Outcomes Associated With Early vs. Delayed Invasive Strategy in NSTEMI Complicated by High Degree AV Block: A Nationwide Analysis.

Background: High degree atrioventricular block (HDAVB) is an uncommon complication of non-ST-segment elevation myocardial infarction (NSTEMI) that frequently necessitates pacemaker implantation. This contemporary analysis compares need for pacemaker implantation based on the timing of intervention in acute NSTEMI complicated by HDAVB.Methods: We used 2016-2017 National Inpatient Sample database to identify admissions with NSTEMI and HDAVB. Time to coronary intervention from initial admission was used to segregate the admissions into two groups: early invasive strategy (EIS) (<24 hours) and delayed invasive strategy (DIS) (>24 hours). Multivariable linear and logistic regression analysis was performed to compare in-hospital outcomes among the two groups.Results: Out of 949,984 NSTEMI related admissions, coexistent HDAVB was present in 0.7% (n=6725) patients. Amongst those, 55.61% (n=3740) hospitalizations included invasive intervention (EIS=1320, DIS=2420). Patients treated with EIS were younger (69.95 years vs. 72.38 years, P<0.05) and had concomitant cardiogenic shock. Contrarily, prevalence of chronic kidney disease, heart failure, and pulmonary hypertension was higher in DIS group. EIS was associated with lower length of stay and total hospitalization cost. In-hospital mortality and pacemaker implantation rates were not significantly different between patients in the EIS and DIS groups.Conclusion: HDAVB is a rare complication of NSTEMI and often associated with right coronary artery disease. The timing of revascularization does not appear to influence the rate of pacemaker placement in NSTEMI complicated by HDAVB. Further studies are needed to assess if early invasive strategy can benefit all patients with NSTEMI and HDAVB.

Pacemaker dependency after transcatheter aortic valve implantation with the self-expanding Medtronic CoreValve System.

BACKGROUND/OBJECTIVES: To determine pacemaker (PM) dependency at follow-up visit in patients who underwent new permanent pacemaker implantation (PPI) following transcatheter aortic valve implantation (TAVI). METHODS: Single center prospective observational study including 167 patients without previous PM implantation who underwent TAVI with the self-expanding Medtronic CoreValve System (MCS) between November 2005 and February 2011. PM dependency was defined by the presence of a high degree atrioventricular block (HDAVB; second [AV2] and third degree [AV3B]), or a slow (<30 bpm) or absent ventricular escape rhythm during follow-up PM interrogation. RESULTS: A total of 36 patients (21.6%) received a new PM following TAVI. The indication for PM was AV2B (n=2, 5.6%), AV3B (n=28, 77.8%), postoperative symptomatic bradycardia (n=3, 8.3%), brady-tachy syndrome (n=1, 2.8%), atrial fibrilation with slow response (n=1, 2.8%) and left bundle branch block (n=1, 2.8%). Long term follow-up was complete for all patients and ranged from 1 to 40 months (median (IQR): 11.5 (5.0-18.0 months). Of those patients with a HDAVB, 16 out of the 30 patients (53.3%) were PM independent at follow-up visit (complete or partial resolution of the AV conduction abnormality). Overall, 20 out of the 36 patients (55.6%) who received a new PM following TAVI were PM independent at follow-up. CONCLUSION: Partial and even complete resolution of peri-operative AV conduction abnormalities after MCS valve implantation occurred in more than half of the patients.