Design and characteristics of the prophylactic intra-operative ventricular arrhythmia ablation in high-risk LVAD candidates (PIVATAL) trial.

BACKGROUND: The use of a Left Ventricular Assist Device (LVAD) in patients with advanced heart failure refractory to optimal medical management has progressed steadily over the past two decades. Data have demonstrated reduced LVAD efficacy, worse clinical outcome, and higher mortality for patients who experience significant ventricular tachyarrhythmia (VTA). We hypothesize that a novel prophylactic intra-operative VTA ablation protocol at the time of LVAD implantation may reduce the recurrent VTA and adverse events postimplant. METHODS: We designed a prospective, multicenter, open-label, randomized-controlled clinical trial enrolling 100 patients who are LVAD candidates with a history of VTA in the previous 5 years. Enrolled patients will be randomized in a 1:1 fashion to intra-operative VTA ablation (n = 50) versus conventional medical management (n = 50) with LVAD implant. Arrhythmia outcomes data will be captured by an implantable cardioverter defibrillator (ICD) to monitor VTA events, with a uniform ICD programming protocol. Patients will be followed prospectively over a mean of 18 months (with a minimum of 9 months) after LVAD implantation to evaluate recurrent VTA, adverse events, and procedural outcomes. Secondary endpoints include right heart function/hemodynamics, healthcare utilization, and quality of life. CONCLUSION: The primary aim of this first-ever randomized trial is to assess the efficacy of intra-operative ablation during LVAD surgery in reducing VTA recurrence and improving clinical outcomes for patients with a history of VTA.

Ventricular pacing and myocardial function in patient with congenital heart block.

INTRODUCTION: Pacing-induced cardiomyopathy (PICM) is a potential complication of chronic right ventricular (RV) pacing, but its characterization in adult patients is often complicated by pre-existing cardiomyopathy. This study investigated the incidence of PICM in patients with congenital heart block (cHB) who have conduction disease from birth without confounding pre-existing cardiac conditions. METHODS AND RESULTS: This retrospective cohort analysis included 42 patients with cHB and baseline left ventricular ejection fraction (LVEF) ≥50%. Kaplan-Meier analysis was used to assess freedom from cardiomyopathy (defined as LVEF <50%) between paced and nonpaced patients. Patients were 26 ± 3 years old at first presentation, 64% were women and baseline LVEF was 60.0 ± 0.2%. Median follow-up from birth was 35 (interquartile range [IQR]: 20-42) years with a median of 6.7 years (IQR: 3.6-9.2) at our institution. Thirty-two patients received pacing at mean age 21 ± 3 years. Patients receiving a pacemaker (PM) were significantly more likely to develop a cardiomyopathy (p = .021) and no patient developed a cardiomyopathy in the absence of a PM. Four patients who developed a new cardiomyopathy were upgraded to biventricular pacing, leading to stabilization or improvement of LVEF. CONCLUSION: In a relatively young and healthy cHB cohort, RV pacing is associated with a higher risk of developing a cardiomyopathy. These data confirm the deleterious effects of RV pacing on myocardial function in patients without pre-existing structural cardiac disease and has clinical implications to the management of patients with cHB.

Maternal focal atrial tachycardia during pregnancy: A systematic review.

INTRODUCTION: The presentation and optimal management of maternal focal atrial tachycardia (AT) during pregnancy are unknown. The objective of this study is to conduct a comprehensive summary of the existing evidence. METHODS AND RESULTS: A systematic review of all reported cases of maternal focal AT during pregnancy was performed. The primary search queried PubMed using the MeSH terms "supraventricular tachycardia" and "pregnancy." A stepwise ancillary search included article bibliographies, citations listed by the Google internet search engine, and PubMed using the MeSH terms "atrial tachycardia" and "pregnancy." In total, 28 citations that described 32 patients were retrieved. A case from our institution was added. Detailed information was available for 30 patients. Clinical characteristics at presentation included a mean ± standard deviation of 28.3 ± 5.7 years for maternal age and 24.6 ± 7.7 weeks for gestation age. Suspected tachycardia-induced cardiomyopathy was present in 20 of 30 (67%) patients and left ventricular ejection fraction improved in 15 of 15 (100%) patients with follow-up measurements. Medication failure was common. Focal AT resolved spontaneously after delivery in eight of nine (89%) patients treated with only medications. Automaticity was suggested by discrete electrograms at sites of origin and lack of reported inducibility and termination with programmed stimulation in all patients who underwent electrophysiology studies. There were nine cases of successful catheter ablation with zero fluoroscopy since 2010. CONCLUSIONS: Automaticity is the dominant mechanism for patients with maternal focal AT during pregnancy. Catheter ablation with zero fluoroscopy is an emerging therapy for medically refractory cases.

