Role of dofetilide in patients with ventricular arrhythmias.

BACKGROUND OR PURPOSE: To assess effectiveness of dofetilide in reducing the burden of ventricular arrhythmias (VAs). BACKGROUND: Prior small sample studies show that dofetilide has benefit in reducing VA. However, large sample investigations with long-term follow-up are lacking. METHODS: Two hundred seventeen consecutive patients admitted between January 2015 and December 2021 for dofetilide initiation for control of VA were assessed. Dofetilide was successfully started in 176 patients (81%) and had to be discontinued in the remaining 41 patients (19%). Dofetilide was initiated for control of ventricular tachycardia (VT) in 136 patients (77%), whereas 40 (23%) patients were initiated on dofetilide for reducing the burden of premature ventricular complexes (PVCs). RESULTS: The mean follow-up was 24 ± 7 months. In total, among the 136 VT patients, 33 (24%) died, 11 (8%) received a left ventricular assist device (LVAD), and 3 (2%) received a heart transplant during follow-up. Dofetilide was discontinued in 117 (86%) patients due to lack of sustained effectiveness during follow-up. Dofetilide use was associated with similar odds of the composite outcome of all-cause mortality/LVAD/heart transplant (OR: 0.97, 0.55-4.23) in patients with ischemic cardiomyopathy (ICM) compared to those with non-ischemic cardiomyopathy (NICM). Dofetilide did not reduce PVC burden during follow-up in the 40 patients with PVCs (mean baseline PVC burden: 15%, at 1-year follow-up: 14%). CONCLUSIONS: Dofetilide use was less effective in reducing VA burden in our cohort of patients. Randomized controlled studies are needed to confirm our findings.

Radiofrequency catheter ablation of ventricular arrhythmias in patients with hypertrophic cardiomyopathy.

BACKGROUND: Compared to other non-ischemic substrates, there is limited data on the role and outcome of catheter ablation in HCM. The objective of this study is to assess the safety and efficacy of catheter ablation for the treatment of VT in patients with HCM. METHODS: Fourteen patients with HCM and drug refractory VT who underwent catheter ablation at a single center were included in this study. The data was evaluated retrospectively. Acute success, procedure-related complications, and long-term outcomes were documented during follow up. RESULTS: Among the 14 patients (mean age 48.2 ± 8.2 years, 85.7% males, mean LVEF 42.6 ± 6.5%), 4 had an apical aneurysm. Eleven patients had evidence of scar-related VT and three patients had a bundle-branch re-entry VT. The most common sites for scar-related VT were the border-zones of the apical aneurysms, basal septum, and LV lateral wall. Patient either underwent an endocardial ablation or a combined endocardial and epicardial ablation. Acute success was achieved in all patients. In 6 patients VT was terminated during ablation. In two patients, non-clinical VTs were inducible at the end of the procedure. No major or minor complications were observed during and after the procedure in all patients. During long-term follow up, elimination of VTs reached 78%. CONCLUSION: Catheter ablation of VT in patients with HCM is safe and successful in eliminating VT. Combining endocardial and epicardial ablation techniques can potentially lead to better outcomes in these patients. Bundle branch re-entry should be considered as a potential mechanism of VT in patients with HCM.

Catheter ablation of ventricular tachycardia: strategies to improve outcomes.

Catheter ablation of ventricular arrhythmias has evolved considerably since it was first described more than 3 decades ago. Advancements in understanding the underlying substrate, utilizing pre-procedural imaging, and evolving ablation techniques have improved the outcomes of catheter ablation. Ensuring safety and efficacy during catheter ablation requires adequate planning, including analysis of the 12 lead ECG and appropriate pre-procedural imaging. Defining the underlying arrhythmogenic substrate and disease eitology allow for the developed of tailored ablation strategies, especially for patients with non-ischemic cardiomyopathies. During ablation, the type of anesthesia can affect VT induction, the quality of the electro-anatomic map, and the stability of the catheter during ablation. For high risk patients, appropriate selection of hemodynamic support can increase the success of VT ablation. For patients in whom VT is hemodynamically unstable or difficult to induce, substrate modification strategies can aid in safe and successful ablation. Recently, there has been an several advancements in substrate mapping strategies that can be used to identify and differentiate local late potentials. The incorporation of high-definition mapping and contact-sense technologies have both had incremental benefits on the success of ablation procedures. It is crucial to harness newer technology and ablation strategies with the highest level of peri-procedural safety to achieve optimal long-term outcomes in patients undergoing VT ablation.

