Unregulated online sales of cardiac implantable electronic devices in the United States: A six-month assessment.

BACKGROUND: An estimated 1 million patients require cardiac implantable electronic devices (CIEDs) but go without annually. This disparity exists in low-to-middle-income nations largely owing to the cost of CIED hardware. Humanitarian reuse of CIEDs has been shown to be safe and feasible. However, recent publications have raised concern that promotion of CIED reuse may foster a CIED "black market," to the dismay of manufacturers, regulators, and clinicians alike. OBJECTIVE: To determine if unregulated CIED sales for potential human use is a real issue by investigating unregulated public online CIED sale listings in the United States of America. METHODS: An observational study was undertaken over 6 months using multiple internet search engines from May 1 to November 1, 2019. We cataloged usable CIEDs (still in packaging, manufactured <7 years) and pricing. Manufacturers were contacted to determine status of sellers and unregulated CIEDs using model/serial numbers. RESULTS: In total, 58 CIEDs-47 implantable cardioverter-defibrillators and 11 permanent pacemakers-from 4 manufacturers were listed for sale on 3 websites. During the study period, 8 of 11 pacemakers and 37 of 47 implantable cardioverter-defibrillators were sold (price range: $100-$1500 [US dollars]). No new listings were seen in the last 3 months of observation, possibly owing to concomitant industry investigation. CONCLUSION: There does exist a public online market for unregulated CIED sales in the United States. This specific market seems to be small and unlikely to significantly expand with active monitoring by manufacturers and regulators.

Orchestrated regulation of energy supply and energy expenditure: Transcriptional coexpression of metabolism, ion homeostasis, and sarcomeric genes in mammalian myocardium.

BACKGROUND: During the development of heart failure, the myocardium undergoes profound electrical remodeling, characterized by prolongation of action potential duration, changes in Ca(2+) homeostasis, and slowing of conduction. OBJECTIVE: We tested the hypothesis that the electrical remodeling, indexed by the expression of ion channel and transporter genes, occurs in the context of a coordinated regulation of metabolism and signaling processes observed in heart failure. METHODS: A meta-analysis of myocardial murine and human microarray data sets was performed. RESULTS: We identified transcripts that were coordinately expressed with 132 myocardial ion channel and transporter genes in 18 murine and human myocardial microarray data sets. The genes coexpressed with ion channels were subsequently grouped into Gene Ontology (GO) categories, revealing 4 major, mutually exclusive GO clusters: 55 ion channel and transporter genes were coexpressed with major bioenergetic pathways (oxidative phosphorylation, citric acid cycle, glycolysis, and fatty acid metabolism) and contractile processes (muscle contraction, sarcomere, and Z disc), while 36, 16, and 25 ion channel transcripts were associated with the GO clusters of signal transduction, transcription/translation, and a nonspecified cluster, respectively. Myocardial expression of ion channel genes coexpressed with metabolic processes was >10-fold higher than that of ion channels associated with the other 3 clusters. In addition to transcriptional coexpression, major myocardial ion channels were found to physically interact with metabolic pathways based on protein-protein interaction data. CONCLUSION: Electromechanical and metabolic remodeling processes are intricately linked at the transcriptional level, suggesting an orchestrated regulation of energy supply (metabolism) and energy expenditure (muscle contraction and ion homeostasis) in mammalian myocardium.

Assessment of cardiac involvement in myotonic muscular dystrophy by T1 mapping on magnetic resonance imaging.

BACKGROUND: Patients with myotonic muscular dystrophy (DM) are at risk for atrioventricular block and left ventricular (LV) dysfunction. Noninvasive detection of diffuse myocardial fibrosis may improve disease management in this population. OBJECTIVE: To define functional and postcontrast myocardial T1 time cardiac magnetic resonance characteristics in patients with DM. METHODS: Thirty-three patients with DM (24 with type 1 and 9 with type 2) and 13 healthy volunteers underwent cardiac magnetic resonance for the assessment of LV indices and the evaluation of diffuse myocardial fibrosis by T1 mapping. The association of myocardial T1 time with electrocardiogram abnormalities and LV indices was examined among patients with DM. RESULTS: Patients with DM had lower end-diastolic volume index (68.9 mL/m(2) vs 60.3 mL/m(2); P = .045) and cardiac index (2.7 L/min/m(2) vs 2.33 L/min/m(2); P = .005) and shorter myocardial T1 time (394.5 ms vs 441.4 ms; P < .0001) than did control subjects. Among patients with DM, there was a positive association between higher T1 time and LV mass index (2.2 ms longer per g/m(2); P = .006), LV end-diastolic volume index (1.3 ms longer per mL/m(2); P = .026), filtered QRS duration (1.2 ms longer per unit; P = .005), and low-amplitude (<40 mcV) late-potential duration (0.9 ms longer per unit; P = .01). Using multivariate random effects regression, each 10-ms increase in myocardial T1 time of patients with type 1 DM was independently associated with 1.3-ms increase in longitudinal PR and QRS intervals during follow-up. CONCLUSIONS: DM is associated with structural alterations on cardiac magnetic resonance. Postcontrast myocardial T1 time was shorter in patients with DM than in controls, likely reflecting the presence of diffuse myocardial fibrosis.