Clinical implications of elective replacement indicator setting changes in patients with dual-chamber pacemaker devices.

OBJECTIVE: This study sought to determine if single-chamber operation and/or loss of rate response (RR) during elective replacement indicator (ERI) in patients with dual-chamber pacemakers lead to increased symptom burden, healthcare utilization, and atrial fibrillation (AF). BACKGROUND: Dual-chamber pacemakers often change from dual- to single-chamber pacing mode and/or lose RR functionality at ERI to preserve battery. Single-chamber pacing increases the incidence of heart failure, AF, and pacemaker syndrome suggesting these changes may be deleterious. METHODS: A retrospective analysis of 700 patients was completed. Three comparisons were analyzed: Comparison 1: mode change and RR loss versus no change; Comparison 2: RR loss only versus no change; Comparison 3: mode change only versus no change (in patients with no RR programmed at baseline). RESULTS: In Comparison 1, 121 (46%) patients with setting changes experienced symptoms (most often dyspnea and fatigue/exercise intolerance) versus 3 (4%) without setting changes (p < .0001). Similar results were noted in Comparisons 2 and 3 (p = .0016 and p = .0001, respectively). In Comparison 1, patients with setting change sought provider contact more than patients without setting changes (p = .0001). A significant difference was not noted in Comparison 2 or 3. Overall 14 (2%) patients were hospitalized, all of whom had setting changes. CONCLUSIONS: Setting changes at ERI including a change from dual- to single-chamber pacing and/or loss of RR results in a significantly increased symptom burden and increased healthcare utilization.

Documentation of shared decision making around primary prevention defibrillator implantations.

INTRODUCTION: Patients eligible for primary prevention implantable cardioverter-defibrillator (ICD) therapy are faced with a complex decision that needs a clear understanding of the risks and benefits of such an intervention. In this study, our goal was to explore the documentation of primary prevention ICD discussions in the electronic medical records (EMRs) of eligible patients. METHODS: In 1523 patients who met criteria for primary prevention ICD therapy between 2013 and 2015, we reviewed patient charts for ICD-related documentation: "mention" by physicians or "discussion" with patient/family. The attitude of the physician and the patient/family toward ICD therapy during discussions was categorized into negative, neutral, or positive preference. Patients were followed to the end-point of ICD implantation. RESULTS: Over a median follow-up of 442 days, 486 patients (32%) received an ICD. ICD was mentioned in the charts of 1105 (73%) patients, and a discussion with the patient/family about the risks and benefits of ICD was documented in 706 (46%) charts. On multivariable analyses, positive cardiologist (hazard ratio [HR]: 7.9, 95% confidence of intervals [CI]: 1.0-59.7, P < .05), electrophysiologist (HR: 7.7, 95% CI: 1.9-31.7, P < .001), and patient/family (HR: 9.9, 95% CI: 6.2-15.7, P < .001) preferences toward ICD therapy during the first documented ICD discussion were independently associated with ICD implantation. CONCLUSIONS: In a large cohort of patients eligible for primary prevention ICD therapy, a discussion with the patient/family about the risks and benefits of ICD implantation was documented in less than 50% of the charts. More consistent documentation of the shared decision making around ICD therapy is needed.

