Supravalvular Arrhythmia

Predictors and Long-Term Outcome of Ablation of Discrete Pre-potentials in Patients With Idiopathic Ventricular Arrhythmias Originating From the Aortic Sinuses of Valsalva

Background: The predictability and long-term outcome of the discrete pre-potential (DPP) of idiopathic ventricular arrhythmias (VAs) arising from the aortic sinuses of Valsalva (ASV) have not been fully identified.

Methods: Of 687 consecutive patients undergoing ablation of outflow tract VAs, there were 105 (15.3%) patients with VAs originating from the ASV region who were included. Detailed mapping was performed within the ASV in all patients. Electrocardiographic, electrophysiological parameters, and long-term success rate were compared between patients with and without the DPPs.

Results: A DPP was recorded in 67 of 105 (63.8%) patients, including 38 left sinus of Valsalva (LSV)-VAs (38/105, 36.2%) and 29 right sinus of Valsalva (RSV)-VAs (29/105, 27.6%). The patients with DPPs had wider QRS duration (152 ± 17 vs. 145 ± 14 ms, p < 0.001). The average of earliest activation time was significantly earlier in patients with DPPs (−38.6 ± 8.5 vs. −27.7 ± 5.7 ms, p < 0.001). Mean time from the first lesion to elimination of VAs was shorter in patients with DPPs (2.3 ± 2.1 s vs. 4.9 ± 1.0 s, p < 0.001). A stepwise logistic multivariable analysis identified only younger age as a significant predictor of DPP (age ≤ 35.5 years predicted DPP with 92.9% positive predictive value). During a follow-up duration of 42.5 ± 22.3 months, 63 (94.0%) patients with DPPs and 30 (78.9%) patients without DPPs remained free of recurrent VAs (p = 0.027).

Conclusion: Discrete pre-potentials were observed in 63.8% of patients with VAs arising from the ASV. Ablation in patients with DPPs was associated with higher long-term success. DPPs were seen more commonly in younger (age ≤ 35.5 years) patients.

Limitation of standard ECG criteria to localize an outflow tract PVC

Multiple ECG algorithms exist to localize outflow tract PVCs. They can be invaluable in pre-procedure planning and patient counseling. We describe a case where the published algorithm for PVC localization did not predict the site of origin and successful ablation site. This case highlights the strengths and limitations of established ECG PVC localization algorithms.

Electrophysiological and Molecular Mechanisms of Sinoatrial Node Mechanosensitivity

The understanding of the electrophysiological mechanisms that underlie mechanosensitivity of the sinoatrial node (SAN), the primary pacemaker of the heart, has been evolving over the past century. The heart is constantly exposed to a dynamic mechanical environment; as such, the SAN has numerous canonical and emerging mechanosensitive ion channels and signaling pathways that govern its ability to respond to both fast (within second or on beat-to-beat manner) and slow (minutes) timescales. This review summarizes the effects of mechanical loading on the SAN activity and reviews putative candidates, including fast mechanoactivated channels (Piezo, TREK, and BK) and slow mechanoresponsive ion channels [including volume-regulated chloride channels and transient receptor potential (TRP)], as well as the components of mechanochemical signal transduction, which may contribute to SAN mechanosensitivity. Furthermore, we examine the structural foundation for both mechano-electrical and mechanochemical signal transduction and discuss the role of specialized membrane nanodomains, namely, caveolae, in mechanical regulation of both membrane and calcium clock components of the so-called coupled-clock pacemaker system responsible for SAN automaticity. Finally, we emphasize how these mechanically activated changes contribute to the pathophysiology of SAN dysfunction and discuss controversial areas necessitating future investigations. Though the exact mechanisms of SAN mechanosensitivity are currently unknown, identification of such components, their impact into SAN pacemaking, and pathological remodeling may provide new therapeutic targets for the treatment of SAN dysfunction and associated rhythm abnormalities.

