Major coronary sinus abnormalities: identification of occurrence and significance in radiofrequency ablation of supraventricular tachycardia

Multiple accessory pathways coexisting with a persistent left superior vena cava: a case report

BACKGROUND

Wolff-Parkinson-White syndrome is characterized by a short PR interval (delta-wave), long QRS complex, and the appearance of paroxysmal supraventricular tachycardia. Patients with Wolff-Parkinson-White syndrome usually have one accessory pathway, whereas cases with multiple accessory pathways are rare. Persistent left superior vena cava is a vascular anomaly in which the vein drains into the right atrium through the coronary sinus at the junction of the left internal jugular and subclavian veins due to abnormal development of the left cardinal vein. The simultaneous presence of multiple accessory pathways and persistent left superior vena cava has not been reported before.

CASE PRESENTATION

A 56-year-old Japanese man with a 5-year history of palpitations was referred for radiofrequency catheter ablation due to increased frequency of tachycardia episodes in the previous 2 months. Persistent left superior vena cava was confirmed by transthoracic echocardiography and computed tomography. An electrophysiological study revealed that the accessory pathways were located in the left lateral wall, anterolateral wall, and posteroseptal region. They were completely ablated with radiofrequency energy application.

CONCLUSIONS

We reported an extremely rare case of a patient with multiple accessory pathways and persistent left superior vena cava. Our case may suggest a potential embryological relationship between the multiple accessory pathways and persistent left superior vena cava.

Ostial atresia of the coronary sinus in patients with supraventricular arrhythmias

Of 3577 patients with supraventricular arrhythmias, 3 demonstrated an atresia of the coronary sinus (CS) ostium. Two patients had the accessory pathways. One had atrial fibrillation. No unroofed CS or apparent persistent left superior vena cava was observed. Venous drainage through a small cardiac vein located on the lateral portion of the tricuspid annulus was observed in all patients. Those cases demonstrated that the incidence of ostial atresia of the CS was 0.084%. Accessory pathways were often accompanied by this anomaly. An abnormal venous orifice located on the lateral tricuspid annulus often functioned as the drainage of the CS flow.

Electrophysiological features and radiofrequency catheter ablation of supraventricular tachycardia in patients with persistent left superior vena cava

BACKGROUND

The electrophysiological features and roles of persistent left superior vena cava (PLSVC) in supraventricular tachycardia (SVT) are not known.

OBJECTIVE

The purpose of this study was to elucidate the electrophysiological features and roles of PLSVC in patients with SVT.

METHODS

We included 37 patients with PLSVC (mean age 43.5 ± 17.1 years; 35.1% men) and 510 patients without PLSVC (mean age 43.9 ± 18.8 years; 48.2% men) who underwent an electrophysiology study for SVT. The number of induced tachycardias, location of the slow pathway (SP) or accessory pathway (AP), and radiofrequency catheter ablation (RFCA) outcomes were compared between patients with and without PLSVC. During RFCA of the left AP, a coronary sinus (CS) catheter was placed into the left superior vena cava (left superior vena cava group) or the great cardiac vein (great cardiac vein group). The RFCA outcomes were compared between the groups.

RESULTS

In patients with PLSVC, 40 tachycardias were induced: atrioventricular nodal reentrant tachycardia (AVNRT) (n = 19), atrioventricular reentrant tachycardia (n = 17), and focal atrial tachycardia (n = 4). Among patients with AVNRT, an SP in the CS was significantly more frequent in patients with PLSVC than in those without PLSVC (47.4% vs 3.8%; P < .001). In patients with the left AP, the number of RFCA attempts and recurrence were lower in the great cardiac vein group than in the left superior vena cava group.

CONCLUSION

An SP in the CS is prevalent in patients with AVNRT and PLSVC. It is useful to place a CS catheter into the great cardiac vein in patients with a left AP and PLSVC.

Coronary sinus cannulation with a steerable catheter during biventricular device implantation

OBJECTIVES

To determine whether a steerable catheter with electrogram guidance (CS-assist group) could facilitate access to the coronary sinus (CS) during cardiac resynchronization therapy (CRT) implantation.

DESIGN

Consecutive patients who underwent CRT implantation were recruited prospectively into the CS-assist group (n = 81) and compared with those using conventional techniques without an electrogram guidance (conventional group, n = 101).

RESULTS

The CS cannulation success rate was clearly greater in the CS-assist group (100%) than that in the conventional group (95%, p < 0.05), with significantly shorter mean procedure time (52.6 ± 20.6 min vs. 73.2 ± 40.9 min, p < 0.01) and fluoroscopy time (3.6 ± 3.2 min vs. 14.2 ± 20.4 min, p < 0.01). In the five CS cannulation failure cases, mean procedure time (144.0 ± 37.0 min) and fluoroscopy time (57.8 ± 24.8 min) were significantly longer than those in the other patients (61.2 ± 32.3 and 8.2 ± 13.6 min, respectively, n = 177, both p < 0.01).

CONCLUSIONS

Using the steerable catheter with real-time electrogram guidance, location of and access to the CS is more rapid and successful, which may improve the success of the CRT implantation and may give significant time savings.

