RESUMO
Our aim was to study the changes in electrolytes "represented by the Anion Gap" [AG] in the patients complaining of congenital cyanotic heart disease [CCHD] and we tried to correlate these changes to the severity of clinical manifestations and the hemodynamic state. The present study included twenty five patients complaining from CCHD. Nineteen of them were males [76%] and 6 were females [24%]. The study was concluded on and two types of CCHD, tetralogy of Fallot [TOF], [77 patients, 68%] and transposition of great arteries [TGA], [8 patients, 32%]. Their age ranged between 5 days and 4 years. Ten age and sex matched children were also selected as control group. All were presented to Cardiology Clinic in New Children Hospital, Cairo University. All subjects participating in this study underwent the following: Full History taking, thorough clinical examination, 12-lead ECG, cardiac series X-ray, full echocardiographic study, catheterization and anion gap detection. The study revealed that, in patients with CCHD, the level of HC03 and Na are nearly the same as in normal children, while CI is highly different. Regarding the severity of clinical manifestations, a highly significant positive correlation was observed between the anion gap and severity of clinical manifestations in patients with TGA, while there was no significant correlation between the anion gap and severity of clinical manifestations in TOF patients, thus the anion gap may be used as an indicator of the severity of clinical manifestations in TGA patients. Ako a negative correlation was observed between the level of HCOJ and the severity of clinical manifestations of these patients. The anion gap was found to have a significant negative correlation with the ejection fraction [EF] of the patients and a new equation may be used for anion gap calculation as follows: [AG 48.82 - 0.41 x EF]
Conclusion and Recommendations: the anion gap should be a routine laboratory investigation in every case of CCHD, especially TGA. From this study, we can conclude that measurement of anion gap could be of help in follow-up of severity of case of CCHD and so routine assessment of this parameter is recommended. The use of the newly developed equation could be of help of assessment of EF and consequently the severity of cardiac condition of the patients. The anion gap can be calculated in patients with CCHD using the EF: Y = a - bx [where Y anion gap, a 48.82, b = 0.41 and x = EF]