Intracardiac Echocardiography to Guide Catheter Ablation of Idiopathic Ventricular Arrythmias

Catheter ablation is the most effective treatment option for idiopathic ventricular arrhythmias. Intracardiac echocardiography (ICE) has been increasingly used during ablation procedures, allowing real-time visualization of cardiac anatomy, and improving our understanding of the relationships between different cardiac structures. In this article we review the adjuvant role of ICE to guide mapping and ablation of ventricular arrhythmias in the structurally normal heart.

[Localization of ventricular premature contractions by 12-lead ECG]

The advances in imaging and 3D mapping systems in the last decade allowed a better correlation of ventricular premature contractions (PVCs) with anatomical structures. With regard to PVCs, interpretation of the 12-lead ECG is still crucial for the management of patients and the planning of therapies. Although there is an armamentarium of indices and algorithms to exactly pinpoint the origin of a PVC in advance, a thorough understanding of cardiac anatomy and impulse propagation, together with an awareness of the surface ECGs limitations, provides a sufficiently close approximation. PVCs from the diaphragmatic part of the ventricular cavae exhibit a superiorly directed axis, whereas PVCs from superior parts of the heart show an inferior axis. A right bundle branch block morphology or positive concordance of the precordial leads yields a high probability of left ventricular origin of a PVC. A left bundle branch block morphology is indicative of a right ventricular or septal origin of a PVC. Using the transition zone, one can estimate the origin of a PVC with regard to anterior or posterior regions of the heart: A late precordial transition is indicative of a right ventricular origin, an early precordial transition suggests a left ventricular focus. An absent transition in the sense of negative concordance is indicative for an apical origin. The intertwined course of the ventricular outflow tracts makes PVC localization more difficult. Here, shape and height of the R‑wave in V₁-V₃ help to narrow the origin down. PVCs from structures like the papillary muscles, the moderator band or infundibular bands are challenging to interpret and evidence of the limitations of the surface ECG. Based on the information gained by the aforementioned approach, a prediction of prognosis and possible treatment success is possible.

Differentiation of the right versus left outflow tract ventricular arrhythmias using local activation time at the His bundle electrogram

Background

Although multiple algorithms based on surface electrocardiographic criteria have been introduced to localize idiopathic ventricular arrhythmia (VA) origins from the outflow tract (OT), their diagnostic accuracy and clinical usefulness remain limited. We evaluated whether local activation time of the His bundle region could differentiate left and right ventricular OT VA origins in the early stage of electrophysiology study.

Methods

We studied 30 patients who underwent catheter ablation for OT VAs with a left bundle branch block pattern and inferior axis QRS morphology. The interval between the local V signal on the mapping catheter placed in the RVOT and His bundle region (V(RVOT)-V(HB) interval) and the interval from QRS complex onset to the local V signal on the His bundle region (QRS-V(HB) interval) were measured during VAs.

Results

The V(RVOT)-V(HB) and QRS-V(HB) intervals were significantly shorter in patients with LVOT VAs. The area under the curve (AUC) for the V(RVOT)-V(HB) interval by receiver operating characteristic analysis was 0.865. A cutoff value of ≤ 50 ms predicted an LVOT origin of VA with sensitivity, specificity, and positive and negative predictive values of 100%, 62.5%, 40%, and 100%, respectively. The QRS-V(HB) interval showed similar diagnostic accuracy (AUC, 0.840), and a cutoff value of ≤ 15 ms predicted an LVOT origin of VA with a sensitivity, specificity, and positive and negative predictive values of 100%, 70.8%, 45.2%, and 100%, respectively.

Conclusion

The V(RVOT)-V(HB) and QRS-V(HB) intervals could differentiate left from right OT origins of VA with high sensitivity and negative predictive values.

Modern mapping and ablation techniques to treat ventricular arrhythmias from the left ventricular summit and interventricular septum

Managing arrhythmias from the left ventricular summit and interventricular septum is a major challenge for the clinical electrophysiologist requiring intimate knowledge of cardiac anatomy, advanced training and expertise. Novel mapping and ablation strategies are needed to treat arrhythmias originating from these regions given the current suboptimal long-term success rates with standard techniques. Herein, we describe innovative approaches to improve acute and long-term clinical outcomes such as mapping and ablation using the septal coronary venous system and the septal coronary arteries, alcohol ablation, coil embolization, and ablation of all early sites among others.

