Palpitation may be a terrifying event for children and pose diagnostic problems for pediatric cardiologists. Routine methods often fail to document episodic arrhythmia because the episodes may be brief or infrequent or both. The purpose of this study was to evaluate and compare values of non-invasive and invasive techniques. Twenty-three children (mean age 11.7 +/- 2 years, range 7-16 years) with recurrent palpitation attacks (> 2 times), who had normal physical examinations, ECG, echocardiography, 24 hour ambulatory ECG monitoring and treadmill exercise tests, were included in the study. Redline Model CG 4000 TTE recorders were given to patients for 10 or 20 days. We performed an intracardiac electrophysiologic study (EPS) on 14 patients. The mean number of palpitation attacks was 11.3 +/- 7.4 (median: 5), lasting 9.6 +/- 7 (median 3) minutes. The number of transmitting records was 2 +/- 1.4 (1-20). Of the 23 patients, only 15 (65%) transmitted during the palpitation attacks. Twenty-four-hour ambulatory ECG monitoring findings were normal in all patients. One patient had a wide QRS tachycardia attack in the TTE records. We stimulated ventricular tachycardia in the same patient in the EPS. Among the other patients who transmitted TTE records during palpitation attacks, we diagnosed two cases of concealed accessory pathway and eight cases of dual AV nodal pathway in the EPS. In conclusion, TTE is a sensitive and accurate method for diagnosis and follow-up of patients with cardiac arrhythmia. It can be used before invasive studies in children with recurrent palpitation attacks.