-income children (mean age, 3.9 years) were assessed on four different days over a 6-month period. One-week stability (r = 0.39 to 0.50) and 6-month stability (r = 0.56) of reactive systolic blood pressure levels were highly significant. Reactive systolic blood pressure level was more stable than resting systolic or diastolic blood pressure in this sample. Sex, body mass index, family cardiovascular disease history, and child Type A behavior all were unrelated to systolic blood pressure reactivity. Systolic blood pressure reactivity to exercise appears to be an enduring characteristic that emerges in early childhood.

Arousal↗

Systolic function of the hypertrophied left ventricle.

The effects of left ventricular hypertrophy (LVH) on systolic function were studied by echocardiography in 61 hypertensive patients. LV mass index (LVMI) and relative wall thickness (h/r ratio) were used together as LVH indices, and three patterns of LV adaptation to the pressure overload were observed: 13 patients had normal LVMI and h/r ratio (no LVH); 32 patients had increased h/r ratio, with normal or increased LVMI (concentric LVH); 16 patients had increased LVMI and normal h/r ratio (eccentric LVH). Cuff arterial pressure was lower in patients without LVH than in those with LVH, but both LVH indices correlated weakly with systolic, diastolic, and mean blood pressure (r = 0.22 to 0.33). Eccentric LVH showed peculiar hemodynamics, characterized by high cardiac output (CO) and normal total peripheral resistance (TPR), whereas CO was normal and TPR moderately and severely increased in patients without LVH and with concentric LVH, respectively. In the group without LVH, peak systolic stress (PSS) and systolic blood pressure/end-systolic volume index (SBP/Ves) were increased, whereas end-diastolic diameter (EDD), end-systolic stress (ESS), and fractional shortening (FS) were normal; thus, the ejective performance was preserved by increased contractility. The group with concentric LVH had normal PSS, ESS, EDD, and FS and increased SBP/Ves, showing that systolic function was normal or supernormal in the presence of adequate LVH. The group with eccentric LVH had increased PSS, ESS, and EDD, whereas FS and SBP/Ves were both normal; thus, the ejective performance was preserved--in spite of an inadequate LVH and increased afterload--through the action of preload reserve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Left ventricular end-systolic pressure and wall thickness relation for the assessment of regional myocardial contractility in man (author's transl)].

In 28 patients (pts) (5 normal subjects (N), 12 pts with valvular heart disease, 6 with cardiomyopathy, and 5 with ischemic heart disease), left ventricular (LV) pressure was measured using Millar's catheter tip transducer simultaneously with LV posterior wall thickness (W) by echocardiography. After the control recording, LV peak systolic pressure was altered by about 30 mmHg from the control level by angiotensin (20 ng/kg/min) or nitroprusside (1 gamma/kg/min) to attain two (18 pts) or three (10 pts) different end-systolic pressure points, determined after the steady state was achieved. LV end-systolic pressure and wall thickness (P-W) relation a the three different end-systolic pressure points was found to be linear (r = 0.996) in each of the 10 pts, suggesting that end-systolic P-W relation is independent of afterload. Isoproterenol infused in 4 pts, which led to an increase in peak positive (+) dp/dt by a mean of 28%, increased the slope of the P-W relation by 43.4% of the control value (P less than 0.001), while propranolol, which led to a decrease in peak (+) dp/dt by a mean of 16.7%, reduced the slope by 27.3% (p less than 0.001). This indicates the sensitiveness of the slope of P-W relation to the inotropic change of the myocardium. In N, the slope of the P-W relation was -29.7 +/0 6.0 mmHg/mm (mean +/- SD), while the value in 4 pts with decreased functional capacity (NYHA III or IV) was significantly lower (-13.7 +/- 2.9 mmHg/mm; p less than 0.001). Thus, the present study suggests that the slope of the end-systolic P-W relation is useful in assessing regional myocardial contractility in man.

