Pediatric Cardio-Oncology Medicine: A New Approach in Cardiovascular Care.

Survival for pediatric patients diagnosed with cancer has improved significantly. This achievement has been made possible due to new treatment modalities and the incorporation of a systematic multidisciplinary approach for supportive care. Understanding the distinctive cardiovascular characteristics of children undergoing cancer therapies has set the underpinnings to provide comprehensive care before, during, and after the management of cancer. Nonetheless, we acknowledge the challenge to understand the rapid expansion of oncology disciplines. The limited guidelines in pediatric cardio-oncology have motivated us to develop risk-stratification systems to institute surveillance and therapeutic support for this patient population. Here, we describe a collaborative approach to provide wide-ranging cardiovascular care to children and young adults with oncology diseases. Promoting collaboration in pediatric cardio-oncology medicine will ultimately provide excellent quality of care for future generations of patients.

Malonyl coenzyme A decarboxylase deficiency: early dietary restriction and time course of cardiomyopathy.

Malonyl coenzyme A (CoA) decarboxylase (MCD) deficiency is a rare autosomal recessive organic acidemia characterized by varying degrees of organ involvement and severity. MCD regulates fatty acid biosynthesis and converts malonyl-CoA to acetyl-CoA. Cardiomyopathy is 1 of the leading causes of morbidity and mortality in this disorder. It is unknown if diet alone prevents cardiomyopathy development based in published literature. We report a 10-month-old infant girl identified by newborn screening and confirmed MCD deficiency with a novel homozygous MLYCD mutation. She had normal echocardiogram measurements before transition to high medium-chain triglycerides and low long-chain triglycerides diet. Left ventricular noncompaction development was not prevented by dietary interventions. Further restriction of long-chain triglycerides and medium-chain triglycerides supplementation in combination with angiotensin-converting enzyme inhibitors helped to improve echocardiogram findings. Patient remained asymptomatic, with normal development and growth. Our case emphasizes the need for ongoing cardiac disease screening in patients with MCD deficiency and the benefits and limitations of current dietary interventions.

Mutation site-specific differences in arrhythmic risk and sensitivity to sympathetic stimulation in the LQT1 form of congenital long QT syndrome: multicenter study in Japan.

OBJECTIVES: We sought to compare the arrhythmic risk and sensitivity to sympathetic stimulation of mutations located in transmembrane regions and C-terminal regions of the KCNQ1 channel in the LQT1 form of congenital long QT syndrome (LQTS). BACKGROUND: The LQT1 syndrome is frequently manifested with variable expressivity and incomplete penetrance and is much more sensitive to sympathetic stimulation than the other forms. METHODS: Sixty-six LQT1 patients (27 families) with a total of 19 transmembrane mutations and 29 patients (10 families) with 8 C-terminal mutations were enrolled from five Japanese institutes. RESULTS: Patients with transmembrane mutations were more frequently affected based on electrocardiographic (ECG) diagnostic criteria (82% vs. 24%, p < 0.0001) and had more frequent LQTS-related cardiac events (all cardiac events: 55% vs. 21%, p = 0.002; syncope: 55% vs. 21%, p = 0.002; aborted cardiac arrest or unexpected sudden cardiac death: 15% vs. 0%, p = 0.03) than those with C-terminal mutations. Patients with transmembrane mutations had a greater risk of first cardiac events occurring at an earlier age, with a hazard ratio of 3.4 (p = 0.006) and with an 8% increase in risk per 10-ms increase in corrected Q-Tend. The baseline ECG parameters, including Q-Tend, Q-Tpeak, and Tpeak-end intervals, were significantly greater in patients with transmembrane mutations than in those with C-terminal mutations (p < 0.005). Moreover, the corrected Q-Tend and Tpeak-end were more prominently increased with exercise in patients with transmembrane mutations (p < 0.005). CONCLUSIONS: In this multicenter Japanese population, LQT1 patients with transmembrane mutations are at higher risk of congenital LQTS-related cardiac events and have greater sensitivity to sympathetic stimulation, as compared with patients with C-terminal mutations.