Introduction: Prior accurate PVC localization improves the time and outcome of ablative procedures. We developed a new manual Vector Technique (VcT) to localize the PVC origin to cardiac anatomy regions. In contrast, our Cardiac Isochrone Positioning System (CIPS) is a computer based system that localizes the PVC to patient specific cardiac anatomy from the MRI and electrode positions from the 3D Camera. Hypothesis: We hypothesize that this new VcT can rapidly quantitate the location of PVC to anatomical regions whereas CIPS localizes the PVCs to more specific cardiac anatomical segments. Method: The VcT assumes the frontal plane leads are formatted on the chest as an equilateral triangle and the horizontal leads as a partial sphere. Using the concept that a lead recording perpendicular to a dipole vector is zero, the QRS axis vectors of the PVC were calculated manually within 3.8 to 7.5 degrees in the frontal and horizontal planes. CIPS computed the electrode positions by registration of the MRI derived torso model with the 3D image of the patient. The ECG signals were used by both methods to localize the PVC origin to the cardiac anatomy. Result: In 12 patients (below), this manual VcT separated without overlap in the horizontal plane the PVC into Left Ventricle (LV 30-45°), Right Ventricular (RV 308-348°), and Papillary Muscle (PM 128-150°) regions, but not in the frontal plane. CIPS localized 10 PVCs to the same and 2 to adjacent anatomical segments while the vector technique cannot because of the need for a database to create a PVC anatomic segment model. Conclusion: This new VcT can be used by anyone to localize rapidly the PVC by a QRS vector plot to regions like the left & posterior for the RV, left & anterior for the LV, and right & anterior for the papillary muscles while CIPS can localize PVCs more specifically to anatomical segments. Using the 12 lead ECG, this VcT creates a quantitative cardiac anatomical segment model of PVC locations integrated into CIPS that can improve the accuracy of VcT.
In Brugada syndrome (BrS), with spontaneous or ajmaline-induced coved ST elevation, epicardial electro-anatomic potential duration maps (epi-PDMs) were detected on a right ventricle (RV) outflow tract (RVOT), an arrhythmogenic substrate area (AS area), abolished by epicardial-radiofrequency ablation (EPI-AS-RFA). Novel CineECG, projecting 12-lead electrocardiogram (ECG) waveforms on a 3D heart model, previously localized depolarization forces in RV/RVOT in BrS patients. We evaluate 12-lead ECG and CineECG depolarization/repolarization changes in spontaneous type-1 BrS patients before/after EPI-AS-RFA, compared with normal controls.In 30 high-risk BrS patients (93% males, age 37 + 9 years), 12-lead ECGs and epi-PDMs were obtained at baseline, early after EPI-AS-RFA, and late follow-up (FU) (2.7-16.1 months). CineECG estimates temporo-spatial localization during depolarization (Early-QRS and Terminal-QRS) and repolarization (ST-Tpeak, Tpeak-Tend). Differences within BrS patients (baseline vs. early after EPI-AS-RFA vs. late FU) were analysed by Wilcoxon signed-rank test, while differences between BrS patients and 60 age-sex-matched normal controls were analysed by the Mann-Whitney test. In BrS patients, baseline QRS and QTc durations were longer and normalized after EPI-AS-ATC (151 ± 15 vs. 102 ± 13 ms, P < 0.001; 454 ± 40 vs. 421 ± 27 ms, P < 0.000). Baseline QRS amplitude was lower and increased at late FU (0.63 ± 0.26 vs. 0.84 ± 13 ms, P < 0.000), while Terminal-QRS amplitude decreased (0.24 ± 0.07 vs. 0.08 ± 0.03 ms, P < 0.000). At baseline, CineECG depolarization/repolarization wavefront prevalently localized in RV/RVOT (Terminal-QRS, 57%; ST-Tpeak, 100%; and Tpeak-Tend, 61%), congruent with the AS area on epi-PDM. Early after EPI-AS-RFA, RV/RVOT localization during depolarization disappeared, as Terminal-QRS prevalently localized in the left ventricle (LV, 76%), while repolarization still localized on RV/RVOT [ST-Tpeak (44%) and Tpeak-Tend (98%)]. At late FU, depolarization/repolarization forces prevalently localized in the LV (Terminal-QRS, 94%; ST-Tpeak, 63%; Tpeak-Tend, 86%), like normal controls.CineECG and 12-lead ECG showed a complex temporo-spatial perturbation of both depolarization and repolarization in BrS patients, prevalently localized in RV/RVOT, progressively normalizing after epicardial ablation.
