Failure to defibrillate or cardiovert due to premature truncation of biphasic shocks from implantable defibrillators.

BACKGROUND: In 2022 and 2023, Medtronic recalled implantable defibrillators because they may deliver less than full-energy shocks. The 2022 problem truncates the second phase of the waveform (SCP-T2), resulting in ∼32-J shocks, and is mitigated by downloadable software. The 2023 malfunction truncates the first phase of the waveform, resulting in 0- to 12-J shocks due to a glassed feedthrough problem (GFT-T1) that might be avoided by programming B>AX shock polarity. OBJECTIVE: The purpose of this study was to assess the consequences of GFT-T1 and SCP-T2 shocks in the Food and Drug Administration's Manufacturers and User Facility Device Experience (MAUDE) database and to estimate the incidences of GFT-T1 and SCP-T2. METHODS: We analyzed MAUDE reports supplemented by Medtronic data; lead failures were excluded. The incidences of SCP-T2 and GFT-T1 were estimated using USA volumes for devices with glassed feedthroughs. RESULTS: One hundred thirty-two devices delivered truncated shocks: 27 (20.5%) were GFT-T1; 103 (78.0%) were SCP-T2; and 2 (1.5%) truncated both phases (BOTH-T1&2). Of 54 ventricular fibrillation (VF) patients, 21 (38.9%) were not defibrillated by truncated shocks: 8 (38.1%) received GFT-T1 shocks, 12 (57.1%) received SCP-T2 shocks, and 1 received a BOTH-T1&2 shock; 2 patients suffered unrelated deaths; 1 was externally rescued; 1 outcome was unknown; the others were defibrillated by subsequent shocks or terminated spontaneously. The majority of patients (79.1%) shocked for ventricular tachycardia (VT) were converted, primarily (94.1%) by SCP-T2 shocks. Estimated incidences of GFT-T1 and SCP-T2 were 0.0078%-0.0088% and 0.1062%-0.1110%. CONCLUSION: GFT-T1 and SCP-T2 shocks can result in failure to terminate VF/VT, but they may be preventable. Although the incidences of these truncated shocks are very low, heightened surveillance is warranted.

Diagnostic Value of Computed Tomography Angiography for Infective Endocarditis After Right Ventricle Outflow Tract Repair.

Congenital heart disease patients with pulmonary valve replacement or right ventricle-pulmonary artery conduit have increased risk of pulmonary valve endocarditis. We present a 6-patient case series illustrating the diagnostic utility of computed tomography angiography to provide definitive visualization of pulmonary valve vegetation to aid in the diagnosis of endocarditis. (Level of Difficulty: Intermediate.).

Post-Shock Asystole in Patients Dying Out of Hospital While Wearing a Cardioverter Defibrillator.

BACKGROUND: The wearable cardioverter-defibrillator (WCD) prevents sudden cardiac death due to ventricular tachycardia (VT) or ventricular fibrillation (VF) but does not pace for post-shock asystole (PS-A) or bradycardia (PS-B;<50 beats/ min). OBJECTIVES: The purpose of this study was to assess PS-A and PS-B in patients dying out of hospital (OOH) while wearing a WCD. METHODS: The database of the U.S. Food and Drug Administration Manufacturers and User Facility Device Experience (MAUDE) was queried for manufacturers' reports of OOH deaths while patients were wearing a WCD. Excluded were patients who did not receive a shock or were initially shocked for asystole or during resuscitation. RESULTS: From January 2017 to March 2022, 313 patients received an initial WCD shock for VF (n = 150), VT (n = 90), and non-VF/VT rhythms (n = 73). PS-A occurred in 204 patients (65.2%), and PS-B occurred in 111 (35.5%); 85 (41.7%) PS-A patients also had PS-B. Most PS-A patients (n = 185; 90.7%) had an initial shocked rhythm of VF or VT, but 19 patients (9.3%) were initially inappropriately shocked for atrial fibrillation/supraventricular tachycardia (n = 7) and idioventricular (n = 8) or sinus (n = 4) rhythm. PS-A occurred after the first WCD shock in 118 (63.8%) and after the first, second, or third shocks in 159 patients (85.9%). Seven patients had post-shock heart block. Eight patients had permanent pacemakers; 1 became nonfunctional after 1 shock, and 7 showed noncapture and/or asystole after 1 to 4 shocks. CONCLUSIONS: Post-shock asystole appears to be common in patients who die OOH after being shocked by a WCD for VF or VT. PS-A also occurs after inappropriate WCD shocks for non-VF/VT rhythms. Implanted pacemakers may not prevent PS-A after a WCD shock. WCD backup pacing should be explored.

