Association of right bundle branch block or intraventricular conduction delay with recurrence of atrial fibrillation after catheter ablation.

BACKGROUND: The association between bundle branch block (BBB) and recurrence of atrial fibrillation (AF) after catheter ablation is unclear. The aim of this study was to determine whether AF combined with BBB is associated with AF recurrence after catheter ablation. METHODS: A total of 477 consecutive AF patients who underwent catheter ablation were included. The AF patients were divided into three groups according to BBB: AF without BBB (n = 427), AF with right bundle branch block (AF with RBBB) (n = 16), and AF with intraventricular conduction delay (AF with IVCD) (n = 34). RESULTS: Of the 477 AF patients (mean age 57 years, 81% men, median CHA2 DS2 -VASc score of 1), 16 (3.4%) patients had RBBB, and 34 (7.1%) patients had IVCD. During a mean follow-up of 15.2 ± 6.7 months, 119 patients (24.9%) had recurrence of AF. Of these, 111 (26%) patients were in the AF without BBB group, with 2 (12.5%) and 6 (17.6%) patients in the RBBB and IVCD groups, respectively. The Kaplan-Meier estimate of the rate of recurrent AF was not significantly different among the three groups (p = .39). Multivariable analysis showed that persistent AF (HR 1.7, 95% CI 1.15-2.50, p = .007), chronic kidney disease (HR 2.94, 95% CI 1.20-7.17, p = .01), and left atrial diameter (HR 1.04, 95% CI 1.009-1.082, p = .01) were significantly associated with AF recurrence. CONCLUSION: AF with BBB was not significantly associated with the recurrence of AF after catheter ablation in middle-aged patients with low-risk cardiovascular profile.

Predictors of Successful Endocardial Ablation of Epicardial Left Ventricular Summit Arrhythmias.

Endocardial catheter ablation of ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) at remote structures adjacent to the LVS may be an alternative (anatomic approach) but may not be so successful. This type of catheter ablation is successful most commonly in the left ventricular outflow tract followed by the aortic cusps and rarely in the right ventricular outflow tract. A right bundle branch block QRS morphology and anatomic distance between the earliest ventricular activation site in the coronary venous system and endocardial ablation site (<13 mm) could be predictors of a successful endocardial catheter ablation of LVS VAs.

Fascicular ventricular tachycardia arising from the left side His and its adjacent region: a subset of upper septal idiopathic left ventricular tachycardia.

AIMS: Fascicular ventricle tachycardia (FVT) arising from the proximal aspect of left His-Purkinje system (HPS) has not been specially addressed. Current study was to investigate its clinical, electrocardiographic, and electrophysiological characteristics. METHODS AND RESULTS: Eighteen patients who were identified as this rare FVT were consecutively enrolled, and their scalar electrocardiogram and electrophysiological data were collected and analysed. The ventricular tachycardia (VT) morphology was similar to sinus rhythm (SR) in eight patients, left bundle branch block type in one patient, right bundle branch block type in seven patients, and both narrow and wide QRS type in two patients. During VT, right-sided His potential preceded the QRS with His-ventricle (H-V) interval of 36.3 ± 12.4 ms, which was shorter than that during SR (-51.4 ± 8.6 ms) (P = 0.002). The earliest Purkinje potentials (PPs) were recorded within 7 ± 3 mm of left-side His and preceded the QRS by 49.1 ± 14.0 ms. Mapping along the left anterior fascicle and left posterior fascicle revealed an antegrade activation sequence in all with no P1 potentials recorded. In the two patients with two VT morphologies, the earliest PP was documented at the same site, and the activation sequence of HPS remained antegrade. Ablation at the earliest PP successfully eliminated the tachycardia, except one patient who developed complete atrial-ventricular block and two patients who abandoned ablations. After at least 12 months follow-up, 15 patients were free from any recurrences. CONCLUSIONS: Fascicular ventricle tachycardia arising from the proximal aspect of left HPS was featured by recording slightly shorter H-V interval and absence of P1 potentials. Termination of VT requires ablation at the left-sided His or its adjacent region.

