Comparison of Transesophageal and Intracardiac Electrophysiologic Studies for the Diagnosis of Childhood Supraventricular Tachycardias.

In this study, we aimed to compare the results of transesophageal electrophysiologic studies (TEEPS) and intracardiac electrophysiologic studies (IEPS) in a cohort of pediatric patients with SVTs. The medical records of children aged between 0 and 18 years who underwent TEEPS between January 2007 and June 2012 were systematically reviewed, and those without pre-excitation and who underwent subsequent IEPS were identified. Post-procedural diagnoses were compared for compatibility. A total of 162 patients were included in the study with a mean age at diagnosis 11.6 ± 3.6 years. Tachycardia was induced in 152 patients by TEEPS and in 154 patients by IEPS. Overall, in 147 patients, tachycardia was induced by both TEEPS and IEPS. Diagnoses were compatible in 135 out of 147 patients (91.8 %). Nine out of the 12 patients with discrepant results were diagnosed with atrioventricular-reentrant tachycardia (AVRT) and three with atrioventricular nodal reentrant tachycardia (AVNRT) after TEEPS. Following IEPS, TEEPS diagnosis of AVRT was revised to typical AVNRT in 5 patients and atypical AVNRT in 4 patients. Two of the 3 patients who were diagnosed as having AVNRT following TEEPS were confirmed to have atrial tachycardia after IEPS, while the other patient was diagnosed with AVRT. Tachycardia terminated spontaneously in 3 patients, while overdrive pacing was attempted to terminate the tachycardia in 149 patients, with a success rate of 93.2 % (139/149). The diagnostic compatibility between TEEPS and IEPS is quite high. A diagnostic discrepancy mostly occurs in patients diagnosed with AVRT by TEEPS, and the possibility of atypical AVNRT should be considered in patients with a VA ≥70 ms to avoid such discrepancies.

[Microvolt T-wave alternans as a novel method of analysis of changes of repolarization phase and detection of latent electrical instability of the myocardium].

This review considers of modern concepts of microvolt T-wave alternans (TWA): its pathophysiological basis at cellular level, particulars of quantitative analysis of TWA, modulating effects of autonomic nervous system and drugs, prognostic efficacy in predicting susceptibility to ventricular arrhythmia in comparison with other modern prognostic factors of sudden cardiac death.