Catheter-induced premature ventricular complexes (PVCs) may aid in the determination of optimal timing for clinical PVC ablation

BACKGROUND

The aim of the present study is to evaluate whether catheter-induced premature ventricular complexes (PVCs) produced at the presumptive ablation site may aid in the identification of the optimal timing of the earliest local activation for the successful ablation of clinical PVCs.

METHODS

Sixty-three consecutive patients (35 males, age: 53.5 ± 14.4 years) without any exclusion criteria who had undergone PVC ablation between 1 July 2018 and 1 July 2019 constituted our study population. The time interval between the beginning of the EGM and the beginning of the QRS of each catheter-induced PVC (Cath EGM-ECG) and the time interval between the beginning of the EGM of clinical PVCs at the earliest site and the beginning of the QRS of clinical PVCs (PVC earliest EGM-ECG) were noted for each patient. The value of Cath EGM-ECG as a reference for procedural success of ablation was evaluated by examining the relationship between Cath EGM-ECG and PVC earliest EGM-ECG.

RESULTS

Fifty-two patients had successful ablation, and 43 of them (82.7%) had PVC earliest EGM-ECG values greater than or equal to Cath EGM-ECG. Eleven patients had procedural failure, and all of them had PVC earliest EGM-ECG values lower than Cath EGM-ECG. A PVC earliest EGM-ECG value -1.5 ms greater than Cath EGM-ECG predicted successful ablation with a sensitivity of 90.4% and a specificity of 100.0% in the general patient population.

CONCLUSION

Cath EGM-ECG seems to serve as a reliable guide for finding the optimal timing of the earliest site for successful PVC ablation.

Caveolae-Mediated Activation of Mechanosensitive Chloride Channels in Pulmonary Veins Triggers Atrial Arrhythmogenesis

Background

Atrial fibrillation often occurs in the setting of hypertension and associated atrial dilation with pathologically increased cardiomyocyte stretch. In the setting of atrial dilation, mechanoelectric feedback has been linked to the development of ectopic beats that trigger paroxysmal atrial fibrillation mainly originating from pulmonary veins (PVs). However, the precise mechanisms remain poorly understood.

Methods and Results

We identify mechanosensitive, swelling‐activated chloride ion channels (I_Cl,swell) as a crucial component of the caveolar mechanosensitive complex in rat and human cardiomyocytes. In vitro optical mapping of rat PV, single rat PV, and human cardiomyocyte patch clamp studies showed that stretch‐induced activation of I_Cl,swell leads to membrane depolarization and decreased action potential amplitude, which trigger conduction discontinuities and both ectopic and reentrant activities within the PV. Reverse transcription quantitative polymerase chain reaction, immunofluorescence, and coimmunoprecipitation studies showed that I_Cl,swell likely consists of at least 2 components produced by mechanosensitive ClC‐3 (chloride channel‐3) and SWELL1 (also known as LRRC8A [leucine rich repeat containing protein 8A]) chloride channels, which form a macromolecular complex with caveolar scaffolding protein Cav3 (caveolin 3). Downregulation of Cav3 protein expression and disruption of caveolae structures during chronic hypertension in spontaneously hypertensive rats facilitates activation of I_Cl,swell and increases PV sensitivity to stretch 10‐ to 50‐fold, promoting the development of atrial fibrillation.

Conclusions

Our findings identify caveolae‐mediated activation of mechanosensitive I_Cl,swell as a critical cause of PV ectopic beats that can initiate atrial arrhythmias including atrial fibrillation. This mechanism is exacerbated in the setting of chronically elevated blood pressures.