Successful slow pathway ablation in a patient with a rare unroofed type coronary sinus

We report a case of atrioventricular nodal reentrant tachycardia coexistent with a coronary sinus (CS) anomaly. During a standard electrophysiological study, the CS could not be cannulated despite several attempts. A persistent left superior vena cava angiogram through the left brachial vein confirmed an unroofed type CS. Successful slow pathway ablation from the right posterior paraseptum lesion was achieved using an anatomical approach.

Evaluation of femoral approach to coronary sinus catheterisation in electrophysiological and ablation procedures: Single centre experience

BACKGROUND

It has been reported that the cannulation of coronary sinus (CS) from the femoral approach is safer than the traditional subclavian approach but is associated with a lower rate of success. We aimed to test the validity of this claim.

METHOD

We evaluated retrospectively 1320 consecutive patients who underwent electrophysiological study (EPS) or ablation over a period of three years using a prospectively collected data. In cases requiring CS cannulation, it was attempted first from the femoral approach, switching if necessary to a subclavian approach when the femoral route failed.

RESULTS

Out of 1320 patients, 1165 (88.3%) required CS cannulation. The CS was successfully cannulated from the femoral approach in 99.3% of the cases in which it was attempted. One patient (0.09%) developed transient first degree atrioventricular block during an ablation procedure for AV nodal re-entrant tachycardia during cannulation of the CS that resolved within 3 min. Femoral access failed in 8 patients. In 4 of these cases, the procedure was concluded using CS cannulation via subclavian or jugular venous access. In the other 4 cases, the procedure was concluded successfully without CS cannulation, including an AF ablation in which CS cannulation proved impossible by either subclavian or femoral approach.

CONCLUSION

Femoral access can be used for CS cannulation with a high rate of procedural success in the vast majority of patients undergoing EPS and ablation. This approach is safe, and associated with a high rate of procedural success.

Prospective evaluation of the coronary sinus anatomy in patients undergoing electrophysiologic study

BACKGROUND

Previous retrospective studies could find a predominant incidence of coronary sinus (CS) anomalies in patients with accessory pathways and a characteristic anatomy of the CS ostium in patients with atrioventricular nodal reentrant tachycardias (AVNRT).

HYPOTHESIS

In the present prospective study, CS angiograms were prospectively performed to analyze the incidence of CS anomalies and to measure the diameters of the CS ostium.

METHODS

The study included patients referred for electrophysiologic study and catheter ablation of various tachyarrhythmias. The anatomy of the CS and its side branches was visualized [left anterior oblique (LAO) 30 degrees, right anterior oblique (RAO) 30 degrees] by retrograde angiography in 204 consecutive patients (82 women, 122 men, age 45 +/- 15 years); of these, 120 presented with 123 accessory pathways (45 left-sided, 33 right-sided, 45 septal). The diagnosis in the remaining patients was atrioventricular nodal reentrant tachycardia in 43 cases, atrial tachycardia or atrial fibrillation in 12, and ventricular tachycardia in 15. In 14 patients, the indication for the electrophysiologic study was an unexplained syncope. The CS angiogram was evaluated for anomalies and the size of the CS ostium was manually measured in both projections.

RESULTS

Anomalies of the CS defined as diverticula, persistent left superior vena cava, or enlarged CS ostia were found in 18 patients (9%). Of those, CS diverticula were found in nine patients, all with a posteroseptal or left posterior manifest accessory pathway, which was abolished within the neck of the diverticulum in seven patients and at the posteroseptal tricuspid annulus in two patients. Persistence of the left superior vena cava was found in five patients, four had atrioventricular reentrant tachycardia secondary to five accessory pathways (left free wall in four, right midseptal in one), and one patient had atrioventricular nodal reentrant tachycardia (AVNRT). Enlargement of the CS ostium of > 25 mm width was detected in nine patients (5%), of whom four had AVNRT. However, the width of the CS ostium generally did not differ significantly between patients with AVNRT (LAO: 14.4 +/- 5.6; RAO 9.3 +/- 2.4 mm) compared with the control group (LAO 13.4 +/- 4.1; 8.2 +/- 1.9 mm).

CONCLUSIONS

Anomalies of the CS as diverticula, persistent superior vena cava, or enlargement of the CS ostium are predominantly found in patients with accessory pathway-related tachycardias. Diverticula of the proximal CS were found in 7% of patients with accessory pathways; in these cases, ablation succeeded mostly by radiofrequency (RF) current delivery in the neck of the diverticulum. Enlargement of the CS ostium was more often seen in patients with AVNRT than in all other patients. However, in general the measurements of the coronary sinus ostium did not significantly differ in patients with AVNRT compared with the control group.

