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Biomedical subjects

R A Langou

Publications and source records attributed to R A Langou.

At least 37 records · Page 2Linked to original sources
PubMed1978

Modification of intraaortic balloon catheter to permit introduction by cardiac catheterization techniques.

Intraaortic balloon counterpulsation has been widely applied for treatment of left ventricular pump failure and intractable angina. However, its use has been limited by the difficulty of balloon insertion in some patients and vascular complications in others. An AVCO intraaortic balloon was modified by the addition of a central lumen to allow pressure monitoring, injection of contrast medium and passage of a guide wire. The device was successfully used in 15 of 16 patients, including 4 of 5 in whom attempts to place a standard balloon catheter had failed. No significant vascular complications occurred in any patient. The modified balloon catheter appears to increase the efficacy and safety of insertion and allows immediate and continuous monitoring of arterial pressure.

Adult↗
PubMed1978

Coronary surgery for unstable angina pectoris. Incidence and mortality of perioperative myocardial infarction.

The incidence of perioperative myocardial infarction determined by electrocardiogram was examined in 123 consecutive patients having only coronary artery bypass grafting for unstable angina pectoris, at Yale-New Haven Hospital from January 1974 to June 1975. The incidence of myocardial infarction and its mortality were correlated with clinical, haemodynamic, anatomical, and operative factors. Myocardial infarction occurred in 18% of all patients (22/123); 15 inferior, 6 anterior, and 1 anterolateral wall. Three factors appeared to be related to the occurrence of myocardial infarction: left main coronary artery disease (LMCD), (47%, 7/15), increased left ventricular end-diastolic pressure (LVEDP), (27%, 14/52), and cardiopulmonary bypass time more than 60 minutes (24%, 21/88). The mortality of perioperative myocardial infarcation was 13.6% (3/22), while for patients without perioperative myocardial infarction the mortality was 2% (2/101). The overall operative mortality was 4% (5/123). The risk of perioperative myocardial infarction is significantly increased by left main coronary artery disease, increased left ventricular end-diastolic pressure, and cardiopulmonary bypass time more than 60 minutes, in patients undergoing coronary artery surgery for unstable angina pectoris. The mortality of perioperative myocardial infarction is high (13.6%) in patients with unstable angina.

Adult↗
PubMed1978

Correlation of fluoroscopically detected coronary artery calcification with exercise stress testing in asymptomatic men.

Cardiac fluoroscopy followed by a submaximal exercise electrocardiogram was used to evaluate 129 healthy men (average age 49 p 6) for assessment of possible latent ischemic heart disease in an asymptomatic population. Of 108 subjects who completed the exercise protocol, 37 (34%) had at least one fluoroscopically detected calcified coronary artery. Of the 16 subjects with a positive exercise stress test, 13 (81%) had calcification of at least one coronary artery, Thirteen of 37 (35%) with calcification had a positive exercise test. Those with calcification of at least one coronary artery had a ninefold increased risk of a positive exercise stress test (p less than 0.0001). The location of a calcific deposit conferred greater risk of exercise-induced ischemic changes than did multivessel involvement. Forty-seven per cent of men with calcification in the left anterior descending coronary artery had an abnormal exercise electrocardiogram vs. 33% and 16% of persons with left circumflex and right coronary artery calcifications, respectively.

Adult↗
PubMed1978

Tricyclic antidepressants: plasma levels and clinical findings in overdose.

Following amitriptyline or imipramine overdose by 30 patients, total plasma concentrations ranged from 29 to 1732 ng/ml but did not correlate well with physical findings or most electrocardiographic changes. Only those patients with a QRS interval greater than 0.1 second had significantly elevated plasma levels. However, a plasma level ratio of the parent drug (amitriptyline, imipramine) to its respective N-desmethyl metabolite (nortriptyline, desmethylimipramine) greater than or equal to 2.0 was associated with an acute overdose. This ratio was more useful than total plasma levels in differentiating an overdose from a therapeutic dose with associated toxicity and an elevated steady-state plasma level.

Adolescent↗
PubMed1977

Effects of orthostatic postural changes on myocardial oxygen demands.

The effects of orthostatic tilting were studied in 12 mongrel dogs anesthetized with sodium pentobarbital. Orthostasis produced significant decreases in cardiac output and left ventricular dimensions. Secondary decreases in coronary flow and myocardial oxygen consumption were also documented. These changes were attenuated when the animals were pretreated with propranolol. The upright posture may be of value in treatment of angina pectoris.

Animals↗
PubMed1977

Incidence and mortality of perioperative myocardial infarction in patients undergoing coronary artery bypass grafting.

The incidence of perioperative myocardial infarction (MI) determined by electrocardiogram was examined in 168 consecutive patients having only coronary artery bypass grafting at Yale-New Haven Hospital from July 1974 to June 1975. The incidence of MI and its mortality were correlated with clinical, hemodynamic, anatomic, and operative factors. Perioperative MI occurred in 23% of all patients (39/168); 26 in the inferior, 11 in the anterior, and two in the anterolateral wall. Three factors appeared related to the occurrence of MI: 1) abrupt propranolol withdrawal 24 hours prior to surgery (Prop) (32%, 33/103); 2) left main coronary artery disease (LMCD) (37%, 7/19); and 3) cardiopulmonary bypass longer than 60 minutes (CPB) (23%, 30/128). To more precisely predict MI, combinations of factors were examined. The combination of LMCD and CPB was 39%, (7/18) while the absence of either yielded an incidence of only 5.1% (2/39) (P less than 0.001). The mortality of patients with MI was 15.4% (6/39) while in patients without MI the mortality was 1.6% (2/129). We conclude that the risk of perioperative MI is significantly increased by abrupt propranolol withdrawal 24 hours before surgery, left main coronary artery disease, and cardiopulmonary bypass longer than 60 minutes in patients undergoing coronary artery bypass grafting. The mortality of perioperative MI is high, despite previous reports of the benignity of perioperative myocardial infarction.

