An Unusual Case of Non-Reentrant Atrioventricular Nodal Tachycardia

Although uncommonly encountered, dual atrioventricular nodal non-reentrant tachycardia (DAVNNRT) is a well described arrhythmia that can manifest in patients with dual atrioventricular nodal pathways physiology. This arrhythmia is characterized on ECG by a single P wave followed by two conducted QRS complexes, and on intracardiac EGMs by a single atrial electrogram followed by two separate His deflections and ventricular electrograms. Our case demonstrates a rare case of “triple atrioventricular non-reentrant tachycardia” in which a patient was found to have 3 distinct AV nodal pathways and multiple “triple fire responses”, both on surface ECG and intracardiac electrograms.

การสร้างภาพสามมิติ (3D Mapping) ในกลุ่มผู้ป่วยภาวะหัวใจเต้นผิดจังหวะชนิดเร็วที่ได้รับการรักษาโดยการจี้ด้วยกระแสไฟฟ้า (Ablation)

ในปัจจุบันการสร้างภาพสามมิติ (3D Mapping) ในกลุ่มผู้ป่วยภาวะหัวใจเต้นผิดจังหวะชนิดเร็วที่ได้รับการรักษาโดยการจี้ด้วยกระแสไฟฟ้า (RF Ablation) ได้รับความนิยมอย่างแพร่หลายมากขึ้น เนื่องจากการสร้างภาพสามมิติ มีการนำเทคโนโลยีสมัยใหม่เข้ามาช่วยในการสร้างภาพได้แก่ Magnetic Technology, Current-based technology, Hybrid technology ทำให้สามารถสร้างภาพสามมิติออกมาได้หลายรูปแบบอย่างเช่น Anatomical mapping, Local Activation Time mapping (LAT), Bipolar Voltage mapping, Complex Fractionated Atrial Electrogram (CFAEs) Map, Pace map, Merge หรือ Fusion, Reentrant map เป็นต้นโดยภาพที่ได้นอกจากจะแสดงเป็นภาพนิ่งแล้วยังสามารถแสดงเป็น Video Animation ได้อีกด้วยอย่างเช่น Propagation Map, Ripple Map เป็นต้น ทำให้มีความแม่นยำในการรักษา ผู้ป่วยได้รับปริมาณรังสีที่น้อยลง มีความปลอดภัย และลดภาวะแทรกซ้อน ซึ่งก่อให้เกิดประโยชน์สูงสุดแก่ผู้ป่วย คำสำคัญ: การสร้างภาพสามมิติ, การจี้ด้วยกระแสไฟฟ้า

Extensive left atrial low-voltage area during initial ablation is associated with a poor clinical outcome even following multiple procedures.

Introduction Some patients fail to respond to persistent atrial fibrillation (PeAF) catheter ablation in spite of multiple procedures and ablation strategies, including low voltage area (LVA)-guided, linear, and complex fractionated atrial electrogram (CFAE)-guided ablation procedures. We hypothesized that LVA extent could predict non-response to PeAF catheter ablation in spite of multiple procedures. Methods This study included 510 patients undergoing initial ablation procedures for PeAF. LVAs were defined as regions with bipolar peak-to-peak voltages of <0.50 mV after PVI during sinus rhythm. Patients were categorized by LVA size into groups A (0-5 cm2), B (5-20 cm2), and C (over 20 cm2). The primary endpoint was AF-free survival after the last procedure. Results During a median follow-up of 25 (17, 36) months, AF recurrence was observed in 101 (20%) patients after 1.4±0.6 ablation procedures (maximum 4). A Kaplan-Meier analysis showed the AF-free survival rate significantly differed by LVA size. Conclusion Extensive LVA after initial PVI was associated with a poor clinical outcome even following multiple procedures.