Adult↗

[Systolic blood pressure at rest and during submaximal and maximal exercise on ergometer bicycle. The value of automatic and auscultatory determination].

Fifteen normal subjects participated in this comparison of systolic blood pressure measurement determined both automatically (AU) with the Kivex Ergometrics 900 and by the standard auscultatorically method (AM). Maximal exercise, was achieved by work performed on an electronically braked ergometer bicycle. In the first part of this study, simultaneous measurements of systolic blood pressure were made by the Kivex device and by the standard method at rest, every minute during exercise, and one minute after stopping exercise. The differences (two standard deviations) between AU and AM (n = 229) were +/- 19 mmHg at rest, +/- 15 mmHg at submaximal level, and +/- 49 mmHg at maximal exercise level. The acceptable difference was determined to +/- 15 mmHg by Bland and Altman. In the second part of this study, the differences between simultaneously measured auscultatoric systolic blood pressure by two observers (n = 205) was +/- 10 mmHg at rest, +/- 9 mmHg at submaximal level, and +/- 10 mmHg at the maximal exercise level. It can therefore be concluded that Kivex automatic blood pressure device, Ergometrics 900, is unable to measure accurately systolic blood pressure with sufficient agreement in normal subjects at the maximal stress level or at rest. However, at the submaximal exercise level, the Kivex device was able to measure systolic blood pressure with an acceptable agreement with the standard method. Therefore, the blood pressure results obtained by the Kivex device are highly influenced by the exercise level. The agreement between two observers using standard auscultatory method for systolic blood pressure measurement was found to be acceptable at all levels of exercise.

Adult↗

[Effects left ventricle asynchrony on systolic and diastolic function in patients with non-ischemic heart failure].

INTRODUCTION: The asynchrony of the left ventricle--i.e., its nonuniform contraction and relaxation--is an important factor for left ventricular function. Heart failure is often related to abnormal systolic function, sometimes associated with a diastolic dysfunction. We studied the relationship of left ventricular asynchrony to left ventricular function in patients with nonischemic heart failure. MATERIAL AND METHODS: Radionuclide angiography at rest was performed in 25 patients with nonischemic heart failure and in 26 age and sex matched normal subjects. In addition to ejection fraction and peak filling rate, two indices of left ventricular asynchrony were calculated: the coefficient of variation of regional time to end systole and the coefficient of variation of regional time to peak filling rate. These factors indicate how disperse are the regional values of time to end systole and of time to peak filling rate. In fact, the higher the value, the greater the asynchrony. RESULTS: A significant (r = .46, p < .05) inverse correlation was found between the ejection fraction and the coefficient of variation of regional time to end systole in both the normal subjects and the heart failure patients, while the ejection fraction correlated significantly (r = .46, p < .05) with the coefficient of variation of regional time to peak filling rate only in the patients. Moreover, the peak filling rate was inversely correlated (r = .57, p < .05) with the coefficient of variation of regional time to peak filling rate in the heart failure patients but not in the normal subjects. CONCLUSIONS: These results suggest that left ventricular systolic and diastolic asynchrony may contribute to impair left ventricular systolic and diastolic function in patients with nonischemic heart failure.

Adult↗

Hemodynamic correlates of the third heart sound and systolic time intervals.

Bedside diagnostic tools remain important in the care of patients with heart failure. Over the past two centuries, cardiac auscultation and phonocardiography have been essential in understanding cardiac pathophysiology and caring for patients with heart disease. Diastolic heart sounds (S3 and S4) and systolic time intervals have been particularly useful in this regard. Unfortunately, auscultation skills have declined considerably, and systolic time intervals have traditionally required carotid pulse tracings. Newer technology allows the automated detection of heart sounds and measurement of systolic time intervals in a simple, inexpensive, noninvasive system. Using the newer system, the authors present data on the hemodynamic correlates of the S3 and abnormal systolic time intervals. These data serve as the foundation for using the system to better understand the test characteristics and pathophysiology of the S3 and systolic time intervals, and help to define their use in improving the bedside diagnosis and management of patients with heart failure.

