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Biomedical subjects

B R Chaitman

Publications and source records attributed to B R Chaitman.

At least 19 recordsLinked to original sources
PubMed1992

Carbon monoxide exposure of subjects with documented cardiac arrhythmias.

The impact of low-level carbon monoxide exposure on ventricular arrhythmia frequency in patients with ischemic heart disease has not been thoroughly studied. The issue is of concern because of the potential proarrhythmic effect of carbon monoxide in patients with ischemic heart disease. We studied 30 subjects with well-documented coronary artery disease who had an average of at least 30 ventricular ectopic beats per hour over a 20-hour monitoring interval. By using appropriate inclusion and exclusion criteria, subjects were selected and enrolled in a randomized double-blind study to determine the effects of carbon monoxide exposure on ventricular arrhythmia frequency at rest, during exercise, and during ambulatory activities. The carbon monoxide exposure was designed to result in 3% or 5% carboxyhemoglobin levels, as measured by gas chromatography. The carbon monoxide exposure protocol produced target levels in 60 minutes, and the levels were maintained for an additional 90 minutes to provide adequate time to assess the impact of carbon monoxide on the frequency of ventricular ectopic beats. The data on total and repetitive ventricular arrhythmias were analyzed for seven specific time intervals: (1) two hours before carbon monoxide exposure; (2) during the two-hour carbon monoxide or air exposure; (3) during a two-hour rest period; (4) during an exercise period; (5) during an exercise recovery period; (6) six hours after carbon monoxide or air exposure; and (7) approximately 10 hours after exposure, or the remaining recording interval on the Holter monitor. There was no increase in ventricular arrhythmia frequency after carbon monoxide exposure, regardless of the level of carboxyhemoglobin or the type of activity. During steady-state conditions at rest, the number of ventricular ectopic beats per hour was 115 +/- 153 (SD) for room air exposure (0.7% carboxyhemoglobin), 121 +/- 171 for the lower carbon monoxide exposure (3.2% carboxyhemoglobin), and 94 +/- 129 for the higher carbon monoxide exposure (5.1% carboxyhemoglobin). The frequency of complex ventricular ectopy was not altered at the levels of carbon monoxide studied. Secondary analysis of the impact of carbon monoxide on ventricular ectopic beat frequency stratified by baseline ejection fraction, baseline ventricular ectopic beat frequency, and exercise-induced ST-segment changes did not indicate an effect of carbon monoxide on ventricular arrhythmias. In conclusion, low levels of carbon monoxide exposure resulting in blood levels of 3.2% and 5.1% carboxyhemoglobin, as measured by gas chromatography, do not have a proarrhythmic effect on patients with coronary artery disease and frequent ventricular ectopy.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1979

Exercise stress testing. Correlations among history of angina, ST-segment response and prevalence of coronary-artery disease in the Coronary Artery Surgery Study (CASS).

To determine to what extent the diagnostic accuracy of stress testing is influenced by the prevalence of coronary-artery disease, we correlated the description of chest pain, the result of stress testing and the results of coronary arteriography in 1465 men and 580 women from a multicentered clinical trial. The pre-test risk (prevalence of coronary-artery disease) varied from 7 to 87 per cent, depending on sex and classification of chest pain. A positive stress test increased the pre-test risk by only 6 to 20 per cent, whereas a negative test decreased the risk by only 2 to 28 per cent. Aothough the percentage of false-positive results differed between men and women (12 +/- 1 per cent versus 53 +/- 3 per cent P less than 0.001), this difference was not seen in a subgroup matched for prevalence of coronary-artery disease. We conclude that the ability of stress testing to predict coronary-artery disease is limited in a heterogeneous population in which the prevalence of disease can be estimated through classification of chest pain and the sex of the patient.

Angina Pectoris↗
PubMed1979

Coronary artery spasm during exercise in patients with variant angina.

