Dual‐Dye Optical Mapping after Myocardial Infarction: Does the Site of Ventricular Stimulation Alter the Properties of Electrical Propagation?

Introduction: Myocardial infarction (MI) disrupts electrical conduction in affected ventricular areas. We investigated the effect of MI on the regional voltage and calcium (Ca) signals and their propagation properties, with special attention to the effect of the site of ventricular pacing on these properties.
Methods: New Zealand White rabbits were divided into four study groups: sham-operated (C, n = 6), MI with no pacing (MI, n = 7), MI with right ventricular pacing (MI + RV, n = 6), and MI with BIV pacing (MI + BIV, n = 7). At 4 weeks, hearts were excised, perfused, and optically mapped. As previously shown, systolic and diastolic dilation of the LV were prevented by BIV pacing, as was the reduction in LV fractional shortening.
Results: Four weeks after MI, optical mapping revealed markedly reduced action potential amplitudes and conduction velocities (CV) in MI zones, and these increased gradually in the border zone and normal myocardial areas. Also, Ca transients were absent in the infarcted areas and increased gradually 3–5 mm from the border of the normal zone. Neither BIV nor RV pacing affected these findings in any of the MI, border, or normal zones.
Conclusions: MI has profound effects on the regional electrical and Ca signals and on their propagation properties in this rabbit model. The absence of differences in these parameters by study group suggests that altering the properties of myocardial electrical conduction and Ca signaling are unlikely mechanisms by which BIV pacing confers its benefits. Further studies into the regional, cellular, and molecular benefits of BIV pacing are therefore warranted.     

Association between insurance status and in‐hospital outcomes in patients with out‐of‐hospital ventricular fibrillation arrest

BackgroundLack of health insurance is associated with adverse clinical outcomes; however, the association between health insurance status and in‐hospital outcomes after out‐of‐hospital ventricular fibrillation (OHVFA) arrest is unclear.HypothesisLack of health insurance is associated with worse in‐hospital outcomes after out‐of‐hospital ventricular fibrillation arrest.MethodsFrom January 2003 to December 2014, hospitalizations with a primary diagnosis of OHVFA in patients ≥18 years of age were extracted from the Nationwide Inpatient Sample. Patients were categorized into insured and uninsured groups based on their documented health insurance status. Study outcome measures were in‐hospital mortality, utilization of implantable cardioverter defibrillator (ICD), and cost of hospitalization. Inverse probability weighting adjusted binary logistic regression was performed to identify independent predictors of in‐hospital mortality and ICD utilization and linear regression was performed to identify independent predictors of cost of hospitalization.ResultsOf 188 946 patients included in the final analyses, 178 005 (94.2%) patients were insured and 10 941 (5.8%) patients were uninsured. Unadjusted in‐hospital mortality was higher (61.7% vs. 54.7%, p < .001) and ICD utilization was lower (15.3% vs. 18.3%, p < .001) in the uninsured patients. Lack of health insurance was independently associated with higher in‐hospital mortality (O.R = 1.53, 95% C.I. [1.46–1.61]; p < .001) and lower utilization of ICD (O.R = 0.84, 95% C.I [0.79–0.90], p < .001). Cost of hospitalization was significantly higher in uninsured patients (median [interquartile range], p‐value) ($) (39 650 [18 034‐93 399] vs. 35 965 [14 568.50‐96 163], p < .001).ConclusionLack of health insurance is associated with higher in‐hospital mortality, lower utilization of ICD and higher cost of hospitalization after OHVFA.     

A Specific Angiographic View of Left Coronary Artery Bifurcation in the Left Main Percutaneous Coronary Intervention Era

Objectives

We propose a right lateral (90–120° RAO) with 30° cranial angiographic view to expose the bifurcation of the left main coronary artery (LMCA) when previously used routine projections were inefficient at clearly showing this region.

Background

Little has been published in the medical literature regarding angiographic projections dedicated to special anatomies.

Methods

A total of 84 patients were subjected to the proposed projections. A reproducibility study, conducted with the participation of 2 independent observers, judged the effectiveness of the proposed projection. The Prevalence and Bias Adjusted Kappa (PABAK) index, with a 95% confidence interval (CI), was used to demonstrate the intensity of intra/inter‐observer agreement.

