Topographic Distribution of Focal Left Atrial Tachycardias Defined by Electrocardiographic and Electrophysiological Data

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1 Circ J 2005; 69: Topographic Distribution of Focal Left Atrial Tachycardias Defined by Electrocardiographic and Electrophysiological Data Hitoshi Hachiya, MD; Sabine Ernst, MD; Feifan Ouyang, MD; Hercules Mavrakis, MD; Julian Chun, MD; Dietmar Bänsch, MD; Matthias Antz, MD; Karl-Heinz Kuck, MD Background Detailed information about the topographic distribution of focal left atrial tachycardias (FLATs) is limited. Methods and Results A total of 143 atrial tachycardia (AT) foci were successfully ablated in 140 patients (56 men, mean age 44.6±17.9 years). In 36.4% (52/143 ATs), a left atrial (LA) origin of the tachycardia was identified from the site of successful ablation. In 46% (24/52) of FLATs, the site of origin (SO) was near the ostium of a pulmonary vein (PV), and in 36.5% (19/52), the SO was near the mitral annulus (MA). In the remaining ATs, the SO was in the left atrial appendage (LAA), septum, LA roof and inside the coronary sinus. P waves in V1 showed biphasic morphology with an initial negative component in most FLATs originating from the septal MA, superior MA, and LAA. However, P waves in V1 were positive in all patients with FLATs originating from PVs. Negative P waves in avl were always observed in FLATs originating from left PVs. The mean cycle length of FLATs from PVs was significantly shorter than that from the MA. Conclusion Knowledge of the topographic distribution, P-wave morphology, and tachycardia cycle length facilitates successful ablation of FLATs. (Circ J 2005; 69: ) Key Words: Ablation; Focal atrial tachycardia; Left atrium; P-wave morphology; Topographic distribution Several origins of the majority of focal atrial tachycardia (AT) have been identified, such as the atrioventricular (AV) rings, 1 4 crista terminalis, 5 and pulmonary veins (PV). 6,7 However, detailed information about the topographic distribution of focal left atrial (LA) tachycardias (FLATs) is limited and there is a lack of detailed information from large series of patients. In this retrospective study, we report on 51 consecutive patients with 52 FLATs and investigate the value of electrocardiographic criteria for accessing the topographic distribution. Methods Patient Population From January 1999 to May 2003, a total of 143 AT foci were successfully ablated in 140 patients (56 men, mean age 44.6±17.9 years). In 36.4% (52/143 ATs), a LA origin of the tachycardia was identified in 51 patients by both conventional (38 patients) and 3-dimensional (D) mapping (13 patients) techniques and the site of successful ablation. Patient symptoms prior to ablation varied from palpitation and dizziness to pre-syncope. Signed written consent was obtained from all subjects before the electrophysiological study and ablation. (Received August 2, 2004; revised manuscript received October 18, 2004; accepted November 7, 2004) II. Med. Abteilung (Kardiologie), Allgemeines Krankenhaus St Georg, Hamburg, Germany Mailing address: Feifan Ouyang, MD, AK St Georg, 2. Med. Abteilung (Kardiologie), Lohmühlenstr. 5, Hamburg, Germany. Ouyangfeifan@aol.com Electrophysiological Study All patients were studied in the fasting state with sedation. Two standard catheters were positioned: a His bundle recording catheter (Parahis, Biosense Webster) advanced via the femoral vein and a multipolar catheter advanced into the coronary sinus (CS) via the left subclavian vein. A 20-polar catheter (A20, Biosense Webster) was also placed at the right atrial (RA) free wall via a femoral approach in some patients. Transseptal access by a modified Brockenbrough technique was performed (SL1, DAIG, St Jude Medical) if LA tachycardia was suspected from the 12-lead ECG and the origin could not be identified by RA mapping. Mapping was performed with a standard 7-Fr, 4- mm-tip ablation catheter (Biosense Webster) together with pulsed mono- or biplane fluoroscopy (HICOR, Siemens) in 38 patients. In addition, on the discretion of the