Non-invasive imaging of cardiac activation and recovery based on the equivalent double layer source model is a non-linear and ill-posed problem. The problem involved is cast in the form of a non-linear parameter estimation, requiring an initial estimate and regularized minimization. While focusing on the estimation of the timing of repolarization, we compared the effect of applying the regularization to either the timing of recovery or to the activation recovery interval (ARI). The results suggest that regularizing the ARI is to be preferred in the estimation of the timing of recovery of the atria as well as of the ventricles.
Noninvasive reconstruction of cardiac electrical activity has a great potential to support clinical decision making, planning, and treatment. Recently, significant progress has been made in the estimation of the cardiac activation from body surface potential maps (BSPMs) using boundary element method (BEM) with the equivalent double layer (EDL) as a source model. In this formulation, noninvasive assessment of activation times results in a nonlinear optimization problem with an initial estimate calculated with the fastest route algorithm (FRA). Each FRA-simulated activation sequence is converted into the ECG. The best initialization is determined by the sequence providing the highest correlation between predicted and measured potentials. We quantitatively assess the effects of the forward modeling errors on the FRA-based initialization. We present three simulation setups to investigate the effects of volume conductor model simplifications, neglecting the cardiac anisotropy and geometrical errors on the localization of ectopic beats starting on the ventricular surface. For the analysis, 12-lead ECG and 99 electrodes BSPM system were used. The areas in the heart exposing the largest localization errors were volume conductor model and electrode configuration specific with an average error <;10 mm. The results show the robustness of the FRA-based initialization with respect to the considered modeling errors.
Abstract Aims Familial ST-segment Depression Syndrome (Fam-STD) is a novel inherited cardiac disease associated with arrhythmias and sudden cardiac death. This study aimed at investigating the cardiac activation pathway in patients with Fam-STD, modelling the electrocardiogram (ECG) phenotype, and performing in-depth ST-segment analyses. Methods and results CineECG analysis of patients with Fam-STD and age- and sex-matched controls. The groups were compared using the CineECG software which included the trans-cardiac ratio and the electrical activation pathway. We simulated the Fam-STD ECG phenotype by adjusting action potential duration (APD) and action potential amplitude (APA) in specific cardiac regions. High-resolution ST-segment analyses were performed per lead by dividing the ST-segment into nine 10 ms subintervals. Twenty-seven Fam-STD patients (74% females, mean age 51.6 ± 6.2 years) and 83 matched controls were included. Among Fam-STD patients, electrical activation pathway analysis in the anterior-basal orientation showed significantly abnormal direction toward the basal areas of the heart starting from QRS 60–89 ms until Tpeak-Tend (all P < 0.001). Simulations with shortened APD and reduced APA in the left ventricle basal regions recapitulated the Fam-STD ECG phenotype. Detailed ST-segment analyses showed significant differences in all nine 10 ms subintervals (all P < 0.01), with the most prominent findings during the 70–79/80–89 ms intervals. Conclusion CineECG analyses indicated abnormal repolarization with basal directions, and the Fam-STD ECG phenotype was simulated by reducing APD and APA in the left ventricle basal regions. Detailed ST-analysis showed amplitudes consistent with the proposed diagnostic criteria for Fam-STD patients. Our findings provide new insight into the electrophysiological abnormalities of Fam-STD.
Purpose: Identification of proper candidates for cardiac resynchronization therapy (CRT) remains challenging. Currently used selection tools and optimization strategies are associated with a 30% non-response rate. Therefore, a novel non-invasive electrical activation mapping technique was applied in CRT candidates. This study was conducted to determine whether this technique could accurately identify lead position and left ventricular (LV) pacing offset in CRT patients. Methods: In 8 patients, a patient specific 3D volume conductor model was reconstructed from MRI images. Body surface potentials were recorded from 65 torso electrodes before and after implantation of a biventricular pacing device. During the post-implant recording, LV pacing offset was varied with 10ms intervals. Ventricular activation maps were computed for each offset, using the fastest route based activation imaging method. Results: In all patients lead positions were correctly identified. Variations in ventricular activation sequence, due to various pacing offsets, were detected with a temporal resolution of 10ms (figure 1B+C). Conclusion: Non-invasive ventricular activation mapping correctly identified left and right lead positions in CRT patients. The complete ventricular activation sequence was visualized during various pacing offsets. This technique offers the prospect to improve selection of CRT candidates, guidance of lead positioning and may be of advantage for CRT optimization. Figure 1: Left panel (A): Ventricular activation map during LV pacing merged with a fluoroscopic recording in LAO view. The site of earliest activation (pink) corresponds with the position of the LV lead. Right panel: Ventricular activation maps during programmed LV offset of 50ms (B), 40ms (C), RV pacing (D) and simultaneous pacing (E). Activation time in milliseconds.