Causes and clinical consequences of inappropriate shocks experienced by patients wearing a cardioverter-defibrillator.

BACKGROUND: The LifeVest® wearable cardioverter-defibrillator (WCD) prevents sudden cardiac death in at-risk patients who are not candidates for an implantable defibrillator. The safety and efficacy of the WCD may be impacted by inappropriate shocks (IAS). OBJECTIVE: The purpose of this study was to assess the causes and clinical consequences of WCD IAS in survivors of IAS events. METHODS: The Food and Drug Administration's Manufacturers and User Facility Device Experience database was searched for IAS adverse events (AE) that were reported during 2021 and 2022. RESULTS: A total of 2568 IAS-AE were found (average number of IAS per event: 1.5 ± 1.9; range 1-48). IAS were caused by tachycardias (1255 [48.9%]), motion artifacts (840 [32.7%]), and oversensing (OS) of low-level electrical signals (473 [18.4%]) (P <.001). Tachycardias included atrial fibrillation (AF) (828 [32.2%]), supraventricular tachycardia (SVT) (333 [13.0%]), and nonsustained ventricular tachycardia/fibrillation (NSVT/VF) (87 [3.4%]). Activities responsible for motion-induced IAS included riding a motorcycle, lawnmower, or tractor (n = 128). In 19 patients, IAS induced sustained ventricular tachycardia or ventricular fibrillation that subsequently were terminated by appropriate WCD shocks. Thirty patients fell and suffered physical injuries. Conscious patients (n = 1905) did not use the response buttons to abort shocks (47.9%) or used them improperly (20.2%). IAS resulted in 1190 emergency room visits or hospitalizations, and 17.3% of patients (421/2440) discontinued the WCD after experiencing IAS, especially multiple IAS. CONCLUSIONS: The LifeVest WCD may deliver IAS caused by AF, SVT, NSVT/VF, motion artifacts, and oversensing of electrical signals. These shocks may be arrhythmogenic, result in injuries, precipitate WCD discontinuation, and consume medical resources. Improved WCD sensing, rhythm discrimination, and methods to abort IAS are needed.

Magnetic field interactions between current consumer electronics and cardiac implantable electronic devices.

BACKGROUND: Electronic products, including the iPhone 12, Apple Watch Series 6, and 2nd Generation AirPods, contain magnets to facilitate wireless charging. Permanent magnets may affect CIED magnet mode features by causing pacemakers to pace asynchronously and defibrillators to suspend arrhythmia detection. This study determined if CIEDs are affected by static magnetic fields from commonly used portable electronics (PE) at any distance and intends to reinforce FDA recommendations concerning consumer PE which contain permanent magnets. METHODS: The maximum magnet field measurement was evaluated by a Gauss meter. The interaction between PE and CIEDs from Boston Scientific and Medtronic were tested ex vivo using a body torso model. The CIED was placed in physiologic saline, and the PE was placed at the surface and at increasing distances of 0.5, 1.0, and 1.5 cm. Interactions were recorded by assessment of magnet mode status. RESULTS: The iPhone 12 had almost three times the static magnetic field measured at the surface as the iPhone XR, but magnetic field strength decreased dramatically with increasing distance. At the surface of the model, PE triggered magnet mode in all CIEDs. The maximum interaction distance for all combinations of CIEDs and Apple products was 1.5 cm. CONCLUSIONS: The iPhone 12 produces a stronger static magnetic field than previous iPhone models. Magnets in PE tested will not interact with CIEDs when they are 15 cm from the implanted device. Since no interaction was observed beyond 1.5 cm, it is unlikely that magnet mode activation will occur during most daily activities.

Variation in Advanced Diagnostic Imaging Practice Patterns and Associated Risks Prior to Superior Cavopulmonary Connection: A Multicenter Analysis.

