Clinical Electrophysiology -> SCA Risk Assessment: -> Other Noninvasive Techniques D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-221 - Periodic Alterations Of Ventricular Activation Patterns Are Triggered By Exercise In Patients With Inherited Cardiac Conditions (ID 1241)

Abstract

Background: Normal epicardial activation patterns during exercise are not known.
Objective: To characterise normal activation on exercise with electrographic imaging (ECGi), and compare with patterns in arrhythmogenic inherited cardiac conditions (ICC).
Methods: We recruited 39 patients to undergo maximal Bruce protocol treadmill test and CT wearing a CardioINSIGHT™ ECGi vest to map ventricular activation. Ventricular conduction stability (V-CoS) was used to test the impact of exercise on electrophysiology by comparing biventricular activation pattern from a matrix of 10 consecutive rest and peak exercise beats.
Results: Normals (n = 9, 43.4 years ±11.1 years) were unaffected relatives of Brugada patients (BrS). Mean exercise heart rate was 142bpm ±18bpm; recovery 95bpm ±10bpm. Total ventricular activation and corrected repolarisation times were unchanged by exercise (49.8 vs 49.6ms, p = 0.93 and 111 vs 119ms, p = 0.24). Mean V-CoS was 98.75% ±0.91% over 100 calculations. Dispersion of activation and repolarisation were not changed by exercise (0.388 vs 0.385 ms/mm, p = 0.93 and 1.49 vs 1.54 ms/mm, p = 0.58). ICC patients (n = 30, 49.9 years ±11.9 years) had lower minimum V-CoS scores than the original 9 normals (91.6% vs 96.7%, p = 0.0018). BrS (n = 14) and HCM (n = 16) subgroups were also significantly lower than controls (p = 0.004, 0.008 respectively). Periodic patterns in V-CoS were observed over consecutive beats; magnitude of periodicity was greater in the ICC (7.27% vs 3.17%, p = 0.0035).
Conclusion: Normal hearts maintain uniform activation, whereas ICC patients have periodic loss of uniform activation that could make the myocardium susceptible to ventricular arrhythmias.
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