investigator, either an electroanatomical mapping system (CARTO, 11 patients) or a non-contact mapping system (ENSITE, 2 patients) was used for 3-D reconstruction of the atrial chambers. If AT was not spontaneously present, isoproterenol was administered intravenously to induce the arrhythmia. Definitions Standard electrophysiological techniques were used to exclude an accessory pathway or AV nodal reentrant tachycardia. The diagnosis of focal AT was made using the following conventional criteria: (a) abnormal P-wave morphology during tachycardia, (b) endocardial activation sequence inconsistent with sinus origin and (c) no evidence of macroreentrant atrial tachycardia. In the patients in whom the electroanatomical or non-contact mapping system was used, focal AT was defined as follows: (a)

2 206 HACHIYA H et al. P-Wave Analysis Surface 12-lead ECG recordings were obtained from all patients. When necessary, the P wave was unmasked from ventricular repolarization during the tachycardia by ventricular extrastimuli. P waves were classified into 4 types: (1) positive: P waves showing deflections above the isoelectric line; (2) negative: P waves inscribed below the isoelectric line; (3) biphasic: P waves showing both positive and negative components; and (4) isoelectric: flat P waves. Follow-up Forty-eight patients with FLAT ablation or their referring physicians were followed up by telephone. Fig 1. Topographic distribution of focal left atrial tachycardias. CS, coronary sinus; LAA, left atrial appendage; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein; inf. MA, inferior mitral annulus; lat. MA, lateral mitral annulus; sep. MA, septal mitral annulus; sup. MA, superior mitral annulus. radiation in all directions from a single site of earliest activation and (b) range of activation times less than the tachycardia cycle length. Ablation Radiofrequency (RF) applications were delivered at the site of earliest bipolar activation (maximal (max) temperature: 55 C, max. duration: 60s, max. power: 40 W). The location of RF application was documented by fluoroscopy and was stored for further evaluation, together with the intracardiac electrograms, on an electrophysiological recording system (Quinton, Pulmocard). When an additional mapping system (CARTO or ENSITE) was used, ablation tags were marked on the 3-D reconstruction for each RF application. Catheter ablation was judged as successful if the tachycardia was successfully terminated and was not inducible by programmed stimulation and/or isoproterenol infusion 30 min after the final RF application. Statistical Analysis Continuous variables are expressed as mean ± standard deviation (SD). An unpaired Student s t-test was performed to calculated differences between sites of origin. A p-value <0.05 was considered significant. Results Topographic Distribution of FLATs The topographic distribution of the FLATs is shown in Figs 1 and 2. In 46% (24/52) of FLATs, the site of origin (SO) was near the ostium of a PV. Interestingly, in 15 (62.5%) of the FLATs originating from PVs the tachycardia was triggered from the right superior PV ostium. In the remaining patients with FLATs from PVs the SO was located in the left superior PV (5 ATs), right inferior PV (2 ATs) or left inferior PV (2 ATs). In 36.5% (19/52) of FLATs, the SO was near the mitral annulus (MA) [septal MA (9 ATs), superior MA (6 ATs), lateral MA (3 ATs), inferior MA, (1 AT)]. In the remaining patients, the SO was located in the LA appendage (4 ATs), left septum (2 ATs), LA roof (1 AT), or inside the coronary sinus (2 ATs). Electrophysiological and Ablation Data We evaluated the earliest local activation time of successful ablation sites and the AT cycle lengths (ATCL) from the PVs and MA. The earliest activation time was defined as the interval from the earliest bipolar electrogram of the mapping catheter to the onset of the P wave during tachy- Fig 2. Distribution of focal left atrial tachycardias. CS, coronary sinus; LAA, left atrial appendage; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein; MA, mitral annulus; PV, pulmonary vein.

