The cardiac sarcoplasmic reticulum calcium-ATPase (SERCA2a), Na+/Ca2+ exchanger (NCX1), and ryanodine receptor (RyR2) are proteins involved in the regulation of myocyte calcium. We tested whether exercise training (ET) alters those proteins during development of chronic heart failure (CHF). Ten dogs were chronically instrumented to permit hemodynamic measurements. Five dogs underwent 4 wk of cardiac pacing (210 beats/min for 3 wk and 240 beats/min for the 4th wk), whereas five dogs underwent the same pacing regimen plus daily ET (5.1 +/- 0.3 km/h, 2 h/day). Paced animals developed CHF characterized by hemodynamic abnormalities and reduced ejection fraction. ET preserved resting hemodynamics and ejection fraction. Left ventricular samples were obtained from all dogs and another five normal dogs for mRNA (Northern analysis, band intensities normalized to glyceraldehyde-3-phosphate dehydrogenase) and protein level (Western analysis, band intensities normalized to tubulin) measurements. In failing hearts, SERCA2a was decreased by 33% (P < 0.05) and 65% (P < 0.05) in mRNA and protein level, respectively, compared with normal hearts; there was only an 8.6% reduction in mRNA and a 32% reduction in protein in exercised animals (P < 0.05 from CHF). mRNA expression of NCX1 increased by 44% in paced-only dogs compared with normal (P < 0.05) but only by 22% in trained dogs (P < 0.05 vs. CHF); protein level of NCX1 was elevated in paced-only dogs (71%, P < 0.05) but partially normalized by ET (33%, P < 0.05 from CHF). RyR2 was not altered in any of the dogs. In conclusion, long-term ET may ameliorate cardiac deterioration during development of CHF, in part via normalization of myocardial calcium-handling proteins.
Atherosclerotic disease of the heart likely has its origins in childhood. The promotion of cardiovascular health in children, however, has been studied only for those practicing in general paediatrics. We hypothesised that paediatric cardiologists do not consistently discuss cardiovascular risk factors with patients and their families. We therefore, carried out a nationwide survey of paediatric cardiologists to determine how often they discussed atherosclerosis and 4 modifiable risk factors, specifically weight, smoking, diet and nutrition, and physical activity. Only two-fifths reported that they discussed atherosclerotic disease frequently to always. For patients with cardiovascular disease, weight was discussed frequently to always by 59%, smoking by 61%, diet and nutrition by 63%, and physical activity by 92%. In contrast, for patients without cardiovascular disease, weight was discussed frequently to always by 35%, smoking by 46%, diet and nutrition by 39%, and physical activity by 62%. These differences are statistically significant (p < 0.003 by χ2 analysis). Cardiovascular risk factors were discussed more consistently as children grew older (p < 0.0001). Respondents stated that, in their opinion, the promotion of cardiovascular health was a role more appropriate for providers of primary care than for paediatric cardiologists (p < 0.0001). Constraints of time, and the perceived role of the cardiologist, were the most common barriers to anticipatory guidance. We suggest that these findings indicate that paediatric cardiologists can assume a more prominent role in preventive cardiology and education, although their precise role or roles, and the optimal methods of anticipatory guidance, remain controversial.
Our case highlights the importance of remaining vigilant in the workup of atypical rashes of the infant, which should include early assessment of serum electrolytes.
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