Participants
Individuals undergoing synchronised DC cardioversion for atrial arrhythmias at Cork University Hospital in Cork, Ireland were approached for participation in this study. A total of 73 individuals (59 men, 14 women) agreed to participate in the study. Inclusion criteria included all subjects greater than 18 years of age who were undergoing synchronised DC cardioversion for an atrial arrhythmia. This included both elective and non-elective admissions and included patients with atrial fibrillation, atrial flutter, and focal atrial tachycardia. Exclusion criteria included a myocardial infarction within the past month, coronary artery bypass grafting within the past month, cardioversion for a ventricular arrhythmia, and any recent shocks by an implantable internal cardioverter defibrillator. All procedures conformed to the Declaration of Helsinki and were approved by the Clinical Research Ethics Committee at University College Cork. Written and informed consent was obtained from all participants.