Activation pattern of the coronary sinus facilitates the differentiation for ventricular outflow tract arrhythmias.

INTRODUCTION: The accuracy of surface ECG algorithms for predicting the origin of outflow tract ventricular arrhythmias (OT-VAs) might be questioned. Intracardiac electrograms recorded at anatomic landmarks could provide new predictive insights. We aim to evaluate the efficacy of a novel criterion utilizing the activation pattern of the coronary sinus (CS) in localizing OT-VAs, including VAs originating from the right ventricular outflow tract (RVOT), endocardial left ventricular outflow tract (Endo-LVOT), and epicardial left ventricular outflow tract (Epi-LVOT). METHODS: We measured the ventricular activation time of the mitral annulus (MA) from the onset of the earliest QRS complex of VAs to the initial deflection over the isoelectric line at local signals, namely the QRS-MA interval. The activation at 3 and 12 o'clock of the MA was recorded as the QRS-MA3 and QRS-MA12 intervals, respectively. Their predictive values were compared to previous ECG algorithms. RESULTS: A total of 68 patients with OT-VAs were enrolled (51 for development and 17 for validation). From early to late, the ventricular activation sequences at MA12 were as follows: Epi-LVOT, Endo-LVOT, and RVOT. In LBBB morphology OT-VAs, the QRS-MA12 interval was significantly earlier for LVOT origins than RVOT origins. In the combined cohort of development and validation cohort, a cut-off value of ≤10 ms predicted the LVOT origin with a sensitivity of 100% and specificity of 78%. The QRS-MA12 interval ≤ -24 ms additionally predicted epicardial LVOT sites of origin. CONCLUSIONS: The QRS-MA interval could accurately differentiate the OT-VAs localization.

Strong desmin immunoreactivity in the myocardial sleeves around pulmonary veins, superior caval vein and coronary sinus supports the presumed arrhythmogenicity of these regions.

Myocardial sleeve around human pulmonary veins plays a critical role in the pathomechanism of atrial fibrillation. Besides the well-known arrhythmogenicity of these veins, there is evidence that myocardial extensions into caval veins and coronary sinus may exhibit similar features. However, studies investigating histologic properties of these structures are limited. We aimed to investigate the immunoreactivity of myocardial sleeves for intermediate filament desmin, which was reported to be more abundant in Purkinje fibers than in ventricular working cardiomyocytes. Sections of 16 human (15 adult and 1 fetal) hearts were investigated. Specimens of atrial and ventricular myocardium, sinoatrial and atrioventricular nodes, pulmonary veins, superior caval vein and coronary sinus were stained with anti-desmin monoclonal antibody. Intensity of desmin immunoreactivity in different areas was quantified by the ImageJ program. Strong desmin labeling was detected at the pacemaker and conduction system as well as in the myocardial sleeves around pulmonary veins, superior caval vein, and coronary sinus of adult hearts irrespective of sex, age, and medical history. In the fetal heart, prominent desmin labeling was observed at the sinoatrial nodal region and in the myocardial extensions around the superior caval vein. Contrarily, atrial and ventricular working myocardium exhibited low desmin immunoreactivity in both adults and fetuses. These differences were confirmed by immunohistochemical quantitative analysis. In conclusion, this study indicates that desmin is abundant in the conduction system and venous myocardial sleeves of human hearts.

The Efficacy of Coronary Sinus Reducer in Patients with Refractory Angina: A Systematic Review and Meta-Analysis.

