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Biomedical subjects

B Massie

Publications and source records attributed to B Massie.

At least 127 records · Page 7Linked to original sources
PubMed1985

Long-term oral administration of amrinone for congestive heart failure: lack of efficacy in a multicenter controlled trial.

A number of uncontrolled studies have indicated that oral administration of amrinone, a phosphodiesterase inhibitor with potent positive inotropic effects in experimental preparations, may be beneficial in patients with chronic congestive heart failure. The present multicenter trial was designed to prospectively evaluate clinical response and change in exercise tolerance during 12 weeks of amrinone therapy in a double-blind, placebo-controlled protocol. Ninety-nine patients with NYHA functional class 3 or 4 congestive heart failure on digitalis and diuretics, of whom 31 were also receiving captopril, were enrolled. After baseline clinical assessment and determination of exercise tolerance, radionuclide left ventricular ejection fraction, and roentgenographic cardiothoracic ratio, patients were randomly assigned to receive amrinone or placebo, beginning at 1.5 mg/kg tid and increasing to a maximum dosage of 200 mg tid. After 12 weeks of therapy or at the last blinded evaluation in patients who did not complete this protocol, there were no significant differences from baseline values between treatment with amrinone or placebo with regard to symptoms, NYHA functional class, left ventricular ejection fraction, cardiothoracic ratio, frequency and severity of ventricular ectopy, or mortality. Exercise tolerance improved significantly from baseline by 37 +/- 10% (mean 163 sec) in patients on amrinone and 35 +/- 11% (mean 149 sec) in patients on placebo, but there was no significant difference between treatments. Adverse reactions were significantly more frequent and more severe on amrinone, occurring in 83% of patients and necessitating withdrawal in 34%.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1984

Monotherapy in mild to moderate hypertension: comparison of hydrochlorothiazide, propranolol and prazosin.

There has been recent interest in using nondiuretic drugs as initial antihypertensive therapy. Therefore, a study was designed to compare the efficacy and the effects on left ventricular function of hydrochlorothiazide, propranolol and prazosin in 13 patients with mild to moderate hypertension. After a 4-week washout period, patients were treated serially with each drug in a randomized order for 2 months each. Dosages were titrated until the patient showed a sitting diastolic blood pressure less than or equal to 90 mm Hg or to a maximum dosage of 100 mg/day of hydrochlorothiazide, 320 mg of propranolol and 20 mg of prazosin. Blood pressure was measured, plasma catecholamine concentrations were assayed and radionuclide determinations of rest and exercise left ventricular function and volume were made at the end of each period as well as after a second 1-month washout period at the end. In the sitting and standing positions, systolic and diastolic blood pressure control was equivalent for all 3 drugs. Goal blood pressure was achieved in 10 of 13 patients receiving hydrochlorothiazide, in 8 of 12 receiving propranolol and in 9 of 13 on prazosin. Importantly, 3 of 4 patients not controlled with prazosin, 5 of 6 uncontrolled with propranolol and 2 of 3 whose blood pressure was not reduced by hydrochlorothiazide were controlled when receiving 1 of the other medications. None of the drugs changed rest or exercise ejection fraction or volume, and side effects were minimal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Abnormal left ventricular filling: an early finding in mild to moderate systemic hypertension.

This study was undertaken to determine the prevalence and significance of diastolic left ventricular (LV) dysfunction in mild to moderate systemic hypertension. Rest and exercise equilibrium blood pool scintigraphy was performed in 39 hypertensive subjects (mean systolic blood pressure [BP] 156 +/- 14 mm Hg [+/- standard deviation]; mean diastolic BP 103 +/- 5 mm Hg) and 11 normal control subjects. These studies were analyzed for ejection fraction (EF), segmental wall motion, peak filling rate (PFR), time to PFR and filling fraction in the first third of diastole normalized for cycle length (first-third filling fraction). EF at rest was similar in the hypertensive patients and control subjects (0.63 +/- 0.09 versus 0.65 +/- 0.07); only 2 patients had a reduced EF. The EF response to exercise was normal in every hypertensive patient (increasing to a mean of 0.74 +/- 0.08); only 1 patient had asynergy. In contrast, even when the 2 patients with abnormal systolic function were excluded, each index of diastolic filling was significantly different from the control group. PFR was lower (2.29 +/- 0.49 vs 2.63 +/- 0.39 end-diastolic volumes per second [EDV/s], p less than 0.05), time to PFR was longer (199 +/- 47 versus 158 +/- 17 ms/s), p less than 0.01) and first-third filling fraction was smaller (0.38 +/- 0.11 vs 0.60 +/- 0.07, p less than 0.001). The latter index fell below the lowest normal value in 84% of the hypertensive patients. The degree of diastolic filling abnormality was not related to the patients' age, heart rate, BP, duration of systemic hypertension or systolic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

A detailed physical and genetic map of two R.ColBM IncFIII plasmids.

