Effect of propranolol on ventricular arrhythmia. The beta-blocker heart attack trial experience

The Beta-Blocker Heart Attack Trial (BHAT) was a multicenter, randomized, double-blind, placebo-controlled trial that tested the effectiveness of propranolol in reducing the mortality rate in patients after myocardial infarction (MI). Twenty-four hour ambulatory ECG monitoring was done on 3279 of the 3837 enrolled patients at baseline (5-21 days after hospital admission) and repeated after 6 weeks of therapy in a random sample of 25% of the study population. Ventricular arrhythmias were divided into seven different categories and the prevalence of each category is presented. Ventricular arrhythmia at baseline appears to increase with patient age, past history of myocardial infarction, and use of diuretics. Other selected variables--sex, CPK ratio and history of smoking, diabetes and hypertension--appear to be less clearly associated with ventricular arrhythmia. Paired data analysis performed on 826 patients who had ambulatory electrocardiograms both at baseline and after 6 weeks of treatment showed an increased prevalence of ventricular arrhythmia at 6 weeks. This increase was blunted by propranolol therapy.

Bundle branch block in acute myocardial infarction

The management of patients with acute myocardial infarction complicated by bundle branch block is a significant clinical problem and represents 8% to 13% of patients with acute infarction. This study reviews the records of 606 patients with myocardial infarction admitted to our coronary care unit. Forty-seven (8%) had complete bundle branch block. The risk of developing high-degree AV block in these 47 patients was reviewed. There are no established therapeutic guidelines for patients with pre-existing bundle branch block and left bundle branch block in acute myocardial infarction. We found a high risk of progression in patients with pre-existing bifascicular block in the presence of anterior wall infarction (25%) as well as in patients with left bundle branch block with acute anterior wall infarction (100%). On the basis of our data and careful review of the literature, we recommend prophylactic pacemaker insertion in these high-risk groups.

Efficacy of sustained-release buccal nitroglycerin in patients with angina pectoris. New and long-acting therapy demonstrated by exercise

The antianginal efficacy of a single sustained-release buccal nitroglycerin (BNTG) tablet was assessed in 16 patients with known coronary artery disease. Patients were trained in bicycle ergometry to induce angina pectoris within three to five minutes. A hemodynamically effective dose of BNTG was identified. Patients were tested at baseline and given placebo and BNTG in a randomized, double-blind manner on consecutive days. They were tested at 0.5, 1, 3, and 5 hours after drug administration. The average increase in exercise duration with BNTG compared with placebo at 0.5 hours was 40 percent (p less than 0.01); at 1 hour was 31 percent (p less than 0.01); at 3 hours was 27 percent (p less than 0.01); at 5 hours was 15 percent (p = NS). In a subset of ten patients in whom the tablet was maintained in the buccal pouch for five or more hours before dissolving, increase in exercise duration was significant at all times tested (p less than 0.05). We conclude that BNTG is an effective modality of administering nitroglycerin for rapid and prolonged effect with reduction in angina pectoris and increase in exercise duration which may persist for at least five hours.

Single catheter technique for accurate cardiac outputs from left ventricle

We report our experience in cardiac output measurements using a single catheter for left ventricular green dye injection with sampling from the side arm of a femoral artery introducer sheath. This technique is compared to thermal dilution (20 patients) and pulmonary artery green dye injection (20 patients). There were no significant differences between the single catheter left ventricular method and the other two accepted methods for measuring cardiac output.

Current incidence of postmyocardial infarction (Dressler's) syndrome

This study examines the current incidence of postmyocardial infarction (Dressler's) syndrome. During 1980, 282 patients with documented myocardial infarction were admitted to our coronary care unit. Early postmyocardial infarction pericarditis was present in 18 patients (6.4%). Six of these patients received steroids and the remainder were treated with salicylates or other anti-inflammatory drugs. Anticoagulation was used in 149 patients (53%) during hospitalization. One hundred forty-four (51%) were receiving heparin and 133 (47%) received no anticoagulation. Information on the patient's status at 6 months was available in 229 patients who were discharged alive. Sixteen patients had died within 6 months after discharge and 4 patients were lost to follow-up study. There were no documented cases of Dressler's syndrome. It is concluded that Dressler's syndrome has decreased in incidence and perhaps disappeared. This decrease is most likely related to decreased use of oral anticoagulants and to more aggressive treatment of postmyocardial infarction pericarditis.

