Cardiology>>>>>Adult Congenital Heart Disease and Pregnancy
Question 11#

You are approached by one of the adult congenital specialist nurses for advice regarding a patient with tetralogy of Fallot (ToF) who has contacted them directly. The patient, who is now 24 years old, had total surgical repair in childhood and has remained well since, but has recently been experiencing palpitations with associated presyncope. The symptoms are transient and there has been no syncope. There are no other relevant symptoms or reduction in exercise capacity. The echocardiogram from clinic a year previously showed moderate–severe PR and moderate RV dilatation. The nurse has performed an ECG which shows SR with first-degree AV block and RBBB (QRS 190 ms).

What is the most appropriate advice?

A. The patient is at risk of malignant arrhythmias and sudden cardiac death; urgent haemodynamic assessment and consideration of an ICD is appropriate
B. It is likely that the patient is experiencing paroxysmal SVTs or symptomatic ectopics; arrange an outpatient 24-hour tape
C. It is common for patients with ToF repair to develop non-sustained RVOT arrhythmias at the site of the surgical scar, and beta-blockers are the initial treatment of choice for symptoms
D. It is possible that the symptoms represent haemodynamic deterioration; an echocardiogram should be arranged to document progression of PR and RV dilatation
E. High degrees of AV block/sinus node dysfunction are probably due to the scar from the VSD patch; the best investigation is an implantable loop recorder with a view to a permanent pacemaker

Correct Answer is A

Comment:

The duration of the QRS is proportional to the size of the RV. It has been shown that a QRS >180 ms is a highly sensitive marker for VT and SCD in previous ToF repair (SCD accounts for a third of late deaths). This patient’s case should be urgently discussed and the option of an ICD considered. Haemodynamic assessment with echocardiography is also important as the PR or RV dilatation may have progressed, with the need for PV intervention. Non-sustained VT is common but is not an indicator of SCD risk. Antiarrhythmics are not indicated if the patient is asymptomatic. The VT is normally of RVOT origin (infundibulectomy or VSD patch). Development of major arrhythmias (AF/flutter and sustained VT) normally reflects haemodynamic deterioration (PR, RV dilatation) and therefore haemodynamic assessment and correction of the lesion can correct the arrhythmia (with the option of surgical/catheter ablation).