Single ventricle patients typically undergo some form of advanced diagnostic imaging prior to superior cavopulmonary connection (SCPC). We sought to evaluate variability of diagnostic practice and associated comprehensive risk. A retrospective evaluation across 4 institutions was performed (1/1/2010-9/30/2016) comparing the primary modalities of cardiac catheterization (CC), cardiac magnetic resonance (CMR), and cardiac computed tomography (CT). Associated risks included anesthesia/sedation, vascular access, total room time, contrast agent usage, radiation exposure, and adverse events (AEs). Of 617 patients undergoing SCPC, 409 (66%) underwent at least one advanced diagnostic imaging study in the 60 days prior to surgery. Seventy-eight of these patients (13%) were analyzed separately because of a concomitant cardiac intervention during CC. Of 331 (54%) with advanced imaging and without catheterization intervention, diagnostic CC was most common (59%), followed by CT (27%) and CMR (14%). Primary modality varied significantly by institution (p < 0.001). Median time between imaging and SCPC was 13 days (IQR 3-33). Anesthesia/sedation varied significantly (p < 0.001). Pre-procedural vascular access did not vary significantly across modalities (p = 0.111); procedural access varied between CMR/CT and CC, in which central access was used in all procedures. Effective radiation dose was significantly higher for CC than CT (p < 0.001). AE rate varied significantly, with 12% CC, 6% CMR, and 1% CT (p = 0.004). There is significant practice variability in the use of advanced diagnostic imaging prior to SCPC, with important differences in associated procedural risk. Future studies to identify differences in diagnostic accuracy and long-term outcomes are warranted to optimize diagnostic protocols.

Leadless pacemaker perforations: Clinical consequences and related device and user problems.

BACKGROUND: Cardiac perforation during leadless pacemaker implantation is more likely to require intervention than perforation by a transvenous lead. This study reports the consequences of Micra pacemaker perforations and related device and operator use problems based on information the manufacturer has submitted to the Food and Drug Administration (FDA). METHODS: FDA's Manufacturer and User Facility Device Experience (MAUDE) database was searched for Micra perforations. Data extracted included deaths, major adverse clinical events (MACEs), and device and/or operator use problems. RESULTS: Between 2016 and July 2021, 563 perforations were reported within 30 days of implant and resulted in 150 deaths (27%), 499 cardiac tamponades (89%), 64 pericardial effusions (11%), and 146 patients (26%) required emergency surgery. Half of perforations were associated with 139 (25%) device problems, 78 (14%) operator use problems, and 62 (11%) combined device and operator use problems. Inadequate electrical measurements or difficult positioning were the most frequent device problems (n = 129); non-septal implants and perforation of other structures were the most frequent operator use problems (n = 69); a combined operator use and device problem resulted in 62 delivery system perforations. No device or operator use problem was identified for 282 perforations (50%), but they were associated with 78 deaths, 245 tamponades, and 57 emergency surgeries. CONCLUSION: The Micra perforations reported in MAUDE are often associated with death and major complications requiring emergency intervention. Device and use problems account for at least half of perforations. Studies are needed to identify who is at risk for a perforation and how MACE can be avoided or mitigated.

Acute Myocardial Infarction-Like Events in Related Patients With a Desmoplakin-Associated Arrhythmogenic Cardiomyopathy.

Patients with familial arrhythmogenic cardiomyopathy typically present with ventricular arrhythmias or progressive heart failure. This paper characterizes a rare presentation of an underlying genetic cardiomyopathy with clinical manifestations mimicking an acute myocardial infarction in 2 siblings, each with the same mutation in the desmoplakin (DSP) gene. (Level of Difficulty: Advanced.).

Multi-institution Assessment of the Accuracy of Cardiac Computed Tomography in Preparation for Superior Cavopulmonary Connection.

