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Biomedical subjects

H Boudoulas

Publications and source records attributed to H Boudoulas.

At least 109 records · Page 6Linked to original sources
PubMed1987

Atrial septal defect: attenuation of respiratory variation in systolic and diastolic time intervals.

The effects of pathologic states on right and left ventricular function have been studied extensively. However, there have been few studies on the interrelations between right and left ventricular function in normal human subjects and in patients with disease. Respiratory effects on ventricular interrelations reflected by diastolic time, right or left ventricular systolic time and ventricular performance (pre-ejection period/ejection time ratio) were studied in 12 normal subjects and 15 patients with a normal pressure-large shunt atrial septal defect. Simultaneous pulmonary artery (intracardiac manometer recordings) and left ventricular external recordings were performed in both groups. Left ventricular diastolic time increased with inspiration in the normal subjects and decreased in the patients with atrial septal defect (12.6 +/- 2.39 [1 SE] versus -13.4 +/- 3.48 ms, p less than 0.001). Left ventricular systolic time and ejection time decreased with inspiration in the normal group and remained unchanged in the patient group (-7.6 +/- 0.95 versus -0.9 +/- 0.77 ms, p less than 0.001 and -10.4 +/- 1.09 versus -1.7 +/- 0.80 ms, p less than 0.001, respectively). Left ventricular pre-ejection period/ejection time ratio increased with inspiration in the normal subjects and remained unchanged in the patients with atrial septal defect (0.03 +/- 0.008 versus 0 +/- 0.01, p less than 0.01). Right ventricular diastolic time decreased with inspiration in normal and patient groups (-8.8 +/- 1.6 versus -17 +/- 3.87 ms).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Stereoselective effects of disopyramide enantiomers in humans.

The effects of 100 mg of (S+)- and R(-)-disopyramide infused over 20 min on systolic time intervals and the QT interval were compared in five healthy volunteers. S(+)-disopyramide maximally prolonged the QTI (QT corrected for heart rate) by 10% (p less than 0.05); R(-)-disopyramide had no effect on QTI. R(-)-disopyramide maximally prolonged the preejection period and shortened the left ventricular ejection time corrected for heart rate (PEPI and LVETI), and increased the ratio of PEP/LVET by 32, 6, and 52%, respectively; S(+)-disopyramide maximally increased PEPI and PEP/LVET 15 and 20%, respectively (p less than 0.05), and had no effect on LVETI. These data suggest that the electrophysiologic effects of disopyramide enantiomers are different, and that S(+)-disopyramide has a less negative inotropic effect than R(-)-disopyramide. Changes in response were fitted to a pharmacokinetic-pharmacodynamic model, which estimated that 72% of the negative inotropic effects associated with racemic disopyramide may be avoided by using S(+)-disopyramide.

Adult↗
PubMed1987

The mitral valve prolapse epidemic: fact or fiction.

In spite of two decades of research, the precise relationship of anatomic mitral valve prolapse (floppy valve) to the neuroendocrine disorder (MVP syndrome) remains unclear. In all likelihood they are two separate genetic disorders which travel together in some fashion. Mitral valve prolapse is a common disorder but progressive mitral regurgitation usually occurs late in life and in only a few patients. Other complications such as bacterial endocarditis, stroke, and sudden death are far less common but can occur at younger ages. The neuroendocrine syndrome in civilian life is mainly seen in young females (interestingly the peak incidence years correspond to peak female sex hormone output) but can be seen in males when subjected to unusual stress such as military service. More recent echocardiographic studies have questioned whether all prolapsing valves are truly abnormal. It has been shown that echographic prolapse can be produced in normal subjects by reducing venous return and impaired venous return may be present in some patients with the MVP syndrome. However, clicks and murmurs are apparently not heard when normal valves prolapse. It is our opinion that the presence of a click or typical murmur requires some anatomic abnormality of the mitral valve. One wonders if minimal valve abnormality (noted and dismissed by Davies) is the valve abnormality present in many young females with MVP syndrome, and that it may remain a mild abnormality throughout life. Recent psychiatric studies suggest that MVP is present in 30% of patients with Panic Disorder. It is not clear that this psychiatric syndrome is the same thing as the MVP syndrome. In Devereux's study, anxiety proneness was no different in the MVP cohort than in relatives without MVP. It is possible that diagnostic mixing of two similar but separate disorders has occurred, as has been the case since World War I. Perhaps the most important question is whether young patients with MVP syndrome and no echocardiographic criteria for "floppiness" will develop progressive mitral regurgitation or other complications in later life. In other words, how often is MVP syndrome in a young individual without echocardiographic evidence of a floppy valve a precourser to eventual progressive mitral regurgitation? Are there two different populations? Because of the long course of the disorder, several more years of observation (and, it is hoped, prospective longitudinal study) will be required to answer this question.