Right-sided approach to left bundle branch area pacing combined with atrioventricular node ablation in a patient with persistent left superior vena cava and left bundle branch block: a case report.

BACKGROUND: Left bundle branch area pacing (LBBAP) is an alternative to right ventricular (RV) and biventricular (BiV) pacing in patients scheduled for pace and ablate treatment strategy. However, current delivery sheaths are designed for left-sided implantation, making the right-sided LBBAP lead implantation challenging. CASE PRESENTATION: We report a case of a right-sided LBBAP approach via right subclavian vein in a heart failure patient with a persistent left superior vena cava scheduled for pace and ablate treatment of refractory atrial flutter. To enable adequate lead positioning and support for transseptal screwing, the delivery sheath was manually modified with a 90-degree curve at the right subclavian vein and superior vena cava junction to allow right-sided implantation. The distance between the reshaping point and the presumed septal region was estimated by placing the sheath on the body surface under fluoroscopy. With the reshaping of the delivery sheath, we were able to achieve LBBAP with relatively minimal torque. Radiofrequency ablation of the atrioventricular node was performed the next day and the pacing parameters remained stable in short-term follow-up. CONCLUSION: With the modification of currently available tools, LBBAP can be performed with the right-sided approach.

Posterior Fascicular Ventricular Tachycardia: A Rare Cause of Tachycardia.

A 13-year male patient with a history of tachycardia attacks was diagnosed to have left posterior fascicular ventricular tachycardia (VT) according to the electrocardiogram (ECG) obtained at the emergency service. This diagnosis was confirmed with advanced electrophysiological studies and the case was diagnosed by genetic evaluation, which was performed to reveal the underlying cause, to have Brugada type 2 syndrome that might be associated with sudden cardiac death. Underlying causes should be evaluated, although idiopathic VTs generally have a good prognosis. Key Words: Brugada syndrome, Posterior fascicular ventricular tachycardia, Right bundle branch block.

Electrocardiographic characteristics and ablation of ventricular arrhythmias originating from the basal inferoseptal area.

AIMS: Ventricular arrhythmias (VAs) from the basal inferoseptal (BIS) area are rare and can pose unique challenges during catheter ablation (CA) due to the anatomic complexity. The study sought to describe the electrocardiographic and clinical characteristics of VAs originating from the BIS area. METHODS AND RESULTS: Patients with VAs and successful ablation at the BIS area from 2016 to 2020 were included. The 12-lead electrocardiogram (ECG), intracardiac findings, and outcomes were analysed. Of 482 patients with VAs referred for CA, 17 (3.5%) had successful ablation at BIS area. There were 12 males, mean age was 66.7 ± 9 years, 82% had ejection fraction <50%. Mean baseline premature ventricular complex burden was 28.6 ± 9%. All patients had a leftward superior axis. Left bundle branch block (LBBB) with early transition in V2 was noted in eight patients and right bundle branch block (RBBB) in nine patients. Detailed mapping of the right ventricle (RV) was performed in 15 patients (88%), coronary sinus (CS)/middle cardiac vein (MCV) in 13 (76%), right atrium (RA) adjacent to the inferoseptal process (ISP) of left ventricle (LV) in 5 (29%), ISP-LV in 13 (76%), and epicardium in 2 (12%). Successful ablation site was in LV in 10 (59%), RV in 2 (12%), CS/MCV in 1 (6%), RA in 1 (6%), and epicardium in 2 (12%). Fifteen patients (88%) required mapping in at least two chambers (range 2-5) and seven patients (41%) required ablation in at least two chambers (range 2-3). CONCLUSIONS: Ventricular arrhythmias originating in the BIS are uncommon. The most common ECG patterns were leftward superior axis, LBBB with transition in V2 or RBBB. The VA foci can be endocardial or epicardial and meticulous mapping/ablation from multiple chambers is often required to eliminate these foci successfully.