Seven patients with typical variant angina without coronary stenoses greater than 50% developed angina and ST-segment elevation during treadmill exercise testing. In all cases the ST-segment elevation occurred in the same leads during exercise testing as during spontaneous attacks at rest. Five of the patients had developed spontaneous coronary spasm during coronary arteriography, in each case in the artery corresponding to the site of ST-segment elevation. In five patients, thallium was injected during the exercise test during which angina and ST-segment elevation occurred. In each case, a large perfusion defect not present at rest was found in the zone corresponding to the site of ST-segment elevation. These findings suggest that coronary artery spasm may occur during exercise in patients with variant angina.

Adult↗
PubMed1978

Long term follow-up of aneurysmectomy for recurrent ventricular tachycardia or fibrillation.

The success of aneurysmectomy in abolishing recurrent ventricular tachycardia or ventricular fibrillation has not been clearly defined. Ten patients who underwent aneurysm resection to control ventricular arrhythmias were studied before and an average of 19 (4 to 42) months following operation. All patients had moderate to large aneurysms and four had asynergy in adjacent segments. Of four patients with significant stenosis in vessels not supplying the aneurysm, three had aortocoronary bypass grafts in addition to their resection. Ambulatory Holter monitoring and a graded exercise test were performed in all patients postoperatively. There was no operative mortality. Two patients who did not have associated revascularization procedures died suddenly 1.5 and 7 months postoperatively. Of the eight survivors, despite clinical improvement, the Holter ECG revealed runs of ventricular tachycardia in three patients and frequent multifocal ventricular extrasystoles in the other five patients. No correlation was found between recurrence of the ventricular arrhythmias and aneurysm size, contraction pattern of other myocardial segments, extent of coronary disease, or the presence of congestive heart failure. In conclusion, aneurysmectomy does not abolish ventricular tachyarrhythmias and probably should be reserved for patients who remain symptomatic despite an adequate medical trial. The persistence of complex arrhythmias following operation warrants a close follow-up in these patients.

Adult↗
PubMed1978

Angiographic evaluation of the natural history of normal coronary arteries and mild coronary atherosclerosis.

Between September 1966 and September 1976, a group of 48 patients with normal coronary arteries or nonsignificant coronary atherosclerosis documented in a first coronary arteriogram underwent a second angiogram because of persistent or recurrent chest pain. The interval between studies was 13 to 108 months (mean 42 months). The indication for the first angiogram was typical or atypical anginal pain. The patients were separated into two groups according to the results of the first angiogram. Group I included 22 patients, 9 men and 13 women, with normal coronary arteries (mean age 49 years, range 28 to 62). Group II included 26 patients, 18 men and 8 women, with coronary stenosis of less than 50% of intraluminal diameter (mean age 49 years, range 38 to 63). The second angiogram revealed normal coronary arteries in all 22 patients in Group I but showed progression of diseases in 7 (27%) of the 26 patients in group II. The coronary arterial narrowings were greater than 50% in four patients and greater than 70% in only two patients. The clinical course, coronary risk factors and interval between angiograms were not useful predictors of progression of disease. The data suggest that coronary artery disease is unlikely to developed in adults with normal coronary arteries and that roughly 75% of adults with nonsignificant atherosclerosis will not show progression of disease over a 3 to 4 year period.

Adult↗
PubMed1978

Improved efficiency of treadmill exercise testing using a multiple lead ECG system and basic hemodynamic exercise response.

One hundred consecutive men with a normal ECG at rest had a maximal treadmill test using 14 leads during and post-exercise. Coronary arteriography performed the following day revealed coronary stenoses greater than or equal to 70% in 66 patients. Test results obtained from a V5 lead were compared to different lead combinations and were correlated with arteriographic findings. A positive exercise test occurred in 37 men using an isolated V5 lead compared to 50 men (P less than 0.05) using 11 leads, 52 men (P less than 0.05) using a combined CM5, CC5, Cl (inferior) lead system and 58 (P less than 0.001) men using all 14 leads. The predictive value of a positive test varied between 89-95% and was not changed significantly by the addition of multiple leads. The 14 lead ECG was positive in 43/45 (96%) patients with multivessel disease. Parameters which helped to predict multivessel disease using 14 leads were 1) the time that ischemia first appeared 2) the pressure-rate product at the time ischemia first appeared, and 3) the maximum workload that could be attained. In general, the magnitude of ST-segment depression and the time required for a positive ECG to return to normal postexercise were not useful predictors of multivessel disease. We conclude that the use of multiple leads improves the sensitivity and efficiency of the maximal treadmill exercise test. The usefulness of exercise test results can be further improved if multiple leads are combined with physiologic data collected during exercise.