Relationship between QRS width and the presence of neoplasm

This study examines the relationship between QRS width and the presence of neoplasia. The QRS width was measured in 236 consecutive ambulatory patients. The patients' body surface area, CBC, SMA 6, and SMA 12 were also recorded. There were 17 out of 34 (50%) patients with neoplasia in the group with QRS less than 0.08 seconds. There were only 19 out of 78 (24%) with neoplasia in the group with QRS greater than or equal to 0.08 seconds (P less than 0.01). We conclude that there is a higher incidence of neoplasia in patients with a QRS less than 0.08 seconds than in patients with a QRS greater than or equal to 0.08 seconds. This difference cannot be explained by age, body surface area, hemoglobin, or any variable in SMA 6 or SMA 12.

Ventricular antiarrhythmic effects of beta-adrenergic blocking drugs: a review of mechanism and clinical studies

Beta-adrenergic blocking drugs are now commonly used in patients with ventricular arrhythmias. This review examines the possible mechanisms of their ventricular antiarrhythmic effect. Actions on the myocardial cell, as well as actions on the central and autonomic nervous system, are reviewed. Many clinical studies have attempted to show the efficacy of beta blockers in controlling ventricular arrhythmia and decreasing the incidence of sudden death after acute myocardial infarction. Although some of these clinical trials tended to show an impact on sudden death, the size of these trials or their design problems do not allow firm conclusions to be made. The Beta Blocker Heart Attack Trial (BHAT) is a placebo-controlled, double-blind, randomized trial of propranolol currently under way in the United States. Important additions to the previous trials include the addition of drug levels to ensure beta-blocking dosage, long-term electrocardiographic monitoring, and a study population of 4200 patients followed for an average of three years. These important design features will be of value in addressing some of the unanswered questions presented in this review.

Natural history of severe sinus bradycardia discovered by 24 hour Holter monitoring

This study follows patients with severe sinus bradycardia (40 beats per minute for 6 seconds or greater) in order to evaluate mortality and the effectiveness of permanent pacemaker insertion. Severe sinus bradycardia was noted on a 24-hour Holter in 95 patients. There were 64 males and 31 females with a mean age of 69 +/- 10 years. All were available for follow-up at 26 +/- 13 months. Twenty-eight required a permanent pacemaker at an average of 2 +/- 3 months after the Holter. Of this group 12 had the Holter for arrhythmia, 11 for cerebral symptoms, 4 for palpitations and 1 for chest pain. Only 1 was taking digitalis and no patients were taking Inderal. Six (21%) died at a mean interval of 21 +/- 15 months following pacemaker insertion. Sixty-seven did not require pacemaker insertion. The indications for Holter monitoring were arrhythmia in 16, palpitations in 19, cerebral symptoms in 20 and chest pain in 12. Four of these patients were on digitalis, 8 on Inderal, and 4 on both. Eleven (16%) died at a mean interval of 12 +/- 7 months after the initial Holter recording. Dizziness and/or syncope reoccurred in 22. Five had these symptoms even after pacemaker insertion. We conclude that severe sinus bradycardia is associated with a significant mortality. Insertion of a permanent pacemaker may decrease recurrent symptoms and slightly increase time of survival, but does not appear to influence the overall survival rate.

Coronary artery spasm appearing as syncope

A 56-year-old man had coronary artery spasm. The initial manifestation of the disease was syncope that occurred at night. Coronary artery spasm was documented by Holter recording and cardiac catheterization. The patient was effectively treated with nitrates and calcium-blocking agents.