Female↗
PubMed1986

Left ventricular mass and systolic performance in chronic systemic hypertension.

This study was undertaken to define the relation between the extent of left ventricular (LV) hypertrophy and ventricular systolic performance in patients with chronic systemic hypertension. Ninety patients with chronic systemic hypertension were compared with 41 normal subjects as determined by angiography. LV mass was estimated from the M-mode echocardiogram. Patients were separated into 3 groups: those with LV mass of less than 2 (group I, n = 58), 2 to 4 (group II, n = 21) and more than 4 (group III, n = 11) standard deviations above mean normal. The ratio of preejection period to LV ejection time (PEP/LVET), percent shortening of the echocardiographic internal diameter (% delta D) and velocity of circumferential shortening (Vcf) were used as indexes of LV systolic performance. The frequency of abnormality, expressed as percent of patients in groups I, II and III, was 33%, 55% and 85% for PEP/LVET, 15%, 35% and 72% for % delta D, and 0%, 15% and 55% for Vcf. For each group PEP/LVET was the most frequently abnormal measure and Vcf was the least frequent abnormality. Calculation of peak and end-systolic wall stress was used as an index of the adequacy of LV hypertrophy. This index was significantly reduced in group I, did not differ from control in group II and was significantly increased in group III, indicating that hypertrophy was appropriate to wall tension in groups I and II. It is concluded that the occurrence of LV dysfunction with increasing LV mass in patients with moderate LV hypertrophy (group I and II) reflects a deficiency in intrinsic contractile performance of the hypertrophied myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Prolonged electrical systole and QT greater than QS2 secondary to coronary artery disease.

Dyssynchronous depolarization-repolarization in the left ventricular (LV) myocardium may produce QT greater than QS2 or long QT. In 41 patients with coronary artery disease (CAD) and LV aneurysm, 46 patients with CAD and a history of acute myocardial infarction (AMI) but no LV aneurysm, and 52 patients with CAD without previous AMI, QT and QS2 were measured simultaneously at a speed of 100 mm/s within 48 hours of cardiac catheterization. Patients receiving class I antiarrhythmic drugs were excluded. The incidence of QT greater than QS2 was significantly greater in patients with LV aneurysm (71%) than in those with previous AMI (22%) and those with CAD but no previous AMI (20%) (p less than 0.001). Likewise, the incidence of long QT corrected for heart rate was significantly greater in patients with LV aneurysm (54%) than in those with previous AMI (7%) and those with CAD and no previous AMI (6%) (p less than 0.0001). The incidence of QT greater than QS2 in another 19 patients with previous AMI who were receiving digitalis therapy was significantly greater (65%) than in those with previous AMI but not receiving digitalis therapy (22%) (p less than 0.001). The incidence of long QT corrected for heart rate and QT greater than QS2 was not statistically different between patients with previous AMI and those with CAD but no previous AMI. The QT greater than QS2 or long QT in patients with aneurysm is probably a result of dyssynchronous depolarization or repolarization within or in the border zone of the LV aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Effect of acute standing and prolonged upright activity on left ventricular hemodynamics, systolic and diastolic intervals, and QT-QS2 relationship.

