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Alternans of repolarization and depolarization in ventricular myocytes
Author(s) -
Chourasia Sonam,
Agarwal Anuj,
Jing Linyuan,
Patwardhan Abhijit
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.595.2
Subject(s) - repolarization , depolarization , cardiology , medicine , ventricular action potential , cardiac action potential , t wave alternans , electrical conduction system of the heart , electrophysiology , electrocardiography , sudden cardiac death
Several studies suggest that repolarization alternans play an important role in initiation of ventricular arrhythmias. While alternans of duration of repolarization, i.e. of action potential duration (APD), has been extensively investigated, little is known about alternans of amplitude of action potentials (APA). The purpose of our study was to examine the relationship between APD and APA alternans and to determine potential mechanisms of APA alternans. Transmembrane potentials were recorded using glass micro‐electrodes in swine ventricular tissue (n=8). From 51 trials we observed that the incidence of APD alternans was 33% of all action potentials recorded for cycle lengths &*8804; 290 ms. Alternans of APA occurred 50% of times when APD alternans occurred and were concordant (long action potentials were also tall) 98% times. Incidence of APD alternans along with APA alternans was 78% with 96% concordance. These results show that occurrence of APA alternans is not rare. Alternans of APA were accompanied by alternans of |dv/dt|max 77 % of times, suggesting that sodium current may underlie alternans of APA. The potential effect of alternans of depolarization phase of the action potential on conduction suggests that this may also play a role in loss of electrical stability. Supported by the American Heart Association (Great Rivers Affiliate) and the National Science Foundation (CBET 07350).