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

Comparison between conventional approach and three-dimensional mapping system in the catheter ablation of accessory pathway associated with coronary sinus diverticulum: A single-center experience

BACKGROUND

Posteroseptal accessory pathways (APs) associated with coronary sinus (CS) diverticulum present a rare and challenge for ablation. This study aimed to compare the safety and efficacy of conventional approach and three-dimensional (3D) mapping system in the catheter ablation.

METHODS AND RESULTS

This was a retrospective study of all patients (from January 2013 to July 2022) who underwent catheter ablation of posteroseptal AP associated with CS diverticula in our center. Patients who underwent catheter ablation using the traditional fluoroscopy method were included in the conventional method group (n = 13). Patients who underwent catheter ablation using the 3D mapping method were included in the 3D mapping group (n = 11). Clinical characteristics, ablation procedure, and outcomes were recorded and analyzed between the two groups. Out of 669 patients with posteroseptal APs, 24 of them (3.6%) were associated with CS diverticula. All patients in both groups successfully completed the electrophysiological study. In the conventional method group, two patients experienced complications (one patient with pericardial effusion and the other patient with femoral arterial hematoma), and two patients had recurrence. However, no patients suffered from complications or recurrence during follow-up. The procedure time and fluoroscopy time in the conventional method group were significantly longer than those in the 3D mapping method group.

CONCLUSIONS

The utilization of 3D mapping led to reduced fluoroscopy time, shorter procedure duration, enhanced acute success rates, and decreased incidence of complications.

Successful catheter ablation of the accessory pathway in an unusual location in a 13-year-old girl with a coronary sinus diverticulum and Wolff-Parkinson-White syndrome

Wolff-Parkinson-White syndrome is a congenital cardiac pre-excitation syndrome that is effectively treated by ablating the accessory pathway. However, accessory pathways located in the posteroseptal region can sometimes be challenging. In this paper, we present the successful ablation of the epicardial posteroseptal accessory pathway through the middle cardiac vein in a 13-year-old girl with a coronary sinus diverticulum and Wolff-Parkinson-White syndrome, after unsuccessful ablation attempts at different locations. If the ablation procedure fails, the possibility of the posteroseptal pathway should be kept in mind, and coronary sinus angiography should be performed. In cases with a coronary sinus diverticulum where ablation is not successful, other coronary sinus structures, for example, the middle cardiac vein should be considered as potential accessory pathways.

Giant diverticulum of coronary sinus with multiple accessory pathways treated with catheter ablation

Coronary sinus abnormalities are usually associated with arrhythmia disorders when symptomatic. We report a 5-year-old 14 kg patient with a giant diverticulum of coronary sinus and Wolff-Parkinson-White syndrome. Catheter ablation therapy was decided during follow-up due to inadequate response to multidrug therapy. Posteroseptal and left posterolateral accessory pathways were established and radiofrequency ablation was performed successfully through coronary sinus.

Ablation of Accessory Pathways with Challenging Anatomy

Although catheter ablation of accessory pathways is deemed highly safe and effective, peculiar location of these pathways might lead to complex and potentially hazardous procedures requiring ablation in anatomic regions such as para-Hisian area, coronary sinus, and epicardial surface. The electrophysiologist should know these possible scenarios to plan the best strategy for safe and effective ablation of these uncommon accessory pathways.

Coronary sinus diverticulum: Importance, function, and treatment

The importance of venous structure in the heart is usually overshadowed by that of the arterial system. Coronary sinus (CS) is a part of cardiac venous apparatus and connects left atria to the right atria. Other than having role in physiological contractions of both atria, it contributes substantially to cardiac electrical conduction system. Due to unique placement and connections of the CS, it has become growing interest in clinical cardiology. It is used in cardiac resynchronization therapy with biventricular pacing, left-sided catheter ablation of arrhythmias, and administration of retrograde cardioplegia in cardiac surgery. In some individuals, CS is presented with anatomical variants. CS diverticulum is a congenital outpouching that provides muscular connection between atria and ventricle. This connection provides a suitable substrate for occurrence of arrhythmias, which even results in life-threatening events such as sudden cardiac death. Early diagnosis leads to treatment with ablation techniques, which ultimately eliminates origins of arrhythmias.

