Could a common nausea drug tame a dangerous heart rhythm?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Men and women 18-100 years of age * ECG-verified AF and/or atrial flutter requiring elective catheter ablation * Receiving guideline-recommended anticoagulation (if CHA2DS2-VASc score is 0 (men) or 1 (women), anticoagulation can be omitted) Exclusion Criteria: * Women of childbearing potential * Subject reported syncope of unknown origin within the previous 6 months * Diagnosis of active thyrotoxicosis * Diagnosis AF from reversible noncardiac causes * Diagnosis of acutely decompensated heart failure * Left ventricular ejection fraction less than or equal to 20% * New York Heart Association class IV heart failure * Diagnosis of severe liver disease (Child-Pugh score greater than or equal to 10) * Cardiac surgery (preceding 2 months) * Not receiving anticoagulation due to contraindications (as determined by treating physician and recorded in the medical record) * Pretreatment QRS \> 180 ms, QTc \> 450 ms within two weeks of screening visit * Heart rate \< 50 beats per minute in SR * Diagnosis of hypotension * Diagnosis of Wolff-Parkinson-White syndrome * Previous ondansetron hypersensitivity or serotonin syndrome * Diagnosis of phenylketonuria * Diagnosis of congenital long QT syndrome * Concomitant therapy with both beta-blockers and a nondihydropyridine CCB * History of drug-induced torsades de pointes or QTc prolongation * Concomitant therapy with QTc-prolonging medications (www.crediblemeds.org), except amiodarone and propafenone * Concomitant therapy with serotonergic drugs (selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, monoamine oxidase inhibitors, mirtazapine, lithium, tramadol), apomorphine, phenytoin, carbamazepine, oxcarbazepine, rifampin. * Left ventricular ejection fraction \< 20% and those with NYHA class IV heart failure with reduced ejection fraction (confirmed by diagnosis or echocardiogram within 6 months of enrollment in screening) * Patients with pre-existing allergies to adhesives * Patients with neuromuscular stimulators