Influence of left atrial and ventricular volumes on the relation between mitral valve annulus and coronary sinus

The aim of this study was to evaluate the anatomic relation between the coronary sinus (CS), mitral annulus, and coronary arteries using 64-multislice computed tomography (MSCT) in patients presenting with a wide range of atrial volumes and left ventricular functions to determine the potential clinical use for percutaneous mitral annuloplasty (PMA). The MSCT data of 165 patients (age 63.65 +/- 12.89 years, 67.3% men) were evaluated. The following variables were measured: CS length, CS ostium area, area of the section of CS when it becomes great cardiac vein, area between CS and atrioventricular groove assessed in volume-rendered 3-dimensional images, axial angle measured as the angle between CS and mitral annulus assessed in axial section, mitral valve annulus (MVA) area, left atrium volume, and left circumflex artery/marginal branch-CS relation referring to mitral annulus. The correlation was inversed between the reduction of the axial angle and all following variables: enlargement of both left ventricular end-systolic (r = -0.429, p <0.001) and end-diastolic (r = -0.428, p <0.001) volumes, left atrial volume (r = -0.361, p <0.001), and MVA (r = -0.324, p <0.001). Similarly, there was inverse correlation between the reduction of the area between CS and atrioventricular groove, and enlargement of both left ventricular end-systolic (r = -0.376, p <0.001) and end-diastolic (r = -0.291, p <0.001) volumes, left atrial volume (r = -0.221, p = 0.001), and MVA (r = -0.155, p = 0.019). Of note, circumflex artery was located between CS and MVA in 77% of the patients, but in patients with severe mitral regurgitation CS crossed circumflex/marginal branch artery more frequently (97% of cases). In conclusion, a close proximity of the CS to the mitral annulus but also to circumflex artery is more likely to occur with left atrial and ventricular enlargement. Thus, MSCT should be considered as part of the selection process of potential candidate to PMA to avoid external compression of circumflex artery/marginal branch by the device.

Characterization of human coronary sinus valves by direct visualization during biventricular pacemaker implantation

BACKGROUND

The precise reasons for failure to cannulate the coronary sinus during biventricular device implantation are unknown. Visualization of the coronary sinus ostium during electrophysiology procedures may enhance understanding of how unusual anatomy can affect successful cannulation of the coronary sinus.

OBJECTIVES

The aim of this study was to describe the morphology of valves at the coronary sinus ostium (CSO) visualized directly with an illuminated fiberoptic endoscope during implantation of biventricular devices.

METHODS

The coronary sinus anatomy of one hundred consecutive patients undergoing implantation of biventricular devices was investigated using a fiberoptic endocardial visualization catheter (EVC).

RESULTS

The CSO was clearly visualized in 98 patients using the EVC. A Thebesian valve was seen in 54% of these. Almost all Thebesian valves were positioned at the inferior (61%) or posterior (33%) aspect of the CSO. Only six patients had Thebesian valves that covered more than 70% of the CSO, but all were successfully implanted with a transvenous left ventricular pacing lead after cannulating the coronary sinus under direct visualization.

CONCLUSIONS

Over half of patients undergoing biventricular device implantation have identifiable Thebesian valves. Even valves covering the majority of the ostial area may be traversed using direct visualization and modern catheterization techniques.

Thoracic Vein Arrhythmias

The thoracic veins are important foci for the genesis of ectopic atrial tachycardia and play a critical role in the pathophysiology of paroxysmal and permanent atrial fibrillation. The pulmonary veins have the highest arrhythmogenic activity and other venous structures (eg, superior vena cava, coronary sinus and ligament of Marshall) have also been shown arrhythmogenic potential. Thoracic veins contain cardiomyocytes with distinct electrical activities and complex anatomical structures. This review summaries the current understanding of the basic and clinical electrophysiology of thoracic vein arrhythmias.

Early human experience with use of a deflectable fiberoptic endocardial visualization catheter to facilitate coronary sinus cannulation

BACKGROUND

Despite improvements in cardiac resynchronization therapy (CRT) implantation techniques, a significant minority of CRT attempts are unsuccessful. Inability to cannulate the coronary sinus (CS) because of difficult anatomy is a major reason for unsuccessful CRT implantation. Direct visualization of intracardiac structures during the implant may facilitate access into the CS. The present study describes CRT implantation with the aid of an endocardial visualization catheter (EVC).

METHODS

Fifty-eight consecutive patients (mean age 72 +/- 12 years; ejection fraction 26.2% +/- 7.0%; New York Heart Association [NYHA] class 2.9) underwent CRT implantation using a steerable fiberoptic EVC (Acumen Medical, Inc., Sunnyvale, CA).

RESULTS

The EVC was able to visualize the CS ostium in all cases. The CS was successfully cannulated in 57 (98.3%) of 58 patients. The time from vascular access to CS visualization was 6 +/- 5 minutes, and the total time to CS access was 8 +/- 6 minutes. Successful left ventricle (LV) lead implantation was accomplished in 55 (94.8%) of 58 patients. Three patients who had a previous history of failed LV lead implantation were successfully implanted using the EVC.

CONCLUSION

Fiberoptic imaging of intracardiac structures during CRT implantation may be performed rapidly in a wide range of patients with an EVC. The ability to visualize right atrial anatomy may aid CS access and LV lead implantation.

A unipolar coronary sinus mapping study of patients with left-sided atrioventricular accessory pathways

So-called unipolar 'PQS pattern' is widely accepted as a hallmark of successful catheter ablation of the left-sided atrioventricular accessory pathway. However, the unipolar nature of the electrogram and the site-dependent appearance of this characteristic pattern are poorly understood. Therefore, unipolar coronary sinus (CS) mapping was performed using a multipolar fine electrode in patients with Wolff-Parkinson-White (WPW) syndrome associated with an antegrade left-sided accessory pathway (case group) and those with a concealed left-sided accessory pathway or atrioventricular nodal reentrant tachycardia (control group) under sinus rhythm and fixed high right atrial, CS ostial, and distal pacing. In both groups, the unipolar CS atrial electrogram showed intrinsic negative deflection (initial positive followed by negative parts) with considerable variation depending on the recording site. This unipolar configuration of the atrial electrogram was not influenced by different activation sequences during pacing at various sites. The case group exhibited a unipolar 'PQS pattern' at successful ablation sites for the left lateral to anterolateral accessory pathway. However, this was not true for the left posteroseptal accessory pathway, possibly because the negative part of the atrial electrogram distorted the 'PQS pattern' as an intervening dip. In conclusion, the site-dependent variations of the unipolar CS atrial electrogram underlie the limited usefulness of the 'PQS pattern' in left posteroseptal accessory pathway localization.