It is generally accepted that upright posture decreases preload and afterload, which could alter left ventricular (LV) performance. It is not known if changes occurring with acute standing persist after prolonged ambulatory activity (amb-act). In seven normal subjects echocardiographic end-diastolic and end-systolic diameters, percent shortening of the internal diameter (% delta D) and end-systolic wall stress (ES-WS), radionuclide diastolic volume and ejection fraction, preejection period over left ventricular ejection time (PEP/LVET), and diastolic time and QT-QS2 were measured supine, within 1 to 2 minutes after standing and after prolonged (60 minutes) amb-act. In addition, serial measurements were performed in PEP/LVET for 105 minutes at 15-minute intervals. With acute standing, end-diastolic diameter, diastolic volume, and ES-WS decreased (p less than 0.01); heart rate and PEP/LVET increased (p less than 0.01); while % delta D and ejection fraction remained unchanged. There was an inverse correlation between change in PEP/LVET and diastolic diameter (r = -0.59), but no correlation between PEP/LVET and ES-WS. The diastolic time per beat and per minute decreased (375 +/- 115 msec from 519 +/- 176 msec [p less than 0.01] and 31.3 +/- 4.2 sec/min from 33.7 +/- 4.5 sec/min [p less than 0.01]). The QT-QS2 increased when compared to supine (-7 +/- 7.6 msec from -22 +/- 7.7 msec [p less than 0.005]), but the QT-QS2 relationship remained normal (QT less than or equal to QS2). All the dynamic changes that occurred with acute standing tended to persist during prolonged amb-act.

Adult↗
PubMed1985

The therapeutic implications of diastolic time changes in systemic hypertension.

Twenty-five patients with chronic systemic hypertension were studied. Systolic time intervals and diastolic time were determined at baseline and after 12 weeks of therapy with nadolol, with or without bendroflumethiazide (treatment phase I), then after 12 weeks of therapy with hydralazine, bendroflumethiazide, or both (treatment phase II). Systolic, diastolic, and mean blood pressures were equally controlled after either treatment regimen. Heart rate was significantly slower after treatment phase I compared to baseline or after treatment phase II (p less than 0.001). Systolic time per minute was significantly shorter and diastolic time per beat and per minute were significantly longer after treatment phase I compared to baseline or after treatment phase II (p less than 0.001). Double and triple products decreased after either mode of therapy; however, these parameters were significantly lower after treatment phase I compared to treatment phase II (p less than 0.01). These changes in systolic and diastolic time and double and triple products may be of clinical significance during therapy of chronic systemic hypertension and may help explain the regression of left ventricular hypertrophy in patients with hypertension treated with sympathetic blocking agents.

Adult↗
PubMed1985

Prevention of bedrest-induced physical deconditioning by daily dobutamine infusions. Implications for drug-induced physical conditioning.

The effects of intermittent infusions of dobutamine were studied in young normal male subjects during a period of bedrest deconditioning to determine whether this synthetic catechol affects physical conditioning processes in humans. 24 volunteers were placed at bedrest and randomized to daily 2-h treatments of saline infusions (control), dobutamine infusions, or maintenance exercise (control). Exercise, hemodynamic, and metabolic studies were performed at base line and at the termination of the 3-wk treatment period. Maximal exercise (duration, oxygen consumption, and workload) fell for the saline group and remained unchanged for the dobutamine and exercise groups. Hemodynamics during exercise were maintained the same as pretreatment base line for the dobutamine and exercise groups, whereas stroke volume and cardiac output dropped and heart rate rose for the saline group. The metabolic profile showed an increased blood lactate response at rest and during submaximal exercise after 3 wk of bedrest for the saline group, and essentially no change for the exercise and the dobutamine groups. Extraction of oxygen across the exercising lower limb rose for the dobutamine group, as did the activity of the skeletal muscle oxidative enzymes, citrate synthetase, and succinate dehydrogenase. In contrast to the exercise control group, the saline and dobutamine groups developed orthostatic hypotension, tachycardia, and accentuation of the renin-aldosterone response over the 3-wk treatment period; for the saline group, this is best explained by the observed fall in blood volume and for the dobutamine group, by the blunting of vascular vasoconstrictive responses. During a period of bedrest deconditioning in humans, infusions of dobutamine maintain many of the physiologic expressions of physical conditioning.

