Tissue voltage discordance during tachycardia versus sinus rhythm: Implications for catheter ablation

BACKGROUND: Electroanatomic mapping systems are an important tool to identify cardiac chamber voltage and assess channels of slow conduction. OBJECTIVE: To assess the correlation between electroanatomic mapping voltage maps obtained during macroreentrant tachycardia compared to sinus rhythm (SR) with a contact mapping system. METHODS: We retrospectively evaluated patients with atrial flutter (AFL) referred for radiofrequency ablation with electroanatomic voltage maps obtained during AFL and SR. The atrium was divided into predetermined segments. Overall atrial and segmental peak-to-peak bipolar voltages in AFL and SR were assessed. To directly compare a region within the same patient, tissue voltage differences during AFL and SR were assessed on the basis of mean voltage difference. RESULTS: Sixteen patients (87% men) had available voltage maps. Eighty-one percent had typical cavotricuspid isthmus-dependent right AFL. A mean of 441.7 ± 153.9 vs 398.1 ± 125.4 total points (P = .22) were sampled during AFL and SR, with a mean of 99.5 ± 58.9 vs 91.2 ± 60.4 points (P = .45) sampled per region. Overall right atrial mean voltage was significantly higher during AFL than SR (0.554 ± 0.092 mV vs 0.473 ± 0.079 mV; P ≤ .001), with the lateral wall (0.707 ± 0.120 mV vs 0.573 ± 0.097 mV; P = .0004) and the cavotricuspid isthmus (0.559 ± 0.100 mV vs 0.356 ± 0.066 mV; P < .0001) also showing higher mean voltage during AFL. When compared within an individual patient, 19% (14 of 75) of the patient regions had a >0.5 mV mean voltage difference and 40% (30 of 75) had a >0.25 mV mean voltage difference. CONCLUSIONS: These data suggest that voltage maps performed during macroreentrant atrial arrhythmias often vary significantly from maps obtained during SR.