CineECG analysis provides new insights into Familial ST-segment Depression Syndrome

Electrocardiographic temporo-spatial assessment of depolarization and repolarization changes after epicardial arrhythmogenic substrate ablation in Brugada syndrome

Aims

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.

Methods and results

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.

Conclusion

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.

The CineECG in ischemia localization in ST-elevation (equivalent) acute coronary syndromes

AIM OF THE STUDY

In this proof of concept study we aimed to visualize and quantify the injury vectors using the CineECG in representative examples of ST elevation acute myocardial infarction (STEMI) and STEMI-equivalent electrocardiograms (ECG's). For this purpose ECG's were selected with different ST deviation patterns in acute anterior wall, inferior or posterolateral wall infarctions.

METHODS

The ST-amplitudes of the individual leads were measured between J-point and 60 ms after the J-point. These data were used to compute the direction and size (i.e. ST-amplitudes) of the injury vectors of the respective STEMI (equivalent)'s and displayed in the frontal, transverse and sagittal view. The relative contribution of the ST vector was computed for each axis (X,Y,Z) and per view using the length of the projected ST vector on the respective plane.

RESULTS

The injury vectors accurately pointed to the area at risk in either proximal, mid or distal occlusions of the respective coronary arteries. Moreover in LCX occlusions, where no or small ST abnormalities in the standard ECG were present, the CineECG was found to be capable in pointing towards the ischemic area. Especially the visualization of the ST-vector in the sagittal plane was found to be contributing.

CONCLUSIONS

These findings suggest that the CineECG could become a useful additional tool to support the clinician. Moreover our preliminary findings suggest that CineECG may be more capable in detecting ischemic changes in situations where the ECG is not supportive, such as in LCX occlusions. Further studies in patient cohorts are needed to confirm these observations.