Mapping can identify individual drivers that maintain ventricular fibrillation

SAN FRANCISCO — Ventricular fibrillation mapping can accurately identify individual drivers, according to data presented at the Heart Rhythm Society Annual Scientific Sessions.

“Knowledge of human ventricular fibrillation is limited, and we had the unique opportunity to demonstrate direct panoramic epicardial visualization of human ventricular fibrillation spectrum in vivo,” Michel Haïssaguerre, MD, professor at the Cardiological Hospital of Bordeaux, France, said during a presentation.

Haïssaguerre and colleagues enrolled 72 patients (mean age, 54 years) from 12 centers with drug-resistant ventricular fibrillation into the study. Ventricular fibrillation electrograms were assessed in 155 spontaneous or induced ventricular fibrillation episodes during the first approximately 18 seconds (before defibrillation) while cycle length mapping was performed. Data from the electrograms were used to characterize ventricular fibrillation frequency distribution, wave propagation using dv/dt parameters and phase maps. Focal or re-entrant activities generating more than two consecutive wavefronts were defined as drivers.

According to the results, the mean ventricular fibrillation endocardial cycle length mapping was 177 ± 25 ms (range, 115-255 ms). The frequency, activation sequence and phase analysis all showed similar results in driver identification. During approximately 75% of the ventricular fibrillation time, rotors or figure of eight re-entries were observed. The ventricular fibrillation cycle length was shortest at re-entry sites compared with remote sites (157 ms vs. 178 ms; P < .001); Haïssaguerre said this confirmed the driver role of the re-entry sites.

Patients with ventricular scar more often had sustained re-entries than patients without it (maximum rotations, 16 vs. 10; P = .01), according to the researchers.

Fifteen patients did not have mappable triggers and were ablated using radiofrequency energy. In 87% of them, ventricular fibrillation noninducibility resulted from localized driver ablation.

“Twenty patients had Brugada syndrome, and ventricular fibrillation was associated with ischemic heart disease in 13 patients,” Haïssaguerre said during a presentation.

In addition, he said “early ventricular fibrillation may be driven by clustered sources offering a novel therapy target in addition to triggers.”

Haïssaguerre said future research should focus on better understanding the electrophysiological and imaging characteristics underlying driver anchoring to better target therapies and identify those at risk for sudden death. – by Tracey Romero

Reference:

Haïssaguerre M, et al. LBCT 01. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 4-7, 2016; San Francisco.

Disclosure: Haïssaguerre reports receiving speaking fees from Biosense Webster and research grants from Biosense Webster, Boston Scientific and CardioInsight Technologies.