The cleavage and genetic maps of two closely related R.ColBM IncFIII plasmids, designated pSAS1201 and pSAS1203, are presented. Restriction analysis of both plasmids with SstI, EcoRI, Bg/II, XhoI, HindIII, and Sa/I indicated that the maps of these two plasmids are superimposable with the exception of a 1.70-MDa DNA segment absent in pSAS1203. Our results provide the first physical and genetic maps of plasmids belonging to the IncFIII incompatibility group.

Chromosome Mapping↗
PubMed1982

Deleterious effects of hydralazine in patients with pulmonary hypertension.

Thirteen consecutive patients with primary and secondary pulmonary hypertension who had normal left ventricular function were treated with hydralazine in an effort to reduce pulmonary vascular resistance and clinical symptoms. Despite marked decreases in systemic vascular resistance (40 per cent; P less than 0.001), hydralazine produced only moderate decreases in pulmonary arteriolar resistance (21 per cent), without improving stroke volume or pulmonary-artery pressure. Instead, mean arterial pressure fell markedly (17.5 mm Hg, P less than 0.01) in association with a reflex increase in heart rate (11 beats per minute, P less than 0.01). Four patients became symptomatically hypotensive within 24 hours of the initiation of treatment; two of these four required pressors for circulatory support, and one died. Progressive renal insufficiency developed in one patient, and a symptomatic decrease in systemic arterial oxygen saturation occurred in another; both changes were reversed upon discontinuation of the drug. In conclusion, hydralazine fails to produce consistent hemodynamic and clinical benefits in patients with primary and secondary pulmonary hypertension, and it frequently causes serious adverse reactions.

Adult↗
PubMed1982

Acute and long-term effects of captopril on exercise cardiac performance and exercise capacity in congestive heart failure.

Although many studies have shown that captopril (CPT) provides acute hemodynamic improvement in patients with severe congestive heart failure (CHF) at rest, little information is available concerning exercise hemodynamic responses to CPT or the effect of this drug on exercise tolerance in CHF. Therefore, we evaluated the hemodynamic effects of CPT at rest and during upright bicycle exercise in 15 patients with stable CHF. CPT (25 to 50 mg) reduces both resting heart rate and mean arterial pressure (84 +/- 11 to 78 +/- 7 bpm, p less than 0.025 and 85 +/- 9 to 64 +/- mm Hg, p less than 0.001). Concomitantly, left ventricular filling pressure dropped dramatically (26 +/- 9 to 15 +/- 7 mm Hg, p less than 0.001), while cardiac and stroke indices rose (2.0 +/- 0.5 to 2.5 +/- 0.6 L/min/m2, p less than 0.001, and 25 +/- 8 to 33 +/- 7 ml/m2, p less than 0.001). Similar directional changes occurred during exercise, with heart rate, mean arterial pressure, and left ventricular filling pressure at maximum exercise being less (123 +/- 15 to 115 +/- 16 bpm, p less than 0.01; 93 +/- 17 to 86 +/- 14 mm Hg, p less than 0.05; and 35 +/- 10 to 30 11 mm Hg, p less than 0.001, respectively) after CPT ingestion. Peak exercise cardiac index rose slightly (3.6 +/- 0.7 to 3.9 +/- 0.6 L/min/m2) but not significantly. Six patients followed long term on CPT underwent elective recatheterization after 3 months. In these, the beneficial hemodynamic changes seen acutely persisted or further improvement was noted, both at rest and during exercise. Most impressively, peak exercise cardiac index rose from 3.6 +/- 0.7 to 4.6 +/- 1.0 L/min/m2 (p less than 0.05), and this was associated with an increase in exercise duration (8.0 +/- 2.2 to 11.5 +/- 1.4 minutes, p less than 0.05) and exercise work load (332 +/- 32 to 468 +/- 52 kp-m/min, p less than 0.05). These findings indicate that in patients with severe CHF, oral CPT provides markedly beneficial augmentation of cardiac function during activity as well as at rest; moreover, chronic CPT therapy substantially increases exercise capacity in this setting.