BACKGROUND: Patients with single ventricle (SV) congenital heart disease (CHD) undergo several interventions in the first years of life. Advanced diagnostics are required for interstage assessment of anatomy, but are associated with significant diagnostic risk. We sought to evaluate image quality, risk, and accuracy of cardiac computed tomography (CCT) for evaluation of anatomy prior to superior cavopulmonary connection (SCPC) compared to surgical findings across 2 institutions. METHODS: A retrospective evaluation of image quality, risk, and accuracy of pre-SCPC CCT was performed at 2 institutions between January 1, 2010 and September 30, 2016. RESULTS: CCT was performed in 90 SV CHD patients with a median age of 4.03 months (interquartile range [IQR] 3.36, 5.33) prior to SCPC. Image quality was optimal (84%) or good (16%) in all patients, without significant discrepancy compared to surgical findings. 7 patients (8%) required interventional cardiac catheterization subsequent to CCT and before surgical intervention. 49% of scans were performed without sedation, 43% of scans were performed with mild to moderate sedation, and 8% of scans were performed with general anesthesia. The median total procedural dose-length product (DLP) was 18 (IQR 14, 26) mGy*cm, estimating an age adjusted radiation dose of 1.4 millisievert (mSv). One minor (1%) adverse event was reported within 24 h of the CCT. Surgical complications were unrelated to the presurgical findings. CONCLUSIONS: CCT for pre-SCPC evaluation is safe, with excellent accuracy for anatomy at the time of surgical intervention across 2 institutions. In select patients, noninvasive evaluation with CCT may be indicated.

Major adverse clinical events associated with implantation of a leadless intracardiac pacemaker.

BACKGROUND: Leadless intracardiac pacemakers were developed to avoid the complications of transvenous pacing systems. The Medtronic Micra™ transcatheter pacemaker is one such system. We found an unexpected number of major adverse clinical events (MACE) in the Food and Drug Administration's Manufacturers and User Facility Device Experience (MAUDE) database associated with Micra implantation. OBJECTIVE: The purpose of this study was to describe these MACE and compare them to implant procedure MACE in MAUDE for Medtronic CapSureFix™ active-fixation transvenous pacing leads. METHODS: During January 2021, we queried the MAUDE database for reports of MACE for Micra pacemakers and CapSureFix leads using the simple search terms "death," "tamponade," and "perforation." Reports from 2016-2020 were included. RESULTS: The search identified 363 MACE for Micra and 960 MACE for CapSureFix leads, including 96 Micra deaths (26.4%) vs 23 CapSureFix deaths (2.4%) (P <.001); 287 Micra tamponades (79.1%) vs 225 tamponades for CapSureFix (23.4%) (P <.001); and 99 rescue thoracotomies for Micra (27.3%) vs 50 rescue thoracotomies for CapSureFix (5.2%) (P <.001). More Micra patients required cardiopulmonary resuscitation (21.8% vs 1.1%) and suffered hypotension or shock (22.0% vs 5.8%) than CapSureFix recipients (P <.001). Micra patients were more likely to survive a myocardial perforation or tear if they had surgical repair (P = .014). CONCLUSION: Micra leadless pacemaker implantation may be complicated by myocardial and vascular perforations and tears that result in cardiac tamponade and death. We estimate the incidence is low (<1%). Rescue surgery to repair perforations may be lifesaving. MACE are significantly less for implantation of CapSureFix transvenous ventricular pacing leads.

Multi-institution assessment of the use and risk of cardiovascular computed tomography in pediatric patients with congenital heart disease.

BACKGROUND: Cardiac computed tomography (CT) is increasingly used in pediatric patients with congenital heart disease (CHD). Variability of practice and of comprehensive diagnostic risk across institutions is not known. METHODS: Four centers prospectively enrolled consecutive pediatric CHD patients <18 years of age undergoing cardiac CT from January 6, 2017 to 1/30/2020. Patient characteristics, cardiac CT data and comprehensive diagnostic risk were compared by age and institutions. Risk categories included sedation and anesthesia use, vascular access, contrast exposure, cardiovascular medication, adverse events (AEs), and estimated radiation dose. RESULTS: Cardiac CT was performed in 1045 pediatric patients at a median (interquartile range, IQR) age of 1.7 years (0.3, 11.0). The most common indications were arterial abnormalities, suspected coronary artery anomalies, functionally single ventricle heart disease, and tetralogy of Fallot/pulmonary atresia. Sedation was used in 8% and anesthesia in 11% of patients. Peripheral vascular access was utilized for 93%. Median contrast volume was 2 â€‹ml/kg. Beta blockers were administered in 11% of cases and nitroglycerin in 2% of cases. The median (IQR) total procedural dose length product (DLP) was 20 â€‹mGy∗cm (10, 50). Sedation, vascular access, contrast exposure, use of cardiovascular medications and radiation dose estimates varied significantly by institution and age (p â€‹< â€‹0.001). Seven minor adverse events (0.7%) and no major adverse events were reported. CONCLUSION: Cardiac CT for CHD is safe in pediatric patients when appropriate CT technology and expertise are available. Scans can be acquired at relatively low radiation exposure with few minor adverse events.