Uncovering a unique path: Antidromic AVRT utilizing a left anteroseptal Mahaim-like accessory pathway

A 40-year-old man presented to our emergency department 2 hours after onset of shortness of breath, palpitations, and presyncope secondary to an adenosine-responsive wide complex tachycardia. Electrophysiology study was diagnostic for antidromic atrioventricular (AV) reentrant tachycardia utilizing a muscular connection from the anterior interventricular vein to the left ventricle with Mahaim-like properties, successfully treated with ablation in the distal coronary sinus (CS) system. This case highlights accessory pathways (a) with unique features (i.e., Mahaim-like characteristics) and (b) involving musculature from the distal CS system, thereby limiting the value of endocardial ablation for durable treatment. Importantly, the coronary venous system is an accessible vascular network for evaluation and catheter ablation of such arrhythmias.

Ablation of atrioventricular-nodal-reentrant- tachycardia in a patient with left-sided superior vena cava and dilated coronary sinus

Atrioventricular (AV)-nodal-reentrant-tachycardia is a rare association in a patient with persistent left-sided superior vena cava and dilated coronary sinus. There are a few inherent difficulties in ablation in this condition, viz., difficulty in localization of good site for ablation and difficulty in stabilization of the ablation catheter at the designated site, making it difficult to produce transmural lesions and increasing risk of producing AV block. We hereby present a case highlighting the difficulties and possible solutions for them.

Autopsy findings of an isolated persistent left superior vena cava in an intrauterine dead fetus

Persistent left superior vena cava (PLSVC) is one of the cardiac system abnormalities with a 0.3-0.5% incidence and caused by inadequate obliteration of the left anterior cardinal vein during embryonic development. Prognosis of PLSVC is generally assumed to be good if it is not accompanied by other cardiac system abnormalities. During the routine ultrasound control of a patient at 25th week of pregnancy at the Obstetrics and Gynecology Department of Mersin University, PLSVC anomaly was detected in an intrauterine fetus. Then, intrauterine death occurred and after removal of the deceased fetus, PLSVC diagnosis was confirmed by autopsy. According to the autopsy findings, right superior vena cava (SVC) and azygos vein were found in normal course. PLSVC opened into the right atrium via enlarged coronary sinus. There was no connection between the two SVCs. On the left side of posterior mediastinum, instead of hemiazygos or accessory hemiazygos veins, a vein symmetrical to azygos was opened into PLSVC, similar to the one on the right. No other cardiac anomaly associated with PLSVC or any other pathology in the other parts of body that could be responsible for death was discovered during autopsy. There was no evidence indicating that PLSVC played any role in intrauterine exitus of the present case. However, as mentioned in the literature, the ectopic beats in the atrium wall of patients with isolated PLSVC and enlarged coronary sinus may lead to pathologies in the conduction system of the heart. Considering the intrauterine death of an isolated PLSVC case associated with cardiac conduction pathologies, we recommend that the common assumption of 'isolated PLSVC is not associated with death' should be reviewed by studies on large series and even intrauterine cases should be closely monitored for cardiac arrhythmia.

Coronary sinus cannulation predicts atrioventricular nodal reentry as mechanism of supraventricular tachycardia

Introduction

Common clinical teaching, for invasive electrophysiology, is that if the first year fellow cannulates the coronary sinus (CS) in his first attempt, the arrhythmia is more likely to be atrioventricular nodal reentry tachycardia (AVNRT). This general perception has not yet been clinically tested. We evaluated this theory in prospective patients undergoing an electrophysiological study (EPS) for paroxysmal supraventricular tachycardia (PSVT).

Methods

Cohort study. CS ease of cannulation (CSCS) was graded as: 1) 1st year fellow cannulates in first attempt; 2) 1st year fellow needs more than one attempt or maneuver to cannulate the CS; 3) staff physician cannulates in first attempt after the fellow was unsuccessful; 4) staff physician requires more than one maneuver to cannulate the CS; 5) staff physician judges that the cannulation process was extremely difficult.

Results

Of the 1361 patients undergoing EPS in our institution, 165 were selected. Age was 49 ± 15 years. AVNRT occurred in 77.6%, atrioventricular reentry tachycardia (AVRT) in 15.1% and atrial tachycardia (AT) in 7.3% of cases. The CSCS = 1 was more prevalent in AVNRT, 89% versus 68% AVRT and 58.3% of AT (P = 0.0005). Patients with CSCS = 1 have a higher chance of the PSVT being AVNRT (odds ratio: 4.41; 95CI: 1.84–10.56; P = 0.0009).

Conclusion

The CSCS predicts the likelihood of the induced PSVT being AVNRT as compared to AVRT and AT. More studies are required to try to associate this finding to clinical patient characteristics to create a score for PSVT mechanism prediction.