A recurrent concealed parahisian accessory pathway

This case demonstrates the interest of ablating in the aortic root in case of resistant parahisian accessory pathways with failure of the right side approach. Failure on the right side may be due to fear of creating an AV block of failure to ablate critical fibers in the parahisian position.

The Role of Intravenous Dopamine on Hemodynamic Support during Radiofrequency Catheter Ablation of Poorly Tolerated Idiopathic Ventricular Tachycardia

Background and Objectives

Hemodynamically unstable idiopathic ventricular tachycardias (VTs) are a challenge for activation or entrainment mapping technique. Mechanical circulatory support is an option, but is not always readily available. In this study, we investigated the safety and efficacy of hemodynamic support using intravenous (IV) dopamine solely during radiofrequency catheter ablation (RFCA) of hemodynamically unstable VT.

Subjects and Methods

Seven out of 86 patients with hemodynamically unstable idiopathic VT underwent de novo RFCA using dopamine in our single center. They were included in the study and reviewed retrospectively to investigate the procedural characteristics and outcomes.

Results

All patients were male, and the mean age was 50.7±5.3 years. One patient had implantable cardioverter-defibrillator for the secondary prevention. No evidence of myocardial ischemia was found in all patients. During the procedure, the mean blood pressure during VT without dopamine was 52.3±4.1 mmHg and increased to 82.6±3.8 mmHg after administering dopamine (Δ28.8±3.2 mmHg; total average dopamine dosage was 1266.1±389.6 mcg/kg). In all patients, activation mapping was safely applied, and VTs were terminated during energy delivery. Non-inducibility of clinical VT was achieved in all cases. There was no evidence of deterioration due to hypoperfusion during the peri-procedural period. No recurrence of ventricular tachyarrhythmias was observed in any of the patients, during a median follow-up of 23.0±6.1 months.

Conclusion

Hemodynamic support using IV dopamine during RFCA of hemodynamically unstable idiopathic VT facilitated detailed mapping to guide successful ablation.

Radiofrequency Ablation of a Nonsustained Ventricular Tachycardia Arising from the Left Coronary Cusp of a Bicuspid Aortic Valve: A Case Report

Radiofrequency ablation is the therapy of choice for the suppression of medically intractable symptomatic ventricular arrhythmias. Here we present the case report of a 50-year-old woman with bicuspid aortic valve (BAV) and symptomatic nonsustained ventricular tachycardia arising from the left ventricular outflow tract (LVOT). The origin of the ventricular arrhythmia was confirmed in the left coronary cusp (LCC) of the BAV. The patient underwent a successful radiofrequency ablation. LCC of a tricuspid aortic valve is a common origin of idiopathic LVOT tachycardia; however, little is known for these types of arrhythmias when located in the cusps of a BAV.

Ablating Premature Ventricular Complexes: Justification, Techniques, and Outcomes

We reviewed the underlying principles that allow for safe and effective ablation for premature ventricular complexes. Clinical scenarios that necessitate consideration for ablation, the underlying anatomy, and the unique consideration to maximize energy delivery without compromising safety are sequentially examined.

Catheter ablation of anteroseptal accessory pathways from the aortic cusps: A case series and a review of the literature

Data regarding catheter ablation of anteroseptal accessory pathways through the aortic cusps are limited. We describe two cases of true para-Hisian accessory pathways successfully ablated from the aortic cusps (right coronary cusp and non-coronary cusp, respectively) along with a review of the current literature. Due to the close proximity to the atrioventricular node and the high risk of complication, mapping of the aortic cusps should always be considered in the case of anteroseptal accessory pathways. Anteroseptal accessory pathways can be safely and effectively ablated from the aortic cusps with good long-term outcomes.