Optimizing diastolic filling by pacing in nonobstructive hypertrophic cardiomyopathy.

BACKGROUND: Treatment options for symptomatic patients with nonobstructive hypertrophic cardiomyopathy (nHCM) are limited. OBJECTIVE: The purpose of this study was to determine the effect of sequential atrioventricular (AV) pacing, from different right ventricular (RV) sites with varying AV delays, on the diastolic function and functional capacity of patients with nHCM. METHODS: Twenty-one patients with symptomatic nHCM and normal left ventricular (LV) systolic function were prospectively enrolled. Inclusion criteria included PR interval >150 ms, E/e' ≥15, and an indication for implantable cardioverter-defibrillator (ICD) implantation. Doppler echocardiographic study was performed during dual-chamber pacing at various AV intervals. Pacing was performed at 3 RV sites: RV apex (RVA), RV midseptum (RVS), and RV outflow tract (RVO). The site and sensed AV delay (SAVD) at which optimal diastolic filling occurred were chosen based on diastolic filling period and E/e'. During ICD implantation, the RV lead was implanted at the site identified by the pacing study. Devices were programmed in DDD mode at the optimal SAVD. During follow-up, diastolic function and functional capacity were assessed. RESULTS: Among the 21 patients (age 47.8 ± 7.7 years; 81.0% male), baseline E/A and E/e' were 2.4 ± 0.6 and 17.2 ± 2.2, respectively. There was an improvement in diastolic function (E/e') in 18 patients (responders) when pacing from the RVA (12.9 ± 3.4; P <.001) than from the RVS (16.6 ± 2.3) and RVO (16.9 ± 2.2). Among responders, optimal diastolic filling occurred at SAVD of 130-160 ms with RVA pacing. Nonresponders had longer duration of symptoms (P = .006), lower LV ejection fraction (P = .037), and higher late gadolinium enhancement burden (P <.001). During 13.5 ± 1.5 months of follow-up, there was an improvement (Δ) in diastolic function (E/e' -4.1 ± 0.5), functional capacity (New York Heart Association functional class -1.5 ± 0.3), and reduction in N-terminal pro-brain natriuretic peptide level (-55.6 ± 12.3 pg/mL) compared to baseline. CONCLUSION: Pacing at an optimized AV delay from the RVA improves diastolic function and functional capacity in a subset of patients with nHCM.

Three-dimensional-guided and ICE-guided transseptal puncture for cardiac ablations: A propensity score match study.

INTRODUCTION: Transseptal puncture (TSP) is routinely performed for left atrial ablation procedures. The use of a three-dimensional (3D) mapping system or intracardiac echocardiography (ICE) is useful in localizing the fossa ovalis and reducing fluoroscopy use. We aimed to compare the safety and efficacy between 3D mapping system-guided TSP and ICE-guided TSP techniques. METHODS: We conducted a prospective observational study of patients undergoing TSP for left atrial catheter ablation procedures (mostly atrial fibrillation ablation). Propensity scoring was used to match patients undergoing 3D-guided TSP with patients undergoing ICE-guided TSP. Logistic regression was used to compare the clinical data, procedural data, fluoroscopy time, success rate, and complications between the groups. RESULTS: Sixty-five patients underwent 3D-guided TSP, and 151 propensity score-matched patients underwent ICE-guided TSP. The TSP success rate was 100% in both the 3D-guided and ICE-guided groups. Median needle time was 4.00 min (interquartile range [IQR]: 2.57-5.08) in patients with 3D-guided TSP compared to 4.02 min (IQR: 2.83-6.95) in those with ICE-guided TSP (p = .22). Mean fluoroscopy time was 0.2 min (IQR: 0.1-0.4) in patients with 3D-guided TSP compared to 1.2 min (IQR: 0.7-2.2) in those with ICE-guided TSP (p < .001). There were no complications related to TSP in both group. CONCLUSIONS: Three-dimensional mapping-guided TSP is as safe and effective as ICE-guided TSP without additional cost.