3 Anatomic Distribution of LA Tachycardias cardia. The earliest activation time was 56.2±21 ms for PV ATs and 42.7±17 ms for MA ATs (no significant difference, p=0.115). The mean cycle length of FLATs from the PVs was significantly shorter than that from the MA (313.8±58.9 ms vs 366.8±57.2 ms, p=0.04) (Table 1). A mean total number of 9.2±8.6 RF applications was delivered for successful ablation. The average procedure time was 287.3±135.4 min and mean fluoroscopy time was 27.9±19.4 min. Table 1 Electrophysiological Data PV MA p value EAT (ms) 56.2± ± ATCL (ms) 313.8± ± ATCL, atrial tachycardia cycle length; EAT, earliest activation time at the successful ablation site; MA, mitral annulus; PV, pulmonary vein. P-Wave Morphology The P-wave morphology of the FLATs is presented in Table 2. The P wave in ECG lead V1 was positive in all patients with FLATs originating near the ostia of the PVs (Table 2; Figs 3,4). In FLATs originating from left PVs, a negative P wave was also always observed in lead avl (Fig 4). Using the criterion that a negative P wave in V1 in patients with FLATs indicates a PV origin resulted in a sensitivity of 100%, specificity of 78.6%, positive predictive accuracy of 80% and negative predictive accuracy of 100%. The sensitivity and specificity of a negative P wave in avl in patients with FLATs originating from a PV ostia to identify left side PV were 100% and 100%, respectively. Interestingly, the P wave in V1 showed a biphasic morphology (negative followed by positive deflection) in 89% of FLATs originating from the septal MA, 83.3% from the superior MA, and in 75% of FLATs from the LA appendage (Fig 5A,B). A simple algorithm to specify the SO of FLATs is shown in Fig 6. Follow-up Data There were no recurrences during a mean follow-up of 33±14 months and 41 of 48 patients are free of antiarrhythmic drugs. There was no PV stenosis in the patients who underwent catheter ablation for FLATs originating near a PV ostium. Discussion There are several published studies of focal AT. 1 8 Kistler et al studied 7 patients with focal AT originating from the MA 4 and 27 patients with 28 PV ATs 7 and performed detailed qualitative and quantitative P-wave analysis. However, there are limited data about the topographic distribution of FLATs in large series of patients. Table 2 P-Wave Morphology of Left Atrial Tachycardias Origin of tachycardia ECG lead I avl V1 II III avf RSPV (n=15) Positive 46.7% 33.3% 100% 66.7% 46.7% 66.7% Negative Biph 6.6% 46.7% 0 20% 53.3% 33.3% Iso 46.7% 20% % 0 0 LSPV (n=5) Positive % 100% 100% 100% Negative 20% 100% Biph Iso 80% LIPV (n=2) Positive % 0 100% 0 Negative 100% 100% Biph % 0 100% Iso RIPV (n=2) Positive 50% 0 100% 100% 0 50% Negative Biph 50% 100% % 50% Iso Septal MA (n=9) Positive 22% 11% 0 33% 33% 33% Negative 0 11% 11% Biph 56% 67% 89% 67% 67% 67% Iso 22% 11% Superior MA (n=6) Positive % 66.7% 66.7% 66.7% Negative % Biph 33.3% 33.3% 83.3% 33.3% 33.3% 33.3% Iso 66.7% 33.3% LAA (n=4) Positive 50% 0 25% 100% 100% 100% Negative 50% 100% Biph % Iso Biph, biphasic; Iso, isoelectric; LAA, left atrial appendage; LIPV, left inferior pulmonary vein; LSPV, left superior pulmonary vein; RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein; MA, mitral annulus.

4 208 HACHIYA H et al. Fig 3. (Left) 12-lead ECG showing P-wave morphology during tachycardia. The P wave is positive in leads I, II, III, avf, and V1 6, negative in lead avr, and biphasic with an initial positive deflection followed by a negative deflection in avl as the arrow indicates. (Right) Tracings during atrial tachycardia originating from RSPVos show surface ECG leads I, II, V1, and intracardiac electrograms recorded from a mapping catheter, a catheter at the His bundle region, and a catheter inside the coronary sinus. Note that electrograms from the mapping catheter in the RSPVos indicate the successful ablation site (the local electrogram precedes the onset of the P wave by 97 ms). A, atrial electrogram; H, His bundle electrogram; V, ventricular electrogram; RSPVos, right superior pulmonary vein ostium. Fig 4. (Left) 12-lead ECG showing P-wave morphology during tachycardia. The P wave is positive in leads II, III, avf, and V1 6, negative in lead avl (as arrow indicates), and isoelectric in lead I. (Right) Tracings during atrial tachycardia originating from LSPVos show ECG leads I, II, V1, and intracardiac electrograms recorded from a mapping catheter, a catheter at the His bundle region, and a catheter inside the coronary sinus. Note that electrograms of the mapping catheter in the LSPVos indicate the successful ablation site (arrow) as the local electrogram precedes the onset of the P wave by 42 ms. A, atrial electrogram; H, His bundle electrogram; V, ventricular electrogram; LSPVos, left superior pulmonary vein ostium.