First in human: the effects of biventricular pacing on cardiac output in severe pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) carries high morbidity and mortality despite available treatment options. In severe PAH, right ventricular (RV) diastolic pressure overload leads to interventricular septal bowing, hindering of left ventricular diastolic filling and reduced cardiac output (CO). Some animal studies suggest that pacing may mitigate this effect. We hypothesized that eliminating late diastole via ventricular pacing could improve CO in human subjects with severe PAH. Using minimal to no sedation, we performed transvenous acute biventricular (BiV) pacing and right heart catheterization in six patients with symptomatic PAH. Hemodynamic measurements were taken at baseline and during BiV pacing at various 20-ms intervals of V-V timing. We compared baseline CO to (1) CO while pacing the RV first by 80 ms (mimicking RV-only pacing), and then to (2) CO during pacing at the V-V timing that resulted in the highest CO. All participants were female, PASP 74 ± 14 mmHg, QRS duration 104 ± 20 ms. Compared with baseline, the CO decreased when the RV was paced first by 80 ms (7.2 ± 1.0 vs. 6.2 ± 1.1 L/min, p = 0.028). Pacing with optimal V-V timing produced CO similar to baseline (7.2 ± 1.0 vs. 7.4 ± 1.4, p = 0.92). Two patients (33%) met the predefined endpoint of a 15% increase in CO during pacing at the optimal V-V timing. In symptomatic PAH, V-V optimized acute BiV pacing does not consistently improve CO. However, acute BiV pacing did improve CO in a subset of this cohort. Further research is needed to identify predictors of response to cardiac resynchronization therapy in this population.

Coronary artery injury related to catheter ablation of cardiac arrhythmias: A systematic review.

INTRODUCTION: Catheter ablation (CA) has emerged as the preferred modality of treatment for many cardiac arrhythmias. Anatomical sites of ablation are often located in close proximity to coronary arteries. However, the incidence of CA-related coronary injury has not been well studied. We sought to systematically evaluate all cases of CA-related coronary injuries. METHODS AND RESULTS: A PubMed search was conducted from inception until May 1, 2017 using the keywords "coronary artery" and "ablation." We identified 2817 published articles of which 43 articles met our inclusion criteria representing 61 cases of coronary artery injury attributed to CA procedures from 1992 to 2017. Posteroseptal accessory pathway ablation was associated with the highest incidence of coronary injury (35.6% of cases), followed by cavotricuspid isthmus-dependent flutter (19.3%). The right coronary artery was the site of injury in over two-thirds of all reported cases. Coronary injury was detected intraprocedurally in about half of the cases (43.1%), whereas it was a delayed presentation in the other half. Coronary intervention was performed in a third of all cases (32.7%). There were a total of three deaths attributed to coronary artery injury. CONCLUSIONS: Most (91.8%) coronary injuries are a result of anatomic proximity to the site of ablation. Awareness of the relation between coronary artery course and anatomical site of ablation could prevent myocardial damage and improve procedural safety.

Diagnostic and therapeutic value of implantable loop recorder: A tertiary care center experience.

BACKGROUND: Implantable loop recorders (ILRs) are effective in achieving symptom-rhythm correlation. However, diagnostic yield in routine clinical practice is not well established. METHODS: Patients undergoing ILR implantation between April 2010 and May 2015 were included. All devices were enrolled in remote monitoring with automatic arrhythmia detection and P sense algorithms switched "ON." Symptom-rhythm correlation was assessed and changes in management were recorded. RESULTS: A total of 312 patients (57% male, age 53 ± 22 years; median CHADS2VaSc score  =  1) were included in this study. ILRs were implanted for evaluation of syncope in 206 (66.0%), presyncope in 23 (7.4%), unexplained palpitations in 51 (16.3%), and cryptogenic stroke in 27 (8.7%) patients. ILR monitoring yielded a diagnosis that changed management strategy in 146 (46.8%) patients over a median of 12 (1-42) months. Out of 163 (52.2%) patients with symptoms during the monitoring period, 100 (61.3%) had an arrhythmia. ILR was useful in ruling out an arrhythmic cause for symptoms in 63 (38.7%) patients. ILR results led to pacemaker implantation in 23 patients (7.4% overall and 11.2% of those with syncope) after median follow-up of 3 months. A new diagnosis of atrial fibrillation was made in 38 (12.2%) patients, 11 of whom were initiated on oral anticoagulants. ILR results led to pacemaker implantation in 31 patients (9.9% overall and 19.0% of those with syncope) after median follow-up of 3 months. A new diagnosis of atrial fibrillation was made in 38 (12.2%) patients, nine of whom were initiated on oral anticoagulants. Overall, ILR led to a change in management in 47% patients with a number needed to implant of 2.1 to change management. CONCLUSION: ILR monitoring is effective in achieving symptom-rhythm correlation and results in changes in management in nearly half of implanted patients. Additional studies are needed to evaluate cost efficacy of ILR and the optimal monitoring duration.