The future of fellowship training in clinical cardiac electrophysiology: Program directors' perspective 2008.

BACKGROUND: At the Clinical Cardiac Electrophysiology (CCEP) program directors' annual meeting during the 2008 scientific sessions of the Heart Rhythm Society, a consensus emerged for an urgent need to strengthen and rejuvenate fellowship training in clinical cardiac electrophysiology. OBJECTIVE: A writing group of the Heart Rhythm Society Clinical Research and Training Committee was charged with defining these issues. METHODS: A comprehensive questionnaire designed by the writing group was used to conduct an on-line survey of the 101 CCEP program directors in the United States. Data collected included types of programs, current status of programs, duration of fellowship, teaching responsibilities of faculty, responsibilities of fellows, and volume of electrophysiology procedures. Survey responses were collated and analyzed by the writing group. RESULTS: Given the rapid evolution and increased complexity of current electrophysiology procedures, program directors were of the opinion that 1 year of clinical electrophysiology training may no longer be adequate. A need to strengthen both research and didactic training components of fellowship training was also acknowledged. The number of electrophysiology procedures performed by trainees varied greatly between programs, and standardization of didactic training and procedural volume would be welcomed. Recent trends were recognized that indicate the need for a detailed national work-force analysis in CCEP. CONCLUSION: Through this national survey, program directors identified specific areas of need for standardization and strengthening of current fellowship training in CCEP. Based on these, specific measures can be taken to ensure the future of CCEP training.

Cardiac magnetic resonance assessment of dyssynchrony and myocardial scar predicts function class improvement following cardiac resynchronization therapy.

OBJECTIVES: We tested a circumferential mechanical dyssynchrony index (circumferential uniformity ratio estimate [CURE]; 0 to 1, 1 = synchrony) derived from magnetic resonance-myocardial tagging (MR-MT) for predicting clinical function class improvement following cardiac resynchronization therapy (CRT). BACKGROUND: There remains a significant nonresponse rate to CRT. MR-MT provides high quality mechanical activation data throughout the heart, and delayed enhancement cardiac magnetic resonance (DE-CMR) offers precise characterization of myocardial scar. METHODS: MR-MT was performed in 2 cohorts of heart failure patients with: 1) a CRT heart failure cohort (n = 20; left ventricular ejection fraction of 0.23 +/- 0.057) to evaluate the role of MR-MT and DE-CMR prior to CRT; and 2) a multimodality cohort (n = 27; ejection fraction of 0.20 +/- 0.066) to compare MR-MT and tissue Doppler imaging septal-lateral delay for assessment of mechanical dyssynchrony. MR-MT was also performed in 9 healthy control subjects. RESULTS: MR-MT showed that control subjects had highly synchronous contraction (CURE 0.96 +/- 0.01), but tissue Doppler imaging indicated dyssynchrony in 44%. Using a cutoff of <0.75 for CURE based on receiver-operator characteristic analysis (area under the curve: 0.889), 56% of patients tested positive for mechanical dyssynchrony, and the MR-MT CURE predicted improved function class with 90% accuracy (positive and predictive values: 87%, 100%); adding DE-CMR (% total scar <15%) data improved accuracy further to 95% (positive and negative predictive values: 93%, 100%). The correlation between CURE and QRS duration was modest in all cardiomyopathy subjects (r = 0.58, p < 0.001). The multimodality cohort showed a 30% discordance rate between CURE and tissue Doppler imaging septal-lateral delay. CONCLUSIONS: The MR-MT assessment of circumferential mechanical dyssynchrony predicts improvement in function class after CRT. The addition of scar imaging by DE-CMR further improves this predictive value.

Magnetic resonance assessment of the substrate for inducible ventricular tachycardia in nonischemic cardiomyopathy.

BACKGROUND: Patients with left ventricular dysfunction have an elevated risk of sudden cardiac death. However, the substrate for ventricular arrhythmia in patients with nonischemic cardiomyopathy remains poorly understood. We hypothesized that the distribution of scar identified by MRI is predictive of inducible ventricular tachycardia. METHODS AND RESULTS: Short-axis cine steady-state free-precession and postcontrast inversion-recovery gradient-echo MRI sequences were obtained before electrophysiological study in 26 patients with nonischemic cardiomyopathy. Left ventricular ejection fraction was measured from end-diastolic and end-systolic cine images. The transmural extent of scar as a percentage of wall thickness (percent scar transmurality) in each of 12 radial sectors per slice was calculated in all myocardial slices. The percentages of sectors with 1% to 25%, 26% to 50%, 51% to 75%, and 76% to 100% scar transmurality were determined for each patient. Predominance of scar distribution involving 26% to 75% of wall thickness was significantly predictive of inducible ventricular tachycardia and remained independently predictive in the multivariable model after adjustment for left ventricular ejection fraction (odds ratio, 9.125; P=0.020). CONCLUSIONS: MR assessment of scar distribution can identify the substrate for inducible ventricular tachycardia and may identify high-risk patients with nonischemic cardiomyopathy currently missed by ejection fraction criteria.