IKr contributes to the altered ventricular repolarization that determines long-term cardiac memory
Key result
Pacing-induced cardiac memory in dogs is characterized by a transcriptionally induced change in epicardial I(Kr) that alters ventricular repolarization.
Why the study?
Does pacing-induced cardiac memory alter IKr and IKs currents in a canine model?
Population
Conscious, chronically instrumented dogs
Comparison
Pacing from the postero-lateral left ventricular… vs Unpaced controls
Design
Preclinical
Follow-up
3 weeks
Authors
Discussion
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Member takes
Implication
May explain pacing effects on repolarization in dogs; leaves open translation to human arrhythmias.
Structured PICO
Does pacing-induced cardiac memory alter IKr and IKs currents in a canine model?
P
Population
Conscious, chronically instrumented dogs paced from the postero-lateral left ventricular wall for 3 weeks to study cardiac memory.
I
Intervention
Pacing from the postero-lateral left ventricular (LV) wall at rates 5-10% faster than sinus rate for 3 weeks
C
Comparator
Unpaced controls
O
Outcome
Action potential duration (APD) to 50% and 90% repolarization and delayed rectifier currents (IKr and IKs) in epicardial and endocardial tissues and myocytessurrogate
Main Result
p-value: p=<0.05
A transcriptionally induced change in epicardial IKr contributes to the altered ventricular repolarization characteristic of cardiac memory.
Cite This Study
Obreztchikova et al. (2006) studied Cardiac memory. Pacing from the postero-lateral left ventricular wall at rates 5-10% faster than sinus rate vs. Unpaced controls was evaluated on Action potential duration (APD) and transmural I(Kr) gradient (p=<0.05). Pacing-induced cardiac memory in dogs is characterized by a transcriptionally induced change in epicardial I(Kr) that alters ventricular repolarization.