Surgical myectomy versus alcohol septal ablation for obstructive hypertrophic cardiomyopathy: A propensity score–matched cohort

Objectives

In patients with hypertrophic cardiomyopathy, obstruction of the left ventricular outflow tract can be relieved by surgical septal myectomy or alcohol septal ablation, but uncertainty remains regarding long-term results and comparative effectiveness of alcohol septal ablation. This study aims to compare short- and long-term outcomes of the 2 procedures.

Myocardial infarction classification and its implications on measures of cardiovascular outcomes,quality, and racial/ethnic disparities

Heart disease continues to be the leading cause of death in the United States, with approximately 805 000 cumulative deaths from myocardial infarctions (MI) from 2005 to 2014. Gender and racial/ethnic disparities in MI diagnoses are becoming more evident in quality review audits. Although recent changes in diagnostic codes provided an improved framework, clinically distinguishing types of MI remains a challenge. MI misdiagnoses and health disparities contribute to adverse outcomes in cardiac medicine. We conducted a literature review of relevant biomedical sources related to the classification of MI and disparities in cardiovascular care and outcomes. From the studies analyzed, African Americans and women have higher rates of mortality from MI, are more probably to be younger and present with other comorbidities and are less probably to receive novel therapies with respect to type of MI. As high-sensitivity troponin assays are adopted in the United States, implementation should account for how race and sex differences have been demonstrated in the reference range and diagnostic threshold of the newer assays. More research is needed to assess how the complexity of health disparities contributes to adverse cardiovascular outcomes. Creating dedicated medical quality teams (physicians, nurses, clinical documentation improvement specialists, and medical coders) and incorporating a plan-do-check-adjust quality improvement model are strategies that could potentially help better define and diagnose MI, reduce financial burdens due to MI misdiagnoses, reduce cardiovascular-related health disparities, and ultimately improve and save lives.     

Cardiac Implantable Electronic Devices in Patients With Left Ventricular Assist Systems

Recent progress and evolution in device engineering, surgical implantation practices, and periprocedural management have advanced the promise of durable support with left ventricular assist systems (LVAS) in patients with stage D heart failure. With greater uptake of LVAS globally, a growing population of LVAS recipients have pre-existing cardiac implantable electronic devices (CIEDs). Strategies for optimal clinical management of CIEDs in patients with durable LVAS are evolving, and clinicians will increasingly face complex decisions regarding implantation, programming, deactivation, and removal of CIEDs. Traditional decision-making pathways for CIEDs may not apply to LVAS-supported patients, as few patients die of arrhythmic causes and many arrhythmias may be well tolerated. Given limited data, treatment decisions must be individualized and made collaboratively among electrophysiologists, advanced heart failure specialists, and patients and their caregivers. Large, prospective, well-conducted studies are needed to better understand the contemporary utility of CIEDs in patients with newer-generation LVAS.     

Psychopharmacology and Cardiovascular Disease

This review discusses common mental health disorders and their associations with cardiovascular disease risks. Commonly found mental health disorders include depression, anxiety, and personality types. The link between depression and cardiovascular disease mortality has been established. Depression is also common in patients with heart failure. In addition to discussing psychological disorders, a review of psychotropic drugs is also included. Drugs are described for therapy for depression and anxiety, as well as associations with cardiovascular drug-drug interactions. Drug-drug interactions are more common and potentially dangerous in elderly patients, in whom the conditions often coexist. The most common drug-drug interactions involve the P450 system of enzymes.     

Near‐Fatal ICD Lead Dysfunction with Implications for ICD Testing

A 31‐year‐old male patient with an implantable cardioverter defibrillator (ICD) experienced ventricular fibrillation. After resuscitation, no communication between the device and an ICD programmer was possible. The ICD was explanted, no signs of destruction were visible, and the ICD leads revealed normal values. A new ICD was implanted, interrogation values were stable. However, immediately after defibrillation testing the connection between programmer and ICD was interrupted and could not be established again. The device showed burn marks and a hole in the can. Analysis revealed an isolation defect of the ICD lead, which was not detectable with standard interrogation.     

A Survey of the Practice of Lead Extraction in the United States

Background: Endovascular lead extraction is an important component of the management of patients with chronically implanted arrhythmia control devices. Although it is associated with the potential for significant morbidity and mortality, there is little information about its scope and practice. Methods: We surveyed 1,000 physician members of the Heart Rhythm Society via e‐mail solicitation. Results: Of the 252 respondents (25%), 221 (88%) reported either performing extractions themselves (63%), or having privileges at a hospital where extractions are performed (25%). Electrophysiologists perform extractions at most sites (83%) but cardiac surgeons perform endovascular lead extraction at a significant minority of sites (20%). Most respondents report low annual volumes of extractions at their site: 15% reported <10 procedures/year, 42% 10–25 procedures/year, 23% 26–50 procedure/year, and only 19% reported >50 procedures/year. Thirty‐six percent of respondents reported that extractions were done in the operating room (OR) with surgeon present or immediately available, 39% in the electrophysiology (EP) lab with surgeon and OR identified and available, and 25% in EP lab without a surgeon or OR identified. The overall risks of lead extraction were felt to be 1–5% of major complication and 0.5–1% of mortality, roughly in line with published data. Conclusions: While there is agreement as to the risk of major complication and death from lead extraction, the degree of surgical availability varies considerably. The new guidelines document recommends the ability to promptly initiate an emergent surgical procedure, and this should be an important goal for all extractionists. (PACE 2010; 33:721–726)     

Utility and Safety of Axillo‐subclavian Venous Imaging with Carbon Dioxide (CO2) Prior to Chronic Lead System Revisions

Background: Prior to attempting placement of one or more electrodes to revise existing rhythm control devices, patency of the central veins should be documented, in view of a high incidence of significant chronic occlusions. Since iodinated contrast venography may be contraindicated in select situations, imaging of the axillo‐subclavian venous system with gaseous carbon dioxide (CO₂) was evaluated prospectively in 23 consecutive individuals who were considered for revision of previously implanted pacemaker or automatic cardioverter defibrillator lead systems. Methods: Approximately 20 mL of CO₂ were manually infused via CO₂ primed injection tubing into a vein at or above the level of the antecubital fossa ipsilateral to the side of prior lead placements. Digital subtraction imaging over the axillo‐subclavian region, lower neck, and mediastinum was performed. Formal interpretation was obtained from one of three interventional radiologists and at least one electrophysiologist. Results: Significant venous occlusions were identified in five (22%) patients. Vascular access utilized for the subsequent 18 revisions performed included the imaged patent ipsilateral vein in 14 patients and the contralateral, right‐sided subclavian venous system in three patients. One patient required epicardial left ventricular lead placement. There were no complications from venography. Conclusions: Axillo‐subclavian venography with gaseous CO₂ in patients undergoing pacemaker or implantable cardioverter defibrillator lead revisions is feasible and safe when use of iodinated dye is contraindicated. This technique should be employed in patients with azotemia, dye contrast allergies, or significant inflammation in the vicinity of the intravenous line insertion. (PACE 2010; 790–794)