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Biomedical subjects

K A Comess

Publications and source records attributed to K A Comess.

27 records · Page 2Linked to original sources
PubMed1982

Kinetics of the digoxin-aspirin combination.

Digoxin interacts kinetically with many drugs in man. These interactions may result in digoxin toxicity. Aspirin has been shown to raise serum digoxin levels in the dog. We evaluated the effect of aspirin on digoxin single-dose kinetics in eight healthy adults. Aspirin induced no change in digoxin total body clearance, volume of distribution, elimination half-life, or renal or creatinine clearance. Trough serum salicylate levels ranged from 93 to 163 microgram/ml. We conclude that no alteration is required in digoxin dosing when aspirin is used.

Adult↗
PubMed1982

Effect of antidysrhythmic drugs on the heart rate and blood pressure response to treadmill exercise.

The heart rate and blood pressure response to exercise are clinically important parameters evaluated during treadmill testing. These responses may be altered by cardiac drugs. We evaluated the effect of procainamide and disopyramide on the heart rate and blood pressure response to treadmill exercise in 9 healthy volunteers. Each subject performed one Bruce protocol treadmill test while on each of three treatments: placebo, procainamide 1.0 g t.i.d.; disopyramide 150 mg t.i.d. The order of the treatments was randomized in a Latin square design. The study was conducted double-blind. The drugs slightly increased the resting heart rate, but had no significant effect on exercising heart rate or blood pressure. We conclude that the use of procainamide or disopyramide does not interfere with the interpretation of results of treadmill testing.

Adult↗
PubMed1981

Clinical implications of the blood pressure response to exercise.

The blood pressure response during exercise testing is useful in evaluating cardiac status. Failure of the systolic pressure to rise with increases in work load, or a hypotensive response, are signs of significant heart disease. In the patient with coronary artery disease, the maximal systolic pressure achieved during exercise correlates with survival. Exertional hypotension in coronary artery disease is an insensitive, but highly specific, indicator of three-vessel disease or significant left ventricular dysfunction.

Adult↗
PubMedDate not supplied

Pharmacology and clinical use of mexiletine.

Mexiletine is an antiarrhythmic agent with structural and electrophysiologic properties similar to those of lidocaine. Mexiletine decreases ventricular automaticity while shortening both action potential duration and effective refractory period. The drug may be administered orally or intravenously. Hepatic metabolism is the major route of elimination. The elimination half-life is approximately 10 hours, but longer in patients with acute myocardial infarction, chronic congestive heart failure or hepatic insufficiency. Mexiletine suppresses ventricular ectopy in the acute phase of myocardial infarction. The drug is effective for some patients in whom lidocaine has failed. It suppresses chronic ventricular ectopy and is well tolerated in approximately two-thirds of stable outpatients treated with this agent. In that population, mexiletine is comparable in efficacy to quinidine, procainamide and disopyramide. It is effective in 30-50% of patients with ventricular arrhythmias refractory to other antiarrhythmic drugs. In patients with refractory arrhythmias, the efficacy of mexiletine may be enhanced by combination with propranolol, quinidine or amiodarone. Adverse reactions limit use of mexiletine in approximately 20% of patients. Gastrointestinal and central nervous system side effects are the most common. Mexiletine does not depress myocardial function. Aggravation of arrhythmias is uncommonly observed. The usual intravenous dose of mexiletine is 150-250 mg over at least 10 minutes. Long-term oral dosages are usually 200-300 mg 3 or 4 times daily.

Arrhythmias, Cardiac↗
PubMedDate not supplied

Diagnostic reliability of M-mode echocardiography for detecting mitral valve prolapse in 50 consecutive panic patients.

Fifty consecutive panic patients had M-mode echocardiographs read independently by two cardiologists with expertise in echocardiography. In this prospective study, there was poor interrater reliability (22 of 50; K = 0.11) for diagnosis of mitral valve prolapse (MVP). On repeat evaluation 10 months later there was also unacceptable intrarater reliability for each reader: 22 of 35 (K = 0.41) and 22 of 35 (K = 0.45). We conclude that M-mode echocardiography is clinically unreliable for establishing the diagnosis of mitral valve prolapse. These findings suggest that the variable reporting of M-mode-determined mitral valve prolapse in psychiatric populations may reflect differences among echocardiologists rather than differences in cardiac pathology. The clinical implications of these findings are discussed.

Agoraphobia↗
PubMedDate not supplied

Pseudocolor displays in B-mode imaging applied to echocardiography and vascular imaging: an update.

Cardiac and vascular ultrasound systems incorporting colorized gray-scale display options to supplement the standard B-mode gray-scale image have recently reappeared on the market from several manufacturers. As yet, the clinical benefit of this "new" technology is unknown, and recommendations and protocols for its best application are not available. This article reviews the limitations of the gray-scale displays currently used, the rationale of the color-supplemented B-mode image, and some of the potential applications to cardiac and vascular ultrasound.

Color↗
PubMedDate not supplied

Avoidance of retrograde catheterization by Doppler echocardiographic diagnosis of Björk-Shiley aortic valve dysfunction.

A 74-year-old man with a history of prior Björk-Shiley aortic valve replacement was admitted with chest pain and dyspnea. Results of physical examination and cinefluoroscopy suggested a dysfunction of the prosthetic valve; imaging echocardiography was not helpful. Nonimaging continuous wave Doppler examination confirmed severe prosthetic aortic valve dysfunction, necessitating emergent replacement, and potentially hazardous retrograde catheterization of the prosthesis was avoided.

Aged↗