Coronary sinus morphology in different types of supraventricular tachycardias

Anatomy for ablation of atrioventricular nodal reentry tachycardia and accessory pathways

The atrioventricular (AV) valve plane and the central septum are of particular importance for electrophysiological diagnosis and interventional therapy of supraventricular tachycardias because accessory electrical connections of various types may be present in addition to the specific conduction system. Although modern 3D electroanatomic reconstruction systems including high-density mapping can be of great assistance, detailed knowledge of the anatomic structures involved, their complex three-dimensional arrangement, and their electrical properties in conjunction with electrophysiological features of supraventricular arrhythmias is essential for safe and efficient electrophysiological treatment. The aim of this article is to present current anatomical, topographical, and electrophysiological findings against the background of historical, seminal, and still indispensable literature.

Association Between the Coronary Sinus Ostial Size and Atrioventricular Nodal Reentrant Tachycardia in Patients With Pulmonary Arterial Hypertension

Aims

The incidence of atrioventricular nodal reentrant tachycardia (AVNRT) is higher in pulmonary arterial hypertension (PAH) patients than in the general population. AVNRT is reportedly associated with a larger coronary sinus (CS) ostium (CSo). However, the correlation between AVNRT and CSo size in PAH patients is poorly investigated. We aimed to investigate the impact of CSo size on AVNRT and identify its risk factors in PAH.

Methods and Results

Of 102 PAH patients with catheter ablation of supraventricular tachycardia (SVT), twelve with a confirmed AVNRT diagnosis who underwent computed tomographic angiography were retrospectively enrolled as the study group. The control group (PAH without SVT, n = 24) was matched for sex and BMI at a 2:1 ratio. All baseline and imaging data were collected. Mean pulmonary artery pressure was not significantly different between the two groups (65.3 ± 16.8 vs. 64.5 ± 17.6 mmHg, P = 0.328). PAH patients with AVNRT were older (45.9 ± 14.8 vs. 32.1 ± 7.6 years, P = 0.025), had a larger right atrial volume (224.4 ± 129.6 vs. 165.3 ± 71.7 cm3, P = 0.044), larger CSo in the left anterior oblique (LAO) plane (18.6 ± 3.3 vs. 14.8 ± 4.0 mm, P = 0.011), and larger CSo surface area (2.08 ± 1.35 vs. 1.45 ± 0.73 cm2, P = 0.039) and were more likely to have a windsock-shape CS (75% vs. 16.7%, P = 0.001) than those without AVNRT. A linear correlation was shown between CSo diameter in the LAO-plane and the atrial fractionation of the ablation target for AVNRT (R2 = 0.622, P = 0.012).

Conclusion

Anatomical dilation of the CSo is a risk factor for AVNRT development in patients with PAH.

Cryoablation of atypical atrioventricular nodal reentry tachycardia

AIM

Data on ablation for atypical recurrent atrioventricular nodal reentry tachycardia (AVNRT) and long-term follow-up are generally sparse. Furthermore, the rate of recurrence and safety of cryoablation for atypical AVNRT has not been established. We compared patients cryoablated for atypical AVNRT and typical AVNRT during long-term follow-up.

METHODS

All patients (n = 2612) who underwent catheter ablation for AVNRT at the Karolinska University Hospital between January 2009 and August 2019 were analyzed. A total of 91 patients undergoing first-time cryoablation for atypical AVNRT were included. A control group with first-time cryoablation for typical AVNRT was matched in a 1:1 ratio. Patients were followed-up for recurrences for a median of 5.0 years (interquartile range: 3.1-7.5 years).

RESULTS

After 5 years, AVNRT recurrence occurred in 10 patients (11.0%) in the atypical AVNRT group and in 8 patients (8.8%) in the typical AVNRT group (hazard ratio: 1.31 [95% confidence interval: 0.52-3.32]; p = 0.568). The duration of the index procedure was significantly longer for atypical compared to typical AVNRT ablation (132.1 ± 49.2 min vs. 110.1 ± 38.8 min; p = 0.001). Transient AV blocks occurred in a similar fashion in the atypical compared to typical group (11 [12.1%] vs. 4 [4.9%]; p = 0.103). However, no ablation induced persistent AV block developed in either group.

CONCLUSION

Cryoablation for atypical AVNRT showed similar rate of recurrences and safety compared to typical AVNRT during long-term follow-up.

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.

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.

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.

Anatomical Basis for the Cardiac Interventional Electrophysiologist

The establishment of radiofrequency catheter ablation techniques as the mainstay in the treatment of tachycardia has renewed new interest in cardiac anatomy. The interventional arrhythmologist has drawn attention not only to the gross anatomic details of the heart but also to architectural and histological characteristics of various cardiac regions that are relevant to the development or recurrence of tachyarrhythmias and procedural related complications of catheter ablation. In this review, therefore, we discuss some anatomic landmarks commonly used in catheter ablations including the terminal crest, sinus node region, Koch's triangle, cavotricuspid isthmus, Eustachian ridge and valve, pulmonary venous orifices, venoatrial junctions, and ventricular outflow tracts. We also discuss the anatomical features of important structures in the vicinity of the atria and pulmonary veins, such as the esophagus and phrenic nerves. This paper provides basic anatomic information to improve understanding of the mapping and ablative procedures for cardiac interventional electrophysiologists.

