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Biomedical subjects

H Boudoulas

Publications and source records attributed to H Boudoulas.

At least 127 records · Page 7Linked to original sources
PubMed1983

Relationship of angiographic and echographic dimensions in chronic left ventricular dilatation.

Recently discrepancies have been reported between echocardiographic (Echo) % delta D and angiocardiographic (Angio) ejection fraction (EF), particularly in valvular regurgitation. One hundred and twelve patients with varying degrees of LV dilatation were studied in the right anterior oblique position with M-mode Echo. None had localized contraction abnormalities. There were 20 normals, 33 with primary myocardial disease, and 59 with mitral and/or aortic regurgitation. Echo end-diastolic diameter (EDD) and end-systolic diameter (ESD) were consistently smaller than Angio calculated EDD and ESD, and the difference was magnified at larger EDDs (p less than 0.01). The result is a relatively poor correlation of Echo % delta D and Angio EF (r = 0.69), compared to r = 0.98 for Angio % delta D and EF, both from Angio visualization. However, if valvular disease patients are excluded, the correlation improves to 0.82. The mechanisms for these disparities include increased sphericity as the ventricle dilates, and in the case of valvular disease where the EF is better for any degree of dilatation, the echo measurement errors for EDD and ESD are different.

Adolescent↗
PubMed1983

Assessment of ventricular function by combined noninvasive measures: factors accounting for methodologic disparities.

We studied the predictive accuracy and disparities among cineventriculographic ejection fraction, pre-ejection period over left ventricular ejection time (PEP/LVET) obtained from the systolic time intervals and the percent shortening of the internal echocardiographic diameter (% delta D) in assessing left ventricular performance in 453 consecutive patients without valvular heart disease. In 308 patients all three tests were normal, and in 78 patients all three tests were abnormal. Overall agreement (predictive accuracy) among ejection fraction (normal greater than or equal to 57), % delta D (normal greater than or equal to 28%) and PEP/LVET (normal less than or equal to 0.42) was 85%. In 67 patients disparities among the tests as measures of global left ventricular performance were found. The major mechanisms accounting for such disparities were: (a) large segmental contraction abnormalities which selectively distort the % delta D and ejection fraction and (b) diminished isovolumic pressure (less than 45 mmHg) which distorts PEP/LVET. When patients with segmental contraction abnormalities and low isovolumic pressure were excluded the agreement between PEP/LVET and ejection fraction was 97%, ejection fraction and % delta D 98% and PEP/LVET and % delta D 97%. The combined uses of systolic time intervals and echocardiogram minimizes error due to segmental contraction abnormalities and isovolumic pressure. If both PEP/LVET and % delta D are concordant the agreement with ejection fraction is 94% for normal and 99% for abnormal left ventricular function.

Adult↗
PubMed1983

Comparison between electrophysiologic studies and ambulatory monitoring in patients with syncope.

The efficacy of 24-hour ambulatory monitoring and electrophysiologic studies was determined in sixty-five patients with a history of syncope or pre-syncope. Patients with an obvious cause of syncope and/or significant arrhythmias on the resting ECG were excluded. Monitoring and electrophysiologic studies were performed within one week. Arrhythmias and/or electrophysiologic abnormalities which were considered to be the cause of syncope or pre-syncope were detected with monitoring in 31 patients and with electrophysiologic studies in 42 patients. By combining both methods symptoms were explained in 51 patients (78%). In 22 of the patients arrhythmias were detected with both methods. Thus, in a group of patients with no obvious cause of syncope, abnormalities were readily detected with monitoring and electrophysiologic studies. These methods are complimentary and should be used (monitoring usually first) in the appropriate symptomatic patient.

Arrhythmias, Cardiac↗
PubMed1983

Effect of hemodialysis on left ventricular performance.