Background: Refractory angina is a frequently encountered phenomenon in patients with coronary artery disease, often presenting therapeutic challenges to the clinical cardiologist. Novel treatment methods have been explored in this direction, with the coronary sinus reducer (CSR) being among the most extensively-investigated. Methods: We conducted a systematic review of the literature for studies assessing the efficacy of CSR in patients with refractory angina. The primary endpoints of interest were procedural success and the improvement in angina according to the Canadian Cardiovascular Society (CCS) by at least one class. Secondary endpoints were the rate of periprocedural adverse events, the improvement by at least 2 CCS classes, and the mean change in CCS class. A random-effects meta-analysis of proportions (procedural success, improvement by ≥ 1 or ≥ 2 classes, periprocedural adverse events) or means (mean CCS class change) were performed. I 2 was chosen as the metric for between-study heterogeneity. Publication bias was assessed by the inspection of funnel plots and Egger's regression test. We examined the risk of bias according to the Newcastle-Ottawa Scale. Results: From a total of 515 studies identified from the original search, 12 studies were finally included for data extraction. Based on their meta-analysis, we observed a high CSR procedural success (98%, 95% confidence interval (CI) 96 to 99%) with a low rate of periprocedural complications (6%, 95% CI 5 to 7%), while most patients exhibited an improvement by at least 1 CCS class (75%, 95% CI 66 to 83%) after the intervention. A significant proportion of patients demonstrated an improvement by at least 2 CCS classes (39%, 95% CI 34 to 45%), with a mean change of -1.24 CCS class (95% CI -1.40 to -1.08). Conclusions: CSR is associated with high implantation success rates and significant improvements in angina symptoms for patients with refractory angina.

Myocardial Blood Flow Determination From Contrast-Free Magnetic Resonance Imaging Quantification of Coronary Sinus Flow.

BACKGROUND: Determination of myocardial blood flow (MBF) with MRI is usually performed with dynamic contrast enhanced imaging (MBFDCE ). MBF can also be determined from coronary sinus blood flow (MBFCS ), which has the advantage of being a noncontrast technique. However, comparative studies of MBFDCE and MBFCS in large cohorts are lacking. PURPOSE: To compare MBFCS and MBFDCE in a large cohort. STUDY TYPE: Prospective, sequence-comparison study. POPULATION: 147 patients with type 2 diabetes mellitus (age: 56+/-12 years; 106 male; diabetes duration: 12.9+/-8.1 years), and 25 age-matched controls. FIELD STRENGTH/SEQUENCES: 1.5 Tesla scanner. Saturation recovery sequence for MBFDCE vs. phase-contrast gradient-echo pulse sequence (free-breathing) for MBFCS . ASSESSMENT: MBFDCE and MBFCS were determined at rest and during coronary dilatation achieved by administration of adenosine at 140 µg/kg/min. Myocardial perfusion reserve (MPR) was calculated as the stress/rest ratio of MBF values. Coronary sinus flow was determined twice in the same imaging session for repeatability assessment. STATISTICAL TESTS: Agreement between MBFDCE and MBFCS was assessed with Bland and Altman's technique. Repeatability was determined from single-rater random intraclass and repeatability coefficients. RESULTS: Rest and stress flows, including both MBFDCE and MBFCS values, ranged from 33 to 146 mL/min/100 g and 92 to 501 mL/min/100 g, respectively. Intraclass and repeatability coefficients for MBFCS were 0.95 (CI 0.90; 0.95) and 5 mL/min/100 g. In Bland-Altman analysis, mean bias at rest was -1.1 mL/min/100 g (CI -3.1; 0.9) with limits of agreement of -27 and 24.8 mL/min/100 g. Mean bias at stress was 6.3 mL/min/100 g (CI -1.1; 14.1) with limits of agreement of -86.9 and 99.9. Mean bias of MPR was 0.11 (CI: -0.02; 0.23) with limits of agreement of -1.43 and 1.64. CONCLUSION: MBF may be determined from coronary sinus blood flow, with acceptable bias, but relatively large limits of agreement, against the reference of MBFDCE . LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Septal venous channel perforation during left bundle branch area pacing: a prospective study.

