Farruggio S¹, Khorgami MR², Zanai R¹, Calvaruso D¹, Ortiz Ruiz DA¹, Agati S¹, Di Mambro C¹, Caruso E^1*
1. Department of Pediatric Cardiology, Mediterranean Pediatric Cardiology Center “Bambin Gesù”, San Vincenzo Hospital, Taormina (ME), Italy.
2. Cardiac Electrophysiology Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran

*Corresponding Author: Dr. Elio Caruso, Department of Pediatric Cardiology, Mediterranean Pediatric Cardiology Center “Bambin Gesù”, San Vincenzo Hospital Contrada Sirina 98039 Taormina (ME), Italy.

 

Case Report

We report a very rare case of ventricular tachycardia (VT) in a two-month-old female infant, with congenital heart disease (CHD), vascular and anorectal malformations.

She was born full-term by cesarean section at 38 weeks of gestational age, from unrelated parents with a family history negative for CHD. At birth she presented good clinical condition, APGAR of 9 at 1’ and 5’ minutes after delivery, normal blood pressure, her body weight at birth was 3.040 kg with 93% of O2 blood saturation (O2 BS), and physical examination showed a grade 3/6 holosystolic murmur and anorectal atresia.

Echocardiogram showed atrial septal defect ostium secundum type shunting left-to-right (Fig. 1 A), patent ductus arteriosus (PDA) shunting aorta-to-pulmonary artery, left-superior caval vein (LSCV) draining directly in the left atrium (Fig. 1 D) with unroofed coronary sinus, and subaortic perimembranous ventricular septal defect (VSD) wide about 5 mm (Fig. 1 B-C) shunting mainly left-to-right (Fig. 1 C).

The patient after one day from the birth underwent to colostomy surgery in another hospital and about after two months was referred to our intensive care unit (ICU) for dyspnea and frequent premature ventricular contractions (PVCs) during hospitalization in the other center. Baseline ECG made in the other hospital showed a sinus rhythm (SR) with a heart rate (HR) of 150 beats per minute (bpm), high P-wave voltage (> 0.25 mV in the limb leads), normal PR interval (120 ms) and cardiac axis, increased QRS voltage in precordial leads, nonspecific ST-T wave changes. ECG monitor in ICU showed a suspected supraventricular tachycardia (SVT) with narrow QRS, then a first therapeutic approach was done with iv adenosine bolus at the dosage of 0,1 mg/kg increasing dosage to 0,2 mg/kg until 0,4 mg/kg without resolution of arrhythmia. The patient was pale, dyspnoic with good blood pressure. A transesophageal electrophysiological study was performed, after informed consent obtained from parents, on the doubt of an SVT refractory to adenosine. Atrial stimulation started by 10 mA for 10 ms with an HR faster than the baseline and adjusted according to the stimulus threshold (Esodik 6 fr quadripolar catheters (FIAB programmable cardiac stimulator 8817) was attempted in ICU, without sedation, showing atrial capture with high rate overdrive without interrupting the arrhythmia. Esophageal atrial pacing was done with a shorter cycle length than RR interval, as a result, we observed the QRS duration became narrower with overdrive pacing, later, after stopped atrial pacing, we expected the QRS duration became wider due to the behavior of the cardiac conduction system with atrial pacing. Therefore, after the last paced beat, the ventricular arrhythmia reappears with the same cycle length (Fig. 2 B). After these quick attempts in our ICU, 12 lead ECG showed tachyarrhythmia with a QRS complex wide 0,08 ms (high age limit) with atrial retroconduction and HR of 280 bpm (Fig. 2 A). A few minutes later ECG showed wide QRS tachycardia alternated to SR and ventricular bigeminy (Fig. 2 C). A differential finding between SVT and VT is the similarity of bigeminy PVCs during sinus rhythm with QRS morphology during tachycardia (Fig. 2 A-C). Therefore, the final diagnosis was VT for the followed findings: VA dissociation (Fig. 3) with ventricular rates exceeding atrial rates (AV ratio < 1:1), QRS duration at the high upper limit for age (0,08 sec) with inferior axis configuration, and morphology of QRS complex suggested a monomorphic VT originating from right ventricular outflow tract (RVOT-VT) [1].

 

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