Evaluation of coronary sinus morphology by three-dimensional transthoracic echocardiography in patients undergoing electrophysiological study

BACKGROUND

In this study, we aimed to evaluate the coronary sinus (CS) morphology with three-dimensional transthoracic echocardiography (3D-TTE) in patients with supraventricular tachycardia (SVT) who underwent electrophysiological study (EPS).

METHODS

This cross-sectional study was conducted with 187 patients who underwent EPS between November 2016 and April 2017. Patients were divided into three groups: atrioventricular nodal reentrant tachycardia (AVNRT) (n = 72), non-AVNRT SVT (n = 58), and normal EPS (n = 57). All patients were evaluated with electrocardiography, TTE, and 3D-TTE.

RESULTS

The CS diameter (CSD) and area (CSA) were found significantly lower in the normal EPS group than in the other groups. There was no significant difference in the CSD between AVNRT and non-AVNRT SVT groups. However, it was found that the CSA was significantly larger in the AVNRT group than in the non-AVNRT SVT group. In linear regression analysis, age and left atrial diameter were determined as independent predictor for CSD and CSA (P < 0.001 for each one).

CONCLUSIONS

The CSD and CSA assessed by 3D-TTE were different and dilated in the patients with SVT compared to those in the normal individuals. There was no significant difference in the CSD between the AVNRT and non-AVNRT SVT groups. However, the AVNRT group had a larger CSA than the non-AVNRT SVT group.

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 morphology in pediatric patients with supraventricular tachycardia

PURPOSE

The anatomic basis of atrioventricular node reentrant tachycardia (AVNRT) remains incompletely characterized in children. Differences in coronary sinus (CS) size and morphology have been observed in adults with AVNRT but have not been well characterized in children.

METHODS

Children (< 18 years) brought to the EP lab with supraventricular tachycardia for ablation underwent CS venography. A blinded pediatric interventional cardiologist performed CS measurements, which were indexed to body surface area. Patients were excluded if they were < 25 kg or had significant congenital heart disease.

RESULTS

Forty-six patients (age 14.2 ± 3.3 years) met inclusion criteria, 17 with AVNRT and 32 with an accessory pathway (AP). CS ostium (LAO projection, end-systole) was 7.8 ± 2.9 mm/m² for the AVNRT group versus 6.0 ± 2.5 mm/m² for the AP group (p = 0.04). CS "windsock" morphology was more prevalent in the AVNRT group (16/17, 94.1%) than the AP group (11/32, 34.3%) (p < 0.001). Within the AVNRT group, there was no correlation between CS ostium size and tachycardia cycle length (R = 0.01, p = 0.96), fast-pathway ERP (FPERP) (R = 0.42, p = 0.12), or A2-H2 at the FPERP (R = 0.25, p = 0.39).

CONCLUSIONS

Children with AVNRT have larger CS ostia and more prevalent windsock morphology. CS size/morphology did not correlate with EP properties of the AVNRT substrate. These features may explain the basis for the development of the electrophysiologic substrate for dual AV node physiology in children.

Atrial Arrhythmia Ablation in Adult Congenital Heart Disease with a Persistent Left-side Superior Vena Cava

We herein report a case of atrial tachycardia (AT) originating from the dilated coronary sinus (CS) connected to a persistent left superior vena cava. The earliest activation site of AT was localized at the superior CS ostium, identified using a novel ultra-rapid high-density mapping system (Rhythmia™). Successful ablation was performed at the corresponding position. This report demonstrated the utility of an ultra-rapid high-density mapping system in identifying arrhythmogenic foci in adult cases of congenital heart disease.

Morphometry of the triangle of Koch and position of the coronary sinus opening in cadaveric fetal hearts

AIMS

The aim of the present study was to determine the variations in the position of the coronary sinus (CS) ostium in normal cadaveric fetal (28 weeks or more) hearts and to assess the impact that these variations had on the dimensions of the triangle of Koch (TK).

METHODS

This cross-sectional analytical study was conducted on 28 fetal hearts. The dimensions and area of the TK were calculated by two methods, M1 (anatomical) and M2 (clinical). The position of the CS was defined with respect to the tendon of Todaro. Differences between M1 and M2 were estimated using the paired T test. Pearson's correlation coefficient and the adjusted correlation coefficient were used to estimate the strength of association between measurements made by the methods.

