Localized Reentry Arising from a Spontaneous Scar in the Anterior LA Detected by High-Density Multi-Electrode Automated Mapping

Case Description

In a 78-year-old patient who presented with a symptomatic irregular heart rate of 95-140 bpm, resting ECG revealed a supraventricular tachycardia with an atrial cycle length of 410-430 ms and Wenckebach-type AV conduction.

After transesophageal echocardiography exclusion of intra-atrial thrombi, a biatrial high-density three-dimensional map was acquired using a 14-pole circular mapping catheter and the Abbott EnSite Precision™ Cardiac Mapping System, which includes the EnSite™ AutoMap Module (Figure 1). The map was then automatically field scaled using EnSite™ NavX™ Navigation and Visualization Technology, Sensor Enabled™.  For this tachycardia, the Automap thresholds were set as score = 38%, cycle length tolerance = 11 ms, and signal-to-noise ratio = 11.5 with enhanced noise rejection “on.” The reference EGM was CS 9/10 with a detection set to peak positive (Max). Roving collection used all 13 bipolar electrograms from the circular mapping catheter, annotating signals where the first deflection met the sensitivity threshold of 0.300 mV (Figure 2).

There were 1399 voltage and activation points collected with 801 points used by the system. Combining voltage and activation mapping modalities as well as standard entrainment manuevers, a localized reentry using a spontaneous scarring of the anterior LA wall as slow conduction zone could be identified (Figure 3).

During mapping, the atrial tachycardia stopped mechanically several times, but could be re-induced easily with programmed and burst stimulation via the coronary sinus catheter. Intracardially, the cycle length was mainly stable (430 ms), but would also show alternating cycles of 410 and 430 ms. 

A single radiofrequency application (38W; 1 min) led to immediate AT termination (Figure 4). In light of the varying AT cycle lengths suggesting the presence of several conductive channels inside the scar, a larger area covering the majority of the anterior LA scar was ablated.

About the Technology

Part of the Abbott advanced ablation and integrated lab portfolios, the EnSite Precision™ cardiac mapping system is designed to provide automation, flexibility, and precision in cardiac mapping during cardiac arrhythmia treatments. Prominent European electrophysiology labs and hospitals have embraced this next-generation platform, which has been used in thousands of cases in Europe since receiving CE Mark in January 2016. The system was cleared for use in the United States in December 2016 and is available in other markets as well, including Hong Kong and Singapore. 

Summary

This case illustrates the ability of this novel automated mapping system to generate high-density maps that assist in locating and pathophysiologically characterizing even very complex and challenging arrhythmias.

Disclosures: Dr. Werner reports she is an employee of Abbott Germany. The authors have no conflicts of interest to report regarding the content herein.  

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This article is published with support from Abbott.