Use of alprenolol in acute cardiac arrhythmias

Alprenolol, a new beta adrenergic receptor blocking agent, was evaluated as an antiarrhythmic drug in 49 patients with 78 episodes of premature contractions or tachyarrhythmias of supraventricular or ventricular origin. A clinically and statistically significant reduction in frequency of premature contractions was obtained. In addition, a clinically and statistically significant reduction in ventricular rate occurred in those patients with tachyarrhythmias. No severe adverse effects were noted during the study. The results indicate that alprenolol can be used safely and effectively in the treatment of cardiac arrhythmias occurring during acute myocardial infarction. Congestive heart failure was not considered a contraindication when it was judged clinically that the arrhythmia aggravated the heart failure.     

The role of cryosurgery in the management of cardiac arrhythmias

In the late 1970s, cryoablation of the AV node, accessory pathways, and ventricular tachycardia was first demonstrated and the technique was thought likely to assume an increasing importance in the surgical management of cardiac arrhythmias. However, more than 10 years later, cryotherapy is relatively sparingly used in these situations, and is at best an adjunctive means of therapy. The principal reason for this may lie in what was thought to be its major advantage: the fact that it is a highly selective, precise means of ablating myocardial tissue. Whereas electrophysiological mapping of tachycardia is able to identify apparently localized areas of arrhythmia substrate, relatively wide surgical destruction of myocardial tissue is frequently required to ensure successful tachycardia abolition: discrete, precise means of ablation are at a disadvantage. The future role for cryosurgery would seem to lie in those areas of arrhythmia management where selective ablation of substrate is essential. The ability of cryosurgery to modify (rather than simply ablate) AV nodal physiology in patients with AV nodal re-entrant tachycardia is such that it is likely to rival the recently reported catheter techniques for modification of the AV node.     

Devices for the management of ventricular arrhythmias in cardiac failure

Heart failure is a common clinical syndrome with a high morbidity and mortality. Despite advances in medical treatment, death from dangerous ventricular arrhythmias is frequently implicated. Emerging evidence supports the use of the implantable cardioverter defibrillator for selected patients. This includes secondary prevention indications for patients who have survived life-threatening ventricular arrhythmias. In addition, patients who have not suffered spontaneous sustained ventricular arrhythmias, but who are at high risk for sudden arrhythmic death are starting to be recognized as candidates for ICD therapy. At present the only primary prevention indication with a good evidence base is the presence of inducible ventricular arrhythmias at electrophysiologic testing in patients with prior myocardial infarction, impaired left ventricular systolic function and non-sustained ventricular tachycardia on Holter monitoring. Studies planned or in progress are likely to expand further the role of device therapy in the treatment of patients with cardiac failure.     

Transtelephonic electrocardiographic transmission for management of cardiac arrhythmias

Brief periods of transtelephonic electrocardiographic transmission conducted at periodic intervals or during sporadic symptoms may provide an inexpensive and reliable alternative to extended ambulatory electrocardiographic tape recordings. Sixty-one patients were enrolled in a transtelephonic electrocardiographic transmissions program. In 51 patients with documented arrhythmias (group I), telephone electrocardiographic transmissions were used to monitor antiarrhythmic drug therapy. In 10 patients, telephone electrocardiographic transmission was used in an attempt to diagnose infrequent symptoms suggestive of arrhythmia (group II). Of the 650 telephone electrocardiographic transmissions received, 73 (11%) revealed a clinically significant event, whereas 577 (89%) did not show any significant disturbances of cardiac rhythm. Of the 61 patients entered into the program, 29 (48%) had a clinically significant event identified during 1 or more transmissions. In group I, transtelephonic electrocardiographic transmission prompted a change in therapy in 37% of the patients. Of the 10 patients in group II, clinically significant events were noted during telephone electrocardiographic transmissions in each patient. Assuming a yield of 1 clinically significant event detected per 10 telephone electrocardiographic transmissions and a similar yield on long-term ambulatory electrocardiographic recordings, use of telephone electrocardiographic transmissions offers a cost-effective means of following patients with significant cardiac arrhythmias who are receiving potent antiarrhythmic drugs. In addition, telephone electrocardiographic transmission is a suitable diagnostic technique for patients with infrequent symptoms suggestive of cardiac arrhythmias.     

Cardiac arrhythmias: the role of pharmacologic intervention

The growing menu of drugs used to treat arrhythmias in children enhances the importance of antiarrhythmic selection based on the application of underlying electrophysiologic and pharmacokinetic principles, as well as a reduction of the side effect to benefit ratio. No attempt has been made in this report to discuss the diagnosis of arrhythmias in children, nor is the list of agents we discuss all-encompassing. Rather, the major thrust has been to promote an understanding of the important relationship between anatomic considerations, basic electrophysiology, and developmental pharmacology in directing therapy. We wish to emphasize that many of the studies quoted in this report are investigational, and that not all of the applications listed in the text and tables are approved for use in pediatric patients in the United States. Nevertheless, the information may serve as a guideline to developing management strategies for the individual child with an arrhythmia. Given the number of new antiarrhythmic agents under development, it would be no surprise if, in a few years, a paper such as this one discussed several new drugs we have not mentioned. We hope that the principles we have outlined will serve as a framework for incorporating these new agents into clinical practice as they become available.