AIMS: To characterize the diagnosis, frequency, and procedural implications of septal venous channel perforation during left bundle branch area pacing (LBBAP). METHODS AND RESULTS: All consecutive patients undergoing LBBAP over an 8-month period were prospectively studied. During lead placement, obligatory septal contrast injection was performed twice, at initiation (implant entry zone) and at completion (fixation zone). An intuitive fluoroscopic schema using orthogonal views (left anterior oblique/right anterior oblique) and familiar landmarks is described. Using this, we resolved zonal distribution (I-VI) of lead position on the ventricular septum and its angulation (post-fixation angle θ). Subjects with and without septal venous channel perforation were compared. Sixty-one patients {male 57.3%, median age [interquartile range (IQR)] 69.5 [62.5-74.5] years} were enrolled. Septal venous channel perforation was observed in eight (13.1%) patients [male 28.5%, median age (IQR) 64 (50-75) years]. They had higher frequency of (i) right-sided implant (25% vs. 1.9%, P = 0.04), (ii) fixation in zone III at the mid-superior septum (75% vs. 28.3%, P = 0.04), (iii) steeper angle of fixation-median θ (IQR) [19 (10-30)° vs. 5 (4-19)°, P = 0.01], and (iv) longer median penetrated-lead length (IQR) [13 (10-14.8) vs. 10 (8.5-12.5) mm, P = 0.03]. Coronary sinus drainage of contrast was noted in five (62.5%) patients. Abnormal impedance drops during implantation (12.5% vs. 5.7%, P = NS) were not significantly different. CONCLUSION: When evaluated systematically, septal venous channel perforation may be encountered commonly after LBBAP. The fiducial reference framework described using fluoroscopic imaging identified salient associated findings. This may be addressed with lead repositioning to a more inferior location and is not associated with adverse consequence acutely or in early follow-up.

The optimal slow pathway ablation site in atrioventricular nodal reentrant tachycardia cases with an inferiorly located His bundle.

INTRODUCTION: The optimal slow pathway (SP) ablation site in cases with an inferiorly located His bundle (HIS) remains unclear. METHODS AND RESULTS: In 45 patients with atrioventricular nodal reentrant tachycardia, the relationship between the HIS location and successful SP ablation site was assessed in electroanatomical maps. We assessed the location of the SP ablation site relative to the bottom of the coronary sinus ostium in the superior-to-inferior (SPSI), anterior-to-posterior (SPAP), and right-to-left (SPRL) directions. The HIS location was assessed in the same manner. The HIS location in the superior-to-inferior direction (HISSI), SPSI, SPAP, and SPRL were 17.7 ± 6.4, 1.7 ± 6.4, 13.6 ± 12.3, and -1.0 ± 13.0 mm, respectively. The HISSI was positively correlated with SPSI (R2 = 0.62; P < .01) and SPAP (R2 = 0.22; P < .01), whereas it was not correlated with SPRL (R2 = 0.01; P = .65). The distance between the HIS and SP ablation site was 17.7 ± 6.4 mm and was not affected by the location of HIS. The ratio of the amplitudes of atrial and ventricular potential recorded at the SP ablation site did not differ between the high HIS group (HISSI ≥ 13 mm) and low HIS group (HISSI < 13 mm) (0.10 ± 0.06 vs. 0.10 ± 0.06; P = .38). CONCLUSION: In cases with an inferiorly located HIS, SP ablation should be performed at a lower and more posterior site than in typical cases.

Elucidating left atrial electrical potential with microelectrode catheter: A case of coronary sinus ostial atresia with small persistent left superior vena cava.

A 51-year-old woman presented with recurring palpitations. Electrocardiography revealed narrow QRS tachycardia with short RP configuration. Computed tomography showed coronary sinus (CS) ostial atresia along with a small persistent left superior vena cava (PLSVC). Electrophysiological study identified the retrograde earliest atrial activation site (EAAS) at the CS ostium without decremental properties, and para-Hisian pacing suggested retrograde atrioventricular nodal conduction. Using a 1.6-Fr microelectrode catheter distally placed in the CS via the PLSVC, EAAS was confirmed within the left atrium, not the CS ostium. Transseptal approach revealed a left lateral accessory pathway, which was successfully eliminated.

The effectiveness and safety of temporary transvenous cardiac pacing leads placement into coronary sinus vein in patients with sick sinus syndrome.