Outcomes in patients with electrocardiographic left ventricular dyssynchrony following transcatheter aortic valve replacement.

BACKGROUND: Left bundle branch block (LBBB) and atrioventricular (AV) conduction abnormalities requiring permanent pacemaker (PPM) implantation occur frequently following transcatheter aortic valve replacement (TAVR). The resultant left ventricular (LV) dyssynchrony may be associated with adverse clinical events. OBJECTIVES: The purpose of this study was to assess the adverse outcomes associated with LV dyssynchrony due to high-burden right ventricular (RV) pacing or permanent LBBB following TAVR in patients with preserved left ventricular ejection fraction (LVEF). METHODS: Consecutive TAVR patients at the University of Michigan from January 2012 to June 2017 were included. Pre-existing cardiac implantable electronic device, previous LBBB, LVEF <50%, or follow-up period <1 year were excluded. The primary outcome was all-cause mortality. Secondary outcomes included cardiomyopathy (defined as LVEF ≤45%), a composite endpoint of cardiomyopathy or all-cause mortality, and the change in LVEF at 1-year follow-up. RESULTS: A total of 362 patients were analyzed (mean age 77 years). LV dyssynchrony group (n = 91 [25.1%]) included 56 permanent LBBB patients, 12 permanent LBBB patients with PPM, and 23 non-LBBB patients with PPM and high-burden RV pacing. Remaining patients served as control (n = 271 [74.9%]). After adjusted analysis, LV dyssynchrony had significantly higher all-cause mortality (adjusted hazard ratio [HR] 2.16; 95% confidence interval [CI] 1.07-4.37) and cardiomyopathy (adjusted HR 14.80; 95% CI 6.31-14.69). The LV dyssynchrony group had mean LVEF decline of 10.5% ± 10.2% compared to a small increase (0.5% ± 7.7%) in control. CONCLUSION: Among TAVR patients with preserved LVEF and normal AV conduction, development of postprocedural LV dyssynchrony secondary to high-burden RV pacing or permanent LBBB was associated with significantly higher risk of death and cardiomyopathy at 1-year follow-up.

Best Practices for the Catheter Ablation of Ventricular Arrhythmias.

Techniques for catheter ablation have evolved to effectively treat a range of ventricular arrhythmias. Pre-operative electrocardiographic and cardiac imaging data are very useful in understanding the arrhythmogenic substrate and can guide mapping and ablation. In this review, we focus on best practices for catheter ablation, with emphasis on tailoring ablation strategies, based on the presence or absence of structural heart disease, underlying clinical status, and hemodynamic stability of the ventricular arrhythmia. We discuss steps to make ablation safe and prevent complications, and techniques to improve the efficacy of ablation, including optimal use of electroanatomical mapping algorithms, energy delivery, intracardiac echocardiography, and selective use of mechanical circulatory support.

Catheter Ablation for Ventricular Arrhythmias in Hypertrophic Cardiomyopathy.

Implantable cardioverter-defibrillators are the mainstay of therapy for prevention of sudden cardiac death in high-risk patients with hypertrophic cardiomyopathy (HCM). Catheter ablation is a useful option for patients with recurrent, drug refractory monomorphic ventricular tachycardia (VT), and device therapy. Compared with other nonischemic substrates, there are limited data on the role and outcomes of catheter ablation in HCM. The challenges of VT ablation in HCM patients include deep intramural and epicardial substrates, suboptimal power delivery, and higher recurrence due to progression of disease. Patient selection, using cardiac MRI scar localization, and optimizing ablation techniques can improve outcomes in these patients.

Ventricular Tachycardia in Granulomatous Myocarditis: Role of Catheter Ablation.

Granulomatous myocarditis is an inflammatory disease of the myocardium, characterized by lymphocytic infiltration with characteristic granuloma formation. Although a host of disease processes can elicit myocardial granulomas, two common entities are cardiac sarcoidosis and cardiac tuberculosis. Cardiac arrhythmias in this condition are frequent and management of ventricular arrhythmias can be challenging, especially in those with drug-refractory ventricular tachycardia and electrical storm. In this review, we highlight the role of catheter ablation for ventricular tachycardia and optimal patient selection for catheter ablation, based on cardiac imaging.