Systolic time intervals (STI) and echocardiograms (Echo) were performed before and 30 min after hemodialysis (H) in 19 stable patients (pts) with chronic renal failure undergoing maintenance H. The % shortening of the internal diameter (% delta D), the mean velocity of circumferential fiber shortening (VCF), and the ratio of the pre-ejection period to the left ventricular (LV) ejection time (PEP/LVET) were used as indices of LV performance; the electromechanical systole corrected for heart rate (QS2I) was used as an index of adrenergic activity. After hemodialysis, LV function was improved in 9 pts, Group (GI) and decreased in 10 pts (GII). Changes due to H are shown. The % delta D and VCF before H were normal in GI but abnormal in GII (31.6 +/- 1.4 vs 24.5 +/- 1.4 and 1.07 +/- 0.06 vs 0.88 +/- 0.04, respectively). Systolic blood pressure remained unchanged in GI but decreased in GII (-9.5 +/- 4 mm Hg, p less than 0.01). Body weight decreased significantly (p less than 0.05) and equally in both Gs (-1.2 +/- 0.03 in GI and -1.6 +/- 0.03 in GII). Serum electrolytes, creatinine, and hemoglobin were identical in both Gs before and after H. LV performance improved in pts with LV dysfunction before H, but decreased in pts with normal LV function before H. The decreased afterload in GII and the different effect of alterations in preload and afterload in the failing and normal LV most likely account for these changes. STI and Echo provide simple techniques to assess changes in LV function due to H and one is complementary to the other.

Adult↗
PubMed1983

Anthropometric characteristics, cardiac abnormalities and adrenergic activity in patients with primary disorders of sleep.

Sixty-one patients (pts) with sleep apnea (SA), 35 with narcolepsy (N) and 24 with idiopathic hypersomnolence (H) were studied in the Clinical Research Center. The height to body weight ratio was less than normal in SA pts (0.32 +/- 0.01 vs 0.45 +/- 0.01, p less than 0.01), but normal in N and H pts (0.45 +/- 0.02 and 0.45 +/- 0.01, respectively). Twenty-four hour urinary epinephrine (E) plus norepinephrine (NE) was greater than normal (p less than 0.01), but not different among SA, N and H pts. The incidence of mitral valve prolapse (MVP) was greater in N (49%) and H (58%) compared to SA (20%) (p less than 0.01). The ratio of the pre-ejection period to the left ventricular ejection time (PEP/LVET) was abnormal (greater than 0.42) in 36% of the pts with SA and only in one pt with N and H (p = 0.02). The % shortening of the echocardiographic internal diameter (% delta D) was abnormal (less than 28%) in 28% of pts with SA and normal in all pts with N and H (p = 0.02). The incidence of malignant ventricular dysrhythmias (24 hour Holter) was 26% in SA, 3% in N and 4% in H (p = 0.04). Thus, pts with impaired alertness have high adrenergic tone despite evidence for a role of catecholamines in wakefulness. Left ventricular dysfunction, malignant dysrhythmias and obesity are common findings in SA, while MVP is very common in N and H.

Adult↗
PubMed1983

Effect of physical training on exercise hemodynamics in patients with stable coronary artery disease. The use of impedance cardiography.

Seventeen consecutive patients with stable coronary artery disease with a previous history of myocardial infarction were studied for evaluation of the effect of physical training on exercise hemodynamics. The patients were divided into two groups: Group A (n = 10), the control group and Group B (n = 7), the rehabilitated group. Patients in Group B had physical training for five months. The mean exercise time in Group B (trained group) was significantly greater than in Group A (17.0 +/- 3.3 vs 11.6 +/- 3.2, p less than 0.01). Cardiac output was measured by impedance cardiography. The resting hemodynamic parameters were not statistically different between the two groups. At sub-maximal levels of exercise, the blood pressure X heart rate product was the same in both groups. At maximal workload, the heart rate X blood pressure product was the same in both groups, while the cardiac output was significantly greater in Group B compared to Group A (16.0 +/- 5.7 vs 12.1 +/- 3.2 1/min, p less than 0.001). These results suggest that physical training may improve cardiac function during exercise.

Blood Pressure↗
PubMed1983

Hemodynamics in acute myocardial infarction the use of impedance cardiography.

Thirty-two consecutive patients with acute myocardial infarction (AMI) were studied during the first seven days following AMI. The stroke volume was measured by impedance cardiography. The patients were divided into two groups: Group A (n = 22), with clinically uncomplicated myocardial infarction and Group B (n = 10) with evidence of congestive failure, but not of pulmonary edema. Patients in Group B had predominantly anterior wall myocardial infarction compared to Group A (p less than 0.05). The heart rate was significantly greater in Group B compared to Group A (p = 0.0002). The systolic blood pressure, the mean blood pressure, stroke volume index, and left ventricular stroke work index were significantly lower (p less than 0.05) in Group B than Group A. Impedance cardiography can be easily applied to follow the course of the patients during the acute phase of myocardial infarction.