Reappraisal of electrocardiographic criteria for localization of idiopathic outflow region ventricular arrhythmias.

BACKGROUND: Electrocardiographic (ECG) criteria have been proposed to localize the site of origin of outflow region ventricular arrhythmias (VAs). Many factors influence the QRS morphology of VAs and may limit the accuracy of these criteria. OBJECTIVE: The purpose of this study was to assess the accuracy of ECG criteria that differentiate right from left outflow region VAs and localize VAs within the aortic sinus of Valsalva (ASV). METHODS: One hundred one patients (mean age 52 ± 16 years; 55 [54%] women) undergoing catheter ablation of right ventricular outflow tract (RVOT) or ASV VAs with a left bundle branch block, inferior axis morphology were studied. ECG measurements including V2 transition ratio, transition zone index, R-wave duration index, R/S amplitude index, V2S/V3R index, V1-3 QRS morphology, R-wave amplitude in the inferior leads were tabulated for all VAs. Comparisons were made between the predicted site of origin using these criteria and the successful ablation site. RESULTS: Patients had successful ablation of 71 RVOT and 38 ASV VAs. For the differentiation of RVOT from ASV VAs, the positive predictive values and negative predictive values for all tested ECG criteria ranged from 42% to 75% and from 71% to 82%, respectively, with the V2S/V3R index having the largest area under the curve of 0.852. Morphological QRS criteria in leads V1 through V3 did not localize ASV VAs. The maximum R-wave amplitude in the inferior leads was the sole criterion demonstrating a significant difference between right ASV, right-left ASV commissure, and left ASV sites. CONCLUSION: ECG criteria for differentiating right from left ventricular outflow region VAs and for localizing ASV VAs have a limited accuracy.

Minimally decremental atriofascicular accessory pathway with bidirectional conduction.

Atriofacicular pathways of Mahaim type are typically decrementally conducting accessory pathways without retrograde conduction properties, located on the right ventricular free wall at the tricuspid annulus. We report a patient with an atriofascicular pathway with minimal anterograde decremental conduction. Both long and short V-H antidromic atriofascicular reentrant tachycardias were induced and mechanism confirmed with electrophysiologic testing. Additionally, orthodromic atriofascicular reentrant tachycardia with narrow and right bundle branch block morphologies were inducible. Mahaim pathway was successfully ablated with elimination of both antidromic and orthodromic tachycardias.

Phrenic nerve stimulation, a rare complication of pacemaker: A case report.

RATIONALE: The phrenic nerve stimulation (PNS) is a rare complication after pacemaker setting. We report a case report that describes this complication and how it can be resolved. PATIENT CONCERNS: An 88-year-old man presented himself to the emergency geriatric unit with intermittent painless abdominal contraction due to phrenic nerve stimulation. He has a history of transcatheter aortic valve implantation with cardiac resynchronization therapy pacemaker due to persistent left bundle branch block. DIAGNOSES: All the usual causes for abdominal spasms were eliminated and the possibility of a link with the pacemaker was considered. The phrenic nerve stimulation is a rare complication of a pacemaker implantation. It can be clinically nonrelevant but challenging to diagnose for those not familiar with cardiac devices technology. INTERVENTIONS: Initial setting was an axis of stimulation between distal left ventricular (LV) and right ventricular. It was changed to LV and D1-M2. OUTCOMES: This noninvasive procedure managed to eradicate the involuntary abdominal spasms. LESSONS: PNS could be challenging to diagnose for those not familiar with cardiac devices technology but easy to manage with noninvasive methods.

Alternating and gradually changing narrow QRS complex tachycardia in a patient with heart failure: What is the mechanism?