Aged↗
PubMed1982

Hemodynamic and radionuclide effects of acute captopril therapy for heart failure: changes in left and right ventricular volumes and function at rest and during exercise.

Although the resting hemodynamic effects of captopril in congestive heart failure are known, little information is available about the hemodynamic response to captopril during exercise or about changes in noninvasive measurements of the size and function of both ventricles. In this study, 14 stable New York Heart Association class III patients were given 25 mg or oral captopril. Rest and exercise hemodynamic measurements and blood pool scintigrams were performed simultaneously before and 90 minutes after captopril. The radionuclide studies were analyzed for left and right ventricular end-diastolic volumes, end-systolic volumes, ejection fractions and pulmonary blood volume. The primary beneficial responses at rest were decreases in left and right ventricular end-diastolic volumes from 388 +/- 81 to 350 +/- 77 ml (p less than 0.01) and from 52 +/- 26 to 43 +/- 20 volume units (p less than 0.01), respectively, and in their corresponding filling pressures, from 24 +/- 10 to 17 +/- 9 mm Hg and 10 +/- 5 to 6 +/- 5 mm Hg (both p less than 0.001). Although stroke volume did not increase significantly, both left and right ventricular ejection fractions increased slightly, from 19 +/- 6% to 22 +/- 5% and from 25 +/- 9% to 29 +/- 11%, respectively (both p less than 0.01). During exercise, similar changes were noted in both hemodynamic and radionuclide indexes. Thus, in patients with moderate symptomatic limitation from chronic heart failure, captopril predominantly reduces ventricular volume and filling pressure, with a less significant effect on cardiac output. These effects persist during exercise, when systemic vascular resistance is already very low. Radionuclide techniques are valuable in assessing the drug effect in these subjects, particularly when ventricular volumes are also measured.

Aged↗
PubMed1982

Hemodynamic differences between supine and upright exercise in patients with congestive heart failure.

Although the differences in hemodynamic responses to supine and upright exercise have been studied in normal subjects and in patients with angina pectoris, no such comparison has been made in patients with congestive heart failure. Many investigators measure exercise hemodynamics in heart failure patients to assess the effect of vasodilator and inotropic drugs. Both modes of exercise have been used and have often yielded differing results. We compared the hemodynamic response to supine and upright exercise in 14 patients with stable, New York Heart Association class III chronic heart failure. During upright exercise, peak heart rate was higher (124 +/- 15 vs 115 +/- 18 beats/min, p less than 0.025) and peak mean arterial pressure was lower (102 +/- 15 vs 95 +/- 17 mm Hg, p less than 0.25), yielding similar double products. Although the peak left ventricular filling pressure was slightly lower during upright exercise (40 +/- 7 vs 35 +/- 10 mm Hg, p less than 0.05), the maximum cardiac and stroke indexes were not significantly different (3.6 +/- 0.8 vs 3.4 +/- 0.8 l/min/m2 and 30 +/- 8 vs 30 +/- 6 ml/m2, upright vs supine exercise). In contrast to these relatively similar hemodynamic responses, exercise capacity was significantly greater during upright exercise (peak work load 336 +/- 84 vs 293 +/- 73 kpm/min, p less than 0.1; maximum oxygen consumption 12.1 +/- 2.4 vs 9.8 +/- 1.9 ml/min/kg, p less than 0.001). We conclude that either exercise method may be used to assess the hemodynamic effects of drugs, but that exercise capacity should be measured in the upright position.

Aged↗
PubMed1981

Contrast enhancement of thallium-201 myocardial scintigrams: improved sensitivity with diminished specificity in coronary disease detection.

Thallium-201 myocardial scintigraphy (TMS) has become an increasingly popular noninvasive technique with a high diagnostic specificity, but a somewhat lower sensitivity for coronary disease (CAD) detection. Many centers now routinely employ computer techniques to contrast enhance scintigrams, but the resulting changes in sensitivity and specificity have not been carefully evaluated. In the present study, three observers with different levels of experience blindly interpreted both unprocessed and enhanced exercise TMS from 40 patients with CAD and from 15 without significant obstructions. The sensitivity for CAD achieved by each observer was higher with the enhanced scintigrams (increase from an average of 80% to 93%), but there was concomitant loss of specificity (from 93% to 73%). Similarly, significant changes were present in the sensitivity and specificity with which ischemic regions were diagnosed. In addition, contrast enhancement facilitated interpretation of TMS studies, particularly in making comparisons between exercise scintigrams and subsequent rest or redistribution images. Contrast enhancement affected the interpretations of the inexperienced observer most significantly. We conclude that contrast enhancement improves TMS sensitivity but results in some loss of specificity. The variable effect of enhancement on observers with different levels of experience suggests that laboratories should critically evaluate their own results before routinely employing computer processing.

