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Biomedical subjects

S C Vlay

Publications and source records attributed to S C Vlay.

69 records · Page 4Linked to original sources
PubMed1985

The utility of aprindine blood levels in the management of ventricular arrhythmias.

Sixty-four patients with a history of ventricular tachycardia and ventricular fibrillation refractory to conventional therapy received aprindine to abolish recurrent episodes of symptomatic ventricular tachycardia. Fifty-six patients became asymptomatic and were followed up for a mean period of 23 months. Aprindine dose was adjusted to minimize adverse reactions but still control arrhythmia. Survival analysis was performed for the group with aprindine levels greater than 1.5 micrograms/ml and the group with levels of 1.5 micrograms/ml or less. At the end of the study, 65% of the patients with a high level were alive and asymptomatic as compared with only 35% of the patients with a low level (p less than 0.036). In patients at risk of recurrent sudden cardiac death, high aprindine levels maintained after abolition of symptomatic ventricular tachycardia were associated with improved survival.

Aprindine↗
PubMed1985

Nitrate therapy in angina and congestive heart failure.

Nitrates are vasodilators of venous and arterial smooth muscle commonly prescribed both for angina and congestive heart failure. Primarily venodilators, nitrates also affect the systemic circulation if administered in sufficient dosage. In the coronary circulation, the principal effect is on the large epicardial and collateral vessels. Blood is shunted toward the ischemic subendocardium. In the majority of patients with angina, relief of symptoms by nitrates is primarily due to hemodynamic effects on preload and afterload, unless the patient has coronary spasm. In patients with congestive heart failure, nitrates decrease the resistance to the emptying of blood from the left ventricle as well as the filling pressure. Nitrates are relatively well tolerated, except for an initial throbbing headache which rapidly resolves as tolerance develops. Nitrates are available in a multitude of forms including sublingual, oral, topical, transmucosal, intravenous, and spray preparations. Oral preparations undergo a first-pass effect in the liver, requiring larger doses. Other forms avoid this problem by direct transdermal absorption or the intravenous route. The latter has the advantage of rapid administration and ease of titration. The choice of nitrate depends upon the clinical situation.

Angina Pectoris↗
PubMed1984

Prognostic assessment of survivors of ventricular tachycardia and ventricular fibrillation with ambulatory monitoring.

The ability to assess prognosis in patients with serious ventricular arrhythmias treated with antiarrhythmic drugs by the degree of complexity on the 24-hour ambulatory electrocardiogram was evaluated in 59 survivors of ventricular tachycardia (VT) and ventricular fibrillation. After conventional therapy had failed, patients were treated with investigational drugs until symptomatic VT was abolished. A Holter monitor recording, obtained once the therapeutic regimen was established, was graded for the presence or absence of asymptomatic VT. Fifty-two patients were asymptomatic at discharge and were followed for 700 days. Of 44 patients followed for 1 year, none had recurrent syncope or died if asymptomatic VT was absent at 1 month (p less than 0.002). After 700 days, 27 patients (82%) without asymptomatic VT at 1 month were doing well, compared with 11 patients (58%) with asymptomatic VT at 1 month (p less than 0.002). In patients at risk for sudden cardiac arrest, early abolition of asymptomatic VT on ambulatory monitoring can be used to predict a good long-term clinical response.

Adolescent↗
PubMed1984

The use of encainide in atrial fibrillation.

Based on its electrophysiologic characteristics, encainide, a new type 1 antiarrhythmic agent, was selected for a therapeutic trial in a case of refractory paroxysmal atrial fibrillation. This approach represents an attempt to manage the pathophysiologic disturbance of atrial fibrillation by selection of a drug that would be expected to have specific effects on the conduction system.

Anilides↗
PubMed1984

Relationship of specific coronary lesions and regional left ventricular dysfunction to prognosis in survivors of sudden cardiac death.

We prospectively evaluated the relationship of specific coronary arterial and left ventricular segments to subsequent clinical outcome in 80 persons who were survivors of sudden cardiac death and had failed conventional antiarrhythmic therapy. There were 68 men and 12 women with an average age of 51 years who were treated with investigational antiarrhythmic agents, rendered asymptomatic, and followed for 16 +/- 14 (SD) months. At the end of the study 48 patients (60%) were alive and asymptomatic while 32 (40%) had experienced either recurrent syncope (five) or sudden cardiac death (27). The independent relationship of clinical and angiographic variables was performed in a univariate fashion using a Kaplan-Meier survival analysis and then multivariate logistic analysis was used to simultaneously consider all clinical and arteriographic variables. The results reconfirmed the importance of ejection fraction and left ventricular filling pressure on outcome. However, coronary arterial and left ventricular segmental analyses provided additional predictive power. Specifically, the survival outcome was found to be inversely related to the degree of proximal left anterior coronary (LAD) arterial narrowing: at 1 year 90% of patients with minimal LAD narrowing were alive/asymptomatic in contrast with 70% who had partial and 40% who had complete proximal LAD obstruction (p less than 0.005). Analysis of the posterobasal left ventricular segment wall motion demonstrated that 100% of patients with minimal dysfunction were alive/asymptomatic at 1 year, whereas only 52% of patients with severe dysfunction were alive (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Comparison of lorcainide and quinidine in the treatment of ventricular ectopy.