A 23-year-old woman with palpitations for 9 years was referred for catheter ablation. ECG showed an irregular narrow complex tachycardia with alternating and gradually changing QRS morphologies after alternating and changing RR intervals, with a clear pattern of 2 alternating QRS complexes. An electrophysiology study was performed and confirmed that the mechanism of tachycardia was an automatic left-side His-Purkinje system (HPS) ventricular tachycardia. The gradually changing type-2 QRS complexes was the conduction delayed in the left anterior fascicle due to the short RR interval or the short left-side HH interval. Nine months after the index electrophysiology study, the patient encounter a progressive of heart failure with increased heart rate to 130-150 bpm during rest. Radiofrequency ablation was performed at the upper-septum for eliminating the tachycardia and resulted in complete atrioventricular block. A permanent pacemaker with left bundle branch pacing was implanted. Twelve months after the ablation, the enlarged heart shrink to normal with normal left ventricular ejection fraction. In conclusion, careful interpretation of the ECG can identify the sinus P waves followed by irregular narrow complexes, thus avoiding misdiagnosis and unnecessary treatment. Unifocal HPS tachycardia could present with alternating and gradually changing narrow QRS complexes tachycardia and lead to tachycardia cardiomyopathy. Electrophysiology study and catheter ablation were useful for the diagnosis and treatment of HPS tachycardia but with high risk of atrioventricular block. However, successfully elimination the tachycardia would resolve and reverse the enlarged heart and deteriorative heart function.

Remote magnetic-guided ablation for three origins of idiopathic ventricular arrhythmias with right bundle branch block and superior axis.

BACKGROUND: Idiopathic ventricular arrhythmias (IVAs) with right bundle branch block (RBBB) and superior axis commonly originate from posterior mitral annulus (PMA), the left ventricular (LV) posterior fascicle (LPF), and the LV posterior papillary muscles (PPM). HYPOTHESIS: Remote magnetic navigation (RMN)-guided ablation might be safe and effective for these three origins of IVAs. METHODS: Thirty consecutive IVA patients with RBBB and superior axis (11 MPA-IVAs, 11 LPF-IVAs, and 8 PPM-IVAs) were included in this study. Electrical mapping and ablation with RMN were performed in the LV through a trans-septal approach. Navigation index, defined as the ratio of total radiofrequency (RF) time and the time from first burn to last burn, was used to determine the efficiency of RMN-guided ablation. RESULTS: The overall acute success rate was achieved in 93% (PMA, 100%; LPF, 91%; PPM, 88%; p > 0.05). No complication occurred in this study. The procedure time of PPM-IVAs group was 34 and 14 min longer when compared with MPA-IVAs and LPF-IVAs group, respectively, without an increase of X-ray time. The mean navigation index was 0.45 ± 0.20. The PPM-IVAs group had an underperforming navigation index value (0.29 ± 0.11) (p < 0.01), as longer RF time was required in the PPM-IVAs group. CONCLUSIONS: RMN-guided ablation can achieve a high acute success rate for IVAs with RBBB and superior axis. The lower navigation index for PPM-IVAs indicated that increasing the RF time and improving the catheter contact should be considered when using RMN.

Conduction disturbances in low-surgical-risk patients undergoing transcatheter aortic valve replacement with self-expandable or balloon-expandable valves.

Despite a considerable improvement in TAVR devices and procedures, together with a reduction in procedural complications, the rate of conduction disturbances (CD) remained stable over the years. Indeed, the CD rate is still significantly higher than in surgical aortic valve replacement, and represents one of the main limitations to the expansion of TAVR to younger low-risk patients. The aim of the present study was to assess the incidence and predictors of CD in low-risk patients undergoing TAVR. Among 637 patients without preexisting CD who underwent TAVR, 116 (18.2%) were considered at low surgical risk. Up to 25% of low-risk patients presented with persistent CD at discharge. The pacemaker implantation rate was similar in the low-risk group compared to the intermediate-/high-risk group (8.7% vs 10.6%, p = 0.55). Moreover, the rate of new persistent left bundle branch block (LBBB) following TAVR was also similar between both groups (18.1% vs 22.1%, p = 0.34). At 1-year follow-up, LBBB was persistent in 62.5% of patients and 3 of them required a pacemaker implantation. Depth of valve implantation, baseline QRS duration and mean aortic transvalvular gradient were identified as independent predictors of CD in low-risk patients. Patients at low surgical risk showed an equivalent CD rate than intermediate-/high-risk patients. The depth of valve implantation was the main predictor of CD in low-risk patients undergoing TAVR. Baseline QRS duration and mean aortic transvalvular gradient were also associated with increased CD.

