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Biomedical subjects

P R McLaughlin

Publications and source records attributed to P R McLaughlin.

At least 19 recordsLinked to original sources
PubMed1992

Serial follow-up of adults with repaired tetralogy of Fallot.

OBJECTIVES AND BACKGROUND: Sudden death has long been considered a major contributor to mortality in pediatric patients with corrected tetralogy of Fallot. However, this may not apply to the patient with repaired tetralogy of Fallot who has survived into adulthood. Consequently we followed up a cohort of such adults to establish the clinical outcome and risk factors affecting their survival. METHODS: A baseline group of 151 adult patients with repaired tetralogy of Fallot were followed up for a mean of 3.2 years. The overall mortality rate was low (0.009 death/patient-year). Four patients died during follow-up, but only two deaths can be attributed to tetralogy of Fallot repair, and there were no sudden cardiac deaths. Clinically 94% of patients have remained in New York Heart Association functional class I. A subset of 36 patients were followed up for a mean of 6.7 years. This group had three sets of serial testing at 3-year intervals consisting of right heart catheterization at the initial study only, 24-h Holter ambulatory electrocardiographic (ECG) monitoring, exercise ECG and rest and exercise radionuclide angiography. RESULTS: Exercise capacity assessed by serial exercise stress testing remained stable over the follow-up period, whereas the presence of exercise-induced arrhythmias steadily decreased. Most patients had no significant arrhythmias and had no significant change in severity of arrhythmia with time. Radionuclide angiography showed significant improvement in exercise right ventricular ejection fraction over time but a progressive decrease in left ventricular ejection fraction at both rest and exercise. However, the left ventricular ejection fraction is still within the normal limits for our laboratory. CONCLUSIONS: Adults with repaired tetralogy of Fallot have a very good prognosis and a low risk of sudden death. However, ventricular function may change over time and should be carefully monitored.

Adult↗
PubMed1992

Persistence of viral genome into late stages of murine myocarditis detected by polymerase chain reaction.

BACKGROUND: Enteroviruses have been considered as the most common etiologic agents in clinical myocarditis and dilated cardiomyopathy; however, their pathogenetic role remains unknown. Hence, the relation of viral replication and development of cardiomyopathy has been determined in a murine model of myocarditis by evaluating the persistence of viral genome during acute and chronic stages of myocarditis by means of Northern blot hybridization and polymerase chain reaction (PCR). METHODS AND RESULTS: DBA/2 mice (n = 146) were injected peritoneally with 10 plaque-forming units of encephalomyocarditis (EMC) virus, and the control mice (n = 33) were injected with normal saline. Animals were randomly killed at 4, 7, 10, 14, 21, 28, 35, and 42 days after infection. Histology revealed acute myocardial necrosis with massive inflammatory cell infiltrate peaking on day 14 followed by increasing fibrosis and declining chronic inflammation features compatible with dilated cardiomyopathy between days 21 and 42. Northern blot analysis of control and infected hearts showed detectable viral RNA in the infected hearts initially at day 4, peaking by day 7, diminishing between day 7 and day 14, and absent at day 21 and day 28. However, potential viral remnants present in low quantities and undetectable by Northern blot were further detected by PCR followed by confirmation with an internal oligonucleotide probe after day 14 up to day 42. CONCLUSIONS: Viral RNA signals on Northern blot showed a strong correlation with massive myocyte necrosis on day 14, but the viral RNA fragment was consistently detectable into late stages of cardiomyopathy on days 21, 28, 35, and 42 by PCR. This indicated that the mature virions are fully developed early in infection and are capable of persisting in the myocardium after virus-mediated myocytolysis stage. Therefore, PCR is an extremely sensitive method for detecting residual viral genome and viral persistence in the myocardium and may offer insights into the pathogenesis of chronic myocarditis leading to dilated cardiomyopathy.

Animals↗
PubMed1992

Cardiac output response to continuous positive airway pressure in congestive heart failure.

