Calcium Chloride During CABG Curbs Subsequent Atrial Fibrillation

Injecting calcium chloride (CaCl2) into the major atrial ganglionated plexi (GP) during isolated coronary-artery bypass grafting (CABG) appears to prompt a major reduction in atrial fibrillation (AF), according to a proof-of-concept randomized trial.

"This readily available, inexpensive treatment may significantly reduce the incidence of postoperative atrial fibrillation and associated healthcare costs," Dr. Sunny S. Po of the University of Oklahoma Health Sciences Center, in Oklahoma City, told Reuters Health by email.

Postoperative AF (POAF) is one of the most common complications of cardiac surgery, Dr. Po and colleagues note in The Journal of the American College of Cardiology.

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Suppression of the function of the atrial GPs (using botulinum toxin) they add, has been shown to reduce the incidence of POAF. In light of these and other findings, the researchers hypothesized that calcium-mediated neurotoxicity might be induced by injecting CaCL2 into the four major atrial GPs. This may suppress "the function of the major atrial GPs and atrial neural network that play a crucial role in initiating POAF."

To investigate, the team studied 200 patients with a variety of conditions, including congestive heart failure, hypertension and stroke/transient ischemic attack, but no history of AF or significant valvular disease. They underwent isolated, off-pump CABG and were randomized to receive CaCl2 or sodium chloride (sham) GP injections.

During seven days of follow-up using continuous telemetry and Holter monitoring, 36% of the sham group and 15% of the CaCl2 group developed POAF (hazard ratio, 0.366; P=0.001). Moreover, say the researchers, the approach "also led to a lower AF burden and less frequent use of esmolol and amiodarone to treat POAF."

Length of hospitalization did not differ between the two groups and there was evidence to suggest that the "sympathetic/parasympathetic balance was not perturbed by CaCl2 injection," the team reports.

Dr. John Alexander of Duke University in Durham, North Carolina, who wrote an accompanying editorial, told Reuters Health by email that the study "nicely shows that intraoperative ganglionic ablation with calcium chloride reduces peri-operative atrial fibrillation in patients undergoing CABG surgery."

"However," he added, "what is important that we don't know, for calcium chloride ganglionic ablation or any other intervention to prevent peri-operative AF, is whether preventing peri-operative AF reduces the long-term adverse outcomes that are associated with this transient peri-operative arrhythmia."

—David Douglas

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