Risk of development of delayed atrioventricular block after slow pathway modification in patients with atrioventricular nodal reentrant tachycardia and a pre-existing prolonged PR interval

• Published in: European heart journal Vol. 22; no. 1; pp. 89 - 95
• Main Authors: Li, Y.-G., Grönefeld, G., Bender, B., Machura, C., Hohnloser, S.H.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.01.2001
• Subjects: atrioventricular block; Atrioventricular nodal reentrant tachycardia; Biological and medical sciences; Cardiac dysrhythmias; Cardiology. Vascular system; Case-Control Studies; Catheter Ablation - adverse effects; Catheter Ablation - methods; complications; Electrocardiography, Ambulatory; Electrophysiologic Techniques, Cardiac; Female; Follow-Up Studies; Heart; Heart Block - diagnosis; Heart Block - epidemiology; Heart Block - etiology; Heart Conduction System - surgery; Humans; Incidence; Male; Medical sciences; Middle Aged; Postoperative Complications - epidemiology; PR interval; Prospective Studies; radiofrequency catheter ablation; Risk Factors; Tachycardia, Atrioventricular Nodal Reentry - surgery; Human; Prognosis; Arrhythmia; Reentry; Heart block; Heart disease; Atrioventricular bloc; PR interval; Cardiovascular disease; Paroxysmal junctional tachycardia; Conduction disorder; Excitability disorder
• ISSN: 0195-668X; 1522-9645
• DOI: 10.1053/euhj.2000.2182

Aims The objective of this prospective study was to assess risk factors for the development of atrioventricular block following slow pathway modification in patients with atrioventricular nodal reentrant tachycardia and a pre-existing prolonged PR interval. Methods and Results Of 346 consecutive patients with atrioventricular nodal reentrant tachycardia undergoing slow pathway modification, 18 patients (62±7 years; five females) were found to have a prolonged PR interval prior to ablation. Total elimination of the functional slow pathway was assumed if the antegrade effective refractory period following slow pathway modification was longer than the cycle length of atrioventricular nodal reentrant tachycardia. To detect atrioventricular node conduction disturbances, 24-h Holter recordings were performed 1 day prior to slow pathway modification, and 1 day, 1 week, 1, 3 and 6 months after the procedure. Six patients developed late atrioventricular block. The incidence of delayed atrioventricular block following successful slow pathway modification was higher in patients with, compared to patients without, prolonged PR interval at baseline (6/18 vs 0/328,P <0·001). In the former group, the antegrade effective refractory period was longer in patients with, compared to those without, a delayed atrioventricular block (492±150ms vs 332±101ms,P <0·05). The incidence of delayed atrioventricular block was higher in patients with total elimination of the slow pathway compared to patients without (5/7 vs 1/11,P <0·01). Conclusions Slow pathway modification in patients with atrioventricular nodal reentrant tachycardia and a prolonged PR interval is highly effective. However, there is a significant risk of development of delayed atrioventricular block, particularly when the procedure results in total elimination of the slow pathway.