ABSTRACT
To study the diagnosis and treatment of tachycardia induced dilated cardiomyopathy in infants and children with unexplained systolic dysfunction. The present study was conducted on 22 patients were regularly attending the arrhythmology clinic section of pediatric cardiology unit at Cairo University Hospital suffering from significant arrhythmias induced heart failure that determined clinically and by investigations. All cases were subjected to the following; full medical history taken, thorough clinical examination, chest and heart x-ray, 12 leads ECG, 24 hours electrocardiographic recording [Holter monitoring] and standard echocardiographic evaluation included real time two-dimensional echocardiogram, M-mode and Doppler measurement. All studied cases with tachycardia induced DCM underwent medical treatment of arrhythmia with remission of the DCM. Studied cases showed good response to medical treatment in the form of anti-arrhythmic drugs [amiodarone alone [12] or in combination with sotalol [8] / lanoxin [1] or verapamil [1]] where sinus rhythm with normalization of ventricular function was achieved in treated cases. The manifestations of heart failure were eliminated clinically [via return of heart rate and respiratory rate to normal values for age] and radiologicaly. Holter monitoring was done only for 19 cases and showed return to sinus rhythm with normal heart rate for age [<0.001 highly significant] and improvement of echocardiographic variables [LVEDD, LVESD, EF and Fractional shortening for age]. One child continued to have frequent episodes of tachycardia and underwent successful AV nodal ablation with permanent pacemaker implantation. Two out of the 22 patients on amiodarone could be managed with only digoxin and verapamil after their ventricular function had returned to normal. Tachycardia induced cardiomyopathy is a reversible form of dilated cardiomyopathy and heart failure, where its diagnosis requires high index of suspicion. Medical treatment with amiodarone and/or B-blockers is a safe and effective treatment strategy for infants and children with tachicardiomyopathy. This approach may avoid unnecessary ablations in children or at least postpone it till the procedure would be safer