Blood pressure response is impaired in patients with exercise-induced ventricular ectopy

Exercise-induced ventricular ectopy (EIVE) has clinical and prognostic significance. But the mechanism underlying EIVE-related mortality still remains unclear. This study aims to assess blood pressure alteration in patients with EIVE and to identify the potential causes of increased mortality in this patient group. A total number of 3611 patients were screened within a 1-year period, and patients with a structural heart disease, coronary artery disease, hypertension, diabetes mellitus, thyroid dysfunction, and chronic renal disease were excluded from the study. A total number of 98 patients with no chronic disease, who were retrospectively diagnosed with EIVE, were included in the study as patient group and 116 patients without EIVE were included as control group. The median age, gender distribution, laboratory test results, and echocardiographic findings were similar between the two groups. Systolic blood pressure (SBP) alterations during exercise stress testing were found to be significantly different (P < .001). Moreover, EIVE group had significantly higher peak SBP (P < .001). A significant positive relation was found between peak SBP level and ventricular ectopy count (r:0.27, P = .006). Our study showed that EIVE patients without a structural heart disease or a chronic disease had higher peak SBP levels. Higher SBP alteration can be related to ventricular ectopy occurrence during exercise stress testing, which can be a possible reason underlying the increased rate of mortality among EIVE patients.

Ventricular Arrhythmias from the Left Ventricular Summit: Critical Importance of Anatomy, Imaging, and Detailed Mapping to Allow Safe and Effective Ablation

Ventricular arrhythmias arising from the region of the left ventricular summit can be challenging for catheter-based percutaneous ablation. A detailed knowledge of the anatomy of this region and the need of high-density mapping of surrounding structures are critical in ensuring safe and effective ablation. This case-based review focuses on the particular challenges with ablation in this region.

Effect of burden and origin sites of premature ventricular contractions on left ventricular function by 7-day Holter monitor

Recent studies have shown that premature ventricular contractions (PVCs) could enlarge the heart, but its risk factors are incompletely understood as a single 24-hour recording cannot reflect the true PVC burden due to day-to-day variability. Our purpose was to investigate the effect of burden and origin sites on left ventricular (LV) function in patients with PVCs by 7-day Holter electrocardiography (ECG). From May 2012 to August 2013, 112 consecutive patients with PVCs were recruited from the authors' affiliated hospital. All patients received 2-dimensional transthoracic echocardiography, 12-lead routing ECG and 7-days Holter ECG. Serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured. A total of 102 participants with PVCs were included in the final analysis. Origin of PVCs from the tricuspid annulus had the highest burden and NT-proBNP level. LV papillary muscle had a higher LV ejection fraction (EF) level and a lower LV end-systolic dimension (ESD) than other PVC foci (P<0.05). The high burden group had a higher LV end-diastolic dimension (EDD) and LVESD but lower LVEF than the other two groups (P<0.05). Female, older age, physical work, and history of PVCs had a significantly positive correlation with symptoms. Male, older age, physical work, and high burden were positive predictors of enlarged LVEDD, LVESD and higher serum NT-proBNP level, but lower LVEF. Seven-day dynamic ECG Holter monitor showed the true PVC burden on patients with PVCs. PVCs with a lower burden or origin from the LV papillary muscle and the fascicle were relatively benign, while PVCs with a higher burden or origin from the tricuspid annulus may lead to cardiac dysfunction.

Electrophysiologic characteristics of ventricular arrhythmias arising from the aortic mitral continuity-potential role of the conduction system

INTRODUCTION

Catheter ablation of ventricular arrhythmia (VA) at the fibrous aortic mitral continuity (AMC) has been described, yet the nature of the arrhythmogenic substrate remains unknown.

METHODS

Procedural records of 528 consecutive patients undergoing ablation of VA at Mayo Clinic, Rochester, MN, were reviewed. The electrocardiographic and electrophysiologic characteristics of patients with successful ablation at the AMC were analyzed to characterize the underlying arrhythmogenic substrate.

