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.