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Nitroglycerin to Ameliorate Coronary Artery Spasm During AF Ablation
Quick Takes
- Pulse field ablation results in mostly subclinical vasospasm of the right coronary artery when performing ablation at the cavotricuspid isthmus.
- High doses of parenteral nitroglycerin are useful to prevent severe coronary spasm.
Study Questions:
What is the potential of focal pulsed field ablation (PFA) to provoke coronary spasm during cavotricuspid isthmus ablation, and does nitroglycerin use mitigate the risk of vasospasm in this setting?
Methods:
During atrial fibrillation (AF) ablation, a focal PFA catheter was used for cavotricuspid isthmus ablation. Angiography of the right coronary artery was performed before, during, and after PFA. After the initial exploratory phase of no nitroglycerin versus various doses of nitroglycerin, two primary administration strategies were studied: 1) multiple boluses (3-2 mg every 2 min) into the right atrium (n = 10), and 2) a bolus (3 mg) into the right atrium with continuous peripheral intravenous infusion (1 mg/min; n = 10).
Results:
Without nitroglycerin, cavotricuspid isthmus ablation provoked moderate-severe vasospasm in 4 of 5 (80%) patients (fractional flow reserve 0.71 ± 0.08). With repetitive nitroglycerin boluses, severe spasm did not occur, and mild-moderate vasospasm occurred in only 2 of 10 (20%). Using the bolus + infusion strategy, severe and mild-moderate spasm occurred in 1 and 3 of 10 patients (aggregate 40%). No patient had ST-segment changes.
Conclusions:
The authors conclude that ablation of the cavotricuspid isthmus using a focal PFA catheter routinely provokes right coronary vasospasm, and that pretreatment with high doses of parenteral nitroglycerin prevents severe spasm.
Perspective:
PFA is a new, mostly nonthermal ablative energy modality. It has comparable efficacy to conventional thermal ablation, but it offers important safety advantages: no esophageal injury or pulmonary vein stenosis, and rare phrenic nerve injury. PFA creates a powerful electrical field and causes dielectric breakdown of cell membranes. Prior studies of a pentaspline PFA catheter revealed the potential for severe vasospasm of the coronary arteries. It was unclear whether such dramatic coronary spasm could still occur with focal PFA catheters.
The authors of the current study show that indeed the focal PFA catheter when used for the treatment of typical atrial flutter routinely causes subclinical right coronary artery spasm. Prophylactic nitroglycerin administration in doses higher than “normal” prevented severe vasospasm on concurrent coronary angiograms. This will be a major safety consideration as the PFA application becomes more widespread. The degree of coronary vasospasm provoked by other PFA catheters and waveforms will no doubt require further study.
Clinical Topics: Arrhythmias and Clinical EP
Keywords: Ablation, Nitroglycerin, Spasm
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