Time course of changes in heart rate and blood pressure variability in rats with myocardial infarction

Abstract

Our aim was to determine the time course of changes in autonomic balance in the acute (1 and 3 days), sub-acute (7 days) and chronic (28 days) phases of myocardial infarction (MI) in rats. Autonomic balance was assessed by temporal and spectral analyses of blood pressure variability (BPV) and heart rate variability (HRV). Pulsatile blood pressure (BP) recordings (30 min) were obtained in awake and unrestrained male Wistar rats (N = 77; 8-10 weeks old) with MI (coronary ligature) or sham operation (SO). Data are reported as means±SE. The high frequency (HF) component (n.u.) of HRV was significantly lower in MI-1- (P<0.01) and MI-3-day rats (P<0.05) than in their time-control groups (SO-1=68±4 vs MI-1=35.3±4.3; SO-3=71±5.8 vs MI-3=45.2±3.8), without differences thereafter (SO-7=69.2±4.8 vs MI-7=56±5.8; SO-28=73±4 vs MI-28=66±6.6). A sharp reduction (P<0.05) of BPV (mmHg2) was observed in the first week after MI (SO-1=8.55±0.80; SO-3=9.11±1.08; SO-7=7.92±1.10 vs MI-1=5.63±0.73; MI-3=5.93±0.30; MI-7=5.30±0.25). Normal BPV, however, was observed 4 weeks after MI (SO-28=8.60±0.66 vs MI-28=8.43±0.56 mmHg2; P>0.05). This reduction was mainly due to attenuation of the low frequency (LF) band of BPV in absolute and normalized units (SO-1=39.3±7%; SO-3=55±4.5%; SO-7=46.8±4.5%; SO-28=45.7±5%; MI-1=13±3.5%; MI-3=35±4.7%; MI-7=25±2.8%; MI-28=21.4±2.8%). The results suggest that the reduction in HRV was associated with decrease of the HF component of HRV suggesting recovery of the vagal control of heartbeats along the post-infarction healing period. The depression of BPV was more dependent on the attenuation of the LF component, which is linked to the baroreflex modulation of the autonomic balance.

Ontogenetic peculiarities of autonomic regulation of the cardiovascular system of male rats by parameters of heart rate variability

“…Отримані нами результати показників варіабельності серцевого ритму в самців ювенільного та молодого віку мають збіжність та відображаються у дослідженнях інших авторів [11,[15][16][17]. Оскільки, проаналізувавши літературні джерела, не було виявлено інформації щодо показників ВСР у самців старечого віку періоду виражених старечих змін, то доцільно буде розглядати отримані нами в ході дослідження дані новими у відповідному аспекті досліджень.…”

Hemodynamic Changes and Autonomic Nervous System After Acute Myocardial Infarction in Rats Submitted to Left Coronary Artery Ligation

“…A gradual recovery of the normal autonomic activity in the heart after MI has been demonstrated. Aires et al 29 evaluated the time course of changes in autonomic balance. The HF component obtained from HRV was significantly reduced in the acute phase after infarction.…”

The Effect of Subdiaphragmatic Vagotomy on Heart Rate Variability and Lung Inflammation in Rats with Severe Hemorrhagic Shock

“…The activity of the autonomic nervous system can be evaluated by heart rate variability analysis (HRV) (McCraty and Shaffer, 2015). Inter-beat interval can be extracted from electrocardiogram or pulsatile blood pressure recording as time interval between consecutive heartbeats (Aires et al, 2017). A few previous studies have shown that HRV can estimate the autonomic nervous system activity in hemorrhagic shock (Nogami et al, 2010).…”