Correlation Between the Effective Refractory Period and Activation-Recovery Interval Calculated From the Intracardiac Unipolar Electrogram of Humans With and Without dl-Sotalol Treatment

Abstract

eterogeneous distribution of ventricular repolarization can contribute to the construction of the arrhythmogenic substrate of ventricular tachyarrhythmia, and this has been well documentted in experimental studies of optical mapping and/or tridimensional repolarization analysis. 1-3 However, in clinical electrophysiologic studies (EPS), the beat-to-beat change in the distribution of intraventricular repolarization is difficult to analyze.Previous experimental studies reported that the activation -recovery interval (ARI) calculated from the unipolar electrogram was approximate to the local effective refractory period (ERP) under various conditions. 4,5 Thus, analysis of ARIs from intracardiac multipolar electrode catheters may be helpful in assessing the distribution of ventricular refractoriness from a clinical viewpoint. Because it has not been well clarified whether the ARI calculated from human intracardiac electrograms reasonably corresponds to local refractoriness, we examined the relationship between ERP and ARI during clinical EPS. The analysis was performed in patients treated with dl-sotalol, as well as in the control state, because dl-sotalol is commonly used in the treatment of sustained ventricular tachyarrhythmia, and its antiarrhythmic effect is considered to be mediated by prolongation of the refractoriness and homogenization of the dispersion of refractoriness of the heart. 6,7 Therefore, if the ARI calculated from the intracardiac unipolar electrogram was reasonably approximate to the local ERP under treatment with dlsotalol, the therapeutic effect of dl-sotalol could be evaluated by measuring the ARI in EPS. Methods SubjectsNineteen patients were enrolled and of these, an EPS was performed without any medication, except for diuretics In experimental studies and/or human body surface mapping, the activation -recovery interval (ARI) is used as a parameter to estimate local repolarization. However, it has not been clarified whether the ARI calculated from the intracardiac unipolar electrogram of humans reasonably represents the local effective refractory period (ERP). Measurement of ARIs at multiple ventricular sites can be helpful in assessing the dispersion of ventricular refractoriness of humans, so we examined the relationship between ERP and ARI in the control state and under treatment with dl-sotalol during clinical electrophysiologic studies (EPS). Of 19 patients, an EPS was performed in the control state in 12 and during treatment with dl-sotalol in the other 7. Quadripolar electrode catheters with an interelectrode distance of 5 mm were placed at the right atrium and in the right ventricle. Using atrial pacing, the heart rate was increased incrementally by 10 beats/min, and ERP and ARI were measured for each pacing rate. The ERP at the right ventricle was measured by single extrastimulation between the first and third distal electrodes of the catheter in the right ventricle, and the ARI was calculated from the second distal unipolar electrode of the same catheter as the interval between t...

Intercellular coupling through gap junctions masks M cells in the human heart

“…It has been shown more than a decade ago that these ARIs are markers of APD 90 in dogs [27]. Recently, this close association was corroborated by the demonstration of a similar close relationship between ARIs and effective refractory periods in intact human hearts [28]. Our wedge preparation was substantially larger than the four preparations of Drouin et al [6], which may have led to a different state of electrical uncoupling.…”

Parasympathetic dysfunction and antiarrhythmic effect of vagal nerve stimulation following myocardial infarction

“…ARI was calculated by subtracting activation time from repolarization time. ARI has been previously validated and shown to correlate well with local action potential duration (56)(57)(58)(59). In addition, it serves as a method of recording action potential duration without causing myocardial injury.…”

Determination of the Upper Limit of Vulnerability Using Implantable Cardioverter-Defibrillator Electrograms

“…[7][8][9] The activation-recovery interval has been used to assess local repolarization in canines 11 and humans. 12,13 Activationrecovery intervals recorded from point electrodes act as a spatial average and are thus dominated by the action potentials of cells closest to the recording site. 7 …”