Increasing ventricular rates during AF may lead to cerebral hypoperfusions, hypertensive events
Patients with permanent atrial fibrillation (AF) may improve cognitive outcomes with a rate control strategy aimed at around 60 bpm, suggests a recent study.
The investigators simulated AF at different ventricular rates (50, 70, 90, 110 and 130 bpm) using two coupled lumped parameter validated models (systemic and cerebral circulation) and compared these to corresponding control normal sinus rhythm simulations (NSR). They evaluated haemodynamic outcomes and occurrence of critical events (hypoperfusions and hypertensive events) along the internal carotid artery-middle cerebral artery pathway up to the capillary-venous bed.
Increasing ventricular rates at the distal cerebral circle level (downstream middle cerebral artery) resulted in a decreased heart rate-related dampening of the haemodynamic signals compared to NSR (p=0.003 and p=0.002 for flow rate and pressure, respectively). Such response led to a significant progressive increase in critical events in the distal cerebral circle (p<0.001) as ventricular rate increased during AF.
In contrast, the lowest ventricular response rates resulted in more hypoperfusions (p<0.001) at the systemic-proximal cerebral circle level (up to middle cerebral artery) compared to faster AF simulations.
“This computational study suggests that higher ventricular rates relate to a progressive increase in critical cerebral haemodynamic events at the distal cerebral circle,” the investigators said. “Thus, a rate control strategy aiming to around 60 bpm could be beneficial in terms of cognitive outcomes in patients with permanent AF.”
AF is linked to cognitive impairment/dementia, independently of clinical cerebrovascular events such as stroke or transient ischaemic attack, and one of its potential mechanisms is the occurrence of AF-induced transient critical haemodynamic events, according to the investigators.