CardioExchange Archive

An 11-year-old boy presents with palpitations. He has no family history of heart disease and is asymptomatic while playing competitive sports. His cardiac physical examination is normal, but his ECG (shown below) shows a Wolff-Parkinson-White pattern with a short PR interval and delta waves.

A systematic echocardiogram reveals normal LV function, normal atrioventricular valves, and trabeculations of the LV apex and inferolateral wall. MRI (shown below) confirms the diagnosis of LV noncompaction.

The treating cardiologist decides to explore the possibility of an ablation of the symptomatic preexcitation pathway.

Questions:

1. What do you think the patient’s prognosis would be after an ablation?
2. Would you prescribe aspirin or other anticoagulation therapy?
3. What activity restrictions, if any, would you give the boy after ablation of the accessory pathway?

Response:

James Fang, MD

November 1, 2011

Cardiac conditions in children are always very agonizing for parents, physicians, and the patient. Getting children to identify their symptoms can also be very difficult.

This 11-year-old boy has WPW and symptoms that, though modest (e.g., palpitations), warrant further investigation. The pathway is probably left-sided and posteroseptal, in that the complexes are negative in the inferior leads and the R wave becomes prominent early over the precordium, increasing the risk for heart block with ablation. However, my non-electrophysiologist’s attempt at localizing the pathway from the 12-lead should be taken with a (large) grain of salt.

In minimally symptomatic or asymptomatic patients, an EP study may be suggested to delineate high-risk features such as inducibility of sustained atrial fibrillation or AV reentrant tachycardia and antegrade conduction of the accessory pathway. In such high-risk situations, multiple pathways are often present, which can make ablation more difficult technically. However, ablative therapy is safe and effective in experienced hands. Getting children to take chronic medications is also challenging, particularly over the long term.

In one of the few randomized experiences I could find, Pappone and colleagues randomized a small group of asymptomatic children with high-risk EP features to ablation or no ablation (N Engl J Med 2004; 351:1197). Ablation appeared to limit the incidence of significant arrhythmias, but the study was small with limited follow-up. Notably, children with evidence of structural heart disease were excluded.

It is unclear to me whether the patient truly has LV noncompaction (LVNC), as most of the criteria for LVNC that I’m aware of are for adults and I don’t know how common abnormal “hypertrabeculation” is on pediatric MRIs. In my experience, LVNC in children is usually associated with other congenital heart defects. Genetic testing can sometimes help to confirm the diagnosis. I am not aware of an association of WPW with LVNC specifically, but there is a well-known association with Epstein’s anomaly. Rarely, WPW can be seen with glycogen storage diseases that may mimic hypertrophic cardiomyopathy (e.g., Danon’s disease), but LVNC is typically related to sarcomeric gene defects. LVNC appears to be inherited in an autosomal dominant pattern, so generations are generally not skipped, which is relevant in this case because no family history is reported.

Here are my answers to the questions:

1. Prognosis should be good following ablation, as the Pappone study illustrates, if there is no concomitant cardiomyopathy (which is, of course, the question at hand).

2. Aspirin or warfarin is not needed, unless by protocol for a few weeks after the procedure (which is likely operator-dependent).

3. I would not restrict the patient’s postprocedure activities on the basis of the MRI findings alone. However, it would be interesting to see what the patient’s postablation EKG looks like, as a clearly abnormal EKG following ablation would favor a diagnosis of a cardiomyopathy.

Update:

Thierry Legendre, MD

November 15, 2011

I referred this patient to a specialized pediatric cardiology unit. The treating clinician has decided to investigate his conduction pathways during the coming months, and he has been prescribed aspirin. Heavy physical activity has been discouraged.

In response to Dr. Fang’s comment, I would like to specify that the association of Wolff-Parkinson-White syndrome and LV noncompaction was described in 4 of 27 pediatric patients by Ichida et al. (J Am Coll Cardiol 1999; 34:233) and in 6 of 36 patients by Pignatelli et al. (Circulation 2003; 108:2672), all without congenital heart defects.