A Revised Definition of Left Bundle Branch Block Using Time to Notch in Lead I.

Importance: Current left bundle branch block (LBBB) criteria are based on animal experiments or mathematical models of cardiac tissue conduction and may misclassify patients. Improved criteria would impact referral decisions and device type for cardiac resynchronization therapy. Objective: To develop a simple new criterion for LBBB based on electrophysiological studies of human patients, and then to validate this criterion in an independent population. Design, Setting, and Participants: In this diagnostic study, the derivation cohort was from a single-center, prospective study of patients undergoing electrophysiological study from March 2016 through November 2019. The validation cohort was assembled by retrospectively reviewing medical records for patients from the same center who underwent transcatheter aortic valve replacement (TAVR) from October 2015 through May 2022. Exposures: Patients were classified as having LBBB or intraventricular conduction delay (IVCD) as assessed by intracardiac recording. Main Outcomes and Measures: Sensitivity and specificity of the electrocardiography (ECG) criteria assessed in patients with LBBB or IVCD. Results: A total of 75 patients (median [IQR] age, 63 [53-70.5] years; 21 [28.0%] female) with baseline LBBB on 12-lead ECG underwent intracardiac recording of the left ventricular septum: 48 demonstrated complete conduction block (CCB) and 27 demonstrated intact Purkinje activation (IPA). Analysis of surface ECGs revealed that late notches in the QRS complexes of lateral leads were associated with CCB (40 of 48 patients [83.3%] with CCB vs 13 of 27 patients [48.1%] with IPA had a notch or slur in lead I; P = .003). Receiver operating characteristic curves for all septal and lateral leads were constructed, and lead I displayed the best performance with a time to notch longer than 75 milliseconds. Used in conjunction with the criteria for LBBB from the American College of Cardiology/American Heart Association/Heart Rhythm Society, this criterion had a sensitivity of 71% (95% CI, 56%-83%) and specificity of 74% (95% CI, 54%-89%) in the derivation population, contrasting with a sensitivity of 96% (95% CI, 86%-99%) and specificity of 33% (95% CI, 17%-54%) for the Strauss criteria. In an independent validation cohort of 46 patients (median [IQR] age, 78.5 [70-84] years; 21 [45.7%] female) undergoing TAVR with interval development of new LBBB, the time-to-notch criterion demonstrated a sensitivity of 87% (95% CI, 74%-95%). In the subset of 10 patients with preprocedural IVCD, the criterion correctly distinguished IVCD from LBBB in all cases. Application of the Strauss criteria performed similarly in the validation cohort. Conclusions and Relevance: The findings suggest that time to notch longer than 75 milliseconds in lead I is a simple ECG criterion that, when used in conjunction with standard LBBB criteria, may improve specificity for identifying patients with LBBB from conduction block. This may help inform patient selection for cardiac resynchronization or conduction system pacing.

Anticoagulation Patterns in Patients with Atrial Fibrillation Following Percutaneous Coronary Intervention in an Academic Center.

A common dilemma facing physicians treating patients with atrial fibrillation (AF) who have undergone percutaneous coronary intervention (PCI) is the management of oral anticoagulation (OAC) therapy, because there is also an indication for dual antiplatelet therapy in these patients. The purpose of this study was therefore to evaluate anticoagulation patterns in this patient population in an attempt to identify patterns of risk factors that may influence OAC prescribing habits. This retrospective study entailed a review of a total of 4,648 patients from two academic hospitals who underwent PCI between 2008 and 2016. We ultimately included 211 patients who had AF and an indication for OAC. Chart review revealed patients' risk factors, CHA2DS2-VASc and HAS-BLED scores, and antithrombotic regimens. Only 105 (49.8%) patients who met the indications for OAC were actually placed on OAC post-PCI. There was no significant relationship between discharge on OAC and HAS-BLED score (t = 0.14; p = 0.44) or CHA2DS2-VASc score (t = 0.76; p = 0.22). Patients younger than 65 years of age were prescribed more triple therapy (56% versus 33%; p < 0.01) or any OAC (69% versus 41%; p < 0.01) on discharge in comparison with patients 65 years of age or older. The older patient group had a significantly higher average CHA2DS2-VASc score (4.4 versus 3.2; p < 0.01) and a higher average HAS-BLED score (2.8 versus 2.4; p < 0.01). Ultimately, this study indicated that less than half of AF patients with an indication for OAC were placed on OAC post-PCI. There was no association between discharge on OAC and CHA2DS2-VASc score, HAS-BLED score, or any other individual risk factor, with the exception of age.

Left Atrial Appendage Occlusion Complicated by Appendage Perforation Rescued by Device Deployment.

The Watchman device is a transcatheter left atrial appendage (LAA) occluding device used in patients with nonvalvular atrial fibrillation (NVAF) and a high CHADS2-VA2SC score who are poor long-term anticoagulation candidates. Pericardial effusion related to device deployment and perforation can be a life-threatening complication. While not common in hands of experienced operators, management may require surgical intervention. Here we present a rare case of LAA perforation, which was corrected by successful repositioning of the device foregoing the need for surgical management.