Current status and barriers in pulmonary hypertension care delivery in India: A qualitative analysis.

Although pulmonary hypertension (PH) is widely prevalent in India, care delivery for this condition has unique challenges in a lower middle-income country (LMIC). To describe care delivery for patients with PH and associated barriers in India. We interviewed physicians across eight healthcare systems in India about PH clinical care using semi-structured enquiries to understand care delivery and associated challenges in their specific practice as well as the associated health system. Qualitative analysis was performed using content analysis methodology. Physicians reported that common causes for PH in their practice were rheumatic mitral valve disease, coronary artery disease, and congenital heart disease (CHD). No center had a dedicated PH program. Only one center had a specific protocol for PH management. Diagnostic evaluations were limited, and right heart catheterizations were recommended for patients with CHD. Pulmonary vasodilator therapy was used for severe symptoms or markers of severe disease. Agents used to treat PH were widely variable across physicians and prostacyclins are unavailable in India. Barriers included limited training in PH for physicians, lack of consensus guidelines for PH specific to LMIC, and lack of financial incentives for health care systems to organize dedicated PH programs. Other barriers included poor patient health literacy and socioeconomic barriers that limit ability to test and treat PH. PH care delivery in India is variable with widely differing clinical practices. Dedicated training in PH management and establishing guidelines specific to LMIC like India can form the first step forward.

High rate episodes in a dual chamber pacemaker: What is the mechanism?

Detection of high rate episodes can potentially result from oversensing of physiological or nonphysiological signals. Assessment of lead integrity, lead connection and analysis of noise characteristics on electrograms are decisive steps in the evaluation of oversensing. We report a case of high atrial and ventricular rate episodes due to minute ventilation oversensing in the presence of lead connector issues.

Geographic variation and temporal trends in management and outcomes of cardiac arrest complicating acute myocardial infarction in the United States.

BACKGROUND: Limited studies have evaluated regional disparities in the care of acute myocardial infarction (AMI) patients with cardiac arrest (CA). This study sought to evaluate 18-year national trends, resource utilization, and geographical variation in outcomes in AMI-CA admissions. METHODS AND RESULTS: Using the National Inpatient Sample (2000-2017), we identified adults with AMI and concomitant CA admitted to the United States census regions of Northeast, Midwest, South, and West. Clinical outcomes of interest included in-hospital mortality, use of coronary angiography, percutaneous coronary intervention (PCI), mechanical circulatory support (MCS), hospitalization costs and length of stay. Of 9,680,257 admissions for AMI, 494,083 (5.1%) had concomitant CA. The West (6.0%) had higher prevalence compared to the Northeast (4.4%), Midwest (5.0%), and South (5.1%), p < 0.001. Admissions in the West had higher rates of STEMI, cardiogenic shock, multiorgan failure, mechanical ventilation, and hemodialysis. Northeast admissions had lower use of coronary angiography (52.0% vs. 67.9% vs. 60.9% vs. 61.5%), PCI (38.7% vs. 51.9% vs. 44.8% vs. 46.7%), and MCS (18.4% vs. 21.8% vs. 18.1%, vs. 20.0%) compared to the Midwest, West and South (all p < 0.001). Compared with the Northeast, adjusted in-hospital mortality was higher in the Midwest (odds ratio [OR] 1.06 [95% confidence interval {CI} 1.03-1.08]), South (OR 1.11 [95% CI 1.09-1.13]) and highest in the West (OR 1.16 [95% CI 1.13-1.18]), all p < 0.001. Temporal trends showed a decline in in-hospital mortality except in the West, which showed a slight increase. CONCLUSIONS: There remain significant regional disparities in the management and outcomes of AMI-CA.

Temporary Mechanical Circulatory Support as a Bridge to Heart Transplant or Durable Left Ventricular Assist Device.