Non-vitamin K oral anticoagulants versus warfarin for left atrial appendage thrombus resolution in nonvalvular atrial fibrillation or flutter.

BACKGROUND: Non-vitamin K oral anticoagulants (NOACs) have emerged as alternatives to vitamin K antagonists in select situations. For left atrial (LA) appendage thrombus in nonvalvular atrial fibrillation (AF) or flutter, guidelines recommend oral anticoagulation (OAC) for at least 3 weeks prior to reassessment. Data comparing NOACs to warfarin in this scenario are scarce. METHODS: A retrospective study identified subjects with nonvalvular AF or flutter who were: a) noted to have LA thrombus detected on transesophageal echocardiography (TEE), b) previously not receiving long-term OAC; and c) evaluated for resolution of LA thrombus by follow-up TEE between 3 weeks to less than 1 year of the initial TEE. RESULTS: The study included 45 subjects with mean age 63.2 years, 69% male, 78% white race/ethnicity, 42% paroxysmal, and mean CHA2 DS2 -VASc score 3.4 ± 1.7. All LA thrombi were confined to the appendage. OAC received included apixaban (3), dabigatran (13), rivaroxaban (6), and warfarin (23), The median follow-up time to repeat TEE was 67 (interquartile range, 49-96) days. LA appendage thrombus resolution rates were 76% for the entire cohort, 77% for NOACs, and 74% for warfarin. In univariable logistic regression analysis, LA appendage thrombus resolution was similar for NOACs when compared to warfarin (odds ratio, 1.20; 95% confidence interval, 0.31-4.69; P = .79). CONCLUSIONS: In patients nonvalvular AF or flutter who were OAC naïve at the time of diagnosis with LA appendage thrombus, complete resolution was similar between NOACs and warfarin.

Implantable cardioverter-defibrillator therapy in device recipients who survived a cardiac arrest associated with a reversible cause.

BACKGROUND: Guideline recommendations for implantable cardioverter-defibrillators (ICD) for secondary prevention of sudden cardiac arrest (SCA) have excluded patients with reversible causes. We previously demonstrated mortality benefit with the ICD in survivors of SCA associated with reversible causes other than myocardial infarction (MI) or ischemia treated with coronary revascularization. In the current study, we examined the incidence of ICD therapy in patients with SCA related to reversible causes. METHODS: Data were collected for all patients over the age of 18 years who had survived to hospital discharge after SCA between 2002 and 2012. ICD recipients with reversible causes were divided into 2 groups based on their reversible etiology of SCA: MI + ICD (n = 132) and non-MI + ICD (n = 75). Delivered ICD therapy was examined. RESULTS: Over a follow-up period of 3.8 ± 3.1 years, more patients without MI/ischemia who received an ICD experienced appropriate (adjusted HR, 3.96; 95% CI, 1.32-11.84) but not inappropriate (adjusted HR, 0.65; 95% CI, 0.14-2.97) ICD therapy compared with patients without MI/ischemia. The proportion of patients receiving appropriate (P = 0.012) but not inappropriate (P = 0.80) ICD therapy was also higher in the non-MI + ICD compared with the MI + ICD group. CONCLUSION: We show higher rates of appropriate ICD therapy in survivors of SCA associated with reversible causes other than MI/ischemia. This finding, in conjunction with the previously demonstrated lower all-cause mortality noted in the presence of an ICD in SCA survivors with reversible etiology other than MI/ischemia, further supports consideration of ICD implantation in this population.