Results

The proposed projection was efficient in 79% of the angiograms, with agreement of 0.76 (0.6–0.9; P ≤ 0.001). The origins and the proximal segments of: the anterior descending coronary artery were exposed in 89% of the angiograms, agreement of 0.86 (0.7–1.0; P ≤ 0.001); the circumflex artery were exposed in 83% of the angiograms, with agreement of 0.72 (0.5–1.0; P ≤ 0.001); and the intermediate branch, when present, were exposed in 89% of the angiograms, agreement of 0.79 (0.6–1.0; P ≤ 0.001).

Conclusion

The right lateral (90–120° RAO) with 30° cranial projection is effective, safe, and reproducible. In special situations where routine projections fail, this proposed projection can reveal important details of the anatomy of the bifurcation of the LMCA during conventional coronary angiography or be the working projection during coronary angioplasty. (J Interven Cardiol 2016;29:293–299)

     

Postoperative Atrial Fibrillation or Flutter Following Transcatheter or Surgical Aortic Valve Replacement: PARTNER 3 Trial

ObjectivesThe aim of this study was to assess the incidence and prognostic impact of early and late postoperative atrial fibrillation or flutter (POAF) in patients with severe aortic stenosis (AS) treated with transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR).BackgroundThere is an ongoing controversy regarding the incidence, recurrence rate, and prognostic impact of early (in-hospital) POAF and late (postdischarge) POAF in patients with AS undergoing TAVR or SAVR.MethodsIn the PARTNER (Placement of Aortic Transcatheter Valve) 3 trial, patients with severe AS at low surgical risk were randomized to TAVR or SAVR. Analyses were performed in the as-treated population excluding patients with preexistent atrial fibrillation or flutter.ResultsAmong 781 patients included in the analysis, early POAF occurred in 152 (19.5%) (18 of 415 [4.3%] and 134 of 366 [36.6%] following TAVR and SAVR, respectively). Following discharge, 58 new or recurrent late POAF events occurred within 1 year following the index procedure in 55 of 781 patients (7.0%). Early POAF was not an independent predictor of late POAF following discharge (odds ratio: 1.04; 95% CI: 0.52-2.08; P = 0.90). Following adjustment, early POAF was not an independent predictor of the composite outcome of death, stroke, or rehospitalization (hazard ratio: 1.10; 95% CI: 0.64-1.92; P = 0.72), whereas late POAF was associated with an increased adjusted risk for the composite outcome (hazard ratio: 8.90; 95% CI: 5.02-15.74; P < 0.0001), irrespective of treatment modality.ConclusionsIn the PARTNER 3 trial, early POAF was more frequent following SAVR compared with TAVR. Late POAF, but not early POAF, was significantly associated with worse outcomes at 2 years, irrespective of treatment modality.     

Characteristics of atherosclerotic plaque distribution in coronary artery bifurcations: an intravascular ultrasound analysis

OBJECTIVE: Vessel bifurcations are prone to atherosclerotic plaque accumulation. Using volumetric intravascular ultrasound analysis, we investigated atheroma distribution at human coronary bifurcations in vivo. METHODS: We analyzed plaque distribution in 49 left anterior descending coronary artery-diagonal and 20 left circumflex coronary artery-obtuse marginal bifurcations with <50% angiographic stenosis. Cross-sections were analyzed at 1 mm intervals in segments 5 mm proximal and distal from the bifurcation. Planimetry of the lumen and external elastic membrane (EEM) was performed and plaque thickness measured at four different points relative to the branch: 0 degrees, 90 degrees, 180 degrees and 270 degrees. EEM, lumen and plaque volume and percentage plaque burden (plaque volume/EEM volume) were calculated in the proximal and distal segments. The side-branch take-off angle was analyzed in the cross-sectional images. RESULTS: Volumetric analysis showed that EEM, lumen and plaque were larger (P<0.001) in proximal segments than distal segments, whereas percent plaque burden was similar in these segments. Plaque accumulated on the opposite wall to the flow divider. Plaque distribution tended to be more eccentric in distal segments (P=0.05) compared to proximal segments. In 26 of 69 lesions, an asymmetric side-branch take-off was found and was associated with asymmetric plaque distribution compared to those lesions that had a symmetric side-branch take-off (P<0.01). CONCLUSION: We found characteristic patterns of plaque distribution at coronary bifurcations. Proximal segments demonstrated larger plaque volume than distal segments, despite similar percentages of plaque burden. Plaque volume accumulated opposite to the flow divider, especially in distal segments. The side-branch take-off angle in the cross-sectional plane influenced the plaque distribution in bifurcation lesions.