Advanced heart failure refractory to medical therapy can result in patients presenting with progressively worsening hypoperfusion and cardiogenic shock. Temporary mechanical circulatory support is often necessary as a bridge to heart transplant or durable ventricular assist devices. These devices increase cardiac output. Several options are available for left ventricular support. With the exception of venoarterial extracorporeal membrane oxygenation, all other devices decrease left ventricular end-diastolic pressure. The choice of device should be driven by patient needs and the treating teams comfort. Timely identification of cardiogenic shock and use of shock teams are potential strategies that can help improve survival.

Acute Myocardial Infarction and Papillary Muscle Rupture in the COVID-19 Era.

Mechanical complications of acute myocardial infarction are infrequent in the modern era of primary percutaneous coronary intervention, but they are associated with high mortality rates. Papillary muscle rupture with acute severe mitral regurgitation is one such life-threatening complication that requires early detection and urgent surgical intervention. (Level of Difficulty: Beginner.).

Use and Outcomes Associated With Perioperative Amiodarone in Cardiac Surgery.

Background In randomized controlled trials, perioperative administration of amiodarone has been shown to reduce the incidence of postoperative atrial arrhythmias and length of stay (LOS) among patients undergoing coronary bypass surgery. However, little is known about the use or effectiveness of perioperative amiodarone in routine clinical practice. Methods and Results We studied patients ≥18 years old without a previous history of atrial or ventricular arrhythmias who underwent elective coronary bypass surgery between 2013 and 2014 within a network of 235 US hospitals. Perioperative amiodarone was defined as receipt of amiodarone either on the day of or the day preceding surgery. We used covariate-adjusted modeling and instrumental variable methods to examine the association between receipt of amiodarone and the development of atrial arrhythmias, in-hospital mortality, readmission, LOS, and cost. Of 12 758 patients, 2195 (17.2%) received perioperative amiodarone, 3330 (26.1%) developed atrial arrhythmias postoperatively, and the average LOS was 6.4 days (±2.6 days). Instrumental variable analysis showed that receipt of perioperative amiodarone was associated with lower risk of atrial arrhythmias (risk difference -11 percentage points, 95% CI -19 to -4 percentage points; P=0.002) and a shorter LOS (-0.7 day, 95% CI -1.39 to -0.01 days; P=0.048). There was no association between receipt of perioperative amiodarone and in-hospital mortality, cost, or readmission. Conclusions Among patients undergoing coronary bypass surgery without previous arrhythmias, perioperative amiodarone is associated with a lower risk of atrial arrhythmias and shorter LOS. These findings are consistent with previous randomized trials and lend support to current guideline recommendations.

Comparison of Clinical Outcomes: Bivalirudin With Transfemoral Access Versus Heparin With Transradial Access in Patients With ST segment Elevation Myocardial Infarction.

INTRODUCTION: The best combination of access site and anticoagulant used during primary percutaneous coronary intervention (PCI) in patients presenting with ST segment elevation myocardial infarction is not known. METHODS: We conducted a retrospective cohort study of all patients >18 years of age who underwent primary PCI in 2 large regional ST segment elevation myocardial infarction centers in Massachusetts between 2012 and 2014. The cohort was divided into 3 groups: bival/fem, hep/rad, or off-protocol, based on anticoagulation and access used. We used multiple logistic regression model to compare major cardiovascular events-major adverse cardiovascular events (MACE) and bleeding complications between the 2 on-protocol groups (bival/fem and hep/rad). RESULTS: Of the 1074 patients in this study, there were 443 (41%), 501 (47%), and 130 (12%) patients in bival/fem, hep/rad, and off-protocol groups, respectively. There were significantly higher number of cardiogenic shock patients in the bival/fem compared to the hep/rad group (6.5% vs. 3.0%, P < 0.001). There was a trend toward reduced MACE in the hep/rad group compared to bival/fem (2.8 % vs. 5.1%, P = 0.068). When cardiogenic shock patients are excluded, there is no significant difference in mortality rates (bival/fem: 2.7% vs. hep/rad: 1.0%, P = 0.07) or bleeding complications between the groups (hep/rad: 4.5% vs. bival/fem: 2.1%, P = 0.06). CONCLUSIONS: In patients undergoing primary PCI, there was a trend toward reduced inpatient MACE with the use of heparin and radial access compared with bivalirudin with femoral access. In patients without cardiogenic shock, there is no significant difference in mortality or bleeding rates between the 2 groups.