Defining the distance between the His bundle and first septal perforator: implications for left bundle branch pacing.

BACKGROUND: Left bundle branch pacing (LBBP) is a developing method of native conduction pacing, but cases of injury to the septal perforator arteries during implantation have been reported. Knowing the distance between the His bundle and the first septal perforator artery can help operators implant LBBP leads more safely. METHODS: Using previously performed coronary CT angiography (CCTA) studies, the distance between the His bundle and the first septal perforator was measured. RESULTS: A total of 50 CCTA studies were included. The mean distance from the His bundle to the first septal perforator (His-SP) along the line connecting the His bundle to the RV apex (His-RV apex) was 27.17 ± 7.7 mm with a range of 13.0 to 44.7 mm. The distance was greater than 2.0 cm in 84% of patients. To standardize this distance among patients with varying cardiac structures, the ratio between the His-SP distance and the His-RV Apex distance was also measured. The mean His-SP:His-RV Apex was 0.302 and the median was 0.298. Eighty-six percent of patients had a ratio of greater than 0.20. CONCLUSION: Using this information, operators can aim to implant LBBP leads within 2.0 cm of the His bundle or 20% of the distance between the His bundle and the RV apex with minimal risk of causing vascular injury.

Cardiac implantable device interrogation in left ventricular systolic dysfunction reveals physiologic abnormalities prior to symptom onset in COVID-19: a case series.

Background: COVID-19 has affected individuals across the globe, and those with cardiac implantable electronic devices (CIEDs) likely represent a high-risk group. These devices can be interrogated to reveal information about the patient activity, heart rate parameters, and respiratory rate. Case summary: Four patients with CIEDs and left ventricular dysfunction were admitted to a single institution for COVID-19 infection. Each patient survived hospitalization, and none required intensive care. Retrospectively, CIED interrogation revealed each patient had decreased activity level prior to their reporting COVID-19 symptoms. Similarly, respiratory rate increased before symptom onset for three of the patients, while one did not have these data available. Of the three patients with heart rate variability (HRV) available, two had decreased HRV before they developed symptoms. After hospital discharge, these parameters returned to their baseline. Discussion: This case series suggests physiologic changes identifiable through interrogation of CIEDs may occur prior to the reported onset of COVID-19 symptoms. These data may provide objective evidence on which to base more sensitive assessments of infectious risk when performing contact tracing in communities.

Racial and ethnic differences in left atrial appendage occlusion wait time, complications, and periprocedural management.

PURPOSE: Non-white patients are underrepresented in left atrial appendage occlusion (LAAO) trials, and racial disparities in LAAO periprocedural management are unknown. METHODS: We assessed sociodemographics and comorbidities of consecutive patients at our institution undergoing LAAO between 2015 and 2020, then in adjusted analyses, compared procedural wait time, procedural complications, and post-procedure oral anticoagulation (OAC) use in whites versus non-whites. RESULTS: Among 109 patients undergoing LAAO (45% white), whites had lower CHA2 DS2 VASc scores, on average, than non-whites (4.0 vs. 4.8, p = .006). There was no difference in median time from index event (IE) or initial outpatient cardiology encounter to LAAO procedure (whites 10.5 vs. non-whites 13.7 months, p = .9; 1.9 vs. 1.8 months, p = .6, respectively), and there was no difference in procedural complications (whites 4% vs. non-whites 5%, p = .33). After adjusting for CHA2 DS2 VASc score, OAC use at discharge tended to be higher in whites (OR 2.4, 95% CI [0.9-6.0], p = .07). When restricting the analysis to those with prior gastrointestinal (GI) bleed, adjusting for CHA2 DS2 VASc score and GI bleed severity, whites had a nearly five-fold odds of being discharged on OAC (OR 4.6, 95% CI [1-21.8], p = 0.05). The association between race and discharge OAC was not mediated through income category (total mediation effect 19% 95% CI [-.04-0.11], p = .38). CONCLUSION: Despite an increased prevalence of comorbidities amongst non-whites, wait time for LAAO and procedural complications were similar in whites versus non-whites. Among those with prior GI bleed, whites were nearly five-fold more likely to be discharged on OAC than non-whites, independent of income.

Atrial Fibrillation Triggered by Premature Ventricular Complexes: An Under-Recognized Trigger.

Atrial fibrillation (AF) is a triggered rhythm, and ablation of the trigger is a common strategy for rhythm control. We describe a patient with symptomatic AF who was found to have episodes of AF triggered by premature ventricular complexes, likely by retrograde atrioventricular nodal conduction. (Level of Difficulty: Beginner.).