Computers↗
PubMed1981

Long-term vasodilator therapy for heart failure: clinical response and its relationship to hemodynamic measurements.

To assess the clinical efficacy of chronic vasodilator therapy for refractory congestive heart failure, the long-term follow-up (mean 13 months, range 3-30 months) was evaluated in 56 patients treated with hydralazine, usually in combination with nitrates. In the first 6 months, 73% improved subjectively and 59% improved by one or two New York Heart Association classifications; early improvement was usually sustained. Mortality was high, 22% at 6 months and 37% at 12 months, but was significantly lower in patients who had a clinical response to vasodilators (21% in responders vs 55% in nonresponders at 1 year). The only clinical indicator that differentiated responders from nonresponders was the presence or absence of symptomatic progression before initiation of vasodilator therapy. Pulmonary artery pressure, pulmonary capillary wedge (PCW) pressure and stroke work index (SWI) before and during vasodilator therapy correlated with clinical response and survival. Fifteen of 20 patients with PCW < 20 mm Hg and SWI greater than or equal to 30 g-m/m2 improved and survived, compared with two of 19 with PCS greater than or equal to 20 mm Hg and SWI < 30 g-m/m2. Patients who did not have acute hemodynamic improvement generally did not improve clinically, but neither the percentage change nor the absolute change in any hemodynamic variable predicted outcome in the remaining patients. The findings of this study indicate that vasodilators produce clinical improvement in many patients with refractory heart failure and that hemodynamic measurements are helpful in predicting the outcome of therapy.

Blood Pressure↗
PubMed1981

Postural hypotension and tachycardia during hydralazine--isosorbide dinitrate therapy for chronic heart failure.

Supine and upright hemodynamic measurements were performed in 10 patients with chronic congestive heart failure, before and during vasodilator therapy with hydralazine and isosorbide dinitrate. This combination of drugs produced significant improvement in supine hemodynamic measurements, with the pulmonary capillary wedge pressure decreasing from 26 +/- 5 to 18 +/- 5 mm Hg (mean +/- SD, p less than 0.01) and stroke volume index increasing from 25 +/- 6 to 39 +/- 6 ml/m2 (p less than 0.01), without any significant change in heart rate (HR) or mean arterial pressure (MAP). However, with the patients upright, HR rose significantly (87 +/- 17 to 99 +/- 17 beats/min, p less than 0.05) and MAP fell (84 +/- 10 to 66 +/- 11 mm Hg, p less than 0.001) compared with measurements before treatment. These patients also exhibited potentially deleterious postural changes in HR, MAP, cardiac output, stroke volume index and stroke work index during therapy with the combination of hydralazine and isosorbide dinitrate. Although diuretic therapy (which had been withheld for 12 hours in eight subjects but only for 6 hours in two others) may have played a role in producing these changes, postural hypotension or tachycardia was not noted before vasodilator therapy or during therapy with nitrates or hydralazine. Repeat catheterization after 3 months in six patients revealed a lessening of the postural effects. These findings indicate the need to perform upright as well as supine hemodynamic measurements during the initiation of vasodilator therapy and suggest the need for particular caution in patients with ischemic heart disease.

Heart Failure↗
PubMed1981

Electrophysiologic effects on combined autonomic blockade in patients with sinus node disease.

Thirty-two patients were studied before and after i.v. administration of 0.15-0.20 mg/kg of propranolol. Twenty-one of the 32 underwent combined autonomic blockade with the additional infusion of 0.04 mg of atropine. Twenty other patients with sinus node disease underwent electrophysiologic studies both before and after i.v. administration of 0.04 mg of atropine alone. Spontaneous cycle length, maximal corrected sinus node recovery time, sinoatrial conduction time, secondary pauses and intrinsic heart rate were measured. Secondary pauses were more common in those with abnormal intrinsic heart rates, and they did not correlate with changes in maximal corrected sinus node recovery time or sinoatrial conduction time. In patients with normal intrinsic heart rate, abnormal test measurements usually returned to normal after combined blockade (hypervagotonia); however, some patients showed a new abnormality after propranolol that was not reversible with atropine (catecholamine-dependent). Abnormal test responses in patients with abnormal intrinsic heart rate persisted or increased after combined blockade. We conclude that patients with sinus node disease may be categorized as (1) those with intrinsic sinus node disease; (2) those with normal intrinsic sinus node function but either relative hypervagotonia or catecholamine dependency; and (3) those with abnormal intrinsic sinus node function affected by vagal or catecholamine factors.

