Evaluation of Ventricular Repolarization in Patients Undergoing Cardiac Resynchronization Therapy (CRT) Using Two Modalities: Conventional Biventricular Pacing vs. His-Bundle Pacing

Introduction: Permanent His-bundle pacing (HBP) is being used as an alternative to biventricular pacing (BiVP) for CRT. HBP preserves the physiologic pattern of ventricular activation and markedly reduces ventricular dyssynchrony. While ventricular depolarization with HBP vs. BiVP has been studied, the effects of the 2 modalities on repolarization have not been compared. The purpose of this study was to compare ventricular repolarization in patients with HBP and BiVP. We hypothesize that HBP provides more physiologic repolarization as compared to BiVP. Methods: ECG repolarization parameters were analyzed in patients who underwent HBP and BiVP using the first available ECG post implant. Parameters included: 1) T Peak – T End (Tp-TeApical): Tp-Te in lead V5, and if not measurable, then in V4/V6 2) Tp-TeTotal: Earliest T peak to the latest T end across all precordial leads 3) T Peak Dispersion: Absolute difference between the earliest and latest T peaks across all precordial leads. Data was compared using a two-tailed unequal variance Student’s t-test. Results: Data from 23 HBP patients and 23 BiVP patients was analyzed. The average HBP Tp-TeApical of 74 ± 7ms was less than the BiVP Tp-TeApical of 112 ± 15ms (p\u3c0.01). Similarly, average HBP Tp-TeTotal of 106 ± 11ms was smaller than the BiVP Tp-TeTotal of 145 ± 17ms (p\u3c0.01). The difference between Tpeak dispersion between the two groups was not significant. Conclusion: Tp-Te interval, a known measure of dispersion of repolarization and marker of arrhythmic risk, is more physiologic (lower) with HBP as compared to BiVP. These data suggest that in addition to physiologic depolarization, HBP also provides physiologic repolarization and potentially lower arrhythmic risk compared to BiVP

The Pulmonary Venous Ridge Length to Stratify Stroke Risk in Atrial Fibrillation

Purpose of Study: To evaluate the left superior pulmonary venous ridge length (RL) and the left atrial appendage fractal dimension (LAA FD) as predictors of cardioembolic ischemic stroke (CVA) and transient ischemic attack (TIA) in patients with atrial fibrillation (AF). Materials, Methods and Procedures: A multicenter, retrospective multicenter study was conducted on patients with AF who underwent cardiac CT prior to catheter ablation between 01/01/2010 and 12/31/2015. Patients were grouped by the presence or absence of prior CVA/TIA. Patients with mitral stenosis, prior mechanical aortic valve replacement, ascending aortic arch atheroma, highrisk patent foramen ovale, history of atrial septal repair or device, preexisting LAA thrombus or intra-cardiac tumor, or prior open-heart surgery were excluded. Further exclusion was performed for patients with sub-optimal or unavailable cardiac CT imaging by investigators blinded to clinical data. Blinded investigators obtained RL by measuring the distance between the left superior pulmonary venous ostium and the internal ostium of the left atrial appendage. LAA FD was calculated using semi-automated volume rendering and processing software (ImageJ, Bethesda, MD) [1] and LAA FD are presented as means (95% confidence interval) and were compared between groups using unpaired t-tests. Logistic regression analysis was used to construct receiver operating curves and to assess the abilities of RL and LAA FD to predict prior CVA/TIA. Results: 225 patients met inclusion criteria. Mean RL were 4.32 (3.80-4.93) and 5.20 (4.93-5.48) for patients with (n=24; mean age: 59.4; 70.8% male) and without (n=165; mean age: 59.3; 75.4% male) prior CVA/TIA, respectively(p=0.033). Mean LAA FD were 2.29 (95% CI: 2.24-2.34) and 2.33 (2.32-2.34) for patients with (n=22; mean age: 60.3; 68.2% male) and without (n=171; mean age: 59.3; 74.9% male) prior CVA/TIA, respectively (p=0.052). In a regression model including LAA FD, RL, and established predictive markers, only RL predicted prior CVA/TIA (OR 0.73; 0.54 to 0.98; p=0.034). Discussion: Lower RL values were associated with prior CVA/TIA, whereas LAA FD values were similar between patients with AF with and without prior CVA/TIA. RL is a novel marker that may refine clinical decision-making regarding anticoagulation goals and treatment decisions for patients with AF. Future studies with larger samples should investigate the clinical utility of RL to improve CVA/TIA risk stratification of patients with AF and prospectively reduce the incidence of CVA/TIA in this population

Adverse Outcomes of Atrial Fibrillation Ablation in Heart Failure Patients With and Without Cardiac Amyloidosis: A Nationwide Readmissions Database Analysis (2015-2019)

AIMS: Atrial fibrillation (AF) in patients with cardiac amyloidosis (CA) has been linked with a worse prognosis. The current study aimed to determine the outcomes of AF catheter ablation in patients with CA. METHODS AND RESULTS: The Nationwide Readmissions Database (2015-2019) was used to identify patients with AF and concomitant heart failure. Among these, patients who underwent catheter ablation were classified into two groups, patients with and without CA. The adjusted odds ratio (aOR) of index admission and 30-day readmission outcomes was calculated using a propensity score matching (PSM) analysis. A total of 148 134 patients with AF undergoing catheter ablation were identified on crude analysis. Using PSM analysis, 616 patients (293 CA-AF, 323 non-CA-AF) were selected based on a balanced distribution of baseline comorbidities. At index admission, AF ablation in patients with CA was associated with significantly higher adjusted odds of net adverse clinical events (NACE) [adjusted odds ratio (aOR) 4.21, 95% CI 1.7-5.20], in-hospital mortality (aOR 9.03, 95% CI 1.12-72.70), and pericardial effusion (aOR 3.30, 95% CI 1.57-6.93) compared with non-CA-AF. There was no significant difference in the odds of stroke, cardiac tamponade, and major bleeding between the two groups. At 30-day readmission, the incidence of NACE and mortality remained high in patients undergoing AF ablation in CA. CONCLUSION: Compared with non-CA, AF ablation in CA patients is associated with relatively higher in-hospital all-cause mortality and net adverse events both at index admission and up to 30-day follow-up

Changing Characteristics Of The Surface P Wave With Aging, and Insights Into Inter-atrial Conduction - A Study Of 2,156 Patients Over 9 Decades Of Life

Objective To define changes in surface ECG P-wave morphology, vector, and duration with advancing age, and make inferences about IAC and risk of atrial fibrillatio

Matrix Metalloproteinase Levels Identify Heart Failure Patients with Higher Burden of Atrial Fibrillation

Presented at ACC Mid-Atlantic conference in Washington DC. INTRODUCTION/HYPOTHESIS •Adverse cardiac remodeling and fibrosis provide an arrhythmic substrate for atrial fibrillation (AF), but the role of matrix metalloproteinases (MMPs) as a biomarker is not well understood. MMPs are zinc-dependent endopeptidases known to degrade substrates such as elastin, gelatin and collagen. •In excised human atrial tissue, MMP 2 and 9 levels rise as the AF burden increases from sinus rhythm (“No AF”) to non-permanent AF (“Non-Prm AF”) to permanent AF (“PrmAF”). Higher plasma levels of MMPs are also associated with recurrent AF after cardioversion. •This study sought to elucidate 1) the relationship of these biomarker levels with AF burden and 2) the predictive value of biomarkers for future AF episode in patients with severely reduced left ventricular ejection fraction (LVEF) and implantable cardioverter-defibrillators (ICDs