Introduction: Post ablation atrial tachycardias can be complex and challenging. The Advisor HD Grid multielectrode catheter (Abbott, St Paul, MN, USA) is a high-density mapping catheter developed for mapping complex re-entrant atrial arrhythmias independent of activation wavefronts to electrode orientation, reducing the so-called “bipolar blindness”. The aim of this study was to compare the mapping resolution of this novel multielectrode catheter using either the HD wave or conventional bipolar configuration.
Methods: Patients undergoing catheter ablation for atrial tachycardia (AT) in our centre were prospectively enrolled. Electroanatomic mapping of the left and/or right atrium was performed using the Abbott Advisor HD Grid catheter. Local activation time (LAT), atrial voltage maps, and map density (number of electrograms collected) was determined. Areas of interest where ablation either terminated tachycardia or changed the cycle of length of more than 20% were recorded. We compare mean voltage of electrograms in the areas of interest and analysed map density using HD wave versus conventional bipolar configuration.
Results: Ten patients (65 ± 9.3, 90% male) were included. Mean LA size was 26 cm2. All the patients had at least one previous catheter ablation for atrial fibrillation/atrial tachycardia. The mechanism of AT was macroreentry in 80% of cases, and microreentry or focal in the remaining. Eight ATs were left atrial (three roof-dependent, two mitral-isthmus-dependent, one around right upper pulmonary vein, one microreentrant from the septum and one from the appendage area); two ATs were cavo-tricuspid isthmus dependent. The mean voltage at the area of interest was 1.0 ± 0.6mV for the HD wave versus 0.8 ± 0.6 for the conventional bipolar configuration (p=0.9). Number of electrograms collected for the HD wave was 17,166 versus 10,797 for the bipolar configuration (p=0.04). Acute procedural success was 90%. After a median follow-up of 6 months, freedom from any arrhythmia was 50%.
Conclusion: The Abbott Advisor HD Grid catheter with HD wave algorithm allows higher resolution mapping of complex atrial arrhythmias compared to standard bipolar catheter configuration. HD grid guided ablation achieves a high acute success rate of arrhythmia termination.