Cryoablation versus radiofrequency ablation for atrioventricular nodal reentrant tachycardia: patient pain perception and operator stress.

BACKGROUND: Cryoablation (CRYO) is an alternative to radiofrequency (RF) ablation in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT). This study aims to evaluate the differences in patient pain perception and operator stress between CRYO and RF ablation in the treatment of AVNRT. METHODS: Patients with supraventricular tachycardia underwent electrophysiology study. Twenty patients (eight males, age 46.5 ± 12.5 years) diagnosed with AVNRT were randomized to receive CRYO (11) with a 6-mm-tip catheter or RF (nine) with a 4-mm-tip catheter. Patients' pain perception and operator stress were assessed with a visual analogue scale (VAS) from 0 to 10 at the end of procedure. RESULTS: There was no significant difference in acute procedural success (CRYO 100% vs RF 89%, P = 0.257). There was no complication of permanent atrioventricular block in either group. The number of energy applications was significantly higher in the CRYO group (2.8 ± 1.2 vs 1.6 ± 0.9, P = 0.02). The fluoroscopic time was significantly reduced in the CRYO group (6.0 ± 4.9 vs 10.9 ± 5.4 minutes, P = 0.049) with no difference in procedure time (CRYO 49.3 ± 12.5 vs RF 54.5 ± 17.0 minutes, P = 0.462). Patients in the CRYO group experienced significantly less pain than patients in the RF group (VAS 2.3 ± 2.8 vs 5.4 ± 3.4, P = 0.024). The operator also experienced significantly less stress during CRYO than RF (VAS 1.9 ± 0.8 vs 6.2 ± 1.6, P < 0.001). There was no recurrence in both groups at 6-month follow-up. CONCLUSIONS: CRYO, as compared with RF, produces less pain in patients and less stress in operator in the treatment of AVNRT.

Echocardiographic mapping of left ventricular resynchronization during cardiac resynchronization therapy procedures.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an effective electrical therapy for patients with moderate to severe heart failure and cardiac dyssynchrony. This study aimed to investigate the degree of acute left ventricular (LV) resynchronization with biventricular pacing (BVP) at different LV sites and to examine the feasibility of performing transthoracic echocardiography (TTE) to quantify acute LV resynchronization during CRT procedure. METHODS: Fourteen patients with NYHA Class III-IV heart failure, LV ejection fraction < or = 35%, QRS duration > or = 120 ms and septal-lateral delay (SLD) > or = 60 ms on tissue Doppler imaging (TDI), underwent CRT implant. TDI was obtained from three apical views during BVP at each accessible LV site and SLD during BVP was derived. Synchronicity gain index (Sg) by SLD was defined as (1 + (SLD at baseline--SLD at BVP)/SLD at baseline). RESULTS: Seventy-two sites were studied. Positive resynchronization (R+, Sg > 1) was found in 42 (58%) sites. R+ was more likely in posterior or lateral than anterior LV sites (66% vs. 36%, P < 0.001). Concordance of empirical LV lead implantation sites and sites with R+ was 50% (7/14). CONCLUSIONS: The degree of acute LV resynchronization by BVP depends on LV lead location and empirical implantation of LV lead results in only 50% concordance with R+. Performing TTE during CRT implantation is feasible to identify LV sites with positive resynchronization.

Treatment of atrioventricular nodal re-entrant tachycardia by cryoablation with a 6 mm-tip catheter vs. radiofrequency ablation.

AIMS: To compare recurrence rate and other procedural characteristics in patients undergoing atrioventricular nodal re-entrant tachycardia (AVNRT) treatment with catheter cryoablation (CRYO) delivered by 6 mm-tip catheter or radiofrequency (RF) ablation. METHODS AND RESULTS: This is a retrospective case-control study including 80 patients with AVNRT treated with CRYO from March 2002 to June 2008. They were compared with another 80 consecutive patients who underwent RF ablation for AVNRT within the same period. Procedural success of 97.5 and 95% were achieved in CRYO and RF group, respectively. There was no permanent atrioventricular block (AVB) in the CRYO group, whereas two (2.5%) patients developed permanent first-degree or second-degree AVB in RF group (P = 0.155). Higher recurrence was found in the CRYO group (9 vs. 1.3%; P = 0.032) with no difference in the composite endpoint of procedural failure and recurrence between the groups (P = 0.263). There was significantly shorter fluoroscopy time (18.6 +/- 10.8 vs. 25.9 +/- 17.0 min; P = 0.002) and more energy applications required (3.1 +/- 1.7 vs. 1.9 +/- 1.1; P < 0.001) in the CRYO than the RF group. CONCLUSION: Compared with RF ablation, CRYO with 6 mm-tip catheter for treating AVNRT results in higher recurrence and potentially lower incidence of permanent AVB. Fluoroscopy time has been shown to be reduced by CRYO.