Electrocardiographic and clinical predictors for permanent pacemaker requirement after transcatheter aortic valve implantation: a 10-year single center experience.

BACKGROUND: The aim of this study is to identify clinical, electrocardiographic (ECG) and procedural predictors for permanent pacemaker (PPM) requirement after transaortic valve implantation (TAVI). METHODS: All consecutive patients with severe symptomatic aortic stenosis (SSAS) undergoing TAVI at our single center were included in the study and prospectively followed. All patients had standard 12-leads ECGs recordings before and after TAVI and continuous ECG monitoring during hospital stay. Primary endpoint was to identify electrocardiographic predictors of PPM implantation after TAVI; secondary endpoint was to ascertain other clinical or procedure-related predictive factors of PPM need. PPM implantation was further arbitrarily divided into early and late one (beyond the 3rd day). RESULTS: Among the 431 patients undergoing TAVI between 2008 and 2018, 77 (18%) needed PPM implantation; 47 (11%) had an early procedure, and 30 (7%) a late implant. Preoperative right bundle branch block (RBBB) implies more than five-fold increase of the risk of PPM implantation (OR 5.19, CI 1.99-13.56, P=0.001), whereas the use of a self-expandable prosthesis is associated with an almost three-fold increase of the risk (OR 2.60, CI 1.28-5.28, P=0.008). In the late PPM implantation subgroup, only the history of syncope retains a significant association with such an increased risk (OR 2.71, CI 1.09-6.75, P=0.032). CONCLUSIONS: The need of a PPM in the individual TAVI patient is hardly predictable. However, the finding of pre-existing RBBB, the use of self-expandable prosthesis and history of syncope can individuate patients at increased risk.

Clinical Outcomes According to ECG Presentations in Infarct-Related Cardiogenic Shock in the Culprit Lesion Only PCI vs Multivessel PCI in Cardiogenic Shock Trial.

BACKGROUND: The impact of ECG presentations of acute myocardial infarction (AMI) in cardiogenic shock is unknown. RESEARCH QUESTION: In myocardial infarction with cardiogenic shock, is there a difference in the outcomes and effect of revascularization strategies between non-ST-segment elevation myocardial infarction (NSTEMI) and left bundle branch block myocardial infarction (LBBBMI) vs ST-segment elevation myocardial infarction (STEMI)? STUDY DESIGN AND METHODS: Cardiogenic shock patients from the CULPRIT-SHOCK trial with NSTEMI or LBBBMI were compared with STEMI patients for 30-day and 1-year all-cause mortality. The interaction between ECG presentation and the effect of revascularization strategies on outcomes was evaluated. RESULTS: Of 665 cardiogenic shock patients analyzed, 55.9% demonstrated STEMI, 29.3% demonstrated NSTEMI, and 14.7% demonstrated LBBBMI. Patients differed in mean age (68.0 years in STEMI patients, 71.0 years in NSTEMI patients, and 73.5 years in LBBBMI patients; P = .015), cardiovascular risk factors, and angiographic severity. No difference was found in the 30-day risk of death between NSTEMI and STEMI patients (48.7% vs 43.0%; adjusted OR [aOR], 1.05; 95% CI, 0.66-1.67; P = .85), nor between LBBBMI and STEMI patients (59.2% vs 43.0%; aOR, 1.31; 95% CI, 0.73-2.34; P = .36). Although the univariate risk of death by 1 year was higher in NSTEMI and LBBBMI patients compared with STEMI patients, ECG presentation was not an independent risk factor of mortality after adjustment (NSTEMI vs STEMI: 56.4% vs 46.8%; aOR, 1.21; 95% CI, 0.76-1.92; P = .42; LBBBMI vs STEMI: 69.4% vs 46.8%; aOR, 1.59; 95% CI, 0.89-2.84; P = .12). ECG presentation did not modify the effect of the revascularization strategy on 30-day and 1-year mortality (P = .91 and P = .97 for interaction). INTERPRETATION: In patients with cardiogenic shock, NSTEMI and LBBBMI presentations reflect higher-risk profiles than STEMI presentations, but are not independent risk factors of mortality. ECG presentations did not modify the treatment effect, supporting culprit-lesion-only percutaneous coronary intervention as the preferred strategy across the AMI spectrum.