5 Anatomic Distribution of LA Tachycardias 209 Fig lead ECG showing P-wave morphology during atrial tachycardia. (A) Tachycardia originating from septal mitral annulus. The P wave is isoelectric in lead I, positive in leads II, III, avf, negative in lead avr and avl, and biphasic with an initial negative deflection followed by a positive deflection in V1 (arrow). (B) Tachycardia originating from left atrial appendage. The P wave was unmasked from ventricular repolarization during the tachycardia by ventricular extrastimuli. The P wave is positive in leads I, II, III, avf, and V3 6, biphasic with an initial negative deflection followed by a positive deflection in V1 (as arrow indicates), and V2 and negative in leads avr and avl. Fig 6. Proposed algorithm to specify the site of origin of focal left atrial tachycardias from 12-lead electrocardiographic recordings. A positive P wave in V1 usually indicates an origin near the pulmonary vein (PV) ostia. A biphasic or negative P wave in V1 indicates an origin near either the septal or superior mitral annulus (MA) or the left atrial appendage (LAA). A positive P wave in V1 and negative P wave in avl indicates an origin near the left pulmonary veins. A positive P wave in V1 and biphasic, negative, or isoelectric P wave in avl indicates an origin near the right pulmonary veins. We present detailed topographic distribution data of FLATs in 52 patients, report a statistically significant difference of ATCL between a MA origin and PVs, and provide a simple P-wave morphology algorithm to specify the SO of FLATs. Topographic Distribution of FLATs Focal ATs may arise from any atrial myocardial region, but predominantly originate from confined areas, rendering them accessible to direct RF ablation. 1,4,5 In our study 83% (Fig 2) of FLATs were triggered from the PVs and the MA (Figs 1,2), which shows that the atrial myocardium of the PVs and MA are most arrhythmogenic regions for FLATs. In 46% (24/52) of FLATs, the SO was near the ostium of a PV and in 62.5% (15/24) of the FLATs originating from the PVs, the tachycardia was triggered from the right superior PV ostium. Although Kistler et al also reported in an elegant study that 78% of PV ATs originated from superior PVs, 7 the exact reason why the most frequent PV origin is the RSPV is unclear. In 36.5% (19/52) of the present FLATs, the SO was near the MA. Kistler et al also reported that tachycardias originating from the MA have a propensity to be localized to the superior aspect of this structure, in proximity to the mitralaortic junction. 4 In our study, we observed that the focus was near this region in only 6 (31.6%) of 19 MA ATs (Fig 2). Our results show that septal, lateral and inferior FLAT foci around the MA are also possible. In the remaining patients, the SO was located in the LA appendage (7.7%), the left septum (3.8%), the LA roof (1.9%) or inside the coronary sinus (3.8%) (Fig 2). These particular locations should be considered as possible FLAT foci if mapping in the PVs and MA is negative.