RESULTS

Ten (35.7%) cadavers were male and 18 (64.3%) female. The mean gestational age was 32.4±3.3 weeks. Using M1, the mean dimensions of the triangle in millimeters (mm) were 9.2±2.2, 6.6±1.8, and 6±2.4 respectively for a, b and c. Similarly, the dimensions using M2 were 7±2.1, 4.7±1.5, and 4.8±2.2. The area in mm² was 20.4±10.4 and 11.7±6.7 using M1 and M2 respectively. All measurements were significantly greater with M1. All correlation coefficients were high and significant. The CS ostium and tendon of Todaro maintained a relatively constant positional relationship.

CONCLUSIONS

Significantly higher values were noted in the dimensions of TK using M1. High significant positive correlations were observed in measurements made by the two methods. The CS ostium was relatively constantly placed within the TK.

Novel tips for engaging the coronary sinus guided by right ventricular lead

AIMS

This study investigated the relationship between the ostia of the coronary sinus (CS) and the tricuspid annulus (TA) for CS cannulation using a right ventricular (RV) lead, which could map out the TA by forming a curve when placed at the apex or low septum.

METHODS AND RESULTS

Seventy patients (45 males, 67 ± 12 years) who were admitted for CRT device implant were included in the evaluation of the relationship between the CS ostia and TA. An electrophysiological (EP) mapping catheter was used to probe the CS. The ostium was shown by the CS venography at the left anterior oblique (LAO) 20° and caudal 20°. Local electrograms were collected with CS catheters in the CS or RV. Transthoracic echocardiography was evaluated before each procedure. All CS ostia were located within 3.75 cm around the tip of TA. Sixty-two subjects (Group I, 89%) had CS ostia located under the TA. Eight patients (Group II) with CS ostia over the TA revealed larger left ventricular (LV) size and a smaller ratio of left atrium (LA)/LV size. LV enlargement predicted the presence of CS ostia over the TA. Typical CS electrograms were used to further confirm if the EP catheter was in the CS in all the subjects.

CONCLUSION

Use of the RV lead revealed that the CS ostia had a close relationship with the TA.

Coronary sinus diverticulum as a cause of resistant posteroseptal pathway ablation

Coronary sinus (CS) anomalies such as diverticulum, persistent left superior vena cava or CS ostium dilatation are predominantly found in patients with accessory pathway-related tachycardias. Diverticulum of the proximal CS found in 7-11% of patients with postero-septal or left posterior manifests accessory pathways. We reported a 28 year old gentleman with manifested postero-septal accessory pathway, who underwent repeat electrophysiological study (EPS) and radiofrequency ablation for previously failed ablation. Huge CS diverticulum was identified by angiography as a reason for resistant accessory pathway. Successful RF ablation was achieved at the neck of the diverticulum without complications. Other associated anomalies were ruled out by cardiac computerized tomography (CT) and trans-esophageal echocardiography.

Septal accessory pathway: anatomy, causes for difficulty, and an approach to ablation

Accessory pathway (AP) ablation is one of the most satisfying invasive electrophysiology procedures associated with high success rates and relatively few complications. Nevertheless, when APs are found on the cardiac septum, ablative procedures become complex, and unique pitfalls need to be avoided.These difficulties with septal ablation are magnified in the pediatric population. The relatively small heart, rapid nodal conduction, and proximity of the arterial system specifically complicate septal ablation in children. The electrophysiologist must use every tool in his or her armamentarium, including exact delineation of pathway location, identification of pathway potentials, detection of the presence of pathway slant, etc. In addition, an exact knowledge of the complex anatomy of the cardiac septum, including the posteroseptal space, the aortic cusp region, and the proximity of the AV conduction system and coronary vessels, becomes mandatory.In this review, we describe the developmental anatomy and regional anatomy of septal accessory pathways. We then discuss approaches to map specific to pathways in particularly problematic regions at or near the septum, including venous and aortic cusp related accessory pathways.

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.

Cardiac anatomic considerations in pediatric electrophysiology

Although interventional electrophysiology and the use of radiofrequency energy to cure various arrhythmias primarily developed in the adult population, similar applications in children have grown dramatically over the last decade. The anatomic basis for various arrhythmias is critically important for the pediatric ablationists to appreciate. Such understanding allows the use of alternative technique to affect cure while avoiding complications. Further, because of the relatively small heart and less thick myocardium in children, without the appreciation of the underlying cardiac anatomic relationships, collateral injury, for example to the arterial system, may occur. In this review, the cardiac anatomic consideration important in approaching various supraventricular and ventricular arrhythmias in the normal heart is discussed.

[Treatment of arrhythmias associated with congenital heart disease using transcatheter ablation]

Rhythm disturbances are common long after surgical repair of congenital heart disease. These arrhythmias caused by the progression of the disease itself, however, a significant proportion is a result of the presence of surgical scar. Although interventional electrophysiology procedures are complex and encounter difficulties, pharmacological therapy is often very disappointing.