Coronary venous imaging with electron beam computed tomographic angiography: three-dimensional mapping and relationship with coronary arteries

BACKGROUND

The coronary venous system can provide vascular access for diagnostic and therapeutic procedures. Visualization of the coronary veins and their relationship to other cardiac structures may play an important role in facilitating these procedures. We sought to assess the ability of electron beam computed tomographic angiography (EBCTA) to characterize 3-dimensional (3-D) coronary venous anatomy.

METHODS

Two hundred thirty-one consecutive EBCTA coronary studies were analyzed. The coronary venous system was mapped and analyzed using 2- and 3-D images with definition of diameter and angulations of branch vessels and distance from CS os.

RESULTS

The coronary sinus (CS), great cardiac, middle cardiac, left ventricular (LV) anterior interventricular, LV marginal, LV posterior, left atrial, and right atrial veins were visualized in 100%, 100%, 100%, 100%, 78%, 81%, 6%, and 8% of the studies, respectively, with definition of diameter and angulations of branch vessels and distance from CS os. There was a significant linear correlation between CS diameter and right atrial end systolic volume (R = 0.244, n = 81, P < .05). No significant correlation existed between CS os diameter and other cardiac size or function parameters. The 3-D spatial arrangements between the coronary veins and the coronary arteries in relation to the epicardium were able to be defined, on the basis of the vessel closer to the epicardium in overlapping segments.

CONCLUSIONS

EBCTA can provide 3-D visualization of most components of the coronary venous system and definition of the spatial relationships with coronary arteries. EBCTA may potentially serve as a useful noninvasive tool for coronary venous imaging for procedures involving coronary veins, such as resynchronization therapy.

Longitudinally Partitioned Coronary Sinus: An Unusual Anomaly of the Coronary Venous System

We report a case of a patient with advanced heart failure who had a longitudinally partitioned coronary sinus. With multidirectional fluoroscopic views and a careful approach to the target lumen, a left ventricular lead for biventricular pacing was placed successfully in the left marginal vein.

A Case of Atrioventricular Nodal Reentrant Tachycardia With Atresia of the Coronary Sinus Ostium

We report a case of atrioventricular nodal reentrant tachycardia coexistent with atresia of the coronary sinus ostium. Radiofrequency current application between the supposed coronary sinus ostium and the tricuspid valve was effective at eliminating the tachycardia. A coronary venogram obtained by left coronary arteriography was useful for guiding the mapping catheter to the successful ablation site.

[A 66-year old female patient with tachycardia and syncope]

A 66-year old female patient suffered from paroxysmal tachycardias, palpitations, dizziness and once a short period of unconsciousness. The surface ECG showed preexcitation, and the clinical diagnosis of WPW syndrome was established. The electrophysiological study revealed the rare occurrence of an epicardial posteroseptal accessory pathway. Retrograde venous angiography of the coronary sinus showed a coronary sinus diverticulum. Ablation of the accessory pathway in the neck of the coronary sinus diverticulum was successful. Epicardial accessory pathways in a coronary sinus diverticulum are rare. However, successful ablation of accessory pathways at this site is safely possible.

The coronary sinus: Passive bystander or source of arrhythmia?1 1ASSOCIATE EDITOR: D. GEORGE WYSE

The coronary sinus provides access to the epicardial space of the heart allowing ablation of epicardial accessory pathways, foci of ventricular arrhythmia, and arrhythmogenic areas such as the vein or ligament of Marshall. In addition, its musculature may form atrioventricular accessory connections, participate in macroreentrant atrial arrhythmias, and generate foci of microreentrant atrial tachycardia and fibrillation. Thus, the coronary sinus may serve both as a bystander to arrhythmia circuits as well as an original source of cardiac arrhythmia.

A review of the coronary venous system: a road less travelled

Compared with the coronary arterial system, less attention has been paid to the coronary venous system. In the current era, there are therapeutic options for arrhythmias and for heart failure that use the coronary venous system to access target areas. We review the arrangement of the main cardiac veins to provide a morphologic background to interventionists. In general, the venous system is a useful conduit for delivery of percutaneous transcatheter treatment. But, variability in terms of valves, diameter, angulation, extent of muscular sleeves, proximity to other cardiac structures, and cross-over spatial relationship with branches of coronary arteries have implications for practitioners seeking to make use of the system.

Radiofrequency catheter ablation of posteroseptal accessory pathways--results of a step-by-step ablation approach

INTRODUCTION

Transcatheter radiofrequency ablation of posteroseptal accessory pathways (AP) is challenging. A number of different interventional approaches have been suggested by different groups. The selection of the initial approach is crucial in order to reduce radiation exposure and the number of unsuccessful lesions applied. We present our ablation technique as guided by a simplified electrocardiographic analysis of the delta wave polarity and the electrophysiologic mapping results.