The effects of nasal continuous positive airway pressure (CPAP) were examined during cardiac catheterization in 22 patients with congestive heart failure (CHF). CPAP was applied at a level of 5 cm H2O pressure. Hemodynamic measurements were made at baseline and while on CPAP. We hypothesized that patients with high left ventricular (LV) diastolic pressures would experience an increase in cardiac index (CI). To test this hypothesis, patients were divided into two groups based on their baseline pulmonary capillary wedge pressure (PCWP): one group of 11 whose PCWP was greater than or equal to 12 mm Hg (high-PCWP group) and a second group of 11 whose PCWP was less than 12 mm Hg (low-PCWP group). Among the high-PCWP group (mean PCWP +/- SEM = 19.0 +/- 2.7 mm Hg), CI rose significantly while on CPAP (from 2.48 +/- 0.26 to 2.82 +/- 0.26 L/min/m2, p less than 0.01). Stroke volume index (SVI) also rose significantly (from 52.6 +/- 7.0 to 64.1 +/- 8.0 ml/m2, p less than 0.001). In contrast, among the low-PCWP group (PCWP = 8.3 +/- 0.6 mm Hg), CI decreased significantly while on CPAP (from 3.14 +/- 0.44 to 2.89 +/- 0.62 ml/m2, p less than 0.025). SVI fell but not significantly while on CPAP (from 75.5 +/- 8.4 to 74.2 +/- 8.5 ml/m2). Multiple stepwise linear regression analysis revealed that the only significant correlate of the magnitude of change in CI in response to CPAP was baseline PCWP (r = 0.50, p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Design of a calf muscle ergometer for the study of local muscle blood flow.

A simple ergometer is described that allows highly reproducible plethysmographic measurements of blood flow to be made within 10 seconds of ceasing rhythmic quantitated exercise of the calf muscle. A power output of some 25 Watts is developed with a mechanical efficiency of some 20%. The device seems applicable to a variety of clinical assessments.

Ergometry↗
PubMed1992

Impaired cardiopulmonary response to exercise in moderate hypertension.

OBJECTIVE: To identify the limiting factors of exercise performance in subjects with hypertension associated with left ventricular hypertrophy. The secondary objective was to establish relationship between peripheral function and exercise capacity. DESIGN: Cardiopulmonary exercise testing was conducted using two protocols: a graded exercise test to maximal effort established maximal exercise capacity, followed by a step-incremental test combining gas-exchange measures and radionuclide angiography. The exercise responses were compared within and between groups. SETTING: All hypertensive subjects were selected from the Toronto Tri-Hospital Hypertension Clinic. Normal subjects were recruited from the surrounding community. PATIENTS: Twelve patients with established hypertension and left ventricular hypertrophy (determined by echocardiography) were studied as a referred/volunteer sample. All had no evidence of coincident diseases and were unmedicated at time of testing. A volunteer sample of normal, healthy subjects acted as a control. INTERVENTIONS: Graded exercise to maximum and step-incremental (submaximal and steady-state) exercise was used to quantify cardiopulmonary function during exercise stress. MAIN OUTCOME MEASURES: These included (for exercise performance) maximal oxygen intake (VO2max), the ventilatory anaerobic threshold, total peripheral resistance and blood lactate. Cardiac function measures included ejection fraction and ventricular volumes. RESULTS: Cardiac function data obtained during exercise in hypertensive subjects included an increase in the pressure to volume ratio, but a blunted ejection fraction response at peak exercise (P less than 0.05). Although end-diastolic volume increased during exercise (P less than 0.05), values were lower during both levels of exercise compared with normal subjects. Mean +/- SD end-systolic volume increased from 39 +/- 22 at rest to 42 +/- 23 mL during peak exercise. Hypertensive subjects had a lower VO2 max (mean 27.4 +/- 4.8 mL/kg/min) compared with normals (40.0 +/- 8.5 mL/kg/min) and a lower ventilatory anaerobic threshold (14.4 +/- 2.9 versus 27.6 +/- 5.8 mL/kg/min, P less than 0.005). Furthermore, hypertensive patients had a significantly elevated total peripheral resistance at rest (2.5 +/- 1.0 versus 1.8 +/- 0.4 peripheral resistance units) and at peak exercise (1.6 +/- 0.7 versus 0.8 +/- 0.2, P less than 0.01) compared with normal subjects (P less than 0.05). A correlation coefficient of 0.92 was found between total peripheral resistance and VO2 max in hypertensive subjects (P less than 0.01). CONCLUSIONS: These data suggest that peripheral factors, specifically a failure to reduce significantly total peripheral resistance, limits exercise performance despite a maintenance of left ventricular function during exercise in patients with moderate hypertension. The use of cardiopulmonary exercise testing can help in identifying the underlying cause of exercise intolerance in this population and limited left ventricular reserve at peak exercise, and may offer a sensitive measure of therapeutic end-points.