P436The impact of filter settings on morphology of unipolar fibrillation potentials

Funding Acknowledgements N.M.S. de Groot, MD, PhD was supported by CVON-AFFIP (914728), NWO-Vidi (91717339) and Biosense Webster USA (ICD 783454). Background Using unipolar atrial electrogram morphology as guidance for ablative therapy is regaining interest. Although standardly used in clinical practice during ablative therapy, the impact of filter settings on morphology of unipolar AF potentials is unknown. Purpose This study aims to elucidate consequences of high-pass, low-pass and notch filtering on unipolar atrial fibrillation (AF) potentials. Methods Thirty different filter settings were applied to high-resolution epicardial AF potentials recorded from ten patients. . Local activation times were determined by marking deflections with slope ≤-0.05mV/ms and amplitude ≥0.3mV. Fibrillation potentials were analyzed for peak-to-peak amplitude (mV), number of deflections (f) and fractionation delay time (FDT, interval between first and last deflection), and classified as single potential (SP, f = 1), double potential (DP, f = 2) or complex fractionated potential (CP, f ≥ 3). Results In total, 3000 seconds of AF recordings were analyzed, containing 255,7045 fibrillation potentials. Changing high-pass filtering from 0.5 up to 100 Hz decreased the number of detected fibrillation potentials (with 25-65%), median deflection amplitude (min-max 0.59-0.96 to 0.44-0.57 mV), percentage of DP (25.8-32.9 to 22.5-31.6%) and CP (15.9-36.0 to 7.3-37.8%) as well as median FDT (16-25 to 11-15 ms) (all p &lt; 0.01). Gradually changing low-pass filtering from 400 Hz to 20 Hz induced an exponential decrease in fibrillation potentials (to 0%), percentage of DP (25.8-32.9 to 0%) and CP (15.9-36.0 to 0%), whereas deflection amplitude, percentage of SP and median FDT exponentially increased (0.59-0.96 to 1.82-2.39 mV, 36.1-57.6 to 100%, 16-25 to 33-38 ms, respectively) (all p &lt; 0.01). Notch filtering at 50 Hz decreased the number of detected fibrillation potentials (with ∼1%), median deflection amplitude (0.59-0.96 to 0.59-0.95 mV) (both p &lt; 0.01), whereas the percentage of CP increased (15.9-36.0 to 16.2-37.0%, p = 0.016). Conclusions Filtering significantly impacted of unipolar fibrillation potentials and decreased the number of detected potentials, becoming a potential source of error in identification of LATs, low-voltage areas, fractionated potentials and thus ablative targets during mapping. Potentials (%) Amplitude (mV) SP (%) DP (%) CFP (%) FDT (ms) Default (0.5-400 Hz) 100 0.59-0.96 36.1-57.6 25.8-32.9 15.9-36.0 16.0-25.0 High-pass filtering Decreased Decreased Increased Decreased Decreased Decreased Low-pass filtering Decreased Increased Increased Decreased Decreased Increased Notch filtering Decreased Decreased p = NS p = NS Increased p = NS Impact of filtering on morphology parameters Abstract Figure. Impact of filtering on AF morphology

The Impact of Filter Settings on Morphology of Unipolar Fibrillation Potentials

Using unipolar atrial electrogram morphology as guidance for ablative therapy is regaining interest. Although standardly used in clinical practice during ablative therapy, the impact of filter settings on morphology of unipolar AF potentials is unknown. Thirty different filters were applied to 2,557,045 high-resolution epicardial AF potentials recorded from ten patients. Deflections with slope ≤ − 0.05 mV/ms and amplitude ≥ 0.3 mV were marked. High-pass filtering decreased the number of detected potentials, deflection amplitude, and percentage of fractionated potentials (≥ 2 deflections) as well as fractionation delay time (FDT) and increased percentage of single potentials. Low-pass filtering decreased the number of potentials, percentage of fractionated potentials, whereas deflection amplitude, percentage of single potentials, and FDT increased. Notch filtering (50 Hz) decreased the number of potentials and deflection amplitude, whereas the percentage of complex fractionated potentials (≥ 3 deflections) increased. Filtering significantly impacted morphology of unipolar fibrillation potentials, becoming a potential source of error in identification of ablative targets.