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Biomedical subjects

S C Vlay

Publications and source records attributed to S C Vlay.

At least 37 records · Page 2Linked to original sources

Pharmacological management of acute myocardial infarction.

The routine medical management of patients with acute myocardial infarction (AMI) has undergone major changes in the last decade. Several large-scale trials have firmly established the effectiveness of thrombolytic therapy, beta blockers, and aspirin in the treatment of AMI. The critical issues include reducing myocardial oxygen demand and restoring adequate blood supply to the ischemic regions of the myocardium. As a result, the ability to intervene in patients with AMI has improved significantly. The purpose of this review is to discuss briefly the results of major trials of primary and secondary pharmacological intervention which had a direct impact on the care of patients with AMI. It concludes with current recommendations for the management of patients with AMI.

Adrenergic beta-Antagonists↗

Complications of percutaneous intra-aortic balloon pump use in patients with peripheral vascular disease.

Percutaneous intra-aortic balloon pump use may carry an increased risk for patients with peripheral vascular disease. To determine the incidence and types of associated complications, the medical records of 144 patients who underwent a total of 153 percutaneous intra-aortic balloon pump insertions were reviewed. Patients were divided into two groups. Group 1 was composed of 20 patients with a history of peripheral vascular disease. Group 2 was composed of 124 patients without such history; they underwent a total of 133 insertions. Nineteen major complications (12%) occurred, 12 in group 1 (60% of 20 insertions) and seven in group 2 (5% of 133 insertions). Major complications were further classified by their nature: embolic, occlusive, and technical. All three types of complications occurred more frequently in group 1. Embolic complications occurred more frequently in patients with aneurysms and proved the most lethal, with two of six deaths in group 1 resulting from this complication.

Aneurysm↗

Emergency coronary revascularization using polytetrafluoroethylene conduits in a patient in cardiogenic shock.

There is growing awareness that a particular subset of patients with coronary artery disease who need surgical revascularization do not have autologous vein or internal mammary artery available or surgically applicable. The polytetrafluoroethylene graft has had limited use in aortocoronary bypass procedures. We describe a case of cardiogenic shock secondary to severe coronary artery disease and aortic stenosis, where the use of this synthetic graft contributed to a successful outcome. Angiographic patency was documented at 3 months follow-up. Our experience, plus a review of the literature, supports the use of polytetrafluoroethylene grafts during aortocoronary artery bypass to salvage infarcting or ischemic myocardium, when traditional autologous bypass conduits are not available or applicable.

Aged↗

Short-term variability of ventricular arrhythmia and rapid assessment of drug efficacy.

Statistical criteria for suppression and aggravation of ventricular arrhythmia were defined by means of 50 short-term drug tests performed in 24 patients. Each patient's spontaneous variability (SV) was evaluated by linear regression analysis of hour-to-hour changes in ectopy during 24- to 48-hour Holter monitoring. The response to a single oral dose of disopyramide, 300 mg, flecainide, 200 mg, and propafenone, 450 mg, was measured during a trial lasting 4 hours. Lidocaine was administered intravenously in incremental doses of up to 4 mg/min and was evaluated over 3 hours. Threshold values of ventricular arrhythmia corresponding to 95% confidence limits were calculated from baseline recordings and were used to ascertain the likelihood of a true drug effect. The minimum decrease in hourly ectopy indicating arrhythmia suppression averaged 90.9%, while an increase of at least 947% was required for a proarrhythmic effect. When these efficacy criteria were applied, 16 of 50 short-term tests revealed no drug effect. In contrast, when a 70% threshold derived from studies of daily variability was employed, only 7 of 50 trials were negative. Thus individual determination of hourly arrhythmia variability yields more stringent criteria than extrapolation from day-to-day spontaneous variation.

Aged↗

Update on mechanical intervention in acute myocardial infarction.