Adult↗
PubMed1978

Prediction of multivessel disease after inferior myocardial infarction.

We correlated clinical parameters with angiographic findings in 108 men with a previous isolated inferior myocardial infarction, to determine if these parameters could predict accurately which patients had multivessel disease. Of 71 men in angina class 2-3, 42 had three vessel disease versus only seven of the 37 who were either asymptomatic or angina class 1 (P less than 0.001). Multivessel disease was present in 35 of the 36 who had anterior ST-T abnormalities at rest (P less than 0.001) and 16 of the 17 with cardiomegaly. Among men 55 years and older, the incidence of multivessel disease was 94% compared to 70% in men less than 55 (P less than 0.03). We conclude that functional angina class, age, and the presence of resting anterior ST and T abnormalities are highly predictive of associated left system disease in survivors of inferior infarction.

Angina Pectoris↗
PubMed1977

Significance of exercise-induced junctional S-T depression in evaluation of coronary artery disease.

Isolated junctional S-T depression induced during treadmill exercise testing was correlated with coronary arteriographic findings in 230 patients. Of 75 patients with junctional depression of less than 1.5 mm, 10 had 50% or greater stenosis of at least one major coronary artery and 2 patients (3%) had multivessel disease. Of 42 with junctional depression of 1.5 mm or more and a rapid upsloping S-T segment, 23 had 50% or greater coronary stenosis and 12 of these had multivessel disease. Of 35 with an upsloping pattern (junctional depression of more than 2 mm, upsloping S-T segment depressed 2 mm or more, 0.08 second after the J point), 33 (94%) had 50% or greater coronary stenosis compared with 46 (96%) and 30 (97%) with 2 mm or more junctional depression ahd a horizontal or downsloping S-T segment. In conclusion, multivessel disease is rare with isolated exercise-induced junctional depression of less than 1.5 mm but common when the J point is depressed 1.5 mm or more. Junctional depression of more than 2 mm is associated with the same incidence of coronary disease when the S-T segment is slowly ascending (upsloping pattern) as when it is horizontal.

Adult↗
PubMed1977

Influence of left ventricular function and other parameters on early and late mortality following coronary bypass surgery.

Left ventricular performance, coronary anatomy and postoperative clinical parameters of 66 control patients (group 1) randomly selected from 797 survivors of coronary bypass surgery were compared with those of 45 patients who died within 30 days of operation (group II) and 53 patients who died late (average, 22+/-2 mo) (group III). Average preoperative left ventricular end-diastolic pressure, ejection fraction and mean circumferential fibre shortening rate were significantly better in group I than in group III patients. These same parameters were not significantly different when group I was compared to group II. Abnormal wall motion was significantly less frequent in patients from group I than in patients from group II and III. Triple-vessel disease was present preoperatively in 40 (61%) controls compared with 37 (82%) early deaths (P = 0.021) and 35 (66%) late deaths (NS). The number of grafts placed per patient was not significantly different in the three groups. Perioperative myocardial in farction (MI) and low cardiac output syndrome were the commonest causes of early death. Late complications such as MI and heart failure occurred in 4 (6%) v; 15 (32%) (P = 0.0006) and 4 (6%) v. 27 (57%) (Pless than 0.0001) group I v. group III patients, respectively. Surgical expertise, preoperative ventricular performance and triple-vessel disease are important determinants of early mortality following bypass surgery and preoperative left ventricular performance is one of the most important determinants of late mortality,

Coronary Artery Bypass↗
PubMed1976

Clinical, angiographic, and hemodynamic findings in patients with anomalous origin of the coronary arteries.