Female↗

Predictive value of clinic and ambulatory heart rate for mortality in elderly subjects with systolic hypertension.

OBJECTIVE: To examine the association of clinic and ambulatory heart rate with total, cardiovascular, and noncardiovascular death in a cohort of elderly subjects with isolated systolic hypertension from the Systolic Hypertension in Europe Trial. METHODS: A total of 4682 patients participated, whose untreated blood pressure on conventional measurement at baseline was 160 to 219 mm Hg systolic and lower than 95 mm Hg diastolic. Clinic heart rate was the mean of 6 readings during 3 visits. Ambulatory heart rate was recorded with a portable intermittent technique in 807 subjects. RESULTS: Raised baseline clinic heart rate was positively associated with a worse prognosis for total, cardiovascular, and noncardiovascular mortality among the 2293 men and women taking placebo. Subjects with heart rates higher than 79 beats/min (bpm) (top quintile) had a 1.89 times greater risk of mortality than subjects with heart rate lower than or equal to 79 bpm (95% confidence interval, 1.33-2.68 bpm). In a Cox regression analysis, predictors of time to death were heart rate (P<.001), age (P<.001), serum creatinine level (P =.001), presence of diabetes (P =.002), previous cardiovascular disease (P =.01), triglyceride readings (P =.02), smoking (P =.04), and elevated systolic blood pressure (P =.05), while total cholesterol level was found to be nonsignificant in the model. In the ambulatory monitoring subgroup, clinic and ambulatory heart rates predicted noncardiovascular but not cardiovascular mortality. However, in a Cox regression analysis in which clinic and ambulatory heart rates were included, a significant association with noncardiovascular mortality was found only for clinic heart rate (P =.004). In the active treatment group, the weak predictive power of clinic heart rate for mortality disappeared after adjustment for confounders. CONCLUSIONS: In untreated older patients with isolated systolic hypertension, a clinic heart rate greater than 79 bpm was a significant predictor of all-cause, cardiovascular, and noncardiovascular mortality. Ambulatory heart rate did not add prognostic information to that provided by clinic heart rate.

Age Factors↗

The collateral hemispheric systolic pressure.

Satisfactory calibrated BP tracings were obtained during 385 (85%) of 455 carotid endarterectomies. The pressures were measured from the distal common carotid arteries while the external carotid arteries were clamp occluded. Continuous recordings were made with and without proximal common carotid clamp occlusion. The two systolic pressures resulting in each patient were plotted as a single point on a graph, with the direct carotid systolic pressure on the abscissa and the back carotid systolic pressure on the ordinate. Formulae of the mean values in 101 of the 385 procedures, in which the opposite carotid systems contained severe stenoses or total occlusions, and the other 284 procedures, in which the opposite carotid systems had no notable lesions, demonstrate that the collateral hemispheric systolic pressure depends on the status of the opposite carotid artery and on the central BP. We derived formulae for these two groups of patients to demarcate the lowest collateral hemispheric systolic pressure adequate for hemispheric integrity during and following prolonged operative carotid occlusion or following permanent interruption of carotid blood flow as a result of thrombosis, ligation, or resection without graft replacement.

Arterial Occlusive Diseases↗

Combining left ventricular systolic time intervals and M-mode echocardiography in the evaluation of primary pulmonary hypertension in women.

