Dysfunction of the respiratory diaphragm can contribute to cardiac arrhythmias. Literature review.
Dysfunction of the respiratory diaphragm can contribute to cardiac arrhythmias through several mechanisms:
1. Mechanical and Anatomical Interactions
– The diaphragm and heart are in close proximity, and abnormal diaphragmatic movement (e.g., paralysis, spasm, or excessive excursion) can mechanically affect cardiac function.
-Phrenic nerve dysfunction (which controls the diaphragm) may also influence the pericardium and atria, potentially triggering arrhythmias like atrial fibrillation or ectopic beats.
2. Altered Intrathoracic Pressure
– The diaphragm plays a key role in regulating
intrathoracic pressure during breathing.
– Dysfunction (e.g., paradoxical movement in diaphragm paralysis) can lead to:
– Reduced venous return→ affecting atrial stretch and atrial arrhythmias.
-Increased vagal tone (from erratic breathing patterns) → promoting bradyarrhythmias or AV blocks.
-Sympathetic activation (due to hypoxia from poor respiration) → increasing risk of ventricular arrhythmias.
3. Secondary Effects of Respiratory Dysfunction
-Hypoxia & Hypercapnia (from impaired ventilation) can:
– Disrupt cardiac ion channels → increasing automaticity and re-entry mechanisms.
– Stimulate sympathetic overdrive → triggering PVCs, VT, or AF.
– Sleep-disordered breathing (e.g., OSA) often involves diaphragmatic dysfunction and is strongly linked to nocturnal arrhythmias.
4. Post-Cardiac Surgery Arrhythmias
– Phrenic nerve injury (common after CABG or ablation procedures) can lead to diaphragmatic paralysis, which is associated with postoperative atrial fibrillation (POAF).
Clinical Evidence
– Studies show diaphragmatic paralysis increases arrhythmia risk, especially in patients with underlying heart disease.
– Deep breathing maneuvers (which engage the diaphragm) can sometimes terminate supraventricular tachycardias (SVTs), highlighting the diaphragm’s role in modulating cardiac rhythm.
Conclusion
While not a primary cause, diaphragmatic dysfunction can predispose to or exacerbate arrhythmias via mechanical, autonomic, and respiratory-related mechanisms. Evaluating diaphragmatic function may be relevant in cases of unexplained arrhythmias, especially in patients with neuromuscular disorders, post-thoracic surgery, or sleep apnea.