Appropriate and Inappropriate ICD Shocks in Patients with LVADS: Prevalence, Associated Factors, and Etiologies.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) shocks are a common complication following Left Ventricular Assist Device (LVAD) implantation; however, there is limited data on their frequency and causes. OBJECTIVE: To define the incidence, programming, patient characteristics, and factors associated with appropriate and inappropriate ICD shocks in persons with LVADs. METHODS: We performed a retrospective review at Duke University Hospital of all LVAD recipients implanted between January 1, 2013 to June 30, 2019 with a pre-existing ICD. ICD shocks were adjudicated by the treating physician and a 2nd reviewer for the purpose of this study. RESULTS: Among 421 patients with an ICD in situ undergoing LVAD implant, 147 (33.9%) patients had at least one shock following LVAD implantation. Among 134 patients with complete device history, there were a total of 330 shock episodes: 255 (77.3%) appropriate and 75 (22.7%) inappropriate. Etiologies for inappropriate shocks included SVT (n=66, 20.0%), physiologic oversensing (n=1, 0.3%), and non-physiologic oversensing (n=8, 2.4%) including LVAD electromagnetic interference (n=1, 0.3%). ICD programming with shorter detection delay (p < 0.001) and absence of anti-tachycardia pacing programming (p = 0.001) in high-rate zones was seen more commonly in inappropriate shock than appropriate shock. CONCLUSIONS: The rate of inappropriate shocks in LVAD recipients is very high and is most often due to supraventricular arrhythmias. LVAD electromagnetic interference is a rare cause of ICD shock. Implementation of current consensus AHA recommendations for LVAD programming with long detection delays and high rate cutoffs may help avoid inappropriate ICD shocks.

Left Ventricular Assist Device Outflow Graft Compression: Incidence, Clinical Associations and Potential Etiologies.

BACKGROUND: Left ventricular assist devices (LVADs) have revolutionized the treatment of advanced heart failure, but proliferation of device therapy has unmasked potential complications. Reports have emerged of outflow graft narrowing due to extrinsic compression. METHODS AND RESULTS: The records of patients with LVADs that had been implanted at our institution were reviewed. Those who had postimplantation computed tomography angiographies sufficient to analyze the outflow graft lumen were identified, and the studies were analyzed to characterize the outflow graft lumen. We identified 241 patients; 110 (46%) had suitable computed tomography angiographies. Of those, 15 (14%) had evidence of outflow graft lumen narrowing, all in HeartMate devices and all within the portion covered by the bend relief. Of the 15, 3 underwent invasive examination, all without intraluminal thrombus but, rather, with biodebris between the bend relief and the outflow graft. Patients with HeartWare devices had a wide range of biodebris accumulation surrounding the outflow graft but no cases of lumen narrowing. On multivariable analysis, 1) time from device implant to scan, 2) nonischemic cardiomyopathy and 3) age at implant were significantly associated with higher risk of graft narrowing. CONCLUSION: Outflow graft narrowing can be seen in a number of patients with HeartMate LVADs within the portion covered by the bend relief. In the limited number of patients who underwent invasive evaluation, the narrowing was found to arise from extrinsic compression rather than intraluminal thrombus. The clinical significance of this requires further investigation.

Prevalence of Pediatric Asthma Risk in Santo Domingo, Dominican Republic.

BACKGROUND: Early detection and treatment of pediatric asthma could reduce morbidity and lessen burden on society. Currently there is no known research on the prevalence of pediatric asthma in the Dominican Republic (DR) and no known asthma risk assessment tool for one-time encounters in a fast-paced clinic. OBJECTIVES: To pilot a streamlined version of previously validated screening tools to estimate the prevalence of pediatric asthma risk in Santo Domingo Norte, DR. METHODS: A combined asthma questionnaire and clinical assessment tool was developed and administered to patients aged 2-12 years. FINDINGS: We found that 25.7% of the 74 study participants were categorized as probable asthma, 21.6% were at high risk for asthma, 14.9% elevated risk, and 37.8% not at risk. CONCLUSION: If the prevalence of 25.7% is representative of the DR as a whole, the DR would have one of the highest national rates in Latin America. The study assessment tool was convenient to use, but tool validation is needed.