Adult↗
PubMed1983

Heart rate responsiveness after sustained chronotropic stimulation with a beta 1-adrenergic receptor agonist.

Six normal male human subjects underwent two 72 hr infusions of saline (control) and butopamine, a beta-adrenergic agonist with strong positive chronotropic properties, in order to determine the chronotropic responsiveness of the human heart after sustained chronotropic stimulation. Chronotropic responsiveness was assessed by heart rate responses to intravenous isoproterenol and bicycle ergometry before and serially over 50 hr after discontinuation of the infusions. Chronotropic responsiveness to isoproterenol and exercise was reduced significantly in the butopamine group compared to control; this blunted chronotropic effect persisted beyond 48 hr. Positive inotropic responsiveness, assessed by echocardiography and systolic time intervals, was reduced modestly for the butopamine-treated group up to 24 hr after infusion. Although the precise mechanisms are not fully elucidated, continuous chronotropic stimulation of the human heart with the beta 1 agonist, butopamine, elicits a significant reduction in the heart rate response to isoproterenol and exercise challenges. In addition, the degree and time course of suppression of the chronotropic vs. inotropic responsiveness are disparate.

2-Hydroxyphenethylamine↗
PubMed1982

The QT greater than QS2 syndrome: a new mortality risk indicator in coronary artery disease.

In the normal population the duration of electrical systole (QT) is shorter (mean -26 +/- 13 ms, 1 standard deviation) than that of electromechanical systole (QS2), which it closely parallels throughout the range of resting heart rate. This close association prompted the hypothesis that the duration of QT may be more closely linked physiologically to QS2 than to the heart rate and hence may provide a more potent prognostic indicator than the relation of QT to heart rate. The present study was designed to test this hypothesis. On hundred stable patients 14 months after myocardial infarction were followed up an average of 43 months. Twenty patients had prolongation of QT relative to QS2 (QT greater than QS2) and 13 patients had long QT corrected for heart rate (QTc). There were 20 deaths (16 sudden). The cumulative 5 year survival rate was 35% in patients with QT greater than QS2 and 91% in patients with QT greater than or equal to QS2 (p less than 0.001). There was no significant difference in survival in patients with long QTc compared with patients with normal QTc (69 versus 82%). Univariate and multivariate analysis for the association of QT greater than QS2 with known risk factors, clinical descriptors, drug therapy, systolic time intervals (preejection period/left ventricular ejection time), and frequency of 1, 2 and 3 vessel coronary occlusive artery disease revealed that only the presence of abnormal preejection period/left ventricular ejection time added significantly to the presence of QT greater than QS2 in stratifying 5-year survival into high and low risk groups. Thus, in patients with coronary artery disease, the presence of QT greater than QS2 provides a new risk indicator that is more potent than QT corrected for heart rate.

Aged↗
PubMed1982

Effects of hydralazine on coronary blood flow and myocardial energetics in congestive heart failure.

The acute effects of oral hydralazine, 1 mg/kg, on coronary vascular resistance, coronary blood flow (estimated using the coronary sinus thermodilution technique), and myocardial oxygen consumption were evaluated in 10 patients with chronic (New York Heart Association class III and IV) nonischemic congestive heart failure. Central hemodynamic responses demonstrated a modest decrease in mean arterial pressure, pulmonary capillary wedge pressure and systemic vascular resistance (12%, 15% and 29%, respectively), while the cardiac index increased from 2.3 +/- 0.1 to 3.1 +/- 0.3 and left ventricular stroke work index from 24 +/- 3.7 to 28 +/- 3.4 (p less than 0.01). Heart rate and diastolic filling time did not change. Coronary blood flow increased approximately 50%, from 144 +/- 17 to 218 +/- 30 ml/min, and coronary vascular resistance decreased from 0.55 +/- 0.09 to 0.36 +/- 0.08 mm Hg/ml/min (both p less than 0.01). Oral hydralazine increased myocardial oxygen consumption by 33%, from 15 +/- 1.6 to 20 +/- 2.7 ml/min. Despite this moderate augmentation in myocardial oxygen consumption, the arterial-coronary sinus oxygen difference decreased from 104 +/- 6.2 to 94 +/- 7.5 and the myocardial oxygen extraction ratio decreased from 71% to 64% (both p less than 0.05). The ratio of coronary vascular resistance to systemic vascular resistance decreased with hydralazine therapy, while coronary blood flow increased from 3.5% to 4.3 % of total cardiac output. In this group of patients with nonischemic cardiomyopathy, hydralazine had a favorable effect on the coronary circulation and improved the critical myocardial oxygen supply-demand ratio.