Right bundle branch block ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy more commonly originates from the right ventricle: Criteria for identifying chamber of origin.

BACKGROUND: Right bundle branch block (RBBB) ventricular tachycardia (VT) morphology is a criterion for left ventricular (LV) involvement in arrhythmogenic right ventricular cardiomyopathy (ARVC). OBJECTIVE: The purpose of this study was to determine the frequency and chamber of origin of RBBB VT in patients with ARVC and VT. METHODS: We studied 110 consecutive patients with VT who met the diagnostic International Task Force criteria for ARVC and underwent VT mapping/ablation. Patients with ≥1 RBBB VT were identified. Right ventricular (RV) origin of the RBBB VT was determined based on standard mapping criteria and elimination with ablation. RESULTS: Nineteen patients (17%) had 26 RBBB VTs. Eleven of these 19 patients (58%) had 16 RBBB VTs from the RV, and 9 patients (47%) had 10 RBBB VTs originating from the LV, with 1 patient demonstrating both. RBBB VT from RV most commonly (13/16 RBBB VTs) had an early precordial QRS transition (V2 or V3), with superiorly and typically leftward directed frontal plane axis, consistent with exit from dilated RV adjacent to inferior LV septum, whereas all 10 VTs from LV had RBBB morphology with positive R waves to V5 or V6 and rightward axis in 6 VTs characteristic of basal lateral origin. CONCLUSION: In patients with ARVC and VT presenting for VT ablation, RBBB VT occurs in 17% of cases, with most RBBB VTs (62%) originating from the RV and not indicative of LV origin. Precordial R-wave transition and frontal plane axis can be used to identify the anticipated chamber of origin of RBBB VT.

Complex Re-Entrant Arrhythmias Involving the His-Purkinje System: A Structured Approach to Diagnosis and Management.

OBJECTIVES: This study sought to characterize the presentations, electrophysiological features and diagnostic maneuvers for a series of unique arrhythmias involving the HPS. BACKGROUND: By virtue of its unique anatomy and ion channel composition, the His-Purkinje system (HPS) is prone to a variety of arrhythmic perturbations. METHODS: The authors present a collaborative multicenter case series of 6 patients with HPS-related arrhythmias. All patients underwent electrophysiological studies using standard multipolar catheters. RESULTS: In 3 patients, both typical and reverse bundle branch re-entry were seen, with 1 patient demonstrating "figure of 8" re-entry likely involving the septal fascicle. One patient presented with systolic dysfunction associated with a high premature ventricular complex burden, with the mechanism being bundle-to-bundle re-entrant beats masquerading as dual response to a single sinus impulse. Two patients were diagnosed with interfascicular re-entry. Diagnosis was aided by careful assessment of HV interval in sinus rhythm and ventricular tachycardia, multipolar catheters to assess the activation sequence of the His-right bundle branch, and fascicles and entrainment of different components of the HPS. Cure of the arrhythmia was achieved by ablation of the right bundle branch block in 3 patients, the left septal fascicle in 2 patients, and the left posterior fascicle in 1 patient. CONCLUSIONS: Proper diagnosis of re-entrant arrhythmias involving the HPS may prove challenging. We emphasize a structured approach for diagnosis and effective therapy.