6 210 HACHIYA H et al. Electrophysiological Data In the present study, the mean CL of FLATs from the PVs was significantly shorter than that from the MA (313.8±58.9 ms vs 366.8±57.2 ms, p=0.04). Therefore, the ATCL can be used as a marker of the SO of FLATs. P-Wave Morphology In our study, the P wave in V1 showed biphasic morphology (negative followed by positive spike) in 87% of 15 FLATs originating from the septal and superior MA and in 75% of 4 FLATs originating from the LA appendage. The initial deflection may be caused by the relatively anterior position of both the MA and the appendage compared with that of the PVs, because the downward deflection represents initial forces directed posteriorly and away from V1. 4 Tang et al analyzed P-wave morphology in 31 patients with FLATs and found that use of the criterion of a positive P wave in V1 for predicting LA foci was associated with a sensitivity of 92.9% and specificity of 88.2%. 6 Therefore, the RA should be mapped first when the P wave in V1 is not positive. When detailed mapping of the RA in patients with a non-positive P wave in V1 fails to locate a tachycardia focus, then the septal and superior MA sites should be considered as potential locations. The P waves in V1 were positive in all FLATs originating near the PV ostia, whereas in FLATs originating from left PVs, a negative P wave was also always observed in avl. Using the criterion that a positive P wave in V1 in patients with FLATs indicates a PV origin resulted in a sensitivity of 100%, specificity of 78.6%, positive predictive accuracy of 80% and negative predictive accuracy of 100%. Therefore, when the P wave in V1 is positive in patients with FLATs, detailed mapping around the PV ostia should be performed. The sensitivity and specificity of a negative P wave in avl in patients with FLATs originating from PV ostia to identify left side PVs were 100% and 100%, respectively, and this finding may differentiate left PV FLATs from right PV FLATs (Fig6). A possible explanation for why a negative P wave was always observed in lead avl in FLATs from left PVs is that the vector of atrial activation is directed towards the right side. Study Limitations We did not attempt quantitative P wave analysis because our purpose was to define a practical approach to help physicians detect the SO of FLATs using only qualitative P wave analysis. Conclusion FLATs originate in certain anatomical structures, and specific ECG criteria can be used to differentiate the SO. In the majority of patients, FLATs originate from the PVs and MA. Knowledge of the topographic distribution, P-wave morphology and ATCL facilitates successful ablation of FLATs. Acknowledgment We gratefully acknowledge the assistance of Detlef Henning in preparing the figures. References 1. Morton JB, Sanders P, Das A, Vohra JK, Sparks PB, Kalman JM. Focal atrial tachycardia arising from the tricuspid annulus: Electrophysiologic and electrocardiographic characteristics. J Cardiovasc Electrophysiol 2001; 12: Wit AL, Fenoglio JJ Jr, Wagner BM, Bassett AL. Electrophysiological properties of cardiac muscle in the anterior mitral valve leaflet and the adjacent atrium in the dog: Possible implications for the genesis of atrial dysrhythmias. Circ Res 1973; 32: McGuire MA, de Bakker JM, Vermeulen JT, Moorman AF, Loh P, Thibault B, et al. Atrioventricular junctional tissue: Discrepancy between histological and electrophysiological characteristics. Circulation 1996; 94: Kistler PM, Sanders P, Hussin A, Morton JB, Vohra JK, Sparks PB, et al. Focal atrial tachycardia arising from the mitral annulus: Electrocardiographic and electrophysiologic characterization. J Am Coll Cardiol 2003; 41: Kalman JM, Olgin JE, Karch MR, Hamdan M, Lee RJ, Lesh MD. Cristal tachycardias : Origin of right atrial tachycardias from the crista terminalis identified by intracardiac echocardiography. J Am Coll Cardiol 1998; 31: Tang CW, Scheinman MM, Van Hare GF, Epstein LM, Fitzpatrick AP, Lee RJ, et al. Use of P-wave configuration during atrial tachycardia to predict site of origin. J Am Coll Cardiol 1995; 26: Kistler PM, Prashanthan S, Fynn SP, Stevenson IH, Hussin A, Vohra JK, et al. Electrophysiological and electrocardiographic characteristics of focal atrial tachycardia originating from the pulmonary veins: Acute and long-term outcomes of radiofrequency ablation. Circulation 2003; 108: Volkmer M, Antz M, Hebe J, Kuck KH. Focal atrial tachycardia originating from the musculature of the coronary sinus. J Cardiovasc Electrophysiol 2002; 13:

Focal Atrial Tachycardia Originating From the Non-Coronary Aortic Sinus Electrophysiological Characteristics and Catheter Ablation

Focal Atrial Tachycardia Originating From the Non-Coronary Aortic Sinus Electrophysiological Characteristics and Catheter Ablation Journal of the American College of Cardiology Vol. 48, No. 1, 2006 2006 by the American College of Cardiology Foundation ISSN 0735-1097/06/$32.00 Published by Elsevier Inc. doi:10.1016/j.jacc.2006.02.053