Eight patients with primary pulmonary hypertension underwent systolic time intervals, M-mode echocardiography, and direct hemodynamic studies in order to determine the correlation between noninvasive parameters and hemodynamic variables and to evaluate the utility of these noninvasive studies in primary pulmonary hypertension. The ratio of the pre-ejection period to left ventricular ejection time (PEP/LVET) of the systolic time intervals was abnormally increased (greater than 0.42) for each subject; the increase in the PEP/LVET was secondary to a shortening of the left ventricular ejection time in four patients, prolongation of the pre-ejection period in one, or a combination of such, noted in three patients. In contrast, echocardiographic parameters of left ventricular function, specifically percent change in the minor axis of the left ventricle with systole, velocity of circumferential fiber shortening, and ejection fraction, were normal. In addition, a very good correlation was noted between PEP/LVET and total pulmonary resistance (r value = -0.89, p less than 0.05), while the echocardiographic parameters correlated well with stroke volume and cardiac output (r values ranged from 0.68 to 0.72, p less than 0.05). These results indicate that in primary pulmonary hypertension, the performance of both systolic time intervals and M-mode echocardiography noninvasively provides useful information concerning the hemodynamic status of these patients. Systolic time intervals provide an estimation of overall cardiac-cardiovascular performance, rather than left ventricular function alone, which in turn, is validly examined by M-mode echocardiography.

Adult↗

Noninvasive evaluation of left ventricular performance by the shortest distance between mitral leaflets coaptation and interventricular septum at end-systole.

We attempted to evaluate left ventricular performance from the shortest distance between the mitral leaflets coaptation and the interventricular septum at end-systole (MVC-IVS distance). The subjects were 37 patients with coronary artery disease (CAD) with prior myocardial infarction (MI), 8 with CAD without prior MI, 22 with atypical chest pain, and 4 with aortic regurgitation. The MVC-IVS distance was measured on a two-dimensional echocardiogram obtained from the parasternal or apical long-axis view and frozen at end-systole. Left ventricular end-systolic volume and end-diastolic volume were obtained by left ventriculography, and the left ventricular ejection fraction was calculated. A significant positive correlation was observed between the MVC-IVS distance and the end-systolic volume (r = 0.83, p less than 0.001); a close correlation was observed between the MVC-IVS distance end-systolic volume and ejection fraction by monoexponential fitting (r = -0.91, p less than 0.001). Thus, a significant negative correlation was observed between the MVC-IVS distance and the left ventricular ejection fraction (LVEF) (r = -0.83, p less than 0.001). An MVC-IVS distance of greater than or equal to 30 mm suggests diagnosis of left ventricular dysfunction (LVEF less than 50%) with high sensitivity (94.4%) and specificity (90.6%), while a value less than 30 mm suggests that the left ventricular performance is likely to be normal. Thus one can easily evaluate the left ventricular performance noninvasively using this new index.

Adult↗

Estimation of left ventricular systolic function by nonvolumetric echocardiographic analysis in subjects with poor left ventricular visualization: a pilot study.

BACKGROUND: Accurate assessment of left ventricular (LV) systolic function is an essential requirement in clinical cardiology. Several echocardiographic methods provide quantitative analysis of LV volumes and ejection fraction (EF) based on the precise tracing of endocardial borders. Often, however, technically limited studies prohibit such direct analysis, and alternative techniques must be applied. HYPOTHESIS: Nonvolumetric echocardiographic methods which do not require endocardial edge definition and tracing may accurately provide quantitative LV systolic function data. METHODS: A pilot study was conducted to validate and compare two recently described indirect echocardiographic methods of LV systolic function analysis, with LVEF by radionuclear cardiac angiography (RNCA). Thirty-two consecutive patients undergoing RNCA for clinical indications also underwent echocardiography within 24 h, with LV analysis performed by the techniques of (1) atrioventricular plane displacement (AVPD) and (2) mitral valve leaflet coaptation point to interventricular septum distance at end-systole (MVC-IVS). RESULTS: Thirteen patients had an echocardiogram with poor two-dimensional visualization of LV endocardial borders. One patient could not be evaluated by the MVC-IVS method and two others by the AVPD method because of technical limitations. Chi-square analysis to compare how each method could discriminate between an RNCA LVEF of < or > or = 50% demonstrated high correlations for the AVPD method (r = 0.6530, p < 0.0005) and the MVC-IVS method (r = -0.7029, p < 0.0001). Sensitivity, specificity, positive and negative predictive values, and test accuracy for the AVPD and MVC-IVS methods were 85 and 80%, 88 and 94%, 85 and 92%, 82 and 83%, and 83 and 87%, respectively. CONCLUSION: This pilot study demonstrates that both alternative echocardiographic methods may be useful in the assessment of LV systolic performance, even in the setting of poor LV endocardial border visualization. A larger study is warranted to apply and contrast these methods in different patient subsets.

