Submitted on November 27, 2007
Accepted on April 29, 2008
Persistent alterations in heart rate variability, baroreflex sensitivity and anxiety-like behaviors during development of heart failure in the rat
Marcus Henze1, Davin Hart2, Allen M. Samarel3, John Barakat2, Laurie Eckert1, and Karie E. Scrogin4*
1 Pharmacology, Loyola Universtiy Chicago, Stritch School of Medicine, Maywood, Illinois, United States
2 The Cardiovascular Institute, Loyola University Chicago, Stritch School of Medicine, Mayood, Illinois, United States
3 The Cardiovascular Institute, Loyola University Medical Center, Maywood, Illinois, United States
4 Pharmacology and Experimental Therapeutics, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois, United States
* To whom correspondence should be addressed. E-mail: kscrogi{at}lumc.edu.
Depressed heart rate variability (HRV) and mood are associated with increased mortality in patients with congestive heart failure (CHF). Here, autonomic indices were assessed 3 and 7 weeks after left coronary artery ligation in telemetered rats, after which anxiety-like behaviors were assessed in an elevated plus maze. Low (LF) and high frequency (HF) variability were reduced in CHF rats 3 weeks after infarction (LF: 1.60 Depressed heart rate variability (HRV) and mood are associated with increased mortality in patients with congestive heart failure (CHF). Here, autonomic indices were assessed 3 and 7 weeks after left coronary artery ligation in telemetered rats, after which anxiety-like behaviors were assessed in an elevated plus maze. Low (LF) and high frequency (HF) variability were reduced in CHF rats 3 weeks after infarction (LF: 1.60±0.52 vs. 6.97±0.79 ms2; HF: 1.53±0.39 vs. 6.20±1.01 ms2, P<0.01). The number of sequences of interbeat intervals that correlated with arterial pressure was decreased in CHF rats at 3 and 7 weeks (Wk 3: 26.60 ±10.85 vs. 59.75±11.4 sequences, P<0.05; Wk 7: 20.80 ±8.97 vs. 65.38 ±5.89 sequences, P<0.01). Sequence gain was attenuated in CHF rats by 7 weeks (1.34±0.06 vs. 2.70±0.29 ms/mmHg, P<0.01). Coherence between interbeat interval- and mean arterial blood pressure variability in the LF domain was reduced in CHF rats at 3 (0.12±0.03 vs. 0.26±0.05 k2, P<0.05) and 7 weeks (0.16±0.02 vs. 0.31±0.05 k2, P<0.05). CHF rats invariably entered the open arm of the elevated plus maze first, and spent more time in the open arms (36.0±15 vs. 4.6 ± 1.9%, P<0.05). CHF rats also showed a tendency to jump head first off the apparatus, while controls did not. Together the data indicate that severe autonomic dysfunction is accompanied by escape seeking behaviors in rats with CHF.