RESULTS

Of the 21 patients (mean age 53.2 ± 13.4 years, 47.6% male) who underwent ablation of VA at the AMC with acute success, prepotentials (PPs) were found at the ablation sites preceding the ventricular electrogram (VEGM) during arrhythmias in 13 (61.9%) patients and during sinus rhythm in 7 (53.8%) patients. VAs with PPs were associated with a significantly higher burden of premature ventricular complexes (PVCs; 26.1 ± 10.9% vs. 14.9 ± 10.1%, P = 0.03), shorter VEGM to QRS intervals (9.0 ± 28.5 milliseconds vs. 33.1 ± 8.8 milliseconds, P = 0.03), lower pace map scores (8.7 ± 1.6 vs. 11.4 ± 0.8, P = 0.001), and a trend toward shorter V-H intervals during VA (32.1 ± 38.6 milliseconds vs. 76.3 ± 11.1 milliseconds, P = 0.06) as compared to those without PP. A strong and positive correlation was found between V-H interval and QRS duration during arrhythmia in those with PPs (B = 2.11, R(2) = 0.97, t = 13.7, P < 0.001) but not in those without PPs.

CONCLUSION

Local EGM characteristics and relative activation time of the His bundle suggest the possibility of conduction tissue as the origin for VA arising from the fibrous AMC. Specific identification and targeting of PPs when ablating VAs at this location may improve procedural success.

The anatomic basis for ventricular arrhythmia in the normal heart: what the student of anatomy needs to know

The traditional route for teaching cardiac anatomy involves didactic instruction, cadaver dissections, and familiarization with the main structure and relationships of the cardiac chambers, valves, and vasculature. In contemporary cardiac electrophysiology, however, a very different view of anatomy is required including details rarely appreciated with a general overview. In this review, we discuss the critical advances in cardiac electrophysiology that were possible only because of understanding detailed anatomic relationships. While we briefly discuss the clinical relevance, we explain in depth the necessary structural information for the student of clinical anatomy. Interspersed through the text are boxes that highlight and summarize the critical pieces of knowledge to be borne in mind while studying the fascinating structural anatomy of the human heart.

Advances in management of premature ventricular contractions

Premature ventricular complexes (PVCs) are a common occurrence in clinical practice. The clinical presentation may range from asymptomatic to left ventricular (LV) dysfunction with congestive heart failure. The decision to suppress PVCs is largely based on the presence of symptoms, interference with other therapy (e.g., cardiac resynchronization therapy), or suspicion of PVC-mediated cardiomyopathy. Catheter ablation has emerged as a safe and effective option for the treatment of frequent PVCs. Careful attention to PVC characteristics on surface electrocardiogram has proven useful for the initial localization of the ectopic focus, which may then serve as a guide to procedural planning. The point of interest is often identified with activation mapping, and the ablation site can be further defined with pace mapping techniques. Clinical experience with PVC ablation has been successful in ≥80 % of cases, and the literature reports multiple cases of marked improvement in LV function after eradicating the culprit ectopic focus in patients with PVC-mediated cardiomyopathy.

Approach to the difficult septal atrioventricular accessory pathway: the importance of regional anatomy

Ablation of accessory tracts in the posteroseptal region can be challenging, as illustrated by these 2 cases. Familiarity of the anatomy of this region and recognition of the ECG patterns can help identify the AP origin and potentially improve success rates of ablation. The isoelectric initial preexcited QRS complex with rSR’ pattern in lead V1 of the surface ECG but not the relatively earlier local ventricular activation at PSMA region may indicate a left-sided ablation approach for these APs.

Prevalence, risk, and benefits of radiofrequency catheter ablation at the aortic cusp for the treatment of mid- to anteroseptal supra-ventricular tachyarrhythmias

BACKGROUND

Some outflow tract ventricular tachycardias (VTs) are known to be successfully ablated from the aortic cusp (AC). However, radiofrequency catheter ablation (RFCA) at the AC for the treatment of supraventricular tachyarrhythmia (SVT) has limited experience.

METHODS

We performed RFCA at the AC in 19 patients (male 64.7%, 46.9 ± 21.9 years old) with mid- to anteroseptal SVTs (12 atrial tachycardias [AT], 7 atrioventricular reciprocating tachycardia [AVRT]), and analyzed the prevalence, electrophysiologic findings, clinical outcome, and compilation risk.