METHODS AND RESULTS

Out of 35 manifest APs encountered in the right (n=17) or the left posteroseptum (n=18) in 35 patients, 34 were successfully ablated. Despite their left sided location, 7 of the 18 "left" sided APs were ablated after switching from an initial arterial to a venous approach looking for an appropriate target site in the right posteroseptal space or within the coronary sinus network. The other 11 left sided APs were ablated in the mitral ring, on 2 occasions, on their atrial aspect through a retrograde transmitral approach. On the contrary, 16 of the 17 "right" sided APs were successfully ablated exclusively through a venous approach. Fourteen of these were ablated in the right posteroseptum, in 2 cases, only after reaching their ventricular aspect. Two right sided APs were interrupted in the coronary sinus os and the middle cardiac vein respectively.

CONCLUSION

It appears that even though the electrocardiographic and electrophysiologic location of the AP in the posteroseptal space helps select the appropriate initial approach, it does not always guarantee a successful ablation procedure in the expected site of the corresponding atrioventricular ring. Not uncommonly, it will be necessary to look after intermediate target sites within the coronary sinus to improve the overall ablation success rate.

Identification of fiber orientation in left free-wall accessory pathways: implication for radiofrequency ablation

Previous reports on the anatomic discordance between atrial and ventricular insertion sites of left free-wall accessory pathways were limited and their findings were controversial. The purpose of this study was to explore the fiber orientation and related electrophysiologic characteristics of left free-wall accessory pathways. The study population comprised 96 consecutive patients with a single left free-wall accessory pathway (33 manifest and 63 concealed pathways), who underwent electrophysiologic study and radiofrequency catheter ablation using the retrograde ventricular approach. The atrial insertion site of the accessory pathway was defined from the cinefilms as the site with the earliest retrograde atrial activation bracketed on the coronary sinus catheter during tachycardia, and the ventricular insertion site was defined as the site where successful ablation of the pathway was achieved. Forty-two patients (44%) had their atrial insertion sites 5-20 mm (10 +/- 3 mm) distal to the ventricular insertion sites (proximal excursion), 30 (31%) patients had their atrial insertion sites 5-20 mm (12 +/- 3 mm) proximal to the ventricular insertion sites (distal excursion), and 24 (25%) patients had directly aligned atrial and ventricular insertion sites. Retrograde conduction properties, including 1:1 VA conduction and effective refractory period, were significantly poorer in the pathways with proximal excursion (302 +/- 67, 285 +/- 61 ms respectively) than in those with distal excursion (264 +/- 56, 250 +/- 48 ms respectively) or direct alignment (272 +/- 61, 258 +/- 73 ms respectively). Accessory pathways at the more posterior location had a significantly higher incidence of proximal excursion (P = 0.006), and those at the more anterior location had a higher incidence of distal excursion (P = 0.012). In conclusion, a wide variation in fiber orientations and related electrophysiologic characteristics was found in left free-wall accessory pathways. This may have important clinical implications for radiofrequency ablation.

Catheter ablation of accessory pathways

Radiofrequency catheter ablation is a highly effective, curative treatment for arrhythmias related to accessory atrioventricular connections. Compared with medical therapy, ablation is more definitive, is more cost-effective, and is associated with a lower risk of proarrhythmia. This article updates the reader on the current indications, techniques, and innovations related to ablation of accessory pathways using radiofrequency energy.

Anatomy of atrioventricular nodal reentry investigated by intracardiac echocardiography

Intracardiac echocardiography was used to evaluate posteroseptal space anatomy in patients with atrioventricular nodal reentrant tachycardia compared with patients with other mechanisms of tachycardia. The posteroseptal space was found to be significantly wider in patients with atrioventricular nodal reentry, suggesting an anatomic basis for dual atrioventricular nodal physiology.

Dimension and related anatomical distance of Koch's triangle in patients with atrioventricular nodal reentrant tachycardia

INTRODUCTION

The dimension of Koch's triangle in patients with AV nodal reentrant tachycardia has not been well described. Understanding the dimension and anatomical distance related to Koch's triangle might be useful in avoiding accidental AV block during ablation of the slow pathway. The purposes of this study were to define the dimension of Koch's triangle and its related anatomical distance and correlate these parameters with the successful ablation sites in patients with AV nodal reentrant tachycardia.

METHODS AND RESULTS

We studied 218 patients with AV nodal reentrant tachycardia. The distance between the presumed proximal His-bundle area and the base of the coronary sinus orifice (DHis-OS) measured in the right anterior oblique view was used to define the dimension of Koch's triangle. The distance of the proximal His-bundle recording site from the successful ablation site (DHis-Ab) and the distance as a fraction of the entire length of Koch's triangle (DHis-Ab/DHis-Os) were determined. The mean DHis-Os and DHis-Ab were 25.9 +/- 7.9 and 13.4 +/- 3.8 mm, respectively. DHis-Os negatively correlated with patient age (r = -0.41, P < 0.0001) and body mass index (r = -0.18, P = 0.004). Among the patients with successful ablation sites in the medial area, DHis-Os was longer (27.2 +/- 6.6 vs 24.6 +/- 8.4 mm, P < 0.005), DHis-Ab was similar (12.9 +/- 3.1 vs 13.9 +/- 4.0, P > 0.05) and DHis-Ab/DHis-Os was smaller (0.48 +/- 0.04 vs 0.74 +/- 0.11, P < 0.05). Furthermore, the patients with successful ablation sites in the medial location needed more radiofrequency pulse numbers than those in the posterior location (6 +/- 4 vs 4 +/- 3, P < 0.05).

