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Biomedical subjects

J E Doherty

Publications and source records attributed to J E Doherty.

At least 19 recordsLinked to original sources
PubMed1986

Cardiovascular effects of atropine in postoperative cardiac patients receiving digoxin for ventricular dysfunction.

Digoxin is clinically useful as a cardiac antiarrhythmic and inotropic agent. Its antiarrhythmic actions are mediated through the cholinergic nervous system. The cholinergic system, when activated, can depress ventricular function. We have sought to further increase the cardiovascular effects of digoxin by blocking its cholinergic effects with atropine. Atropine, 1 mg intravenously, was given to 10 postoperative cardiac patients. The cardiovascular time course was monitored by an ECG, radial arterial line, and pulmonary artery thermodilution catheter for 8 hours. A significant increase (p less than 0.05) in the cardiac output (CO), from 5.98 +/- 0.24 L/min to 6.60 +/- 0.34 L/min, was evident within 2 hours after atropine administration. The CO returned to control levels by 6 hours. There were no significant changes in heart rate, systemic vascular resistance, pulmonary artery wedge pressure, or systemic blood pressure. The results indicate that the cholinergic blockade of digoxin with atropine will acutely increase the cardiac output in postoperative cardiac patients.

Atropine↗
PubMed1985

Sensitivity of electrocardiographic criteria for left ventricular hypertrophy according to type of cardiac disease.

The sensitivity of 30 electrocardiographic criteria for left ventricular (LV) hypertrophy, isolated or combined, was examined to determine the relation to the underlying disease. Patients with coronary artery disease (CAD), systemic hypertension, valvular heart disease and cardiomyopathy were evaluated. A cardiac partition technique was used to define ventricular hypertrophy. Single electrocardiographic criteria often showed high sensitivity for 1 disease state, but not for others. Precordial voltage criteria were most sensitive for those with hypertensive and valvular disease. A QRS axis of more than -30 degrees occurred most often in patients with CAD. Both left atrial abnormality and abnormal T-wave inversion of more than 1 mm in V6 occurred with a high sensitivity in general; however, T-wave inversion of more than 1 mm in V6 had a low sensitivity in cardiomyopathy. Methods using combinations of various electrocardiographic criteria improved sensitivity. Using these methods, sensitivity of the electrocardiogram for LV hypertrophy was excellent for patients with systemic hypertension and valvular heart disease and acceptable by usual standards for patients with CAD and cardiomyopathy. Because the use of a single criterion is often ineffective, methods using multiple electrocardiographic criteria to detect LV hypertrophy are recommended when the patients under study have diverse cardiac diseases.

Adult↗
PubMed1985

Coronary artery atherosclerosis observed in men over 14 consecutive years.

The incidence of cardiovascular death and myocardial infarction associated with ischemic heart disease has declined over the past 15 years. Whether this is associated with a decrease in the severity of coronary atherosclerosis is unknown. The extent of coronary atherosclerosis in men was determined by postmortem coronary angiography in 505 patients over an observation period of 14 years. Patients were divided into those with ischemic heart disease (42%) and those without (58%). Mean coronary scores showed no significant trends over the 14-year period in those without ischemic heart disease and for the last 10 years in those with ischemic heart disease. In those few patients evaluated early in the study with ischemic heart disease, a significantly lower coronary score was found compared to subsequent years. This study was performed during an era of declining cardiovascular death rates and a declining incidence of myocardial infarction, and suggests that this decline may relate to favorable changes in pathogenesis rather than to a decrease in extent of coronary atherosclerosis.

Adult↗
PubMed1985

Clinical use of digitalis glycosides. An update.

Digitalis glycosides continue to place high on the list of prescribed drugs. Digoxin is 8th on prescriptions written in the United States in 1980, digitoxin 16th, and digitalis leaf 23rd. There is little doubt that most physicians continue to believe these drugs are useful. The application of more definite indications, smaller doses, and the recognition of the role of pharmacokinetics and drug interactions make use of the glycosides more challenging than ever before in 1985.

Administration, Oral↗
PubMed1979

Evaluation of warning arrhythmias before paroxysmal ventricular tachycardia during acute myocardial infarction in man.

In order to determine the relationship of paroxysmal ventricular tachycardia (PVT) to any antecedent (premonitory) ventricular arrhythmias during the early phases of acute myocardial infarctions, 24-hour Holter monitoring was begun on 52 male patients an average of 12.6 hours after the onset of prolonged chest pain that was documented as acute infraction. Twenty-four patients had PVT and 28 did not. We analyzed in detail the incidence of frequency of premature ventricular complexes (PVCs), prematurity and pairing during the 10 minutes immediately preceding PVT from a continuous 10-minute rhythm strip. There was no positive correlation between PVT and the number or complexity of PVCs in the 10 minutes immediately before ventricular tachycardia. These findings suggest that there is no consistent pattern or frequency of ventricular arrhythmia that could be identified as premonitory for PVT during the immediate pre-PVT period, even during the acute phase of myocardial infarction in man.