Safety, Efficacy, and Dose Protocol of Metoprolol for Heart Rate Reduction in Pediatric Outpatients Undergoing Cardiac CT Angiography. / Segurança, Eficácia e Protocolo de Dose de Metoprolol para Redução de Frequência Cardíaca em Pacientes Pediátricos Externos que Passaram por Angiografia Cardíaca por TC.

BACKGROUND: Image quality and radiation dose are optimized with a slow, steady heart rate (HR) when imaging the coronary arteries during cardiac computed tomography angiography (CCTA). The safety, efficacy, and protocol for HR reduction with beta blocker medication is not well described in a pediatric patient population. OBJECTIVE: Provide a safe and efficient metoprolol dose protocol to be used in pediatric outpatients undergoing CCTA. METHODS: We conducted a retrospective review of all pediatric outpatients who received metoprolol during CCTA. Demographic and clinical characteristics were summarized and the average reduction in HR was estimated using a multivariate linear regression model. Images were evaluated on a 1-4 scale (1= optimal). RESULTS: Seventy-eight pediatric outpatients underwent a CCTA scan with the use of metoprolol. The median age was 13 years, median weight of 46 kg, and 36 (46%) were male. The median doses of metoprolol were 1.5 (IQR 1.1, 1.8) mg/kg and 0.4 (IQR 0.2, 0.7) mg/kg for oral and intravenous administrations, respectively. Procedural dose-length product was 57 (IQR 30, 119) mGy*cm. The average reduction in HR was 19 (IQR 12, 26) beats per minute, or 23%. No complications or adverse events were reported. CONCLUSION: Use of metoprolol in a pediatric outpatient setting for HR reduction prior to CCTA is safe and effective. A metoprolol dose protocol can be reproduced when a slower HR is needed, ensuring faster acquisition times, clear images, and associated reduction in radiation exposure in this population. (Arq Bras Cardiol. 2021; 116(1):100-105).

FUNDAMENTO: Qualidade de imagem e dose de radiação são otimizadas com uma frequência cardíaca (FC) lenta e estável na realização de imagens de artérias coronárias durante a angiografia cardíaca por tomografia computadorizada (CCTA, do inglês cardiac computed tomography angiography) A segurança, a eficácia e o protocolo para a redução da FC com medicamento betabloqueador ainda não foi bem descrita em uma população de pacientes pediátricos. OBJETIVO: Oferecer um protocolo de dose de metoprolol eficiente a ser usado em pacientes pediátricos externos durante a CCTA. MÉTODOS: Realizamos uma revisão retrospectiva de todos os pacientes pediátricos externos que receberam o metoprolol durante a CCTA. As características demográficas e clínicas foram resumidas e a redução média em FC foi estimada utilizando-se um modelo de regressão linear multivariada. As imagens foram avaliadas em uma escala de 1 a 4 (1= ideal). RESULTADOS: Um total de 78 pacientes externos passaram a uma CCTA com o uso de metoprolol. A média de idade foi de 13 anos, a média de peso foi de 46 kg, e 36 pacientes (46%) eram do sexo masculino. As doses médias de metoprolol foram 1,5 (IQR 1,1; 1,8) mg/kg, e 0,4 (IQR 0,2; 0,7) mg/kg para administrações orais e intravenosas, respectivamente. O produto dose-comprimento por exame foi de 57 (IQR 30, 119) mGy*cm. A redução média da FC foi 19 (IQR 12, 26) batimentos por minuto, ou 23%. Não foram relatadas complicações ou eventos adversos. CONCLUSÃO: O uso de metoprolol num cenário de pacientes pediátricos externos para redução da FC antes de uma CCTA é seguro e eficiente. Pode-se reproduzir um protocolo de dose de metoprolol quando for necessário atingir uma FC mais lenta, garantindo tempos de aquisição mais rápidos, imagens mais claras e redução na exposição à radiação nessa população. (Arq Bras Cardiol. 2021; 116(1):100-105).

Reliability and longevity of implantable defibrillators.

