Pre-excitation induced left ventricular dysfunction: A less known cause of cardiomyopathy in children
A 7-year-old boy was diagnosed to have dilated cardiomyopathy (DCM) at the age of 1 year. Medical attention was sought then for lethargy, poor feeding, and rapid breathing. His echocardiography reportedly showed dilated ventricles and a LV ejection fraction of 25%. He had no preceding febrile illness. His ECG was misinterpreted as LBBB pattern. He was initiated on beta-blockers and angiotensin-converting enzyme inhibitors. He responded and had been on regular follow-up.\nOn the last several follow-ups at the centre where he was initially evaluated, he stayed symptom free but his LV dilatation or LV function did not improve. At 7 years of age, the family chose to have further follow-up at our center. In their visit, records were reviewed. ECG revealed short PR interval with delta wave [], the accessory pathway was localized to right posterolateral area possibly. He had no history of palpitation; the echocardiogram showed the LV dilated with ejection fraction of 40% [].\nOn tissue doppler imaging (TDI), there was delay of 60-70 ms from the septal to lateral wall []. There was no paradoxical septal motion. The septal to posterior wall motion delay (SPWMD) was not significant. A possibility of accessory pathway induced dysynchrony was considered that could have possibly caused LV dysfunction.\nAn electrophysiological study confirmed pre-excitation. The pathway effective refractory period was 250 ms. No attempt was made to induce tachycardia. The pathway was mapped to the posteroseptal area of the tricuspid annulus and was successfully eliminated []. The local atrial (A) Ventricular (V) electrograms were fused. The A and V separated in 6 s into delivery. The current was delivered for 60 s and the temperature and power achieved were 55°C and 30 watts, respectively. The immediate post-procedure echocardiogram revealed that there was no dysynchrony between the septal and lateral wall []. His follow-up echo showed that his ventricular dimensions normalized (from 48 to 42 diastolic and 38 to 28 mm end systolic after one year) and function was normal [].