Heparin-induced thrombotic thrombocytopenia

Following subcutaneous therapy with heparin, the patient developed signs and symptoms of vascular occlusion in both legs. This was accompanied by thrombocytopenia and platelet aggregation when the patient's platelets were incubated with heparin. The clinical features and implications of this syndrome are discussed.

Site of origin of ventricular premature beats in patients with mitral valve prolapse

This study examines the site of origin and possible etiology of ventricular premature beats (VPB) in patients with mitral valve prolapse. Ten patients with mitral valve prolapse documented by echocardiogram from the study group. All patients had prolapse of the posterioir leaflet and three additionally had anterior prolapse. There were eight females and two males, with a mean age of 29.1 +/- 11.1 years. All patients were having unifocal VPBs at rest. A vectorcardiogram (VCG) was taken of the VPB by a technique which allowed all VCG loops to be written from the same beat. The VCG analysis indicated that the VPB forces were directed anteriorly, inferiorly, and to the left in six patients. In two patients the VPB was directed posteriorly, inferiorly, and to the left, consistent with right ventricular origin. One of these patients had episodes of ventricular tachycardia. One was anterior, superior, and to the left, and one was markedly anterior, superior, and to the right. In all patients the initial portion of the QRS was inscribed slowly. The three patients with additional anterior prolapse did not show a common difference from those with isolated posterior prolapse. It is concluded that: (1) The majority of these VPBs originate from the posteriorbasal portion of the left ventricle. (2) They originate in the myocardium and not in the Purkinje tissue. (3) There is no relationship between the location of prolapse and the VPB morphology.

Characteristics of ventricular ectopic beats in patients with ventricular tachycardia. A 24-hour Holter monitor study

A total of 99 consecutive 24-hour Holter recordings with ventricular tachycardia were reviewed. Ventricular premature beats which occurred alone, and ventricular premature beats which initiated ventricular tachycardia were examined to determine which characteristics correlated with occurrence of ventricular tachycardia and which predicted rate and duration of ventricular tachycardia. The preceding R-R interval, the coupling interval, and a ratio of the two were examined. We found that ventricular tachycardia rate and duration increase with a shorter coupling interval, and the coupling interval/preceding R-R ratio was significantly different in single beats not initiating ventricular tachycardia. The ratio for the beat initiating ventricular tachycardia was smaller, indicating more prematurity.

Right bundle branch block with periods of alternating left anterior and left posterior hemiblock. Clinical evidence of incomplete fascicular block

The case presented had an electrocardiographic pattern of complete right bundle branch block with alternating periods of left anterior hemiblock and left posterior hemiblock. During one of the periods of alternating hemiblock, an His bundle electrogram was recorded and the His Purkinje (H-V interval) conduction time was within normal limits. In a second episode of alternating hemoblock, periods of Mobitz type II second-degree A-V block were noted. It is postulated that this case provides clinical evidence that incomplete block of a fascicle may occur in spite of an electrocardiographic pattern of complete fascicular block. It is thought that the periods of alternating hemiblock result from a changing relationship between conduction velocity and refractory period.

A-V block in accidental hypothermia

His bundle electrocardiography was performed on a patient with accidental hypothermia on whom the standard electrocardiogram (ECG) showed absent P waves, prominent J waves and a slightly irregular rhythm. Sino-ventricular conduction and a prolonged AH interval not responsive to atropine were found. These abnormalities reversed with rewarming.

Nonprolapsing atrial myxoma; clinical, echocardiographic, and angiographic correlations

The auscultatory features typical of myxoma were absent in a patient with nonprolapsing left atrial myxoma. Angiocardiographic and echocardiographic findings including B-mode cross-sectional scanning are presented.

Alternating Wolff-Parkinson-White (preexcitation) pattern

An electrocardiogram is presented which shows sinus rhythm with alternating Wolff-Parkinson-White (preexcitation) pattern. The frequency of intermittent preexcitation and mechanisms for its production are discussed.