PURPOSE: We hypothesized that data in manufacturers' product performance reports (PPRs) can provide clinically valuable ICD and cardiac resynchronization defibrillator (CRT-D) reliability and longevity information. METHODS: Data were obtained from 2019 PPRs. Kaplan-Meier (K-M) probabilities of freedom from malfunction, normal battery depletion (NBD), and NBD + malfunction were calculated for ICD and CRT-D pulse generators (PGs) with LiMnO2 or LiSVO/CFx batteries marketed in the USA from 2010 to 2019 and compared using the log-rank test. Malfunctions (MAL) included PGs that were found outside specifications. RESULTS: Study population included 1,149,803 ICD and CRT-D PGs: Abbott (ABT; 35.1%), Biotronik (BIO; 4.6%), Boston Scientific (BSC; 23.5%), and Medtronic (MDT; 36.9%). Significant differences in reliability (p < 0.001), defined by freedom from MAL, were found between manufacturers; the majority of 6808 MAL occurred in ABT devices (n = 4045; 59.4%), followed by BSC (n = 2384; 35.0%), MDT (n = 338;5.0%), and BIO (n = 41; 0.6%). Battery failure (n = 890; 57.9%) was the most common cause of MAL compromising therapy; analysis of unique ABT battery MAL-indicated problem appeared a year prior to advisory. Significant differences (p < 0.001) in battery longevity, as defined by freedom from NBD, were found between manufacturers. Overall performance (freedom from NBD + MAL) favored BSC for CRT-D PGs and MDT and BIO for ICDs. BSC subcutaneous ICD reliability was inferior to its transvenous ICD (p < 0.001). CONCLUSION: PPRs contain valuable data that can be aggregated and analyzed to inform physicians. Differences in product reliability exist between manufacturers. Battery longevity has improved, but MAL have significantly impacted performance. PPR data may be useful for assessing product problems and new technology.

Segurança, Eficácia e Protocolo de Dose de Metoprolol para Redução de Frequência Cardíaca em Pacientes Pediátricos Externos que Passaram por Angiografia Cardíaca por TC / Safety, Efficacy, and Dose Protocol of Metoprolol for Heart Rate Reduction in Pediatric Outpatients Undergoing Cardiac CT Angiography

Resumo Fundamento Qualidade de imagem e dose de radiação são otimizadas com uma frequência cardíaca (FC) lenta e estável na realização de imagens de artérias coronárias durante a angiografia cardíaca por tomografia computadorizada (CCTA, do inglês cardiac computed tomography angiography) A segurança, a eficácia e o protocolo para a redução da FC com medicamento betabloqueador ainda não foi bem descrita em uma população de pacientes pediátricos. Objetivo Oferecer um protocolo de dose de metoprolol eficiente a ser usado em pacientes pediátricos externos durante a CCTA. Métodos Realizamos uma revisão retrospectiva de todos os pacientes pediátricos externos que receberam o metoprolol durante a CCTA. As características demográficas e clínicas foram resumidas e a redução média em FC foi estimada utilizando-se um modelo de regressão linear multivariada. As imagens foram avaliadas em uma escala de 1 a 4 (1= ideal). Resultados Um total de 78 pacientes externos passaram a uma CCTA com o uso de metoprolol. A média de idade foi de 13 anos, a média de peso foi de 46 kg, e 36 pacientes (46%) eram do sexo masculino. As doses médias de metoprolol foram 1,5 (IQR 1,1; 1,8) mg/kg, e 0,4 (IQR 0,2; 0,7) mg/kg para administrações orais e intravenosas, respectivamente. O produto dose-comprimento por exame foi de 57 (IQR 30, 119) mGy*cm. A redução média da FC foi 19 (IQR 12, 26) batimentos por minuto, ou 23%. Não foram relatadas complicações ou eventos adversos. Conclusão O uso de metoprolol num cenário de pacientes pediátricos externos para redução da FC antes de uma CCTA é seguro e eficiente. Pode-se reproduzir um protocolo de dose de metoprolol quando for necessário atingir uma FC mais lenta, garantindo tempos de aquisição mais rápidos, imagens mais claras e redução na exposição à radiação nessa população. (Arq Bras Cardiol. 2021; 116(1):100-105)