The role of pharmacologic interventions in acute myocardial infarction (i.e., a combination of intravenous nitroglycerin, intravenous beta-blocker, oral aspirin, and intravenous thrombolysis), has become more standardized, whereas the role of mechanical intervention remains to be defined. Mechanical intervention includes percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting. The number of carefully controlled, randomized trials is limited, particularly with surgery. Nevertheless, in optimal circumstances, when performed within the first few hours of myocardial infarction, surgery can be beneficial in reducing mortality, especially with anterior location of infarct. Surgery may not prevent reinfarction. However, the results of nonrandomized surgical trials done 10 years ago are difficult to compare with modern-day treatment of myocardial infarction with the availability of new agents and PTCA. Angioplasty can be performed safely in the acute phase of myocardial infarction but may not be the ideal choice for all patients. The results may be more optimal if performed when the patient is stable. Clinical factors associated with favorable and unfavorable outcomes have been identified. Mortality is not significantly affected by early versus late PTCA. Certain selected patients benefit from PTCA, particularly those in cardiogenic shock, in whom PTCA has made a dramatic improvement in outcome. To achieve maximal benefit, intervention should be performed early, within the first hours of symptoms. Further well-designed studies may help clarify the role mechanical techniques will play in future combinations of interventional therapy.

Angioplasty, Balloon, Coronary↗

Nifedipine and isosorbide dinitrate alone and in combination for patients with chronic stable angina: a double-blind crossover study.

Since not all patients tolerate beta-blockers, the efficacy of nifedipine and isosorbide dinitrate was evaluated alone and in combination in patients with stable angina pectoris. The study was a randomized double-blind crossover design with patients titrated to maximally tolerated doses of both drugs. Phases included isosorbide dinitrate alone, nifedipine alone, and isosorbide dinitrate plus nifedipine in combination, with efficacy determined by stress testing. Eleven men and one woman patient with a mean age of 60 years and a mean of five anginal episodes/week completed the study. Patients were in New York Heart Association (NYHA) classes I, II, and III. With nifedipine alone compared with isosorbide dinitrate alone, patients had fewer angina attacks/week (p less than 0.02), exercised longer before experiencing angina (p less than 0.03), and had less ST segment depression during (p less than 0.03) or after (p less than 0.05) exercise. When patients received isosorbide dinitrate plus nifedipine, only time to onset of angina during exercise (p less than 0.05) was significantly different from the response with isosorbide dinitrate alone. Analysis of variance between nifedipine and isosorbide dinitrate plus nifedipine was not significant. Diastolic blood pressure with isosorbide dinitrate plus nifedipine (p less than 0.04) was lower than with isosorbide dinitrate alone. No significant differences in systolic blood pressure were noted between the treatment groups. The drugs alone and in combination were relatively well tolerated. Nifedipine alone may be superior to isosorbide dinitrate alone. The combination of isosorbide dinitrate plus nifedipine demonstrated no advantage over nifedipine alone compared with isosorbide dinitrate alone.

Angina Pectoris↗

Internal cardioverter defibrillator: component failure.

Sudden death occurred in a patient with congestive cardiomyopathy, sustained ventricular tachycardia refractory to amiodarone, and an automatic internal cardioverter defibrillator. Interrogation of the AICD at the time of death was indicative of malfunction. Postmortem analysis documented component failure involving a voltage regulating transistor resulting in prolonged charge times.

Cardiomyopathy, Dilated↗

Ventricular reconstruction with vascular prosthesis after aneurysmectomy. Ability to defibrillate and utilize the automatic internal cardioverter defibrillator.

Adjunct surgical procedures for patients with malignant ventricular tachyarrhythmias who require the automatic internal cardioverter defibrillator include aortocoronary artery bypass graft surgery, valvular repair or replacement, subendocardial resection, and aneurysmectomy. Ventricular reconstruction and its compatibility with the AICD are described in a 64-year-old man who required treatment of refractory ventricular tachycardia as well as resection of a large anteroapical aneurysm. Reconstruction using a dacron patch preserved left ventricular geometry but did not adversely affect the ability to defibrillate and allowed successful utilization of the automatic defibrillator.

Cardiac Surgical Procedures↗