BACKGROUND: The temporary pacing lead routinely is placed into right ventricular (RV), which pose a risk of dislocation and cardiac perforation. OBJECTIVE: We aim to evaluate the effectiveness and safety of temporary transvenous cardiac pacing (TTCP) leads placement into the coronary sinus vein (CSV) in patients with sick sinus syndrome (SSS). METHODS: We investigated patients with SSS who underwent TTCP lead placement into the CSV under the guidance of X-ray between January 2013 and May 2023. Patients were randomly divided into two groups: RV group (n = 33) and CSV group (n = 22). The ordinary passive bipolar electrodes were applied in both groups. In RV groups, electrodes were placed into RV. In CSV group, electrodes were placed into CSV. We evaluated the operation duration, fluoroscopic exposure, first-attempt success rate of leads placement, pacing threshold, success rate of leads placement, rate of leads displacement, and complications. RESULTS: Compared with that in RV group, the procedure time, fluoroscopic exposure was significantly prolonged, while the first-attempt success rate of lead placement was obviously increased in CSV group (both p < .05). Compared with that in RV group, the rate of leads displacement is lower in CSV group (both p < .05). There were three patients occurred cardiac perforation in RV group, but no cardiac perforation was reported in CSV group (p > .05). CONCLUSION: TTCP leads placement into the CSV is an effective and safe strategy in patients with SSS. It indicates a high rate of pacing effectiveness with low device replacement and complication rates.

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.

A case of coronary sinus ostium atresia misdiagnosed as patent foramen ovale.

A 15-year-old male patient presented with a 3-year history of recurrent dizziness and headaches and was initially diagnosed with patent foramen ovale. A transcatheter closure procedure was planned and conducted under general anesthesia, utilizing ultrasound guidance through the femoral vein. Preadmission echocardiography confirmed the presence of a patent foramen ovale. However, further investigation with transesophageal echocardiography (TEE) performed under general anesthesia, revealed that the observed atrial septal anomaly was not a patent foramen ovale. Instead, real-time TEE identified it as the left atrial opening of the coronary vein. Subsequent detailed TEE tracking confirmed a rare case of coronary sinus ostium atresia with left atrial reflux of the coronary vein, leading to a significant revision of the initial diagnosis and planned treatment.

Let's put the clues together and find the aetiology in this patient with dilated right heart!

A 39-year-old woman with intermittent palpitations, psoriasis, and a family history of sudden death presented with dilated right heart chambers and an enlarged coronary sinus. Despite a normal bubble study, further evaluation with transesophageal echocardiography revealed an abnormal pulmonary venous return: the left pulmonary veins drained into the coronary sinus. Cardiac computed tomography confirmed this finding, suggesting a partial abnormal pulmonary venous return as the underlying issue. Cardiac catheterization indicated increased pulmonary artery flow with normal pulmonary vascular resistance. The patient was referred for surgery. In this pathway involving the differential diagnosis of right heart dilatation, despite a confusing history and conflicting findings, echocardiographic clues led to the diagnosis.

Developmental Changes of the Coronary Sinus Between the First and Second Trimesters: A Pilot Study.

OBJECTIVE: To assess the coronary sinus (CS) presence, size, and CS to atrial ratio (CS/A) in the first trimester (FT) compared with the second trimester (ST). METHODS: In this IRB-approved retrospective study, fetuses with adequate FT cardiac sweeps and normal ST hearts were included. Maternal and fetal characteristics were obtained. CS and atrial diameters were measured by a single sonologist. The CS/A ratio was compared between FT and ST. Linear regression assessed the relationship between biparietal diameter (BPD) and CS and atrial diameters. Statistical significance was set at P < .05. RESULTS: Among 99 fetuses, the CS was seen in 42/53 (79.2%) in the FT and 14/32 (43.8%) in the ST. No significant associations were found between CS visualization and the factors analyzed. The CS/A ratio was significantly higher in the FT versus ST (0.43 vs 0.25; P < .0001). Combined FT and ST data revealed positive correlations between BPD and both CS (slope = 0.018, P < .0001) and atrial diameters (slope = 0.135, P < .0001), suggesting differential growth rates, with the atrium exhibiting a faster growth rate as BPD increased. CONCLUSIONS: The CS appears prominent in the FT compared with the ST, likely due to differential growth rates between the CS and atrium. Remnants of embryonic structures, differences in myocardial drainage, and hemodynamics may also be contributing factors. Larger prospective studies are needed to confirm these findings and assess the value of the FT CS/A ratio.