CONCLUSION

The site of successful slow pathway ablation was consistently about 13 mm from the site recording the proximal His-bundle deflection in patients with AV nodal reentrant tachycardia despite marked variability in the dimensions of Koch's triangle; therefore, patients with large triangles required ablation in the medial region rather than the posterior region. Care should be taken when delivering radiofrequency energy to the posteroseptal area in patients with shorter DHis-Os to avoid injury to AV node.

Electrophysiologic characteristics and anatomical complexities of accessory atrioventricular pathways with successful ablation of anterograde and retrograde conduction at different sites

INTRODUCTION

Catheter ablation may eliminate anterograde and retrograde accessory pathway conduction at closely adjacent but anatomically discrete sites. However, the mechanisms of this discrepancy, the electrophysiologic and anatomical characteristics, and information about systematic study from a large patient population are not available. The purpose of this study was to investigate the electrophysiologic characteristics and anatomical complexities of the accessory pathway in which anterograde and retrograde conduction was successfully ablated at different sites.

METHODS AND RESULTS

Thirty-eight (10.9%) patients (19 men and 19 women; mean age 37 +/- 2.4 years) fulfilling the criteria of having separate ablation sites for anterograde and retrograde conduction were designated as group I, and the other 310 patients (215 men and 95 women; mean age 47 +/- 0.6 years) were designated as group II. The patients with right-sided free-wall pathways had the highest incidence (18.6%) of separate ablation sites. The anatomical distance between anterograde and retrograde directions (left anterior oblique view, 13 +/- 0.6 vs 8 +/- 0.9 mm, P < 0.01; right anterior oblique view, 17 +/- 0.6 vs 5 +/- 0.7 mm, P < 0.01), and incidence of conduction impairment in one direction after successful ablation of another direction (15% vs 78%, P < 0.05) differed significantly between left and right free-wall pathways. The mean distances obtained from left (7 +/- 0.4 vs 14 +/- 0.4 mm, P < 0.05) and right (7 +/- 1.1 vs 15 +/- 0.9 mm, P < 0.05) anterior oblique views were shorter in patients who had impairment of conduction properties than those in patients without impaired conduction after successful ablation of one direction.

CONCLUSIONS

This study showed that anatomical and functional dissociation of the accessory pathway into anterograde and retrograde components was possible. Further study on the relation between electrophysiologic and pathologic characteristics would be helpful to confirm these findings.

Multiple anterograde atrioventricular node pathways in patients with atrioventricular node reentrant tachycardia

OBJECTIVES

This study sought to investigate electrophysiologic characteristics and possible anatomic sites of multiple anterograde slow atrioventricular (AV) node pathways and to compare these findings with those in dual anterograde AV node pathways.

BACKGROUND

Although multiple anterograde AV node pathways have been demonstrated by the presence of multiple discontinuities in the AV node conduction curve, the role of these pathways in the initiation and maintenance of AV node reentrant tachycardia (AVNRT) is still unclear, and possible anatomic sites of these pathways have not been reported.

METHODS

This study included 500 consecutive patients with AVNRT who underwent electrophysiologic study and radiofrequency ablation. Twenty-six patients (5.2%) with triple or more anterograde AV node pathways were designated as Group I (16 female, 10 male, mean age 48 +/- 14 years), and the other 474 patients (including 451 with and 23 without dual anterograde AV node pathways) were designated as Group II (257 female, 217 male; mean age 52 +/- 16 years).

RESULTS

Of the 21 patients with triple anterograde AV node pathways, AVNRT was initiated through the first slow pathway only in 3, through the second slow pathway only in 8 and through the two slow pathways in 9. Of the five patients with quadruple anterograde AV node pathways, AVNRT was initiated through all three anterograde slow pathways in three and through the two slower pathways (the second and third slow pathways) in two. After radiofrequency catheter ablation, no patient had inducible AVNRT. Eleven patients (42.3%) in Group I had multiple anterograde slow pathways eliminated simultaneously at a single ablation site. Eight patients (30.7%) had these slow pathways eliminated at different ablation sites; the slow pathways with a longer conduction time were ablated more posteriorly in the Koch's triangle than those with a shorter conduction time. The remaining seven patients (27%) had a residual slow pathway after delivery of radiofrequency energy at a single or different ablation sites. The patients in Group I had a longer tachycardia cycle length, poorer retrograde conduction properties and a higher incidence of multiple types of AVNRT than those in Group II.

CONCLUSIONS

Multiple anterograde AV node pathways are not rare in patients with AVNRT. However, not all of the anterograde slow pathways were involved in the initiation and maintenance of tachycardia. Radiofrequency catheter ablation was safe and effective in eliminating critical slow pathways to cure AVNRT.

