Methods
The Queen’s University Health Sciences and affiliated teaching hospitals research ethics board reviewed the study protocol and granted clearance. Data were collected from consecutive patients attending for diagnostic electrophysiologic study at Kingston General Hospital from May 2018 to December 2019. Our inclusion criteria were any patients undergoing procedures with instrumentation using the diagnostic Advisor™ HD Grid mapping catheter (Abbott, Plymouth, MN) with the intent to map and treat clinically relevant arrhythmia using the Ensite Precision™ electroanatomic mapping system (Abbott, Plymouth, MN). We excluded any cases where the HD Grid was not used, AVRT due to an accessory pathway, and cases of typical cavotricuspid isthmus dependent flutter.
Therapy was guided by a combination of EAM data, activation mapping, pacing entrainment criteria and local electrogram features such as bipolar amplitude, onset, and offset (last deflection). Eligible patients were identified using a query of the electronic medical record from the electrophysiology lab database (Mac-Lab™, GE Healthcare). Electrogram data was collected and stored in recorded segments or diagnostic landmark maps for future analysis. For the purposes of this study, all patient demographic and outcome data were collected from electronic medical records, telephone interviews, and paper documents from medical charts. Demographic patient data were collected at the time of the procedure; in addition, we recorded the type of arrhythmia, procedural details, acute and procedure related complications, and outcomes defined as documented or subjective sustained arrhythmia recurrence after 3 months post procedure.
Procedural complications related to atrial instrumentation were pre-defined as bleeding, stroke or TIA, sepsis and death from any cause. Specifically, these complications are considered major as defined by prolonged length of hospital stay, patient readmission for reasons other than arrhythmia recurrence, and/or a change in treatment was ensued because of the complication. Complications that did not meet these criteria were considered minor and not included for further analysis.