Adult↗
PubMed1976

N-dimethylisopropyl propranolol. Effects on myocardial oxygen demands.

N-Dimethylisopropyl propranolol (DMP) is a quaternary derivative which lacks significant beta-adrenergic blocking and local anesthetic effects. It has been reported, nonetheless, to be effective in treating experimental arrhythmias and in limiting the extent of ST-segment elevations following experimental coronary occlusion. The present study examined the effects of DMP on the hemodynamics and myocardial oxygen demands of anesthetized dogs. After a single dose of 3 mg/kg, heart rate fell from 146 +/- 8 to 124 +/- 6 beats/min (P less than 0.0025), and aortic systolic pressure fell from 151 +/- 11 to 141 +/- 9 mm Hg (0.05 less than P less than 0.10), resulting in a 16.8% reduction in the tension-time index. Stroke volume was reduced by 10% despite a 54% increase in left ventricular end-diastolic pressure, suggesting a negative inotropic effect. This was supported by a decrease in maximum extrapolated contractile element velocity from 9.10 +/- 1.05 to 6.61 +/- 65 units/sec (P less than 0.0025). Myocardial oxygen consumption was reduced from 12.0 +/- 1.4 to 9.9 +/- 1.5 ml/min/100 g tissue (P less than 0.05). Myocardial oxygen extraction was unchanged, indicating that the decrease in oxygen consumption resulted from a reduction in myocardial oxygen demand. When heart rate and systolic pressure were artificially restored to control levels, after the administration of DMP, myocardial oxygen consumption remained significantly below the control level. DMP, therefore, appeared to reduce myocardial oxygen demands primarily by its negative inotropic effect. This drug may have application in the treatment of ischemic heart disease.

Animals↗
PubMed1975

Retrograde catheterization of the left atrium in idiopathic hypertrophic subaortic stenosis.

Retrograde catheterization of the left atrium utilizing the Shirley technique was successfully performed in four patients with idiopathic hypertrophic subaortic stenosis. By traversing the inflow tract of the left ventricle on pullback from the left atrium to the aorta, this method served to separate definitively true hypertrophic subaortic stenosis from cavity obliteration. It was accomplished with relative ease and no complications. In patients with suspected idiopathic hypertrophic subaortic stenosis who are to have retrograde left heart catheterization, this approach to the left atrium is recommended as an alternative to the transseptal technique.

Adult↗
PubMedDate not supplied

Localization of the conduction delay occurring during coronary arteriography.

The effect of coronary arteriography on intraventricular conduction was studied in 12 atropinized, open-chest dogs. Left bundle-branch (LB) and cavitary (V) potentials were recorded from a bipolar electrode catheter positioned against the septum below the aortic valve. Subendocardial (SEE) and subepicardial (IME) bipolar potentials were obtained from distal and proximal poles of multipolar electrode needles. Conduction times from LB to V, LB or V to SEE and SEE to IME were obtained during control and during Renografin 76 (REN) and normal saline injections into the left and right coronary arteries. Significant QRS axis changes and increased QRS duration occurred in 6 of 12 dogs simultaneously with LB-SEE and V-SEE delay. In 6 without axis changes, REN produced significant delay and increased QRS duration. Only REN to LCA produced significant changes. Coronary arteriography alters conduction through the distal left ventricular Purkinje system without affecting transmural conduction.

Angiography↗
PubMedDate not supplied

Predictors of operative mortality for coronary bypass grafting in patients with ischemic heart disease.

Predictors for operative mortality (OM) were studied in 172 consecutive patients (pts) undergoing coronary artery grafts (CAG) for angina pectoris.Seventy eight pts had Class IV angina; of the 147 patients given propranolol, 41 were gradually withdrawn from propranolol and finally discontinued 24 hours before surgery, and 106 were abruptly withdrawn from propranolol 24 hours before CAG; 20 pts had left main coronary disease; 156 pts had cardiopulmonary bypass (CPB) time shorter than 20 minutes, and 16 pts had a CPB longer than 120 minutes.The operative mortality was 5.2% (9/172) for the entire group. Class IV angina (OM 7%), abrupt propranolol withdrawal (OM 6.6%), left main coronary artery disease (OM 25%), and CPB longer than 120 minutes (OM 50%), all significantly increased OM. These variables were interdependent, however, as many pts belonged to several predictor categories, combinations of predictors were examined, in order to more accurately predict the risk of individual pts. The combination of left main coronary artery disease and CPB longer than 120 minutes; and Class IV angina and CPB longer than 120 minutes were significantly associated with higher operative mortality.We conclude that Class IV angina, abrupt propranolol withdrawal, left main coronary artery disease and prolonged CPB are potent, interdependent predictors of OM in pts undergoing CAG. Consideration of these predictors, alone and in combination, allows effective prediction of OM for CAG in patients with stable angina pectoris.

Adult↗