Clinical and angiographic features of 31 patients with anomalous coronpary artery origin are reviewed. Of 17 aberrant circumflex arteries from the right sinus of Valsalva or artery, each was retro-aortic, six atherosclerotic, and seven irrigated a small area of myocardium. Of seven anomalous right coronary arteries from the left sinus of Valsalva or artery, each was ante-aortic and two atherosclerotic. Aberrant origin of the circumflex or right coronary artery was a benign anomaly. The proximal course of seven aberrant left coronary arteries from the right sinus of Valsalva or right coronary artery was related to clinical events. The anomaly was best demonstrated in the lateral view. In five cases, coronary blood flow during exercise and myocardial metabolism during pacing were assessed. Two had had a previous infarction with nonatherosclerotic arteries. Exercise coronary blood flow was normal in four and low in one patient. Pacing resulted in lactate production in two with atherosclerotic and one without atherosclerotic arteries. We conclude that anomalous left coronpary origin from the right sinus of Valsalva can result in significant myocardial ischemia and infarction.

Adult↗
PubMed1976

Ventriculography and coronary arteriography in the acutely III patient. Complications, extent of coronary arterial disease, and abnormalities of left ventricular function.

Of 99 patients who underwent "emergency" diagnostic studies, 82 had "unstable angina" (group A), 15 had recent myocardial infarction (group B), and two had intractable congestive heart failure due to acute mitral regurgitation (group C). Two cardiac and two local complications occurred either during the procedure or during the following 48 hours. There were no deaths or myocardial infarctions. Ten (12 percent) patients of group A had "normal" coronary arteries and normal left ventricular function; 13, 26 and 33 patients had one, two, and three coronary arteries involved, respectively. Those with three-vessel disease had a significantly higher left ventricular end-diastolic pressure (LVEDP) and lower ejection fraction (EF) than those with one- and two-vessel disease. Those with previous myocardial infarction had a significantly higher incidence of reduced EF and of wall motion abnormalities than those without a previous myocardial infarction. All patients in group B had significant coronary arterial disease, and 80 percent (12) had abnormal left ventricular function. Their mean LVEDP and EF were significantly higher and lower, respectively, than those found in group A. In conclusion, acutely ill patients were studied with low risk. Most patients had three- or two-vessel disease. Abnormal left ventricular function was related to three-vessel disease and to recent and old myocardial infarction.

Acute Disease↗
PubMed1976

Late development of left ventricular outflow tract obstruction after repair of double-outlet right ventricle.

A 22-year-old woman had exertional chest pain and dyspnea secondary to left ventricular outflow tract obstruction more than a decade after repair of a type I double-outlet right ventricle. The obstruction was the result of (1) failure of the ventricular septal defect and the tunnel created between the left ventricle and aorta to enlarge commensurate with growth of the heart and (2) a markedly hypertrophied parietal band of the crista supraventricularis which surrounded and narrowed the aortic orifice. At reoperation, the ventricular septal defect and the tunnel were enlarged and the hypertrophied crista supraventricularis was partially resected. The patient is asymptomatic 6 months after operation.

Adolescent↗
PubMed1975

Anomalous left coronary artery from pulmonary artery. An eight year angiographic follow-up after saphenous vein bypass graft.

We have presented a 7-week and 8-year postoperative angiographic follow-up of a 36-year-old man who had an anomalous left coronary artery arising from the pulmonary artery and who had an aortocornary bypass graft to the left anterior descending artery. The late study showed 1) a large, well functioning patent graft, 2) lack of significant postoperative change in the size of the right coronary artery and 3) new collateral vessels between the distal left anterior descending and left circumflex coronary arteries and persistence of collateral vessels between the distal right and left circulflex coronary arteries. This report is the longest known angiographic follow-up of a patient with this anomaly who has been treated with bypass surgery.

Adult↗