Electrophysiological mechanisms in successful radiofrequency catheter modification of atrioventricular junction for patients with medically refractory paroxysmal atrial fibrillation

BACKGROUND

Mechanisms and changes of electrophysiological (EP) characteristics in successful radiofrequency (RF) modification of right midseptal and posteroseptal areas for controlling rapid ventricular response to atrial fibrillation (Af) are not clear.

METHODS AND RESULTS

We studied 50 patients with medically refractory paroxysmal Af. Group 1 consisted of 40 patients without dual atrioventricular (AV) node physiology with modification sites located in the mid/posteroseptal area. Of the 40 patients, 36 had successful modification (follow-up of 14 +/- 8 months), and 3 had AV block. Late follow-up electrophysiological study (98 +/- 10 days) showed pattern 1 (67%) with prolongation of AV node effective refractory period (ERP, > or =40 milliseconds) and Wenckebach block cycle length (WBCL, > or =40 milliseconds); pattern 2 (22%) with prolongation of AH interval (> or =20 milliseconds), ERP, and WBCL; and pattern 3 (11%) without any change in AV node conduction parameter. Change in ventricular rate negatively correlated with change of WBCL in patterns 1 (r=-.691, P=.019) and 2 (r=-.90, P=.01). Group 2 consisted of 10 patients with dual AV node pathway; elimination of slow pathway property was performed. Late follow-up electrophysiological study (92+/-7 days) showed that change in ventricular rate negatively correlated with change in AV node ERP (r=-.926, P=.0001) and WBCL (r=-.969, P=.0001). Four patients without significant modification effect had success after RF energy was delivered to higher levels (follow-up, 15+/-7 months).

CONCLUSIONS

RF modification of right mid/posteroseptal area is feasible in 92% of patients with paroxysmal Af. Mechanisms of successful modification might be elimination of posterior input and/or partial injury of the compact node. Furthermore, simple elimination of slow pathway might be inadequate for control of ventricular rate in patients with little difference in conduction properties between fast and slow pathways.

Prediction of successful ablation site of concealed posteroseptal accessory pathways by a novel algorithm using baseline electrophysiological parameters: implication for an abbreviated ablation procedure

BACKGROUND

Radiofrequency catheter ablation of concealed posteroseptal accessory pathways (APS) has been a relatively difficult task for electrophysiologists. Without a detailed mapping procedure, the left versus the right posteroseptal AP could not be distinguished. We investigated the electrophysiological characteristics of concealed posteroseptal APs and defined criteria from baseline parameters to predict the successful ablation site. Validity of the criteria was prospectively verified.

METHODS AND RESULTS

Eighty-nine consecutive patients with a single concealed posteroseptal AP underwent successful radiofrequency catheter ablation. Of the initial 48 patients (group 1), the right posteroseptal area was first mapped. If no ideal electrogram could be obtained, or after several ineffective radiofrequency pulses, the left posteroseptal area was then mapped. Special attention was paid to the stability of the coronary sinus catheter with the most proximal electrode straddling the ostium, verified by coronary sinus venography, in all patients. Six patients (12.5%) had the earliest retrograde atrial activation at the middle electrode of the coronary sinus catheter, and successful ablation could only be achieved at the left posteroseptal area. For patients who presented with the earliest atrial activation at the proximal electrode, the presence of long RP' tachycardia suggested a right endocardial approach, while the delta VA (defined as the difference in the VA intervals between that recorded at the His bundle catheter and that at one of the electrode groups recording the earlier atrial activation) >-25 ms during tachycardia suggested a left endocardial approach. The subsequent 41 patients (group 2) were randomized into two subgroups. The initial mapping site was guided by the algorithm in group 2B, while it was not in group 2A. The successful ablation site could be predicted accurately in 18 (90%) of the 20 patients in group 2B. The radiofrequency pulses, ablation time, and fluoroscopic time were markedly reduced in Group 2B, mainly because of the omission of unnecessary mapping procedure in the right posteroseptal area in patients with "left atrio-left ventricular" fibers.

CONCLUSIONS

By the algorithm based on baseline electrophysiological parameters, the successful ablation site could be accurately predicted in a majority of patients with concealed posteroseptal APs. Radiofrequency pulses, ablation time, and fluoroscopic time were markedly reduced.

Prospective study of retrograde coronary venography in patients with posteroseptal and left-sided accessory atrioventricular pathways

The morphologic features of the coronary vein system was prospectively studied with retrograde venography in 117 patients with left-sided (78 patients) and posteroseptal accessory pathway (39). Findings were compared with accessory pathway localization. A mean of 3.3 +/- 1.5 venous branches draining into the coronary sinus or the great cardiac vein could be visualized. The morphologic condition was described and classified. Incidence, morphologic condition, and distribution did not differ between left-sided and posteroseptal accessory pathway. Venous abnormalities including ectasy, diverticulum, narrowing, angulation, and hypoplasia occurred in 22.2%. Diverticulum and narrowing were present in posteroseptal accessory pathway only and always related to the successful ablation site. In patients with left-sided accessory pathway, ectasy, angulation, and hypoplasia were found. Anomalies were less frequent (9% vs 43.6%, p < 0.001) and had no relation to accessory pathway localization. However, the successful ablation site was in 42.3% located < 5 mm to an angiographically visualized venous branch. In conclusion, posteroseptal accessory pathways are often related to coronary sinus abnormalities. In patients with a left-sided accessory pathway venous malformation is uncommon, whereas a close anatomic relation exists between accessory pathway localization and venous ventricular branches.