Inflow Tract Development.

The development of the inflow tract is undoubtedly one of the most complex remodeling events in the formation of the four-chambered heart. It involves the creation of two separate atrial chambers, the formation of an atrial/atrioventricular (AV) septal complex, the incorporation of the caval veins and coronary sinus into the right atrium, and the remodeling events that result in pulmonary venous return draining into the left atrium. In these processes, the atrioventricular mesenchymal complex, consisting of the major atrioventricular (AV) cushions, the mesenchymal cap on the primary atrial septum (pAS), and the dorsal mesenchymal protrusion (DMP), plays a crucial role.

Clinical anatomy of the coronary venous system and relevance to retrograde cardioplegia and cardiac electrophysiological interventions.

Anomalies of coronary venous system, the valve of the coronary sinus (Thebesian valve) and other cardiac malformations may make interventions through the coronary sinus difficult. These variants may pose a challenge in cannulating the coronary sinus for retrograde cardioplegia and for interventions performed through the coronary sinus by cardiac electrophysiologist/interventional cardiologist. Retrograde cardioplegia is an established method of myocardial protection with advantages, indications, and complications. A good knowledge of the anatomy of the coronary sinus and its variants is important in understanding the difficulties encountered while cannulating the coronary sinus for the delivery of retrograde cardioplegia, cardiac resynchronization therapy, treatment of arrhythmias, and percutaneous mitral valve annuloplasty.

Crazy accessory pathway- going round the bend!

A 15-year-old boy with manifest preexcitation and recurrent palpitations had undergone an unsuccessful ablation procedure elsewhere and was subsequently referred to us. The ECG suggested a left free wall pathway but there was a pattern break in lead V2. This helped localise the accessory pathway to the summit region and achieve success.

Retrograde fast pathway cryoablation inside the coronary sinus for slow-fast atrioventricular nodal reentrant tachycardia in a patient with persistent left superior vena cava.

INTRODUCTION: Persistent left superior vena cava (PLSVC) is accompanied by enlarged coronary sinus (CS) and deformation of the triangle of Koch. This makes anatomical evaluation of the atrioventricular (AV) nodal pathways difficult. METHODS: We attempted cryoablation of retrograde fast pathway located in the enlarged CS roof of PLSVC for slow-fast AV nodal reentrant tachycardia (AVNRT) induced by inadvertent antegrade fast pathway elimination during ablation of left atrial tachycardia. RESULTS: Slow-fast AVNRT was successfully eliminated without AV block progression. CONCLUSIONS: This is the first case of successful retrograde fast pathway ablation of the CS ostial roof for slow-fast AVNRT with PLSVC.

Pulsed-field-ablation for the treatment of atrial fibrillation in patients with congenital anomalies of cardiac veins.