Adult↗
PubMed1985

Quantitation of pulmonary emboli with pulmonary cineangiography: preliminary report.

Pulmonary angiography is considered the definite method of diagnosing pulmonary emboli. It is hypothesized that pulmonary cineangiography is superior to conventional pulmonary angiography for quantitation of pulmonary emboli. The present study was undertaken to test the hypothesis. Six patients with an age range from 27 to 70 years with documented pulmonary emboli by pulmonary angiogram, had pulmonary cineangiograms. Pulmonary angiogram defined pulmonary emboli in nine major vessels in the six patients; while, pulmonary cineangiogram revealed another 10 major vessels with pulmonary emboli, which were either not detected or considered equivocal by the conventional pulmonary angiography. The pulmonary embolic score as an index of the extent of pulmonary emboli was 24 (mean 4 +/- 2.52 1SD) by the conventional pulmonary angiography, while the score was 60 (mean 10 +/- 3.22 1SD) by the pulmonary cineangiography, P less than 0.2. Thus, in cases with pulmonary emboli, pulmonary cineangiogram is superior to conventional pulmonary angiogram for the quantitation of pulmonary emboli.

Adult↗
PubMed1985

Arrhythmic syncope: what to do when ambulatory monitoring is non-diagnostic.

The two new methods for defining arrhythmic syncope described in this report represent important additions to the traditional syncope workup. Both techniques uncovered a substantial number of arrhythmic causes of syncope which had not been found by standard techniques. A major strength of each method is that symptoms can be directly related to the arrhythmia. The 68% incidence of diagnostic EPS abnormalities which we found was identical to the study of DiMarco but higher than reported by others (which have ranged from 12 to 48%) (18, 20, 21). More critical patient selection and more comprehensive study techniques most likely account for these differences. It is our opinion that a significant number of patients whose diagnosis was "syncope of undetermined etiology" in previous studies did indeed have an arrhythmic basis for their symptoms which was not identified. At this point the issue of "cost effectiveness" inevitably arises. Do all patients with syncope in whom a cause is not initially apparent (i.e., up to 50% of such patients) require either TTEM or EPS? The answer is obviously no, not for this whole population. However, the evident power of TTEM and EPS requires that the question should be raised. Furthermore, the results of the invasive EPS study strongly suggest that mortality and morbidity can be reduced. Table 11 shows the relative costs for all of the diagnostic tests for arrhythmic syncope. From this it can be seen that TTEM is quite inexpensive and therefore very cost-effective. It is an ideal adjunct to 24 hour ambulatory monitoring in selected patients. Although invasive EPS studies are costly, it is not difficult to incur equal costs by use of several days of prolonged monitoring, especially if done in the hospital. Thus, in identified patients with abnormal but "not diagnostic" ambulatory monitoring studies, patients with abrupt syncope, patients with frequent symptoms or patients with known underlying heart disease, further evaluation with TTEM or EPS should be strongly considered.

Arrhythmias, Cardiac↗
PubMed1984

Identification of patients with improved survival following coronary bypass surgery.