A quantitative fluoroscopic comparison of the coronary sinus ostium in patients with and without AV nodal reentrant tachycardia

INTRODUCTION

The purpose of this study was to perform a quantitative fluoroscopic analysis of the coronary sinus ostium and its relationship to the His bundle in patients with and without AV nodal reentrant tachycardia. Sites of slow pathway ablation are often near the coronary sinus ostium, which can be located within a few millimeters of the His bundle. Whether such close proximity of the coronary sinus ostium to the His bundle is unique to patients with AV nodal reentrant tachycardia is unknown.

METHODS AND RESULTS

Fifty consecutive patients (mean age 39 +/- 14 years) with no structural heart disease underwent electrophysiologic testing and radiofrequency ablation. The study group consisted of 28 patients with inducible AV nodal reentrant tachycardia or dual AV nodal physiology and 22 patients in the control group. A coronary sinus venogram was performed in each patient. The coronary sinus ostium was similar in size in the study group (11.4 +/- 4.5 mm) and in the control group (10.5 +/- 3.6 mm, P = 0.2). The coronary sinus ostium was funnel shaped in half of the study patients and in half of the control patients (P = 1.0). The mean distance from the upper lip of the coronary sinus ostium to the tip of the His bundle catheter was 9.7 +/- 5.5 mm in the study group and 10.4 +/- 5.1 mm in the control group (P = 0.7). The mean distance from the lower lip of the coronary sinus ostium to the tip of the His-bundle catheter in the study group was 20.1 +/- 6.1 mm and 19.5 +/- 5.6 mm in the control group (P = 0.7).

CONCLUSION

This study demonstrates a wide range of normal coronary sinus ostium diameters, morphology, and anatomic relationships with surrounding structures, with no demonstrable correlation to the presence or absence of dual AV node physiology or AV nodal reentrant tachycardia.

Coronary sinus morphology in patients with atrioventricular junctional reentry tachycardia and other supraventricular tachyarrhythmias

BACKGROUND

Coronary sinus access by electrode catheters is easier in patients with atrioventricular junctional reentry tachycardia (AVJRT) than in patients with other supraventricular tachyarrhythmias. The reason for this has not been addressed.

METHODS AND RESULTS

The size and shape of the proximal coronary sinus were measured in 15 patients with AVJRT and 14 control subjects after angiographic visualization. Coronary sinus dimensions, morphology, and angle of origin from the right atrium were measured. The proximal coronary sinus in patients with AVJRT was larger than in the control population. The mean ostium diameter was 12.2 +/- 2 mm compared with control dimensions of 8.5 +/- 1.5 mm, P = .00001. At a distance of 5 mm from the ostium, the coronary sinus measured 10.2 +/- 1.8 mm compared with 8.1 +/- 1.9 mm, P = .007. The dilatation persisted 10 mm into the coronary sinus, with a measurement of 9 +/- 1.4 mm compared with 7.6 +/- 2 mm, P = .04. In 73% of AVJRT patients, the proximal coronary sinus had the appearance of a wind sock. This morphology was seen only in 7% of control patients, in whom the coronary sinus was tubular (in 93%). There was considerable interindividual variability in the angle of origin.

CONCLUSIONS

The proximal coronary sinus in patients with AVJRT was significantly different from a control population. The ostium was 44% larger and remained more dilated to at least 10 mm from the ostium. The appearance was like a wind sock in AVJRT patients and tubular in the control patients. These findings may have important implications for arrhythmia pathogenesis in such patients.

Radiofrequency catheter ablation of paroxysmal supraventricular tachycardia in patients with congenital heart disease

Radiofrequency catheter ablation was performed in 21 patients who had congenital heart diseases associated with accessory pathway (AP)-mediated tachycardia (14 patients), with atrioventricular (AV) nodal reentrant tachycardia (4 patients), with intraatrial reentrant tachycardia (1 patient), with coexistent AP mediated tachycardia and AV nodal reentrant tachycardia (1 patient) and with coexistent AV nodal reentrant tachycardia and atrial tachycardia (1 patient). Congenital heart diseases diagnosed were seven with Ebstein's anomaly and six with septal defect; the others included patent ductus arteriosus, supravalvular aortic stenosis and left superior vena cava-coronary sinus fistula. Incidence of multiple APs (26.7 vs. 7.7%, P = 0.027), antidromic tachycardia (20.0 vs. 2.9%, P = 0.011), tachyarrhythmia-related syncope (26.7 vs. 7.2%, P = 0.022) and cardiac arrest (13.3 vs. 0%, P = 0.001) was higher in patients with AP and congenital heart diseases. Longer procedure (3.9 +/- 0.7 vs. 2.4 +/- 1.3 h for AP, P = 0.001; 3.0 +/- 0.7 vs. 2.5 +/- 0.8 h for AV nodal reentrant tachycardia, P = 0.001), and radiation exposure times (102 +/- 27 vs. 35 +/- 23 min for AP, P = 0.001; 62 +/- 23 vs. 20 +/- 11 min for AV nodal reentrant tachycardia, P = 0.001) were necessary to achieve a high success rate (95%) in patients with congenital heart disease.