Value of intravenous ATP in the diagnosis and treatment of tachyarrhythmias in children.

Actual researches show that adenosine and its forerunner, ATP, can realise a nodal block in intravenous (i.v.) administration. This effect, even if transient, is of particular usefulness in the therapy of paroxysmal supraventricular tachycardia (PST) in children and adults. 1 mg/kg ATP was administered i.v. to 51 children (aged 3 months to 15 years) admitted to the Intensive Care Unit for severe regular paroxysmal tachyarrhythmias with clinical and ECG symptoms. In 31 cases, the P wave was absent on ECG. In 6 of 31 cases in whom wide QRS complexes were found (over 0.10 sec), a WPW syndrome (4 cases) or bundle branch block (2 cases) was associated. Rapidly i.v. administration monitored electrocardioscopically was followed by ending of PST in 43 children, including those with wide QRS complexes. The highest effectiveness was in junctional tachycardia by re-entering mechanism. The drug was well tolerated, had no side effects or hemodynamic disturbances and this is very important, because in 12 infants already existed symptoms of congestive cardiac failure at their admission. The use of i.v. digoxin with/without propranolol was necessary in 8 cases, in which the repeated ATP administration was ineffective. We consider that i.v. ATP administration in regular tachyarrhythmias in children is very useful for the proper diagnosis of the types with wide QRS complexes and/or when the P wave did not appear on the ECG, and also for the treatment, because ATP has a high effectiveness and an excellent tolerance.

Clinical and evolutive aspects in ventricular preexcitation syndromes in child.

Ventricular preexcitation syndromes (VPS) are very important between cardiac rhythm disturbances in childhood, because their presence can change the clinical and ECG picture and thus the treatment can be very difficult. The authors studied 58 cases of VPS in children (2 weeks-15 years old) admitted in a period of 3 years. The surface ECG showed VPS aspects: in 30% of cases we noticed WPW syndrome type B and the rest presented VPS with Mahaim pathways and Lown-Ganong-Levine syndrome. 4 cases were familial and 1 child a hidden WPW syndrome. In 65% of cases the cardiac symptoms put the diagnosis and 1/3 of cases were discovered by common ECG. The most important cardiac sign of the children with WPW syndrome was the paroxysmal supraventricular tachycardia, 4 cases presenting wide QRS complex. Others types of VPS were without clinical symptoms. The intravenous administration of digoxin + propranolol was the therapy of choice for paroxysmal supraventricular tachycardia in infants and children until 2-3 years old, and propranolol and chinidine after this age. The children older than 2-3 years and/or those with ineffective preventive for recurrent treatment received dysopiramide and specially amiodarone with satisfactory results; it was not necessary the surgical ablation of the aberrant pathway. Ventricular preexcitation syndromes and wrong treatment can induce severe ventricular arrhythmia, so all the tachyarrhythmias with unknown etiology and especially those with wide QRS complex must be investigated very carefully, using and Holter test and the endocavitary electrophysiology, for a correct medical and/or surgical treatment.