Key result
RF ablation targeting P1 or P2 potentials yields ~100% success in verapamil-sensitive ILVT.
Why the study?
The relationship between diastolic potentials recorded during verapamil-sensitive idiopathic left ventricular tachycardia and the reentrant circuit remains uncertain.
Does targeting mid-diastolic and presystolic Purkinje potentials lead to successful radiofrequency ablation in patients with verapamil-sensitive idiopathic left ventricular tachycardia?
Observational (n=20)
Does targeting mid-diastolic and presystolic Purkinje potentials lead to successful radiofrequency ablation in patients with verapamil-sensitive idiopathic left ventricular tachycardia?
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“In 2000, they proved verapamil-sensitivity of the P1. Furthermore, they demonstrated entrainment that captured P1 could reset the common LPFVT. Importantly, radiofrequency catheter ablation was successful at the site with P1 that was distant from the apical inferoseptal exit of the common LPFVT. Interestingly, at this point, LPF showing P2 was involved in their hypothetical macro–re-entry circuit of common LPFVT.”
Mid-diastolic (P1) and presystolic (P2) Purkinje potentials are critical markers of the macroreentry circuit in verapamil-sensitive idiopathic left ventricular tachycardia and serve as highly effective targets for radiofrequency ablation.
OBJECTIVES: The purpose of this study was to determine the relation of diastolic and presystolic potentials recorded during verapamil-sensitive idiopathic left ventricular tachycardia (ILVT) to reentry circuit. BACKGROUND: Successful ablation of verapamil-sensitive ILVT at the zone of slow conduction from which the diastolic potential is recorded has been reported. However, the relationship between the diastolic potential and the reentrant circuit remains a matter of debate. METHODS: Radiofrequency (RF) ablation was performed in 20 patients with verapamil-sensitive ILVT. After identifying the ventricular tachycardia (VT) exit site, we searched for the mid-diastolic potential (P1) during VT. Entrainment followed by RF current application was performed. If the mid-diastolic potential could not be detected, RF current was applied at the VT exit site showing the earliest ventricular activation with a single fused presystolic Purkinje potential (P2). RESULTS: In 15 of 20 patients, both P1 and P2 were recorded during VT from midseptal region. Entrainment pacing captured P1 orthodromically and reset the VT. The interval from stimulus to P1 was prolonged as the pacing rate was increased. Radiofrequency ablation was successfully performed at this site in all 15 patients. After successful ablation, P1 appeared after the QRS complex during sinus rhythm with the identical sequence to that during VT. In the remaining five patients, the diastolic potential could not be detected, and a single fused P2 was recorded only at the VT exit site. Successful ablation was performed at this site in all five patients. CONCLUSIONS: This study demonstrates that P1 and P2 are critical potentials in a circuit of verapamil-sensitive ILVT and suggests the presence of a macroreentry circuit involving the normal Purkinje system and the abnormal Purkinje tissue with decremental property and verapamil-sensitivity.
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Nogami et al. (2000) conducted an observational in Verapamil-sensitive idiopathic left ventricular tachycardia (ILVT) (n=20). Radiofrequency ablation targeting mid-diastolic (P1) or presystolic (P2) potentials was evaluated on Successful ablation. Radiofrequency ablation targeting mid-diastolic (P1) or presystolic (P2) potentials was successful in 100% (20/20) of patients with verapamil-sensitive idiopathic left ventricular tachycardia.
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