RESULTS

1. Among 113 patients with AT, 13 patients had mid- to anteroseptal AT and 12 patients (8.8%, 53.4 ± 19.8 years old, 58.3% female) underwent successful ablation from the non-coronary cusp (NCC; n=10), right CC (RCC; n=1) or left CC (LCC; n=1) without complication (3.1 ± 2.3 times RF delivery, 6.15 ± 3.08 s for termination). During 19.7 ± 9.8 months of follow-up, AT recurred in a patient with multiple foci. 2. Among 580 patients with AVRT, 27 patients had a mid- to anteroseptal bypass tract (4.7%), and 7 of them (1.1%, 2 pre-excitation syndrome, 5 concealed bypass tract) were successfully ablated at the NCC (n=2) or RCC (n=5) (7.0 ± 7.1 times RF delivery, 9.1 ± 4.4s for termination). Among 5 patients with AVRT successfully ablated at the RCC, one patient developed complete heart block 48 h after procedure, and 2 patients recurred AVRT or delta-wave in ECG during 13.9 ± 11.7 month follow-up.

CONCLUSION

Catheter ablation within the AC is an effective procedure to eliminate mid- to anteroseptal SVTs. However, RFCA on RCC requires a caution for heart block in our limited experience.

Electrophysiological characteristics of focal atrial tachycardia surrounding the aortic coronary cusps

BACKGROUND

Catheter ablation of atrial tachycardia (AT) arising near the coronary cusps has been reported in limited numbers of patients. We investigated the electrophysiological characteristics of these ATs in 22 consecutive patients.

METHODS AND RESULTS

This study included 22 patients (mean age ± SD, 53 ± 11 years; 86% female) with ATs arising near the aortic coronary cusps who underwent successful ablation. Activation mapping was performed during tachycardia to identify the earliest activation site. All patients achieved successful ablation through either a retrograde aortic (n=19) or a transseptal (n=3) approach. The successful ablation sites were located in the noncoronary cusp (NCC) (n=16), including 3 near the junction between the NCC and right coronary cusp. The remaining 6 cases were ablated from the left coronary cusp (LCC) (n=3) or the left atrium posterior to the LCC (n=3). For most tachycardias, there were distinctive P-wave morphological features recorded for each cusp location. Furthermore, analysis of the electrogram morphological features recorded during tachycardia at successful ablation sites revealed an atrial/ventricular (A/V) ratio >1 in 14 of 16 NCC ATs; the remaining 2, from the NCC near the junction with the right coronary cusp, showed an A/V ratio ≤ 1. At ablation sites in the LCC, the A/V ratio was <1 (4 of 6 patients) or 1 (remaining 2 patients). During a follow-up duration of 30 ± 13 months, all patients were free of arrhythmias without antiarrhythmic drugs.

CONCLUSIONS

ATs surrounding the aortic coronary cusps can be safely and effectively ablated, with good long-term outcomes. In addition to the P-wave morphological features, the A/V ratio of the local electrogram recording during tachycardia facilitated the localization of successful sites.

Correlative anatomy for the electrophysiologist: ablation for atrial fibrillation. Part II: regional anatomy of the atria and relevance to damage of adjacent structures during AF ablation

Ablation procedures for atrial fibrillation have become an established and increasingly used option for managing patients with symptomatic arrhythmia. The anatomic structures relevant to the pathogenesis of atrial fibrillation and ablation procedures are varied and include the pulmonary veins, other thoracic veins, the left atrial myocardium, and autonomic ganglia. Exact regional anatomic knowledge of these structures is essential to allow correlation with fluoroscopy and electrograms and, importantly, to avoid complications from damage of adjacent structures within the chest. We present this information as a series of 2 articles. In a prior issue, we have discussed the thoracic vein anatomy relevant to paroxysmal atrial fibrillation. In the present article, we focus on the atria themselves, the autonomic ganglia, and anatomic issues relevant for minimizing complications during atrial fibrillation ablation.