Which parameters describe the electrophysiological properties of successful slow pathway RF ablation in patients with common atrioventricular nodal reentrant tachycardia?

OBJECTIVE: Atrioventricular nodal reentrant tachycardia (AVNRT) accounts for about 60% of the patients presenting with paroxysmal supraventricular tachycardia. The radiofrequency (RF) catheter ablation of the slow atrioventricular (AV) node pathway is the preferred therapeutic approach in patients with AV node reentrant tachycardia. The aim of our study was describe the electrophysiological properties of successful slow pathway RF ablation in patients with common atrioventricular nodal reentrant tachycardia.
METHODS: The study design was a retrospective analysis involving fifty consecutive patients (18 males; mean age of 39+/-22 years) who underwent slow pathway ablation because of AVNRT.
RESULTS: Slow junctional beats with a cycle length longer than 550 ms were observed in 39 patients (79%); the presence of rapid junctional beats with a cycle length less than 550 ms was showed in 5 patients (10%). Moreover, in 32 of 50 patients (65%) duration of atrial electrogram more than 40 ms was noticed. Analyzing data reported, we found the statistically significant presence of slow junctional beats (p=0.001) and atrial electrogram >40 ms (p=0.05) in successful RF ablation procedures.
CONCLUSION: In patients with AVNRT undergoing slow pathway ablation, the duration of atrial electrogram >40 ms and slow junctional beats with cycle length >550 ms during the application of RF energy describe the electrophysiological properties of successful slow pathway RF ablation.