role of heart rate variability in the diagnosis of rheumatic fever in children

ABSTRACT

Rheumatic fever is a characteristic constellation of multisystem disease, which occurs after a lag period following pharyngeal infection with group A streptococci Heart Rate Variability [HRV] is defined as the amount of heart rate fluctuations around the mean heart rate. HRV can be used as a mirror of the cardio-respiratory control system and represents one of the most promising and easy markers of sympathetic and parasympathetic function of the autonomic nervous system. Determining HRV changes in children with rheumatic fever, as well as using HRV as a diagnostic marker of rheumatic heart disease. This cross-sectional case-control study included 50 children suffering from rheumatic fever [25 males and 25 females], their ages ranged between 5-12 years with a mean of 8.52 +/- 3.45 year and their mean weight was 27.28 +/- 8.07 Kg. Forty healthy children [20 males and 20 females] of the same age and with a mean weight 25.35 +/- 6.22 Kg were studied as a control group. All cases were subjected to thorough clinical examination, laboratory investigations [erythrocyte sedimentation rate, anti-streptolysin O titer, C reactive protein, X-ray chest and heart, electrocardiographic recording, echocardiographic assessment, and HRV measurement. All indicators of HRV showed a highly statistical significant impairment in cases with rheumatic heart disease compared to controls [P<0.01], and showed a statistical significant decrease in patients with rheumatic carditis with or without heart failure in comparison to controls [P<0.05]. Also, the results of this study showed that patients with rheumatic carditis with or without heart failure had significant increase in average rate and significant decrease in P-R interval in comparison to controls [P <0.05]. Cases urith rheumatic arthritis showed insigniftant decrease in HRV indices [P>0.05]. HRV indices are impaired in patients with rheumatic heart disease and more significantly impaired in patients with rheumatic carditis with or without heart failure, suggesting alteration of autonomic activity in the form of decreased parasympathetic tone on the heart. Therefore, HRV could be used as a diagnostic marker of carditis in cases with rheumatic heart disease .HRV indices are impaired in cases with rheumatic heart disease in spite of taking antifailure drugs that increase HRV, so HRV will be more impaired without treatment with these drugs