Lorcainide, a new type I antiarrhythmic agent, was compared to quinidine in respect to antiarrhythmic efficacy and clinical safety. Thirteen subjects completed an open, randomized, crossover study with analysis of 24-hour ambulatory ECG monitoring and drug blood levels. The QRS and Q-T intervals increased with both lorcainide and quinidine. The mean reduction in total ventricular premature beats (VPBs) with quinidine was 16 percent compared to 68 percent with lorcainide (p less than .05). With lorcainide eight of 13 subjects had a significant (greater than 82 percent) reduction in VPBs compared to only three of 13 subjects taking quinidine (p less than .05). This same relationship was observed when mean VPB/1,000 heartbeats was analyzed. Ventricular tachycardia was no longer present in five of nine subjects taking lorcainide and in two of nine taking quinidine. No relationship could be established between drug level and arrhythmia suppression in this small population. Some CNS effects were reported in both groups, but no significant hematologic, chemical, or urinary adverse effects were seen with either drug. Thus, lorcainide compares favorably to quinidine in regard to arrhythmia suppression, but was limited in its clinical utility by CNS side effects.

Adult↗
PubMed1984

Documented sudden cardiac death in prolonged QT syndrome.

Documentation of the mechanism of sudden death is described in a patient with a prolonged QT interval. Ventricular tachycardia was initiated by a ventricular premature beat (VPB) with a prematurity index similar to previous isolated VPBs. This event occurred despite the fact that the patient was receiving phenytoin sodium, a drug known to shorten the QT interval.

Aged↗
PubMed1982

Ventricular ectopy: etiology, evaluation, and therapy.

Ventricular ectopy occurs commonly. Its significance is related to the degree of complexity and the associated cardiac substrate. Coronary artery disease is the most frequent underlying cause, followed by cardiomyopathy and valvular disease. Symptomatic ventricular arrhythmias require treatment, whereas benign simple ventricular ectopy does not; however, the treatment of asymptomatic high-grade ventricular ectopy remains controversial. Therapy first must be directed toward the cardiac disease. Evaluation of the patient includes Holter monitoring, echocardiography, radionuclide studies, exercise testing, cardiac catheterization, and electrophysiologic testing. Programmed stimulation is useful in the diagnosis and prognosis of ventricular tachycardia, as well as in the evaluation of drug regimen efficacy. After treatment of ischemia and/or failure, specific antiarrhythmic agents, conventional and investigational, alone or in combination, are systematically selected. Should medical therapy alone be insufficient, consideration is given to surgical procedures such as subendocardial resection or ventriculotomy, often in combination with bypass grafting, aneurysmectomy, or valvular replacement. Electronic devices, including pacemakers or automatic internal defibrillators, may also be useful in certain selected cases. Suggested guidelines are proposed for a standardized approach, although therapy for each patient must still be individualized.

Adrenergic beta-Antagonists↗
PubMed1981

Automatic defibrillation in man. The initial surgical experience.

The automatic implantable defibrillator is an electronic device designed to detect and promptly correct malignant ventricular arrhythmias. Nineteen patients, all survivors of multiple cardiac arrests because of ventricular arrhythmias unresponsive to therapy, have undergone implantation of the automatic defibrillator. In seven patients who had had a previous cardiac operation, implantation was performed through a left lateral thoracotomy. A median sternotomy was used in five patients without a previous operation. In six patients cardiac procedures were performed concomitantly with defibrillator implantation. There were no operative deaths. The average follow-up is 6 months, the longest being 14 months. Following implantation, 47 episodes of malignant ventricular arrhythmias were documented. Twenty-six occurred spontaneously (17 of them outside the hospital); all were corrected with a single 25 joule pulse. Seventeen of 21 arrhythmias induced postoperatively were terminated. Although further validation is required, this study demonstrates that the automatic defibrillator is capable of diagnosing and terminating potentially lethal ventricular arrhythmias. Finally, implantation can be safely accomplished in an exceedingly high risk population.

Adolescent↗
PubMed1975

Quantitative relationships between potassium-43 imaging and left ventricular cineangiography following myocardial infarction in man.

To evaluate the quantitative relationships between resting potassium-43 (43K) myocardial imaging and left ventricular segmental contraction abnormalities, 15 patients were studied by both radionuclide and contrast angiographic techniques at least two months following transmural myocardial infarction. The ECG location of infarction involved the anterior wall alone in six patients, inferior wall alone in three patients, both anterior and inferior walls in five patients, and in one patient ECG-anatomic correlation was obscured by newly developed left bundle branch block. 43K defects were noted in all patients. Anterior wall 43K defects were noted in all patients with previous anterior infarction and seven of nine inferior infarcts. These 43K defects were associated with a quantifiable decrease in regional radioactivity of at least 20% of normal appearing zones, and their location correlated with the angiographic site of akinesis or dyskinesis. The extent of the 43K defect (% 43K HP [% potassium 43 hypoperfusion]) was measured by planimetry and averaged 49% of the anterior view image (range 25-66%), 43% of the left anterior oblique image (range 0-58%), with the mean of both views being 47% (range 17-62%). The mean total area of the anterior image was 58 cm2 (range 40-101 cm2). The extent of the 43K defect (% 43K HP) was related to the extent of segmental contraction abnormality (% ACS). Correlations between % ACS and anterior view % 43K HP (r = 0.67), left anterior oblique % 43K HP (r = 0.54), and mean % 43K HP (r = 0.77) were found. The total size of the anterior view image correlated with left ventricular end-diastolic volume (r = 0.79). Thus, in this initial group of patients following transmural infarction, potassium-43 imaging can be accurately and quantitatively correlated with the site and extent of regional ventricular dysfunction as it is assessed by quantitative left ventricular angiography.

Acute Disease↗