Clinical evidence of autonomic dysfunction due to atrial fibrillation: implications for rhythm control strategy.
PURPOSE
The role of the autonomic nervous system in the genesis of atrial fibrillation (AF) has been well studied; however, the converse remains poorly understood. Pulmonary veins (PV) contain receptors important in cardiac reflexes. Here, we evaluated reflex responses in patients with paroxysmal AF (PAF) to lower body negative pressure (LBNP).


METHODS
Thirty-four PAF patients (including 14 PAF patients post successful PV Isolation; PVI) were compared to 14 age and sex-matched controls. Mean arterial pressure (MAP), heart rate (HR), systemic vascular resistance index (SVRI), cardiac index (CI), and stroke volume index (SVI) were measured continuously during - 0, - 20, and - 40 mmHg LBNP. LBNP reduces venous return, deactivating atrial receptors, thereby eliciting a reflex increase in SVRI to maintain MAP.


RESULTS
AF patients have higher BMI than the controls (p = 0.02). In control subjects, LBNP did not alter MAP as SVRI increased. In PAF patients, LBNP resulted in a reduction in MAP (- 4.8%) with attenuated SVRI response (+ 4.2%) compared to controls (p < 0.05). However, in the post-PVI group, SVRI increase was similar to controls (p = 0.12) although that was insufficient to maintain MAP. In all patients, both reduction in SVI and CI and increase in HR were similar in response to LBNP.


CONCLUSIONS
This study provides novel clinical evidence of autonomic dysfunction in PAF patients. Successful PVI results in partial recovery of the cardiac reflex. Therefore, not only does autonomic disturbance predispose to AF but it is also a consequence of AF; potentially contributing to disease progression. This could help explain the dictum "AF begets AF."
['Malik|Varun|V|', 'McKitrick|Douglas J|DJ|', 'Lau|Dennis H|DH|', 'Sanders|Prashanthan|P|', 'Arnolda|Leonard F|LF|http://orcid.org/0000-0001-8173-3318']
D001281:Atrial Fibrillation D001341:Autonomic Nervous System D016022:Case-Control Studies D017115:Catheter Ablation D022062:Electrophysiologic Techniques, Cardiac D005260:Female D006801:Humans D008150:Lower Body Negative Pressure D008297:Male D008875:Middle Aged D011667:Pulmonary Veins
Atrial fibrillation Autonomic nervous system Lower body negative pressure Orthostatic reflexes Pulmonary vein isolation