Adult↗
PubMed1981

Rapidly progressive coronary artery bypass graft atherosclerosis. Report of a case documented by serial coronary arteriograms and pathologic examination.

Atherosclerosis occurred in a coronary artery saphenous vein bypass graft. Serial angiograms are presented documenting subtotal occlusion of this graft which occurred over a nine-month period. Pathologic examination of graft material obtained at surgery demonstrated ulcerating atherosclerotic plaque. The occurrence of early saphenous vein graft atherosclerosis is discussed with particular reference to the possible effects of hyperlipidemia, which was present in this patient.

Arteriosclerosis↗
PubMed1980

Naturally occurring R.ColBM plasmids belonging to the IncFIII incompatibility group.

Two Escherichia coli strains isolated from urinary tract infections were resistant to streptomycin, kanamycin, neomycin, tetracycline and sulphonamides. The strains also produced colicins B and M. The resistance to streptomycin, kanamycin and neomycin and the ability to produce colicins B and M could be transferred to an E. coli K12 recipient. Resistance and colicinogeny markers were transferred together by conjugation, and did not segregate even after interrupted mating or phage P1-mediated transduction. Hence, the drug-resistance and colicinogeny markers were carried by the same plasmid, designated as R.ColBM plasmid. The two R.ColBM plasmids were Fi+ and produced an F-like pilus. They belonged to the IncFIII incompatibility group, being thus the first R plasmids identified in this group. The two plasmids were isolated and their molecular sizes were determined by electrophoresis in agarose gels and by contour length measurements. Both methods showed that both plasmids were about 52 megadaltons.

Bacteriocin Plasmids↗
PubMed1980

Oral hydralazine in chronic heart failure: sustained beneficial hemodynamic effects.

Hemodynamic effects of oral hydralazine (200 to 400 mg/d) were evaluated in 11 patients with chronic heart failure after short-term (24 hours) and long-term (average, 8.3 months) therapy. In seven of 11 patients, hemodynamic changes were evaluated after withdrawal of hydralazine. During early study, cardiac index, stroke volume index, and stroke work index increased by an average of 56%, 59%, and 68%, respectively, and systemic vascular resistance decreased by 39%. During late study, cardiac index (+65%), stroke volume index (+88%), and stroke work index (+98%) remained higher and systemic vascular resistance (-41%) lower than control values. Withdrawal of hydralazine caused a decrease in cardiac index, stroke volume index, and stroke work index and an increase in systemic vascular resistance. Heart rate and arterial, pulmonary capillary wedge, and right atrial pressures did not change significantly. These findings suggest that oral hydralazine produces sustained beneficial hemodynamic effects in patients with chronic heart failure.

Administration, Oral↗
PubMed1979

Congenital abnormalities of the conduction system in two patients with tachyarrhythmias.

Serial sections of the conduction system (CS) were performed in two patients with recurrent tachyarrhythmias. Case 1, a 34-year-old female who had dual atrioventricular (AV) nodal pathways with recurrent paroxysmal supraventricular tachycardia, committed suicide. Autopsy revealed an abnormally formed atrial septum with insertion of eustachian valve on the AV part of the pars membranacea. The intercuspid portion of the pars membranacea was muscular. The AV node was located adjacent to the membranous part of the ventricular septum rather than the central fibrous body. In addition, there was an accessory anterior AV node on the parietal wall of the right atrium. Case 2, a 13-year-old boy with history of recurrent ventricular tachycardia, died suddenly. CS revealed a right-sided, markedly septated bundle. The first part of right bundle branch was divided into three parts, which later joined together. Both cases showed fatty infiltration of the atrial septum, more than normal for the age of the patients. The relationship of the recurrent tachyarrhythmias to the congenital abnormalities in the CS in the two cases and the fatty infiltration is reviewed.

Adolescent↗