ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias--executive summary : a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Supraventricular Arrhythmias).

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ACC/AHA/ESC Guidelines for the Management of Patients with Supraventricular Arrhythmias - Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients with Supraventricular Arrhythmias)

The preexcitation syndromes.

To examine the risk of ventricular fibrillation in patients with the Wolff-Parkinson-White syndrome, we compared patients who had this syndrome and a history of ventricular fibrillation related to preexcitation with patients who had the syndrome without this history. Ventricular fibrillation occurred during atrial fibrillation, with rapid conduction over the accessory pathway, and these patients had a higher prevalence of both reciprocating tachycardia and atrial fibrillation (14 of 25 vs. 18 of 73, P = 0.004) and multiple accessory pathways (five of 25 vs. four of 73, P = 0.012). The shortest preexcitation R-R interval during atrial fibrillation was less in the group with ventricular fibrillation (mean shortest R-R, 180 vs. 240 milliseconds, P less than 0.0001) as was the average R-R interval (mean average R-R, 269 vs 340 milliseconds, P less than 0.0001). Patients with Wolff-Parkinson-White syndrome who are most susceptible to ventricular fibrillation have a history of atrial fibrillation and reciprocating tachycardia, demonstrate rapid conduction over an accessory pathway during atrial fibrillation and have multiple accessory pathways.

Ventricular fibrillation in the Wolff-Parkinson-White syndrome.

This report describes a catheter technique for ablating the His bundle and its application in nine patients with recurrent supraventricular tachycardia that was unresponsive to medical management. A tripolar electrode catheter was positioned in the region of the His bundle, and the electrode recording a large unipolar His-bundle potential was identified. In the first patient, two shocks of 25 and 50 J, respectively, were delivered by a standard cardioversion unit to the catheter electrode, resulting in an intra-His-bundle conduction defect. Subsequent delivery of 300 J resulted in complete heart block. In the next eight patients, an initial shock of 200 J was used. The His bundle was ablated by this single shock in six of these patients and by an additional shock of 300 J in one. In the remaining patient, conduction in the atrioventricular node was modified, resulting in alternating first and second-degree atrioventricular block. A stable escape rhythm was preserved in all patients. The procedure was well tolerated, without complications, and all patients have remained free of arrhythmia, without medication, for follow-up periods of two to six months.

Catheter Technique for Closed-Chest Ablation of the Atrioventricular Conduction System

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice. Its incidence increases with age and the presence of structural heart disease. It is a major cause of stroke, especially in the elderly. Although the causes are diverse, hypertension is common. Most patients experience palpitations, but fatigue, dyspnea, and dizziness are not uncommon. Patients with an uncontrolled ventricular response during AF may occasionally develop a tachycardia-induced cardiomyopathy. There are three therapeutic goals to consider for patients with AF: rate control, maintenance of sinus rhythm, and prevention of thromboembolism. The risks and benefits of each treatment must be considered for each patient. 

### Restoration and Maintenance of Sinus Rhythm 

Several drugs effectively restore and maintain sinus rhythm in patients with AF. To date few data are available to confirm superiority of any particular drug over another for this purpose. Agents such as digitalis, verapamil, diltiazem, and β-adrenergic blockers may be useful during AF to decrease the ventricular response that occurs over the atrioventricular (AV) node, but they rarely terminate AF. Intravenous procainamide is the treatment of choice for patients with Wolff-Parkinson-White syndrome who have a preexcited ventricular response during AF, provided they are hemodynamically stable. Patients who are unstable (eg, those with hypotension or significant heart failure) may require immediate cardioversion. Drugs selected for long-term oral therapy should be given initially in low to moderate doses and titrated upward, depending on effectiveness and side effects. Drug interactions with warfarin and digoxin should be monitored. Proarrhythmia is the most important risk associated with antiarrhythmic drug therapy. Bradyarrhythmias, especially sinus bradycardia, and ventricular tachyarrhythmias, especially torsade de pointes, can occur. Proarrhythmia often occurs during initiation of antiarrhythmic drug treatment. In patients without heart disease who have a normal baseline QT interval, ventricular proarrhythmia is relatively rare, and outpatient initiation of treatment is reasonable. However, patients with structural …

Management of Patients With Atrial Fibrillation A Statement for Healthcare Professionals From the Subcommittee on Electrocardiography and Electrophysiology, American Heart Association

One hundred patients with proved accessory pathways of the Kent bundle type were studied with multiple intracardiac catheters. During the procedure 16 had atrial fibrillation. Two patterns of induction of atrial fibrillation were noted. In most patients an earlier than expected atrial deflection appeared in one of the atrial recordings and was followed by atrial flutter (cycle length less than 220 msec) or atrial fibrillation either immediately or after a brief period of acceleration of atrial rate. In a few patients, intraatrial conduction delay, manifested as 2:1 block or Wenckebach block from the right to the left atrium or vice versa, occurred before the onset of atrial fibrillation. The incidence of atrial fibrillation was not statistically related to any associated cardiac abnormalities. A significantly large incidence of ventricular fibrillation was recorded in patients who had documented atrial fibrillation either before admission or during the catheter study.

Ruth Ann Smith

Papers

Atrial fibrillation in the preexcitation syndrome

Epicardial mapping of ventricular reentrant pathways in the late myocardial infarction period