INTRODUCTION: Anomalous cardiac veins are not rare and pulmonary vein (PV) isolation for atrial fibrillation (AF) treatment should include these veins. Pulsed-field ablation (PFA) is a novel technology for AF ablation with excellent efficacy and safety profile. In this case series, we describe our first experience of isolation of anomalous cardiac veins using PFA in patients with AF. METHODS: We report a series of patients with congenital anomalies of the cardiac veins and AF, treated with PFA. All patients underwent cardiac computed tomography for procedural planning. RESULTS: We included five patients (four males). Anomalous cardiac veins included a connection of a left common ostium to the coronary sinus, a partial and complete drainage of the right superior PV into the superior vena cava (SVC) with and without additional atrial septal defect, a persistent left SVC and an anomalous posterior PV. All anomalous PVs were isolated using PFA. No phrenic nerve palsy or other complications occurred. PFA of an abnormal right superior PV draining into the distal SVC was possible without affecting the sinus node. After a median of 4 months, four patients were free of recurrence. One patient had recurrent AF and perimitral reentry tachycardia, probably facilitated by PFA in the mitral isthmus region during isolation of an anomalous connection of the left common ostium to the coronary sinus. CONCLUSIONS: Using systematic preprocedural imaging and three-dimensional-electroanatomic mapping, the currently available PFA system seems well suited, efficient, and versatile for the treatment of AF in patients with anomalous cardiac veins.

Antidromic and orthodromic reciprocating tachycardias over a novel left-sided accessory pathway involving the vein of Marshall and coronary sinus musculature.

INTRODUCTION: Herein, we present a rare case of the successful ablation of an accessory pathway (AP) involving the Marshall Bundle (MB) and coronary sinus musculature (CSM) in a 40-year-old man with Wolff-Parkinson-White syndrome. METHODS AND RESULTS: An orthodromic reciprocating tachycardia (ORT) was inducible with the earliest atrial activation site located at the posterolateral mitral annulus. The local conduction and the cycle length of ORT was prolonged by peri-mitral ablation; however, it failed to block the AP. The atrial insertion of the AP was identified by remapping during ORT at the left atrial ridge, which was away from the mitral annulus, where ablation was successful. Together with the electrophysiological findings in CSM potentials, we conclude that the epicardial MB-CSM connection functioned as the AP in this patient. CONCLUSION: The novel variant form of AP comprised of MB and CSM should be noted. The atrial insertion of the MB may be the target of catheter ablation.

The Impact of Coronary Sinus Reducer on Arrhythmic Properties in Patients with Refractory Angina.

Background: Treatment with a coronary sinus reducer (CSR) is a new therapeutic option for refractory angina patients. Preclinical studies have shown antiarrhythmic properties of coronary sinus narrowing. The possible antiarrhythmic effect of CSR implantation is unknown. This study aimed to determine the possible antiarrhythmic effects of CSR implantation as assessed by high-resolution electrocardiogram (hrECG) parameters. Methods: 24 patients from the Crossroad study randomized to either CSR treatment (n = 12) or a sham procedure (n = 12) had hrECG recorded at baseline and after 6 months. T-peak and T-end interval (TpTe) defined as the time difference between the peak amplitude of the T wave and the global end of the T wave, spatial angle between QRS complex and T axis defined as the angle between the ventricular depolarization and repolarization vectors using maximal (QRSTP) and mean (QRSTM) vector amplitudes and spatial ventricular gradient (SVG) calculated as integral of ECG voltages over the entire QRST complex were analyzed. Additionally, we analyzed parameters of QT and heart rate variability using time and frequency domain. Results: At baseline, all analyzed parameters were comparable between both groups and heart rate remained constant. The intragroup analysis did not show any significant change in TpTe, QRSTP, QRSTM, SVG, QT, and heart rate variability at follow-up. Furthermore, intergroup comparison between CSR implantation and sham procedure also did not show any significant difference in the change of analyzed parameters. Conclusions: Compared to the sham procedure, CSR implantation did not demonstrate a significant impact on the arrhythmogenic substrate assessed with hrECG. Clinical Trial Registration: Unique Identifier: NCT04121845, https://classic.clinicaltrials.gov/ct2/show/NCT04121845.

Keeping it in the family: Use of the grandmother, mother, and child technique to navigate complex anatomy during Coronary sinus Reducer Implantation.

The Coronary Sinus Reducer® (CSR) is an emerging therapy for refractory angina recommended once no further pharmacologic or coronary revascularization options are available. We present the case of a 72-year-old man who underwent CSR implantation. Complex coronary sinus anatomy necessitated an innovative "grandmother, mother, and child" catheter approach.