Acute Disease↗
PubMed1978

How and when to use the digitalis serum levels.

The indications for measuring serum digoxin levels are suspicion of digitalis intoxication and the need to know the status of digitalization. Pitfalls of interpretation include time of serum sample relative to time of last digitalis dose, age of patient, atrial arrhythmia, electrolyte disturbances, disease state of the patient, recent radioisotopes "on board," abnormal absorption or metabolism, and laboratory error. The serum digoxin level is a useful clinical tool but only when employed with good judgment. Not every patient receiving digitalis requires the measurement of a blood level.

Decision Making↗
PubMed1978

Effect of digitalis on human ventricular refactoriness.

In order to evaluate the effect of digitalis on the effective refractory period of the human ventricle, 14 patients were studied with atrial or ventricular pacing and with the introduction of ventricular extra-stimuli. The ventricular effective refractory period (VERP) was recorded before and after 1.0 to 1.25 mg ouabain given intravenously and the results compared with similar changes in the Q-T interval. During atrial pacing (eight patients) at rates of 70 to 110 beats per minute, ouabain reduced the mean ventricular effective refractory period from 290 +/- 13 ms to 260 +/- 16 ms (P less than 0.01) and the mean Q-T interval was reduced from 372 +/- 18 ms to 359 +/- 19 ms (P less than 0.01); the mean VERP/Q-T ratio was 0.79 +/- 0.04 before ouabain and 0.73 +/- 0.04 after ouabain (P less than 0.01). Utilising ventricular drive pacing (six patients) the mean ventricular effective refractory period was reduced from 245 +/- 16 ms to 226 +/- 13 ms (P less than 0.01) and the mean Q-T interval reduced from 382 +/- 18 ms to 360 +/- 29 ms (P less than 0.01). There was no significant change in the mean VERP/Q-T ratio (0.63 +/- 0.04 before vs 0.63 +/- 0.04 after ouabain). The results demonstrate that clinically effective doses of ouabain produce a significant reduction of the effective refractory period of the human ventricle. This change is accompanied by a reduction in the VERP/Q-T ratio during atrial pacing.

Adult↗
PubMed1978

Ventricular arrhythmias in chronic stable angina pectoris with surgical or medical treatment.

Since both propranolol therapy and saphenous-vein bypass surgery have become accepted treatments for patients with symptomatic coronary-artery disease, it is important to determine if either influences the prevalence of ventricular arrhythmias in these patients. Six-hour dynamic electrocardiography was done on 130 patients with chronic stable angina pectoris at least 1 year after being randomized to surgical or medical therapy. All surgical patients had saphenous-vein grafting; 90% of the medical patients received propranolol. Data analysis showed that even though the overall prevalence of premature ventricular contractions was no different in medical and surgical patients, the prevalence of complex premature ventricular contractions was significantly higher in surgically treated patients not receiving propranolol than in propranolol-treated medical patients (p less than 0.05). However, the survival rate was no different in either group, and the quality of life in the surgical patients remained superior.

Adult↗
PubMed1977

Effect of cholestyramine on digoxin absorption and excretion in man.

Six subjects receiving digoxin therapy for heart disease were studied on two occasions with a single oral dose of 0.5 mg of tritiated digoxin. In every study, all stools and urine were saved for 1 week. Before the second study, treatment with cholestyramine, 4 g every 6 hours, was begun and continued throughout. In three patients, a third study was performed after cholestyramine treatment had been continued for 1 month. Results showed that after cholestyramine administration serum levels, stool output and urinary output of tritiated digoxin varied over a wider range, but cholestyramine had no net short-term effect of any of these variables. After 1 month of cholestyramine administration, there was a small statistically significant increase in stool output of tritiated digoxin and metabolites. In vitro studies suggested that cholestyramine is likely to be a weak digoxin binder in the gut and that changes induced by this resin in digoxin metabolism are not likely to be due to drug binding.

Administration, Oral↗
PubMed1977

Digitalis in pulmonary heart disease (cor pulmonale).

The use of digitalis in pulmonary heart disease has been a topic of great interest for a number of years. The physician's decision to use or not to use digitalis in pulmonary disease has often been an emotional rather than a reasoned one. The diagnostic difficulties from a clinical point of view in separation of pulmonary from cardiac symptoms and findings have also been confusing. The fact that small doses of digitalis may have an inotropic effect on the cardiac muscle has been a difficult concept for many physicians to adopt. On the other hand, the larger doses of digitalis that are often necessary to control the ventricular response in supraventricular arrhythmias sometimes gives rise to confusion. We shall attempt to review the subject in detail and examine indications, contraindications, toxicity, dosage, assessment of benefit, and role of digitalis serum levels in patient management.

Arrhythmias, Cardiac↗