Abstract Background Image quality and radiation dose are optimized with a slow, steady heart rate (HR) when imaging the coronary arteries during cardiac computed tomography angiography (CCTA). The safety, efficacy, and protocol for HR reduction with beta blocker medication is not well described in a pediatric patient population. Objective Provide a safe and efficient metoprolol dose protocol to be used in pediatric outpatients undergoing CCTA. Methods We conducted a retrospective review of all pediatric outpatients who received metoprolol during CCTA. Demographic and clinical characteristics were summarized and the average reduction in HR was estimated using a multivariate linear regression model. Images were evaluated on a 1-4 scale (1= optimal). Results Seventy-eight pediatric outpatients underwent a CCTA scan with the use of metoprolol. The median age was 13 years, median weight of 46 kg, and 36 (46%) were male. The median doses of metoprolol were 1.5 (IQR 1.1, 1.8) mg/kg and 0.4 (IQR 0.2, 0.7) mg/kg for oral and intravenous administrations, respectively. Procedural dose-length product was 57 (IQR 30, 119) mGy*cm. The average reduction in HR was 19 (IQR 12, 26) beats per minute, or 23%. No complications or adverse events were reported. Conclusion Use of metoprolol in a pediatric outpatient setting for HR reduction prior to CCTA is safe and effective. A metoprolol dose protocol can be reproduced when a slower HR is needed, ensuring faster acquisition times, clear images, and associated reduction in radiation exposure in this population. (Arq Bras Cardiol. 2021; 116(1):100-105)

Multimodality Assessment of Anomalous Aortic Origin of the Right Coronary Artery Presenting With Cardiac Arrest.

Anomalous aortic origin of coronary artery (AAOCA) can range from benign anatomic variants to those presenting with sudden cardiac arrest. This unique case of right AAOCA demonstrates detailed anatomic findings from cardiac computed tomography and the effects of transient acute coronary ischemia by cardiac magnetic resonance. (Level of Difficulty: Advanced.).

High shocking and pacing impedances due to defibrillation lead calcification.

PURPOSE: We have reported the calcification of Endotak defibrillation leads that required replacement. The aim of this study was to assess calcified Endotak Reliance leads in the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database and compare them to calcified Sprint Fidelis, Sprint Quattro Secure, Riata, and Durata leads in MAUDE. METHODS: We searched the MAUDE database from 2008 to 2019 for defibrillation lead calcification using the terms "calcium," "calcification," and "calcified". Included were explanted leads whose manufacturers found calcium on the shocking and/or pacing electrode. RESULTS: The MAUDE search identified 113 calcified defibrillation leads that qualified for the study, including 109 Endotak Reliance leads, 1 Sprint Quattro Secure lead, 2 Durata leads, 1 Riata ST lead, and no Sprint Fidelis lead. The sign of calcification was a gradual increase in shocking or pacing impedance. Average implant time was 7.4 ± 3.1 (range: 1.3-16.5) years. Only Endotak Reliance leads had shocking coil calcification (n = 72; 66.0%) and five (6.9%) of these failed defibrillation threshold (DFT) testing. Distal pacing electrode calcification affected 55 (50.4%) Endotak Reliance leads. The four other leads had pacing ring electrode calcification only. CONCLUSION: Endotak Reliance defibrillation leads appear prone to shocking coil and/or distal pacing electrode calcification. High impedances may compromise defibrillation and pacing therapy. Patients who have these leads should be monitored; those exhibiting high shocking impedances should be considered for DFT testing. Lead replacement should be considered for pacemaker-dependent patients whose leads exhibit progressively high impedances.

Outcomes Before and After the Recall of a Heart Failure Pacemaker.

