Premium
Can Body Surface Microvolt T‐Wave Alternans Distinguish Concordant and Discordant Intracardiac Alternans?
Author(s) -
FLORÉ VINCENT,
CLAUS PIET,
SYMONS ROLF,
SMITH GODFREY L.,
SIPIDO KARIN R.,
WILLEMS RIK
Publication year - 2013
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/pace.12139
Subject(s) - t wave alternans , medicine , intracardiac injection , cardiology , body surface , sudden cardiac death , geometry , mathematics
There is convincing experimental evidence that cellular action potential duration (APD) alternans is arrhythmogenic but its relationship with body surface microvolt T‐wave alternans (MTWA) remains unclear. We investigated the relationship between MTWA and APD alternans induced by alternating cycle length (CL) pacing in a pig model. Methods In 10 pigs, catheters in the right atrium (RA) and right (RV) and left ventricle (LV) allowed pacing and recording of monophasic action potentials (MAP). During RA pacing at stable 500‐ms CL, LV was paced at alternating CL (505 ms and 495 ms). Changing the alternating LV (A‐LV) pacing delay changes the size of the region with alternating ventricular activation. Spectral analysis of intracardiac MAP was correlated with body surface MTWA. In a similar setup (during alternating pacing in RV and LV), we investigated concordant versus discordant APD alternans. Results Pacing the LV with subtle alternating cycle lengths at short A‐LV delay leads to broad QRS (97 ± 10 ms), body surface MTWA (mean V alt 4.2 ± 1.8 µV), and positive RR‐interval alternans. At longer A‐LV delay, not resulting in QRS widening (68 ± 5 ms), body surface RR alternans was absent but MTWA remained detectable and was even more pronounced (8.7 ± 5.1 µV, P < 0.01). During both concordant and discordant pacing MTWA was present. The precordial leads were better for detecting discordant APD alternans (8.0 ± 2.9 µV and 12.8 ± 4.52 µV, P = 0.02). Conclusion MTWA is a potent technique to detect subtle and isolated intracardiac APD alternans that is artificially induced by alternating pacing. In the same model, discordant activation alternans can only be discriminated from concordant when using a quantifying approach of MTWA analysis.