Adult↗
PubMed1982

The effect of vasodilator therapy on systolic and diastolic time intervals in congestive heart failure.

To determine the effects of vasodilator drugs on systolic and diastolic time intervals in patients with congestive heart failure, these noninvasive measurements were made in 50 patients with moderately severe disease before and after vasodilator therapy. These data were compared with direct hemodynamic measurements obtained simultaneously from a flow-directed triple-lumen pulmonary artery catheter placed in each patient. Oral vasodilators included isosorbide dinitrate 20 mg (n-8), hydralazine 75 mg (n-8), and 100 mg (n-8), and first-dose prazosin 2 mg (n-8) and 5 mg (n-8). Ten additional patients received intravenous dose-response infusions of isosorbide dinitrate, nitroglycerin, and nitroprusside. Increases in cardiac output and stroke volume effected a decrease (improvement) in the systolic time interval parameter of ventricular performance, PEP/LVET. The correlation coefficient for vasodilator-induced changes in cardiac output vs changes in PEP/LVET was -0.82 (P less than 0.05) and for changes in stroke volume and PEP/LVET was -0.75 (P less than 0.05). In general, the diastolic time period was not significantly affected by these drugs. The systolic time intervals are a simple and useful method for evaluation of vasodilator therapy in patients with congestive heart failure.

Administration, Oral↗
PubMed1982

Effect of beta-adrenergic blockade on physiologic growth in the Wistar rat.

The effect of propranolol (Pr) on body weight was studied in 144 Wistar rats of both sexes from weaning to 17 weeks of age. Pr was administered to 77 of these rats (chosen at random), in a dose of 100 mg/kg body weight daily. Body weights were monitored every third day throughout the study. During their 17th week of age, all the rats were weighed for the last time and then sacrificed. The following organs were carefully dissected and weighed: brain, thymus, lungs, heart, liver, kidneys, adrenals, testes and ovaries. Gain in body weight was significantly reduced in the propranolol treated animals compared to control in both sexes. Organ weights were also less in propranolol-treated rats except for the kidneys of both sexes and the heart and testes of the males. However, the ratio of most organ weights per body weight was greater, indicating that the inhibition of weight gain was less severe in those organs compared to that of total body weight.

Adrenergic beta-Antagonists↗
PubMed1982

Effect of afterload on left ventricular performance in experimental animals. Comparison of the pre-ejection period and other indices of left ventricular contractility.

Afterload reduction has become a routine treatment of patients with severe heart failure. In order to investigate the effect of afterload changes on indices of left ventricular performance, seven anesthetized dogs were studied. Serial alterations of afterload were produced with sodium nitroprusside and methoxamine infusions while the heart rate was maintained constant with right atrial pacing (120/min). High fidelity left ventricular (LV) pressure, aortic pressure (AoP) and systolic time intervals (STI) were measured simultaneously as a control and each time with the AoP changes. LV max dp/dt was measured by an RC differentiation and DP/DT was calculated from the pressure pulses and systolic time intervals. Each change in AoP resulted in a significant change in isovolumic pressure (IP) and the changes were parallel. Changes in pre-ejection period (PEP) and LV max (dp/dt)/(IP) were parallel changes in IP. A significant direct relationship was found between changes in IP and PEP, and an inverse relationship existed between changes in PEP and LV max (dp/dt)/(IP). Changes in LV max dp/dt and calculated DP/DT were parallel and approached unity. Thus, afterload changes with resultant changes in IP directly alter PEP and inversely affect max (dp/dt)/(IP). These effects of pure afterload changes must be considered in clinical pharmacologic studies when LV contractility is evaluated. Furthermore, calculated DP/DT can be used to measure changes in max dp/dt because of the close relationship between these two parameters.

Animals↗