Adult↗
PubMed1992

Fatal esophageal-arterial fistula 17 years following tetralogy of Fallot repair.

Blalock-Taussig shunts (subclavian to pulmonary anastomoses) have remained the most effective palliation in cyanotic heart disease. Late complications are rare but can be devastating. The case of a 26-year-old female with tetralogy and an original Blalock shunt constructed at age four years is reported. Despite subsequent primary repair of the tetralogy and presumed ligation of the Blalock shunt, the patient succumbed to a fatal hemorrhage due to esophageal-arterial fistula involving the Blalock shunt. The circumstances leading to this dramatic outcome are outlined and discussed. It is important for cardiologists caring for congenital heart disease patients to be aware of the late complications of congenital heart surgery, and carry out the proper follow-up investigations.

Adult↗
PubMed1991

Left ventricular functional response to moderate and intense exercise.

The left ventricular (LV) volume and ejection fraction (EF) response to upright exercise was assessed on 15 normal subjects during cycle ergometry. Measures of cardiac function and gas exchange were made at rest, at 85% of the ventilatory anaerobic threshold (VAT; WL1), and at peak exercise (WL2). EF increased from rest (58 +/- 12%) during WL1 (66 +/- 10%), reaching significantly higher values at WL2 (69 +/- 8%; p less than .05). End-diastolic volume increased from rest during WL1 (136 +/- 36 ml vs. 118 +/- 32 ml; p less than .05), becoming significantly higher than rest during WL2 (141 +/- 41 ml). End-systolic volume was unchanged from rest (51 +/- 25 ml) during submaximal exercise (50 +/- 20 ml), but it decreased significantly during WL2 (44 +/- 21 ml; p less than .05). The systolic pressure/end-systolic volume ratio increased from 3.0 +/- 1.7 (rest) to 5.8 +/- 3.0 at WL2 (p less than .05). These results suggest that the Frank-Starling mechanism is operative throughout exercise, particularly during exercise below the VAT. LV performance after the VAT is further augmented by increased contractility with continued, yet diminished, utilization of the Frank-Starling mechanism.

Adult↗
PubMed1990

Validation of left ventricular function parameters acquired with the non-imaging nuclear probe: comparison with tantalum marker cine-fluoroscopy.

We evaluated the accuracy of the non-imaging nuclear probe for measuring various parameters of left ventricular function by comparing these with simultaneous measurements acquired via tantalum marker cine-fluoroscopy. Eight patients with surgically implanted mid-myocardial tantalum markers were studied during cardiac catheterization. High temporal resolution tantalum marker-derived volume/time curves were generated and calibrated to absolute endocardial volumes by comparison with contrast left ventricular angiography. Left ventricular function parameters were acquired at baseline and during atrial pacing, nitroprusside infusion and volume loading. Simultaneous measurements obtained with the nuclear probe and via tantalum marker cine-fluoroscopy were compared. The following correlation coefficients were obtained: ejection fraction, r = 0.49, P less than 0.001; peak ejection rate, r = 0.41, P less than 0.01; mean ejection rate, r = 0.62, P less than 0.001; time to peak ejection, r = 0.73, P less than 0.001; peak filling rate, r = 0.73, P less than 0.001; time to peak filling, r = 0.58, P less than 0.001. Relative changes in end-diastolic volume were accurately tracked by the nuclear probe in six of seven patients (r values 0.77-0.93). These results suggest that measurements of certain left ventricular volume parameters with the nuclear probe may not accurately reflect true volume changes as measured by tantalum marker cine-fluoroscopy. Although, the probe may be useful in tracking relative changes in end-diastolic volume, we would advise caution in using this instrument for studies requiring accurate measurements of ejection and filling parameters.

Cardiac Catheterization↗
PubMed1990

Detection of enterovirus RNA in myocardial biopsies from patients with myocarditis and cardiomyopathy using gene amplification by polymerase chain reaction.

Recent molecular studies have suggested that viral myocarditis frequently underlies human congestive cardiomyopathy; however, only moderately sensitive and specific techniques were used. Polymerase chain reaction (PCR) gene amplification is a sensitive, specific technique ideally suited for the diagnosis of viral disease in small tissue samples where low copy numbers of the viral genome may be present. Using PCR and high stringency condition, we screened biopsies taken from 48 patients with clinically suspected myocarditis or dilated cardiomyopathy. Five patients demonstrated positive enteroviral signals by PCR; two of them had myocarditis by pathology, whereas the other three had changes consistent with cardiomyopathy. Four other patients had myocarditis diagnosed by pathology from 3 months to 1 year earlier but were now negative by both PCR and pathology. Both pathology and PCR were negative for active myocarditis in all other patients. Ventricular samples taken from left ventricular myectomy in four additional patients with hypertrophic cardiomyopathy, normal human ventricle samples, and uninfected monkey kidney cells were also negative by PCR. This study supports a link between viral infection and dilated cardiomyopathy in some patients. PCR gene amplification provides a new diagnostic approach to patients with suspected myocarditis.

