Limitation of transthoracic echocardiography in the diagnosis of congenital heart diseases.

Nowadays, it has been widely accepted that echocardiography is the most efficient, non invasive diagnostic tool to diagnose congenital heart diseases. However, cardiac catheterization remains the gold standard to diagnose and obtain hemodynamic data prior to cardiovascular surgery. In order to find out the accuracy of transthoracic echocardiography in relation to the anatomical diagnosis of congenital heart diseases, 175 consecutive patients who underwent diagnostic cardiac catheterization during January 1999 to December 1999 were reviewed. All of them had complete echocardiographic studies prior to the procedure. The male to female ratio was 1.06:1. The median age at the time of echocardiography was 3.36 (0.01-28.8) years old. The indications of the cardiac catheterization were to demonstrate cardiovascular anatomy 64 per cent, to obtain pulmonary artery pressure and pulmonary vascular resistance 13.7 per cent, and to get both information 22.3 per cent. Tetralogy of Fallot (23.4%) was the most frequent cardiac malformation, followed by complex congenital heart diseases (22.3%), simple left to right shunt (12%), pulmonary atresia with ventricular septal defect (8.6%), tricuspid atresia (5.7%), simple d-transposition of great arteries (4%), etc. From cardiac catheterization; 49 cases (28%) revealed additional data which were surgically important, 3 cases (1.7%) resulted in different diagnoses, and 3 cases (1.7%) revealed additional information which was not surgically important. Inadequate imaging technique (36 cases, 65.5%) and limitation of technique (19 cases, 34.5%) were the reasons for missing anatomical findings of transthoracic echocardiography. Age at the time of echocardiography was not a significant factor affecting the accuracy. Persistent left superior vena cava, multiple aorto-pulmonary collateral arteries, pulmonary artery anatomy, and coronary artery anatomy were the most frequent cardiac lesions misdiagnosed by transthoracic echocardiography that were somewhat surgically important. The incorrect echocardiographic diagnoses were aorto-pulmonary window, patent ductus arteriosus, and vascular ring. Thorough and extensive echocardiographic scanning coupled with cooperative or adequately sedated patients by an experienced operator using an efficient echocardiographic machine might improve the accuracy of transthoracic echocardiography in the diagnosis of congenital heart diseases.

Comparison of supraventricular tachycardia from concealed bypass tract and Wolff-Parkinson-White syndrome.

Supraventricular tachycardia (SVT) is a common problem. There are 2 types of accessory atrioventricular pathway (AP) causing SVT: one can conduct antegradely (WPW syndrome) and another can conduct only in a retrograde direction (concealed bypass tract or CBT). There are little data of the significance and difference of the two types in Thailand. The objectives of this study were to compare characteristics of patients, accessory pathways and outcome of radiofrequency catheter ablation (RFCA) between the 2 types of accessory pathways. We reviewed the electrophysiology report of patients with supraventricular tachycardia from the accessory pathway who were referred for RFCA. There were 74 males and 74 females at a mean age of 37 years. CBT accounts for 44 per cent of SVT from AP. Compared to CBT, WPW syndrome was more in the right-sided location, more associated with heart disease, a higher number of accessory pathways, more inducible atrial fibrillation and more difficult to do ablation. However, the overall success rate of RFCA was similar. Although the recurrence rate was 8.4 per cent, all patients with recurrence were successfully reablated. We concluded from this study that RFCA is a highly effective method for the treatment for both forms of accessory pathway although there are some differences between WPW syndrome and CBT.

Percutaneous balloon pulmonary valvuloplasty in children: experience at Siriraj Hospital.

Twenty-seven children with pulmonary valvar stenosis with pressure gradient (PG) > or = 40 mmHg underwent percutaneous balloon pulmonary valvuloplasty (PBPV) at Siriraj Hospital between February 1993 and August 1996. There were 13 males and 14 females, with an age range from 2 months to 14 years, and body weight from 4.7 to 42.1 kg. The majority (92.6%) were asymptomatic. Before the PBPV, the pulmonary valve annulus (PVA) measured by echocardiography was significantly greater than that measured by cardiac catheterization (15.2 +/- 3.7 vs 14.5 +/- 3.9 mm, P = 0.006). However, there was linear association (r = 0.972) between the two methods. The PG obtained by the two methods showed no significant difference (90.8 +/- 35.3 by echocardiography vs 97.3 +/- 47.2 mmHg by catheterization, P = 0.266). Immediately after PBPV, the right ventricular systolic pressure (113.7 +/- 41.1 pre vs 62.3 +/- 28.1 mmHg post) and the PG 103.4 +/- 43.4 pre vs 49.0 +/- 31.1 mmHg post) were significantly reduced (p < or = 0.0005). At 6-mo follow-up echocardiography, the PG was 28.6 +/- 17.6 mmHg and was significantly reduced (P = 0.0005). The PVA significantly increased at the 12 mo follow-up (15.2 +/- 3.6 pre vs 17.6 +/- 3.8 mm post, P = 0.001). Only minor complications were reported in the present study; bleeding (3.7%), transient bradycardia (7.4%) and pulmonary regurgitation not more than moderate severity (79%). The immediate and intermediate results of PBPV are excellent with a success rate of 85 per cent.