This study was designed to determine whether left ventricular performance measured noninvasively from the systolic time intervals could identify patients in whom coronary bypass surgery may improve survival. 71 patients with two- or three-vessel disease undergoing coronary bypass surgery were compared with 78 matched medically treated patients. All patients had recuperated from myocardial infarction by a mean of 17.6 months when systolic time intervals were performed. Surgical and medical patients were classified preoperatively into those with normal and those with abnormal left ventricular performance by preejection period/left ventricular ejection time (PEP/LVET less than or equal to 0.42 and greater than 0.42, respectively). Survival was analyzed by life table and log-rank test. Cumulative 5-year survival in patients with normal left ventricular performance was not statistically different in surgical and medical groups (96 vs. 93%, respectively). In contrast, cumulative survival in patients with abnormal left ventricular performance was significantly greater in the surgical group when compared to the medical group (84 vs. 62, p less than 0.01). Among the patients with abnormal left ventricular function, the mean PEP/LVET and the average vessel disease were not different in the medical and surgical groups. Multivariate analysis of 17 other clinical and laboratory risk variables were not different between these two groups. It is concluded that coronary bypass surgery my improve survival in patients with two- or three-vessel disease and left ventricular dysfunction.

Actuarial Analysis↗
PubMed1984

Mitral valve prolapse: a marker for anxiety or overlapping phenomenon?

In symptomatic mitral valve prolapse patients (MVP): (1) the frequency and nature of symptoms were analyzed (n = 313); (2) metabolic studies were performed (n = 20), and (3) the response to isoproterenol infusions were studied (n = 16). Chest pain is more often the initial symptom in men; palpitations are more common initially in women. Fatigue, palpitations, dyspnea and arrhythmias are more frequent in women. Chest pain and neurologic events occur with the same frequency in both sexes. Women have more symptoms than men. MVP patients have normal thyroid function tests, normal plasma cortisol, normal diurnal variation of cortisol and normal 24-hour 17-ketosteroids and 17-hydroxycortico-steroids excretion. They have a normal response to oral glucose but higher glucose and insulin levels than controls. MVP patients have increased 24-hour urinary catecholamine excretion. Isoproterenol infusions produce symptoms in a dose-related fashion in MVP patients but not in controls. Isoproterenol infusion-related symptoms included chest pain (7), extreme fatigue (6), dyspnea (6), dizziness (4), numbness (2), panic attacks (2). Isoproterenol infusions produced a greater increase in heart rate in MVP patients compared to controls. Thus, MVP patients have increased catecholamines and hyperresponse to isoproterenol infusion which indicates that their symptoms may be catecholamine related or mediated. The complex relationships of MVP symptoms are not clear; the coexistence of anxiety states and MVP is one explanation; another equally plausible explanation is that MVP may be a specific marker for the symptom complex.

Adrenal Cortex Hormones↗
PubMed1984

Fluoroimmunoassays for procainamide and N-acetylprocainamide compared with a liquid-chromatographic method.

We measured procainamide and its active metabolite, N-acetylprocainamide (NAPA), in 80 sera from 37 patients by a new fluorimmunoassay procedure and an established "high-performance" liquid-chromatographic method. Additive and proportional differences between the methods were 0.07 mg/L and 9%, respectively, for procainamide and 0.62 mg/L and 16% for NAPA. Between-day CVs by the chromatographic and immunoassay methods, respectively, were 3.9% and 2.2% for procainamide at a concentration of 6 mg/L, and 5.1% and 1.2% for NAPA (14 mg/L). We applied a modification of the fluoroimmunoassay for determination of procainamide concentrations, using sera obtained during a pharmacokinetic study, and demonstrated excellent agreement with the chromatographic method.

Acecainide↗
PubMed1984

Indocyanine green clearance following single and chronic cimetidine doses.

Twenty-five indocyanine green (ICG) clearance determinations were performed in four subjects in the presence of quinidine or propranolol before and after one week of treatment with cimetidine, 1200 mg/day, and following a single 600 mg cimetidine dose. There was no significant difference between the mean ICG clearance before cimetidine treatment and that after one week of therapy with cimetidine, while the mean ICG clearance was 25% lower following single cimetidine doses (p greater than 0.05). It is concluded that cimetidine has only a transient hepatic blood flow lowering effect.

Adult↗