Importance: Timely and complete disclosure of medical device defects is necessary to manage patient care safely and effectively. Objectives: To determine if the manufacturer's recommendations following the recall of a medical device were timely and complete, the follow-up information and data provided to patients and physicians were adequate for managing patient care, and the actions taken by the US Food and Drug Administration (FDA) regarding the recall were appropriate. Design, Setting, and Participants: This single-center retrospective case series included 90 of 448 patients who were implanted with a cardiac resynchronization therapy pacemaker at the Minneapolis Heart Institute from May 2003 through January 2011; this pacemaker was recalled in November 2015. In addition, returned product reports submitted by the manufacturer to the FDA via the Manufacturer and User Facility Device Experience (MAUDE) database from January 2008 through December 2018 were analyzed. Main Outcomes and Measures: Clinical outcomes were serious adverse clinical events that occurred before and after the November 2015 recall notifying physicians and patients that the device's battery could fail unexpectedly because of high internal impedance. Technical outcomes were signs and causes of failure. Results: Five of 90 patients observed during 2015 experienced syncope when their pacemakers stopped pacing owing to battery or wire connection defects prior to the recall. Of the 90 patients, 37 (41%) were men, and the median (interquartile range) age at implantation was 71.3 (66.1-78.2) years. Analysis of the MAUDE data revealed that battery failures prior to the recall were associated with serious adverse events that included 1 death, 1 cardiac arrest, 5 syncopal attacks, and 6 heart failure exacerbations; 3 additional prerecall syncopal events were caused by wire connection defects. The manufacturer and the FDA were aware of the battery and wire connection defects for 19 months before issuing the recall, yet the wire connection problem was not included in the advisory and physicians were not informed that interrogating the pacemaker could result in loss of pacing. The FDA classified the recall as class II rather than the more critical class I. Conclusions and Relevance: This case series study of patients implanted with a defective pacemaker found that the pacemaker recall was delayed and that subsequent communications did not include all critical information needed for safe and effective patient care. These findings should prompt reforms in how the medical device industry and the FDA manage future medical device recalls.

Catching up with catch-up: a policy analysis of immunisation for refugees and asylum seekers in Victoria.

This study examines catch-up immunisation for people of refugee-like background in Victoria, exploring effective models of service delivery to complete catch-up vaccinations. The analysis is based on: (i) review of the medical literature, Commonwealth and Victorian government immunisation policy and immunisation patient information; (ii) review of vaccination coverage and service delivery data; and (iii) stakeholder interviews completed in 2014 with 45 people from 34 agencies, including 9 local government areas in Victoria. Although refugees and asylum seekers all need catch-up vaccinations on arrival, they face significant barriers to completing immunisation in Australia. Analysis suggests missed opportunities by service providers and perceptions that catch-up vaccination is time-consuming, difficult and resource-intensive. Service delivery is fragmented across primary care and local government, and pathways depend on age, location and healthcare access. There are strengths, but also limitations in all current service delivery models. Gaps in vaccine funding for refugee-like populations have now been addressed through Commonwealth initiatives, however migration is still not well considered in immunisation policy, and existing systems for notification payments do not capture catch-up vaccination for these groups. Providers identify areas for improvement in professional development and support, patient information, patient-held records and immunisation surveillance data.

Autosomal-dominant biventricular arrhythmogenic cardiomyopathy in a large family with a novel in-frame DSP nonsense mutation.

A novel autosomal-dominant in-frame deletion resulting in a nonsense mutation in the desmoplakin (DSP) gene was identified in association with biventricular arrhythmogenic cardiomyopathy across three generations of a large Caucasian family. Mutations that disrupt the function and structure of desmosomal proteins, including desmoplakin, have been extensively linked to familial arrhythmogenic right ventricular cardiomyopathy (ARVC). Analysis of data from 51 individuals demonstrated the previously undescribed variant p.Cys81Stop (c.243_251delCTTGATGCG) in DSP segregates with a pathogenic phenotype exhibiting variable penetrance and expressivity. The mutation's pathogenicity was first established due to two sudden cardiac deaths (SCDs), each with a biventricular cardiomyopathy identified on autopsy. Of the individuals who underwent genetic screening, 27 of 51 were heterozygous for the DSP mutation (29 total with two obligate carriers). Six of these were subsequently diagnosed with arrhythmogenic cardiomyopathy. An additional nine family members have a conduction disorder and/or myocardial structural changes characteristic of an evolving condition. Previous reports from both human patients and mouse studies proposed DSP mutations with a premature stop codon impart mild to no clinical symptoms. Loss of expression from the abnormal allele via the nonsense-mediated mRNA decay pathway has been implicated to explain these findings. We identified an autosomal-dominant DSP nonsense mutation in a large family that led to SCD and phenotypic expression of arrhythmogenic cardiomyopathy involving both ventricles. This evidence demonstrates the pathogenic significance of this type of desmosomal mutation and provides insight into potential clinical manifestations.