AIM AND METHODS

In the present study we aimed to describe our experience obtained between 2004 and 2006 in patients undergoing transcatheter ablation long after surgery for congenital heart disease.

RESULTS

During this period 26 patients underwent catheter ablation. The procedure was successful in 24 out of the 26 patients (92%). Three patients required redo ablations due to arrhythmia recurrences (11%). There were no major complications related to the intervention. In four patients minor complications occurred (small hematomas).

CONCLUSIONS

Our descriptive data indicate that transcatheter ablation for arrhythmias after surgery for congenital heart disease is a effective safe and more importantly curative procedure. It is associated with reasonable success rate, low complication rate, but slightly higher recurrence rate as compared to the classical electrophysiological interventions.

Characterization of the coronary sinus ostium by cardiac magnetic resonance imaging

The diameter and the angle of the coronary sinus (CS) ostium was analyzed in 101 patients who underwent cardiac magnetic resonance imaging and had left ventricular ejection fractions < or =0.35 (n = 40) or > or =0.65 (n = 61). The angle of the CS ostium in patients with LVEFs < or =0.35 was less acute than in patients with LVEFs > or =0.65 (73 degrees +/- 12 degrees vs 65 degrees +/- 10 degrees, p <0.01). There was no statistically significant difference in the diameter of the CS ostium in patients with LVEFs < or =0.35 compared with those with LVEFs > or =0.65 (8 +/- 3 vs 8 +/- 2 mm, p = 0.5). The diameter and the angle of the CS ostium were not different when analyzed on the basis of the duration of the QRS complex, left atrial dimension, or left ventricular end-diastolic dimension. In conclusion, on the basis of cardiac magnetic resonance imaging data, the angle of the CS is less acute in patients with LVEFs < or =0.35 than in those with LVEFs > or =0.65.

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.

Utilization of Intracardiac Echocardiography to Access the Coronary Sinus for Left Ventricular Lead Placement

This is a presentation of a case series of 10 consecutive patients undergoing implantation of cardiac resynchronization therapy defibrillator (CRT-D). Intracardiac echocardiography (ICE) is utilized to gain access to the coronary sinus. The method used is detailed with a brief discussion of observations gained from this early experience.

[Left superior vena cava: a simple diagnosis by transthoracic echocardiography. A case report]

Persistent left superior vena cava is an anomaly of the systemic venous return occurring in 0.5% of the general population. We report the case of a patient with an incidental diagnosis made during a dyspnea while he had chronic pulmonary disease. The diagnosis was suspected by the presence of a markedly dilated coronary sinus and confirmed by a simple contrast injection into the left antecubital vein. Transesophageal echocardiography and magnetic resonance imaging confirmed the existence of 2 superior vena cava with the left superior vena cava draining into the coronary sinus. This congenital anomaly is of minimal hemodynamic significance when isolated. The diagnosis can be useful for placement of central catheters from left superior approach.

Coronary sinus-ventricular accessory connections producing posteroseptal and left posterior accessory pathways: incidence and electrophysiological identification

BACKGROUND

The coronary sinus (CS) has a myocardial coat (CSMC) with extensive connections to the left and right atria. We postulated that some posteroseptal and left posterior accessory pathways (CSAPs) result from connections between a cuff of CSMC extending along the middle cardiac vein (MCV) or posterior coronary vein (PCV) and the ventricle. The purpose of the present study was to use CS angiography and mapping to define and determine the incidence of CSAPs and determine the relationship to CS anatomy.

METHODS AND RESULTS

CSAP was defined by accessory pathway (AP) potential or earliest activation in the MCV or PCV and late activation at anular endocardial sites. A CSAP was identified in 171 of 480 patients undergoing ablation of a posteroseptal or left posterior AP. CS angiography revealed a CS diverticulum in 36 (21%) and fusiform or bulbous enlargement of the small cardiac vein, MCV, or CS in 15 (9%) patients. The remaining 120 (70%) patients had an angiographically normal CS. A CSMC extension potential (CSE), like an AP potential, was recorded in the MCV in 98 (82%), in the PCV in 13 (11%), in both the MCV and PCV in 6 (5%), and in the CS in 3 (2%) of 120 patients. CSMC potentials were recorded between the timing of atrial and CSE potentials.

CONCLUSIONS

CSAPs result from a connection between a CSMC extension (along the MCV or PCV) and the ventricle. The CS is angiographically normal in most patients.