Cardiac resynchronization therapy for pacing induced cardiomyopathy: Role of baseline right ventricular pacing burden.

BACKGROUND: Cardiac resynchronization therapy (CRT) is indicated for patients with heart failure with reduced left ventricular ejection fraction (LVEF) and chronic right ventricular (RV) pacing burden ≥40% (pacing-induced cardiomyopathy, PICM). It is uncertain whether baseline RV pacing burden impacts response to CRT. METHODS: We conducted a retrospective study of all CRT upgrades for PICM at our hospital from January 2017 to December 2018. Univariate and multivariable-adjusted changes in LVEF, and echocardiographic response (≥10% improvement in LVEF) at 3-12 months post-CRT upgrade were compared in those with RV pacing burden ≥90% versus <90%. RESULTS: We included 75 patients (age 74 ± 11 years, 71% male) who underwent CRT upgrade for PICM. The baseline RV pacing burden was ≥90% in 56 patients (median 99% [IQR 98%-99%]), and <90% in 19 patients (median 79% [IQR 73%-87%]). Improvement in LVEF was greater in those with baseline RV pacing burden ≥90% versus <90% (15.7 ± 9.3% vs. 7.5 ± 9.6%, p = .003). Baseline RV pacing burden ≥90% was a strong predictor of an improvement in LVEF ≥10% after CRT upgrade both in univariate and multivariate-adjusted models (p = .005 and .02, respectively). CONCLUSION: A higher baseline RV pacing burden predicts a greater improvement in LVEF after CRT upgrade for PICM.

Freeman-Sheldon syndrome in a 29-year-old woman presenting with rare and previously undescribed features.

Described are previously unreported features presenting in a case of Freeman-Sheldon syndrome (FSS); these apparently unreported features may substantively inform current therapy and further research. While considered to be primarily a craniofacial syndrome, FSS is officially described as a myopathic distal arthrogryposis. Clinical diagnosis requires microstomia, whistling-face appearance (pursed lips), H-shaped chin dimpling, nasolabial folds, and two or more contractures of hands and feet. Spinal deformities, metabolic and gastroenterological problems, other dysmorphic craniofacial characteristics, and visual and auditory impairments are frequent findings. Differential diagnoses include: distal arthrogryposis type 1, 2B (Sheldon-Hall syndrome) and 3; arthrogryposis multiplex congenita and isolated non-syndromic deformities. Expression is frequently from new allelic variation. Important implications exist for geneticists, neonatologists, paediatricians, plastic surgeons and others to facilitate patients' legitimate opportunity to meaningfully overcome functional limitations and become well. Despite complexities and complications, early craniofacial surgery and aggressive physiotherapy for limb contractures can achieve excellent outcomes for patients.