Biopsy↗
PubMed1990

Are the kinetics of technetium-99m methoxyisobutyl isonitrile affected by cell metabolism and viability?

To investigate the role of cell viability and metabolism on the myocardial kinetics of a new tracer, technetium-99m-methoxyisobutyl isonitrile (Tc-99m-MIBI), 250 microCi/l Tc-99m-MIBI was infused in isolated rat hearts under constant flow conditions. The hearts were studied after inducing irreversible damage by cytochrome c oxidase inhibitor sodium cyanide (n = 8) or sarcolemmal membrane detergent Triton X-100 (n = 8). The control hearts (n = 6) received no toxins. Mean Tc-99m-MIBI peak accumulation activity was significantly reduced after cyanide (51.1 +/- 44.2% of control, p less than 0.01) and Triton (13.8 +/- 2.7% of control, p less than 0.001) administration. Kinetic studies also showed marked reduction in accumulation rates and marked increase in clearance rates for cyanide (p less than 0.01) and Triton (p less than 0.01) groups compared with controls. Potential changes in regional flow distribution were assessed using microspheres. When peak accumulation activity was corrected for these changes, there remained significant differences between the groups. In the cyanide and Triton groups, irreversible cell injury was confirmed by creatine kinase and lactate dehydrogenase release, triphenyl tetrazolium chloride staining, and electron microscopy. All the cells were viable in the control group. We conclude that the accumulation and clearance kinetics of Tc-99m-MIBI are significantly affected by cell viability. Tc-99m-MIBI kinetics appear to be dependent on sarcolemmal integrity and to a lesser extent on aerobic metabolism.

Animals↗
PubMed1990

Effect of intracoronary nifedipine on coronary bloodflow and myocardial metabolism during pacing-induced ischemia.

The effects of intracoronary nifedipine on coronary bloodflow, its regional distribution, myocardial oxygen consumption and lactate metabolism during pacing-induced angina were evaluated in 15 subjects. These responses were directly compared to 10 subjects who received an alcohol-based control solvent. Myocardial bloodflow was measured by thermodilution, with changes in regional coronary flow assessed using a dual radiolabelled (technetium-99m and indium-111) intracoronary microsphere technique and single photon emission tomography. Neither intracoronary nifedipine (100 micrograms) or the control solvent produced changes in systemic arterial pressure (nifedipine -2 mmHg and control +2 mmHg, both not significant). Intracoronary nifedipine markedly increased left ventricular end diastolic pressure (pre-nifedipine 13.0 mmHg versus post nifedipine 20.1, P less than 0.05), while increasing total coronary sinus bloodflow (pre-nifedipine 134 mL/min versus post nifedipine 189, P less than 0.05): Regional coronary bloodflow increased in all myocardial segments, regardless of the severity of coronary stenosis (64 to 132% baseline, all P less than 0.05). In addition, intracoronary nifedipine increased myocardial oxygen consumption (pre-nifedipine 12.3 mL/min versus post nifedipine 15.7, P less than 0.05), with a trend towards improved lactate extraction (pre-nifedipine 0.24 mg/mL versus post nifedipine 0.12, not significant). Although decreased ventricular afterload (left ventricular systolic wall stress) may contribute to nifedipine's antianginal properties, a primary increase in regional coronary bloodflow also appears to be an important factor in the alleviation of myocardial ischemia.

Adult↗
PubMed1988

Catheter occlusion of the persistently patent ductus arteriosus.

