Abstract
BackgroundLocal ventricular refractoriness and its dispersion during ventricular fibrillation (VF) have not been well evaluated, due to methodological difficulties.MethodsIn this study, a non-invasive method was used in evaluation of local ventricular refractoriness and its dispersion during induced VF in 11 patients with VF and/or polymorphic ventricular tachycardia (VT) who have implanted an implantable cardioverter defibrillator (ICD). Bipolar electrograms were simultaneously recorded from the lower oesophagus behind the posterior left ventricle (LV) via an oesophageal electrode and from the right ventricular (RV) apex via telemetry from the implanted ICD. VF intervals were used as an estimate of the ventricular effective refractory period (VERP). In 6 patients, VERP was also measured during sinus rhythm at the RV apex and outflow tract (RVOT) using conventional extra stimulus technique.ResultsElectrograms recorded from the RV apex and the lower esophagus behind the posterior LV manifested distinct differences of the local ventricular activities. The estimated VERPs during induced VF in the RV apex were significantly shorter than that measured during sinus rhythm using extra stimulus technique. The maximal dispersion of the estimated VERPs during induced VF between the RV apex and posterior LV was that of 10 percentile VF interval (40 ± 27 ms), that is markedly greater than the previously reported dispersion of ventricular repolarization without malignant ventricular arrhythmias (30–36 ms). ConclusionsThis study verified the feasibility of recording local ventricular activities via oesophageal electrode and via telemetry from an implanted ICD and the usefulness of VF intervals obtained using this non-invasive technique in evaluation of the dispersion of refractoriness in patients with ICD implantation.
Highlights
Local ventricular refractoriness and its dispersion during ventricular fibrillation (VF) have not been well evaluated, due to methodological difficulties
The endocardial implantable cardioverter defibrillator (ICD) electrodes at the right ventricular (RV) apex were used for recording bipolar electrograms from the RV via telemetry
To estimate ventricular effective refractory period (VERP) during the induced VF, a mean of 61 ± 16 VF intervals were measured in the 11 patients
Summary
Patients Eleven patients with VF or polymorphic VT who have implanted an ICD were studied. The endocardial ICD electrodes at the right ventricular (RV) apex (interpolar distance 9 mm) were used for recording bipolar electrograms from the RV via telemetry. Bipolar electrograms of both the right and left ventricles were simultaneously recorded. In 6 of the 11 patients, the VERP was measured via the ICD electrode at the RV apex during sinus rhythm before the VF induction. In 6 patients, the VERP was measured at the RV apex and outflow tract (RVOT) using a drive-train cycle length (S1) of 400 and 600 ms during a previous electrophysiological study. A value of p < 0.05 was considered as statistically significant
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