Frequency of in-hospital adverse outcomes and cost utilization associated with cardiac resynchronization therapy defibrillator implantation in the United States.

BACKGROUND: The utilization of cardiac resynchronization therapy defibrillator (CRT-D) has increased significantly, since its initial approval for use in selected patients with heart failure. Limited data exist as for current trends in implant-related in-hospital complications and cost utilization. The aim of our study was to examine in-hospital complication rates associated with CRT-D and their trends over the last decade. METHODS AND RESULTS: Using the Nationwide Inpatient Sample, we estimated 378 248 CRT-D procedures from 2003 to 2012. We investigated common complications, including mechanical, cardiovascular, pericardial complications (hemopericardium, cardiac tamponade, or pericardiocentesis), pneumothorax, stroke, vascular complications (consisting of hemorrhage/hematoma, incidents requiring surgical repair, and accidental arterial puncture), and in-hospital deaths described with CRT-D, defining them by the validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code. Mechanical complications (5.9%) were the commonest, followed by cardiovascular (3.6%), respiratory failure (2.4%), and pneumothorax (1.5%). Age (≥65 years), female gender (OR, 95% CI; P value) (1.08, 1.03-1.13; 0.001), and the Charlson score ≥3 (1.52, 1.45-1.60; <0.001) were significantly associated with increased mortality/complications. CONCLUSIONS: The overall complication rate in patients undergoing CRT-D has been increasing in the last decade. Age (≥65), female sex, and the Charlson score ≥3 were associated with higher complications. In patients who underwent CRT-D implantation, postoperative complications were associated with significant increases in cost.

Derivation and validation of a new score to predict long-term survival after sudden cardiac arrest.

BACKGROUND: There is insufficient information about the long-term prognosis of sudden cardiac arrest (SCA) survivors. We therefore derived a clinical score (Sudden Cardiac Arrest-mortality score, SCA-MS) that predicts long-term mortality in patients surviving to hospital discharge and validated it in an independent cohort of SCA survivors. METHODS: A total of 1433 SCA survivors data were collected, who were discharged from the hospitals of the University of Pittsburgh Medical Center between 2002 and 2012. The overall cohort was randomly divided into two near equal cohorts used for the derivation and validation of the SCA-MS, respectively. RESULTS: The derivation cohort included 768 patients and identified serum potassium level>4.2 mg/dL at admission, the presence of atrial fibrillation at any time during the index hospitalization, and the presence of asystole or pulseless electrical activity as the initial documented rhythm as independent predictors of long-term mortality. Based on the multivariable modeling result, one point was assigned to each one of these variables to create the SCA-MS that ranged from 0 to 3. In the validation cohort, the SCA-MS was predictive of long-term mortality (hazards ratio = 1.69, 95% confidence interval 1.50-1.91, P < 0.001) per 1-point increment in the SCA-MS. CONCLUSIONS: We describe a new clinical score that predicts long-term survival after SCA based on serum potassium levels at the admission, presence of atrial fibrillation, and documented rhythm of SCA.

Scar quantification by cardiovascular magnetic resonance as an independent predictor of long-term survival in patients with ischemic heart failure treated by coronary artery bypass graft surgery.

BACKGROUND: Scar burden by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) is associated with functional recovery after coronary artery bypass surgery (CABG). There is limited data on long-term mortality after CABG based on left ventricular (LV) scar burden. METHODS: Patients who underwent LGE CMR between January 2003 and February 2010 within 1 month prior to CABG were included. A standard 16 segment model was used for scar quantification. A score of 1 for no scar, 2 for ≤ 50 % and 3 for > 50 % transmurality was assigned for each segment. LV scar score (LVSS) defined as the sum of segment scores divided by 16. All-cause mortality was ascertained by social security death index. RESULTS: One hundred ninety-six patients met the inclusion criteria. 185 CMR studies were available. History of prior MI was present in 64 % and prior CABG in 5.4 % of patients. Scar was present in 72 % of patients and median LVEF was 38 %. Over a median follow up of 8.3 years, there were 64 deaths (34.6 %). There was no statistically significant difference in mortality between Scar and No-scar groups (37 % versus 29 %). In the group with scar, a lower scar burden (defined either < 4 segments with scar or based on LVSS) was independently associated with increased survival. CONCLUSION: In patients undergoing surgical revascularization, scar burden is negatively associated with survival in patients with scar. However, there is no difference in survival based on presence or absence of scar alone. CMR prior to CABG adds additional prognostic information.