Catheter occlusion of a persistently patent ductus arteriosus was attempted in 40 patients (11 men and 29 women, mean age 7.2 +/- 8.3 years, range 244 days to 40 years), using a transvenously placed Rashkind umbrella occluder (USCI). Thirty-one 12-mm and six 17-mm diameter devices were successfully placed in the ductus (internal diameter average 3.9 mm, range 2 to 9 mm). One procedure was abandoned when fluoroscopy failed to visualize the device. There were 2 immediate embolizations subjected to surgical recovery. A residual shunt was present on the immediate postocclusion ventriculogram in 12 of 37 procedures (32%). Twenty-eight patients (75%) have had at least a follow-up at 3 months with Doppler study and 6 (21%) continued to have shunting into the pulmonary artery. Three of 4 patients have undergone successful placement of a second device and 1 patient's shunting spontaneously resolved at 1 year postimplant, leaving only 2 patients (7%) with persistent shunts. There has been 1 episode of probable prosthetic endarteritis and 1 patient has developed mild narrowing of the left pulmonary artery related to device placement. Catheter occlusion of the patent ductus arteriosus using the Rashkind umbrella appears to be a safe and effective method of non-surgical management.

Adult↗
PubMed1988

Repair of tricuspid atresia: utility of right ventricular incorporation.

During a 10-year period, 62 patients underwent the following modifications of the Fontan operation for repair of tricuspid atresia: direct atriopulmonary connection (N = 15), atriopulmonary connection using a conduit (N = 5), direct atrioventricular (AV) connection (N = 22), and AV connections with a valved conduit (N = 20), including 2 with combined Fontan-arterial switch procedures. The overall hospital mortality was 16.1% (10/62) (70% confidence limits, 11.2 to 22.4%). By multivariate analysis, the risk factors for early and late death included increasing right atrial pressure after repair, use of an atriopulmonary connection, and previous pulmonary artery banding (all variables, p less than 0.05). Postoperative catheterization was performed in 22 patients including 15 with AV valved-conduit connections. Right ventricular (RV) work based on pulmonary artery pressure minus right atrial pressure was correlated with the preoperative RV to left ventricular volume ratio computed from the four-chamber angiographic projection (p = 0.025), and was appreciable only with ratios exceeding about 30%. In 6 of 19 eligible patients, severe conduit obstruction has developed. Considering the survival data, the risk of reoperation, and postoperative hemodynamic findings, analysis of our experience supports the preferential use of nonvalved AV connections in most patients with tricuspid atresia and ventriculoarterial concordance.

Adolescent↗
PubMed1988

The relationship of cardiac diastolic dysfunction to concurrent hormonal and metabolic status in type I diabetes mellitus.

The presence of diabetic cardiomyopathy and its relationship to concurrent hormonal and metabolic status have not been defined in patients with uncomplicated type I diabetes mellitus. Accordingly, radionuclide left ventricular angiograms and simultaneous metabolic profiles were obtained in 8 type I diabetic patients who had no major diabetic complications and in 11 normal subjects. Occult coronary artery disease was excluded by electrocardiogram exercise testing. Hemodynamics and systolic function did not differ between the groups. However, the peak filling rate (PFR; end-diastolic volumes per s) was less in the diabetic patients at rest [mean, 4.1 +/- 0.2 (+/- SE) vs. 4.8 +/- 0.2; P less than 0.05] and during aerobic (6.8 +/- 0.2 vs. 8.30 +/- 0.3; P less than 0.01) and anaerobic exercise (8.8 +/- 0.3 vs. 9.8 +/- 0.4; P less than 0.05). The time to PFR was prolonged in the diabetic patients at rest (174 +/- 10 vs. 133 +/- 7 ms; P less than 0.01) and during anaerobic exercise (126 +/- 5 vs. 103 +/- 6 ms; P less than 0.01). Plasma glucose and insulin levels were elevated in the diabetic patients at rest and during exercise. Otherwise, the metabolic and hormonal levels did not differ between the groups. In the diabetic patients, no single metabolic or hormonal parameter correlated with PFR or time to PFR. Impairment of diastolic filling also did not correlate with level of glycosylated hemoglobin or duration of diabetes. The alteration in diastolic filling present in type I diabetic patients who have no other diabetic complications may represent the earliest functional effect of diabetic cardiomyopathy.

Adult↗
PubMed1987

Congenital heart disease in pregnancy: short- and long-term implications.