Adult↗

Impaired systolic dysfunction of left ventricular longitudinal fibers: a sign of early hypertensive cardiomyopathy.

BACKGROUND: Atrioventricular plane displacement (AVPD) study by M-mode echocardiography can supply useful clinical information about left ventricular (LV) long-axis function. HYPOTHESIS: We assessed the hypothesis that AVPD estimation could be used to detect early hypertensive cardiomyopathy. METHODS: The study population included 81 hypertensive patients with normal LV ejection fraction and fractional shortening, and 50 age- and gender-matched healthy controls. By utilizing M-mode and apical views, the following parameters were estimated: early mitral flow peak velocity (E) and deceleration time (DT), peak velocity of late mitral flow (A), A/E ratio, isovolumic relaxation time (IVRT), total AVPD, AVPD motion during atrial systole (At), systolic AVPD (total AVPD-At), and At/total AVPD ratio. RESULTS: Of 81 hypertensive patients, 16 (19.7%) had a normal (Group 1) and 65 (80.3%) an impaired LV relaxation filling pattern (Group 2). Mean total AVPD-At was significantly lower in Group 2 than in Group 1 (7.1 +/- 2 vs. 10.3 +/- 3 mm, p<0.001) and in Group 1 compared with healthy subjects (10.3 +/- 3 vs. 13.1 +/- 1 mm, p<0.001). Mean At and At/total AVPD were significantly higher in Group 2 than in Group 1 (46.9 +/- 8.6 vs. 37.7 +/- 8.7%, p<0.001), but not in Group 1 compared with healthy subjects (37.7 +/- 8.7 vs. 36 +/- 6%, p>0.05). CONCLUSIONS: Hypertensive patients without overt systolic dysfunction demonstrate LV long-axis systolic dysfunction, while long-axis diastolic dysfunction always coexists with abnormal diastolic filling patterns. This suggests that long-axis systolic dysfunction precedes diastolic dysfunction at the same axis in hypertensive patients.

Adult↗

Impact of chronic oral H2-antagonist therapy on left ventricular systolic function and exercise capacity.

It has been suggested that H2-antagonists may adversely affect left ventricular systolic function. To assess the effects of cimetidine, famotidine, and ranitidine on exercise capacity and left ventricular systolic function, the authors conducted a randomized, double-blind, four-way crossover study in 15 healthy male volunteers with placebo control. Each subject underwent a maximal upright treadmill exercise test, aerobic metabolic assessment, and two-dimensional stress echocardiography on six separate occasions. The initial two treadmill exercise tests with aerobic metabolic assessment and stress echocardiography were performed to minimize the learning effect. In the final four evaluations, subjects were randomized to receive 7 days of oral treatment with cimetidine 400 mg twice daily, famotidine 40 mg daily, ranitidine 150 mg twice daily, and placebo. A comparison of exercise tests, aerobic metabolic assessment, and stress echocardiography results found no significant differences between any of the H2-antagonists and placebo. In addition, there were no significant differences in test results between cimetidine, famotidine, and ranitidine. Specifically, exercise treadmill time, maximal oxygen consumption, respiratory quotient, maximal exercise systolic and diastolic blood pressure, maximal exercise heart rate, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, and ejection fraction were not different between treatments. The authors conclude that 7 days of oral treatment with cimetidine, famotidine, or ranitidine has no deleterious effect on exercise capacity or left ventricular systolic function in healthy subjects.

Administration, Oral↗