Ventricular arrhythmia inducibility in porcine infarct model after stereotactic body radiation therapy.

BACKGROUND: Ventricular arrhythmia (VA) is the primary mechanism of sudden death in patients with structural heart disease. Cardiac stereotactic body radiation therapy (SBRT) delivered to the scar in the left ventricle significantly reduces the burden of VA. OBJECTIVE: The goal of this study was to investigate the impact of SBRT on scar morphology and VA inducibility in a porcine infarct model. METHODS: Myocardial infarction (MI) was created in 10 Yorkshire pigs involving the left anterior descending artery territory. Cardiac positron emission tomography and computed tomography were performed for targeted SBRT. Alternative pigs received SBRT at 25 Gy in a single fraction. The terminal experiment included endocardial mapping, programmed ventricular stimulation, and tissue harvesting. RESULTS: Of the 10 pigs infarcted, 2 died prematurely after MI and 8 (4 MI and 4 MI+SBRT) survived. Mean time from MI to SBRT was 48 ± 12 days, and mean time from SBRT to harvest was 32 ± 12 days. Scar was localized on intracardiac mapping in all pigs, and the scar was denser in the MI+SBRT compared with the MI-only group (33% ± 20% vs 14% ± 11%; P = .07). All 4 MI pigs had inducible VA during programmed stimulation, whereas only 1 of 4 pigs had inducible VA in the MI+SBRT arm (100% vs 25%; P = .07). No myocardial fibrosis was seen in the remote areas in either group. CONCLUSION: SBRT reduced VA inducibility in pigs with scarring after MI. Endocardial mapping revealed denser scar in pigs receiving SBRT compared with those that did not, suggesting that SBRT suppresses VA inducibility through better scar homogenization.

Impact of Weight Gain on Cardiovascular Outcomes in Patients With Atrial Fibrillation.

BACKGROUND: The long-term impact of weight gain (WG) on cardiovascular outcomes among patients with atrial fibrillation (AF) is unclear. METHODS AND RESULTS: We studied 62 871 (mean age, 72±12, 43% women) adult patients with AF evaluated at the University of Pittsburgh Medical Center between January 1, 2010, and May 13, 2021. Serial body mass index, risk factors, comorbidities, and subsequent death and hospitalization were ascertained and stratified according to percentage WG (≥0% to <5%, ≥5% to <10%, and ≥10%). Over 4.9±3.19 years of follow-up, 27 114 (43%) patients gained weight (61%, ≥0% to <5%; 23%, ≥5% to <10%; 16%, ≥10%). Patients with progressive WG were incrementally younger (P<0.001) women (40%, 42%, and 47%) with lower median household income (P=0.002) and active smoking (8%, 13% and 13%), and they were less likely to be on a non-vitamin K oral anticoagulant (39%, 37%, and 32%). WG was incrementally associated with a significant increase in risk of hospitalization for AF (≥10% WG; hazard ratio [HR], 1.2 [95% CI, 1.2-1.3]; P<0.0001), heart failure (≥10% WG; HR, 1.44 [95% CI, 1.3-1.6]; P<0.001; ≥5% to <10% WG; HR, 1.17 [95% CI, 1.1-1.2]; P<0.001), myocardial infarction (≥10% WG; HR, 1.2 [95% CI, 1.3-1.6]; P<0.001) and all-cause stroke (4.2%, 4.3%, and 5.6%) despite significantly lower mean CHADS2Vasc score (2.9±1.7, 2.7±1.6, and 2.7±1.7). Patients with more WG were significantly more likely to receive cardiac and electrophysiologic interventions. CONCLUSIONS: Among patients with AF, WG is incrementally associated with increased hospitalization for cardiovascular causes, particularly heart failure, stroke, myocardial infarction, and AF.