Intraseptal Mapping of Premature Ventricular Complexes Using Multipolar Catheters.

BACKGROUND

Intramyocardial mapping of left ventricular outflow tract (LVOT) premature ventricular complexes (PVCs) via septal coronary venous branches is helpful to define the site of origin (SOO) and guide ablation. The limitation of unipolar far-field signals with wire mapping can be obviated through the use of a multipolar mapping catheter.

OBJECTIVES

This study reports our mapping and ablation experience of suspected LVOT PVCs using intraseptal mapping with multipolar catheters.

METHODS

Patients with suspected LVOT PVCs in whom intraseptal mapping was attempted using multipolar catheters were included. The V2 S-wave and R-wave pattern break (PB) ratios were calculated using the S-wave or R-wave amplitudes in lead V2 divided by the sum of the S-wave or R-wave amplitudes in leads V1 and V3, respectively. Endocardial, intramyocardial, or epicardial SOO was based on activation pattern.

RESULTS

Of 86 patients, multipolar intraseptal mapping was successfully performed in 60 (70%; 30% female, 53% with prior ablation). PVCs were most commonly mapped to an intramyocardial source and least commonly to the epicardium. For left bundle branch block PVCs, a V2 S-wave PB ratio >2.7 ruled in an intramyocardial or epicardial source, whereas a ratio <1.2 ruled out an endocardial source. For right bundle branch block morphology PVCs, a V2 R-wave PB ratio <1.0 ruled out an endocardial source. Acute ablation success was achieved in 98% and freedom from recurrence was 93% at a median follow-up of 12.4 months. Recording of intraseptal late potentials with reversal during PVC was observed in 25 (42%) patients and was associated with long-term success.

CONCLUSIONS

Ablation of LVOT PVCs guided by intraseptal mapping using multipolar catheters is feasible and highly effective. Electrocardiogram predictors of SOO identify patients in whom intraseptal mapping may be useful. Reversal of late potentials with PVCs may represent abnormal substrate in idiopathic PVCs in ostensibly structurally normal hearts.