Author + information
- Cevher Ozcan,
- Zhenping Li,
- Michael Broman and
- Gene Kim
Background: Myocardial energetics is essential for cardiac contractility and electrical property. However, it is not known whether atrial myocardial energetics is disrupted in disease condition such as atrial fibrillation (AF) and heart failure (HF). We hypothesized that AF and HF are associated with impaired bioenergetics in atrial myocardium with disrupted mitochondrial ATP production.
Methods: Explanted hearts from patients (n=24) who underwent heart transplantation for advanced HF were included in this study. Findings in study group were compared to left atrial appendage tissue from patients (n=4) with AF who had no HF. Medical records and electrocardiograms were reviewed for arrhythmia. Adenine nucleotide concentrations in right and left atrial tissue were determined by using high performance liquid chromatography. Mitochondrial succinate dehydrogenase (SDH) was evaluated by immunoblotting.
Results: A total of 10 explanted hearts had no known AF, 8 had history of paroxysmal AF but were in sinus rhythm at the time of explant and 6 had persistent AF and were in AF at the time of explant. Atrial myocardial ATP levels were significantly decreased in patients with HF (11.5±1.3 nmoles/mg) and patients with HF and paroxysmal AF (10.5±1.3 nmoles/mg) compared to the patients with AF without HF (17±3.8 nmoles/mg) (p<0.05). However, the lowest atrial ATP concentrations were observed in patients with HF and permanent AF (5.4±1.2 nmoles/mg) (all p <0.05). Left atrial tissue demonstrated lower ATP levels compare to right atria in all study groups (p<0.05). AMP to ATP ratio indicated increased metabolic stress in all groups, but more prominent in patients with coexisting persistent AF and HF. Reduced atrial myocardial energetics were associated with impaired mitochondrial SDH in AF (0.15±0.07 AU versus 0.33±0.08 AU in HF) (p=0.01).
Conclusions: Atrial myocardial energetic was significantly impaired in AF and HF with decreased ATP content and an increase in the AMP-to-ATP ratio. This was associated with mitochondrial dysfunction with reduced SDH. Thus, mitochondrial ATP synthesis is critical in HF, particularly with AF.
Poster Hall, Hall C
Friday, March 17, 2017, 3:45 p.m.-4:30 p.m.
Session Title: Arrhythmias and Clinical EP: Basic 2
Abstract Category: 4. Arrhythmias and Clinical EP: Basic
Presentation Number: 1152-111
- 2017 American College of Cardiology Foundation