One hundred forty-four pregnancies that occurred in 74 patients with congenital heart disease at the Toronto General Hospital between 1975 and 1986 were reviewed. The patients were divided into two groups, those with acyanotic lesions and those with cyanotic lesions. Maternal and fetal outcomes in these two groups were compared. Patients with cyanotic lesions developed significantly more congestive heart failure and deteriorated more often in functional cardiac status than those with acyanotic lesions (p less than 0.005). Women with obstructive lesions had a higher incidence of pregnancy-induced hypertension than our general population (p less than 0.005). There was one maternal death in the puerperium in a woman with Eisenmenger's syndrome. Preterm births were more frequent in the cyanotic group (p less than 0.01) as were small for gestational age infants (p less than 0.005). In the cyanotic group the mean birth weight was 900 gm less than that in the acyanotic group (p less than 0.005). The major benefits of corrective cardiac surgery were in the cyanotic group and consisted of fewer spontaneous abortions (p less than 0.01) and small for gestational age infants (p less than 0.02) and more term births (p less than 0.01). Long-term follow-up revealed that 19.2% of women with acyanotic lesions had significant cardiac developments, compared with 90% in the cyanotic group (p less than 0.005). One of 87 infants (1.1%) had congenital heart disease and two had Marfan's syndrome.

Female↗
PubMed1987

Right ventricular function: a comparison between blood and crystalloid cardioplegia.

Blood cardioplegia resulted in better left ventricular (LV) function than crystalloid cardioplegia after elective coronary artery bypass operations. However, most methods of cardioplegic delivery may not adequately cool and protect the right ventricle, and right ventricular (RV) dysfunction may limit hemodynamic recovery. Therefore, RV and LV temperatures were measured intraoperatively and RV and LV function were evaluated postoperatively in 80 patients with double-vessel or triple-vessel coronary artery disease who were randomized to receive either blood cardioplegia or crystalloid cardioplegia. Myocardial performance, systolic function, and diastolic function were assessed with nuclear ventriculography by evaluating the response to volume loading. Preoperatively the groups were similar. Intraoperatively, blood cardioplegia resulted in significantly warmer LV and RV temperatures (left ventricle: 15.5 degrees +/- 0.2 degrees C with blood cardioplegia and 12.6 degrees +/- 0.3 degrees C with crystalloid cardioplegia [p less than .0001]; right ventricle: 18.3 degrees +/- 0.3 degrees C with blood cardioplegia and 15.1 degrees +/- 0.3 degrees C with crystalloid cardioplegia [p less than .0001]). Postoperatively, blood cardioplegia resulted in better LV performance (higher LV stroke work index at a similar LV end-diastolic volume index [EDVI]) (p = .01), better LV systolic function (similar systolic blood pressures at smaller LV end-systolic volume indexes [ESVI]), (p = .04), and improved LV diastolic function (lower left atrial pressures at similar LVEDVIs) (p = .03).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1987

Transient biventricular dysfunction following coronary bypass surgery with potassium cardioplegia.

Although myocardial revascularization relieves anginal symptoms, the effect on ventricular function remains controversial. Sixty-six patients undergoing elective coronary bypass surgery with normal right and left ventricular function were studied 1 month preoperatively (PRE), 3-5 hours perioperatively (PERI) and 3-5 months postoperatively (POST). Nuclear ventriculograms were employed to calculate right and left ventricular ejection fractions (RVEF, LVEF), end diastolic volume indices (RVEDVI, LVEDVI) and end systolic volume indices (RVESVI, LVESVI). Cardiac index (CI), stroke index (SI) and an approximation of left ventricular stroke work index (LVSWI) were also calculated from the scintigraphic data. Right and left ventricular ejection fractions were lower perioperatively (PRE:RVEF 37 +/- 2.5, LVEF 61 +/- 3; PERI:RVEF 32 +/- 3, LVEF 51 +/- 4; POST:RVEF 35 +/- 3, LVEF 56 +/- 4%, p less than 0.01 by analysis of variance, ANOVA) despite lower end diastolic volume indices perioperatively, (p less than 0.05 by ANOVA). The ratio of systolic blood pressure to LVESVI was significantly lower PERI than PRE or POST, (p less than 0.01 by ANOVA). SI, LVSWI, LVEF and RVEF were lower perioperatively at any level of LVEDVI or RVEDVI (p less than 0.01 by paired analyses of covariance), suggesting transient depression of right and left ventricular performance perioperatively. Right ventricular recovery was incomplete 4 months postoperatively. The patients were able to exercise longer at higher workloads postoperatively (p less than 0.01 by ANOVA). Chest pain resulted in discontinuation of exercise in 57% of patients PRE but only 5% POST (p less than 0.01), even though all patients were receiving full medical therapy preoperatively and no therapy postoperatively. Myocardial revascularization provided symptomatic relief and increased work capacity. However, right and left ventricular function were transiently depressed in the early perioperative period.

Coronary Artery Bypass↗