Relationship between severity of pulmonary hypertension and coronary sinus diameter

INTRODUCTION AND OBJECTIVE

We investigated the relationship between coronary sinus (CS) diameter and pulmonary artery systolic pressure (PASP) in patients with pulmonary hypertension (PH) and normal left ventricular systolic function.

METHODS

A total of 155 participants referred for transthoracic echocardiography were included in the study. The study population consisted of 100 patients with chronic PH and 55 control subjects. Patients with PH were divided into two groups according to PASP: those with PASP 36-45 mmHg, the mild PH group (n=53); and those with PASP >45 mmHg, the moderate to severe PH group (n=47). CS diameter was measured from the posterior atrioventricular groove in apical 4-chamber view during ventricular systole according to the formula: mean CS=(proximal CS+mid CS+distal CS)/3.

RESULTS

Mean CS diameter was significantly higher in the moderate to severe PH group than in the controls and in the mild PH group (1.12±0.2 cm vs. 0.82±0.1 cm and 0.87±0.1 cm, respectively; p<0.001). It was significantly correlated with right atrial (RA) area (r=0.674, p<0.001), RA pressure (r=0.458, p<0.001), PASP (r=0.562, p<0.001), inferior vena cava diameter (r=0.416, p<0.001), right ventricular E/A ratio (r=-0.290, p<0.001), and E/Em ratio (r=0.235, p=0.004). RA area (β=0.475, p<0.001) and PASP (β=0.360, p=0.002) were found to be independent predictors of CS diameter.

CONCLUSIONS

A dilated CS was associated with moderate to severe pulmonary hypertension, and RA area and PASP were independent predictors of CS diameter.

Anatomic assessment of variations in myocardial approaches to the atrioventricular node

INTRODUCTION

The tissues in the posteroinferior atrioventricular (AV) junction around the AV node are important in procedures for ablating and manipulation of catheters in and around the coronary sinus (CS). However, information with regard to the histological arrangement of perinodal myocardium relative to the CS is lacking.

METHODS AND RESULTS

We examined 21 postmortem human hearts without any abnormalities (9 women; mean age 68.8 ± 14.3 years). After making measurements, the posteroinferior AV junction was removed and processed for histology. Sections were cut parallel to the septum. We assessed the myocardial arrangements from the atrial septum and the CS toward the AV nodal tissue, including the transitional cell zone, and measured the dimensions between the compact AV node and the CS, and the circumference of the CS. We observed 3 patterns of myocardial approaches to the AV node: extension of myocardium from the atrial septum (Group A; n = 6); extension of CS musculature (Group B; n = 6); and both septal and CS musculature (Group C; n = 9). The distance between the AV node and the CS in Group A was significantly longer than in the other groups (mean 11.5 ± 3.1 mm, 1.7 ± 0.6 mm, 3.8 ± 1.5 mm, respectively; P < 0.0001), and the circumference of the CS in Group B was longer than in Group A (mean 31.1 ± 7.9 mm*, 44.4 ± 8.4 mm*, 33.7 ± 6.9 mm, respectively; P < 0.05).

CONCLUSION

The myocardial approaches including the transitional cell zone toward the AV node are variable in normal hearts. The location and size of the CS can affect the myocardial arrangements and the area of transitional cells around the AV node.

The dilated coronary sinus: utility of coronary sinus cross-sectional area and eccentricity index in differentiating right atrial pressure overload from persistent left superior vena cava

BACKGROUND

Pulmonary hypertension and right atrial pressure overload (RAPO) cause dilation of the coronary sinus (CS). Persistent connection of the left superior vena cava (LSVC) to the CS is another cause of CS dilation. The purpose of this study was to evaluate the usefulness of coronary sinus cross-sectional area (CSA) and eccentricity index (EI) in differentiating persistent LSVC from right heart overload and RAPO in patients with dilated CS.

METHODS

We identified 15 patients with a dilated CS by echocardiography. Offline analysis was used to measure CS-CSA and CS-EI at end-diastole in the parasternal long axis plane. EI was defined as B/A, where A is the widest diameter and major axis of the CS, and B is the diameter of the minor axis (perpendicular to and bisecting A at its midpoint). Persistent LSVC was confirmed by either computed tomography or injection of agitated saline in the left antecubital vein.

RESULTS

CS-CSA was significantly larger in PLSVC group than in group with RAPO. Also, CS-EI was lower in PLSVC than in RAPO group (P = 0.0003). EI was the most sensitive and specific discriminator between patients with persistent LSVC vs. RAPO. CS-EI was <0.8 in all PLSVC patients and >0.8 in all RAPO patients (sensitivity and specificity = 100%).

CONCLUSION

Patients with persistent LSVC have a significantly higher CS-CSA than those with elevated RA pressure. When dilated CS is present, a CS-EI <0.8 is 100% sensitive and specific for persistent LSVC. Thus, the CS-EI can be used in cases of dilated CS to diagnose the presence of persistent LSVC with a very high degree of certainty, and can help differentiate this congenital anomaly from RAPO.