Electrophysiologic characteristics of atrial tachycardia originating from the superior vena cava

P-Wave Morphology in Focal Atrial Tachycardia: An Updated Algorithm to Predict Site of Origin

OBJECTIVES

This study sought to report P-wave morphology (PWM) from a series of paraseptal (PS) atrial tachycardia (AT), revise then prospectively evaluate a simplified PWM algorithm against a contemporary consecutive cohort with focal AT.

BACKGROUND

The 2006 PWM algorithm was useful in predicting the origin of focal AT. An updated algorithm was developed given advances in multipolar 3-dimensional mapping, potential limitations of PWM in separating PS sites, and a renewed interest in the P-wave in mapping non-pulmonary vein triggers.

METHODS

The PWM from a consecutive series of 67 patients with PS AT were analyzed. PS sites included were coronary sinus ostium, perinodal, left and right septum, septal tricuspid annulus, superior mitral annulus, and noncoronary cusp. Next the P-wave algorithm was revised and prospectively evaluated by 3 blinded assessors.

RESULTS

The P-wave for PS sites was neg/pos (n = 50), iso/pos (n = 10), or isoelectric (n = 4) in lead V₁ (96%). The P-wave algorithm was modified and prospectively applied to 30 consecutive patients with focal AT who underwent successful ablation. Foci (n = 30) originated from the right atrium (33.3%), left atrium (30%), and PS (36.7%). Using the PW algorithm, the correct anatomic location was identified in 93%. Incorrect interpretation of the terminal positive P-wave component (n = 3) and initial negative P-wave deflection (n = 1) in lead V₁ misidentified 4 paraseptal cases.

CONCLUSIONS

The revised PWM algorithm offers a simplified and accurate method of localizing the responsible site for focal AT. The P-wave remains an important first step in mapping atrial arrhythmias.

Incessant Atrial Tachycardia as First Presentation of Cardiac Angiosarcoma

Primary cardiac angiosarcomas are rare malignant tumors with a very poor prognosis. We present a case of a 48-year-old man with no previous cardiac history who developed an incessant focal atrial tachycardia complicated by tachycardia-mediated cardiomyopathy as a consequence of cardiac angiosarcoma. (Level of Difficulty: Beginner.)

An electrocardiography algorithm combined with clinical features could localize the origins of focal atrial tachycardias in adjacent structures

AIMS

It is difficult to differentiate the origins of focal atrial tachycardias (ATs) in adjacent structures by electrocardiography (ECG) alone. The aim of this study was to evaluate whether the clinical features of these ATs may help differentiate their origins.

METHODS AND RESULTS

One hundred and ninety-four patients (mean age, 43.5 ± 17.9 years; male, 53.6%) who underwent electrophysiological study for focal AT were included. We evaluated accuracy in differentiating the origin of AT by using ECG alone as well as with the addition of the clinical features. Electrocardiographs of ATs originating from the left superior pulmonary vein (LSPV, n = 24) vs. the left atrial appendage (LAA, n = 6), and from the right superior pulmonary vein (RSPV, n = 14) vs. the superior vena cava (SVC, n = 8) showed similar patterns. However, while no ATs from the LAA were found to be related to paroxysmal atrial fibrillation, 22 out of 24 ATs from the LSPV were associated with this condition. After localizing AT by using ECG, this clinical feature helped differentiate the ATs from the LSPV vs. the LAA with 93% accuracy. Moreover, while an on-and-off tachycardia (initiated and terminated more than 10 times per day) was observed in 4 of 8 ATs from the SVC, this pattern was observed in 13 of 14 ATs from the RSPV. After localizing the ATs by using ECG, on-and-off tachycardia helped differentiate the ATs from the RSPV vs. the SVC with 82% accuracy.

CONCLUSION

The clinical features and Holter monitoring can give additional information for differentiating the focal ATs originating from the adjacent structures.

Long-term outcome of catheter ablation in patients with atrial fibrillation originating from nonpulmonary vein ectopy

INTRODUCTION

Data regarding the long-term outcome of catheter ablation in patients with nonpulmonary vein (NPV) ectopy initiating atrial fibrillation (AF) are limited. We aimed to evaluate the long-term result of patients with AF who had NPV triggers and underwent catheter ablation.

METHODS AND RESULTS

The study included 660 consecutive patients (age 54 ± 11 years old, 477 males) who had undergone catheter ablation for AF. Group 1 consisted of 132 patients with AF initiating from the NPV, and group 2 consisted of 528 patients with AF initiating from pulmonary vein (PV) triggers only. Patients from Group 1 were younger than those from Group 2 (51 ± 12 years old vs 54 ± 11 years old, P = 0.001) and were more likely to be females (34.4% vs 25.8%, P = 0.049). The incidences of nonparoxysmal AF (36.4% vs 16.3%, P < 0.001) and right atrial (RA) enlargement (31.3% vs 19%, P = 0.004) were higher, and the biatrial substrates were worse in Group 1 than those in Group 2 (left atrial voltage 1.5 ± 0.7 mV vs 1.9 ± 0.7 mV, P < 0.001, RA voltage 1.6 ± 0.5 mV vs 1.8 ± 0.6 mV, P = 0.014). During a follow-up period of 46 ± 23 months, there was a higher AF recurrence rate in Group 1 than in Group 2 (57.6% vs 38.8%, P < 0.001). The independent predictors of AF recurrence were NPV trigger (P < 0.001, HR 2, 95% CI 1.4-2.85), nonparoxysmal AF (P = 0.021, HR 1.55, 95% CI 1.07-2.24), larger left atrial diameter (P = 0.002, HR 1.04, 95% CI 1.02-1.07) and worse left atrial substrate (P = 0.028, HR 1.3, 95% CI 1.03-1.64).

CONCLUSION

Compared to AF originating from the PV alone, AF originating from the NPV ectopy showed a worse outcome.

Respiratory cycle-dependent atrial tachycardia: prevalence, electrocardiographic and electrophysiologic characteristics, and outcome after catheter ablation

BACKGROUND

Little is known about the tachyarrhythmias relating to respiration. Case reports presented patients with respiratory cycle-dependent atrial tachycardias (RCATs), which cyclically emerge after starting inspiration and cease during expiration.

OBJECTIVE

The aim of the present study was to elucidate the prevalence, characteristics, and long-term outcome after radiofrequency catheter ablation (RFCA) of RCATs.

METHODS

The electrocardiographic and electrophysiologic properties and results of RFCA were analyzed in 60 patients with a total of 71 focal atrial tachycardias (ATs).

RESULTS

Nine RCATs (13%) were observed in 7 patients (12%). RCATs were irregular, with a mean cycle length ranging from 220 to 650 ms, and developed incessantly accounting for 32% ± 14% of the 24-hour heartbeats. The P-wave morphology was positive or biphasic (positive to negative) in V1, and positive in I and II. The electroanatomical mapping demonstrated a centrifugal activation pattern, with the earliest site located at the antrum of the right superior pulmonary vein (RSPV), inside the RSPV, and inside the superior vena cava (SVC) in 4, 2, and 3 RCATs, respectively. Radiofrequency energy delivery at the earliest site or the electrical isolation of the RSPV and SVC suppressed all RCATs. During a follow-up of 25 ± 15 months, 1 RCAT recurred and was eliminated in a second procedure.

CONCLUSION

RCATs were observed in 13% of the focal ATs. As presumed from the P-wave morphologies, their foci converged around the RSPV or inside the SVC. RFCA was effective to eliminate RCATs.