Risks and complications of clinical cardiac electrophysiologic studies: a prospective analysis of 1,000 consecutive patients.

The complications of clinical cardiac electrophysiologic studies were prospectively evaluated in 1,000 consecutive patients studied in one laboratory with an unaltered protocol to better assess the risks of this procedure. There were 728 men and the mean age of the entire group was 58 years (range 16 to 84). Coronary artery disease was the most common type of heart disease (56%) and 200 patients had no identifiable organic heart disease. The indication for study was a ventricular tachyarrhythmia or cardiac arrest in 582 patients. Each patient underwent an initial (baseline) study and 444 patients underwent serial drug studies (2.7/patient). There was one death during these studies. Other major complications included arterial injury (0.4%), thrombophlebitis (0.6%), systemic arterial embolism (0.1%), pulmonary embolism (0.3%) and cardiac perforation (0.2%). Significant arrhythmic complications included catheter-induced permanent complete atrioventricular (AV) block in 1 patient, nonclinical atrial fibrillation that required therapy in 10 patients and severe proarrhythmic events in 12 (3%) of 397 patients undergoing drug studies for ventricular tachyarrhythmias. Cardioversion was required for termination of ventricular tachyarrhythmias in 179 baseline studies (53% of patients with inducible arrhythmia), and in an additional 35 patients, cardioversion was required at least once during follow-up studies. Although clinical cardiac electrophysiologic studies are associated with complications, the risks are small and acceptable.