[Assessment of third-degree congenital atrioventricular block by ergometric tests]

To analyse the use of the exercise testing as the method of initial evaluation, following a prognostic indicative of patients with congenital complete heart block.

Five patients were analysed (3 men and 2 woman) with ages between 7 and 34 years (mean = 22.8). The patients were submitted to a treadmill exercise testing using the Bruce protocol 1 and symptom limited.

In all patients the atrial frequency increased from a median of 74.40 bpm in the basal to 155.20 bpm in the maximum effort; the atrial chronotropism was a little below that calculated based on the age of the patients. The median of the ventricular frequency in the maximum effort was 94.80 bpm, very different from that foreseen and showing a deficit of ventricular chronotropism. The median consumption of oxygen was 35.68ml0(2)/Kg/min. In one patients (20%) there was not any change in the ventricular frequency with the effort, in 3 (60%) complex ventricular arrhythmia arise during the effort and in one (20%) a definitive ventricular pacemaker was implanted.

The exercise testing is a simple method of initial evaluation, providing information as chronotropism, functional capacity and the presence of arrhythmias, that can be very useful in the evaluation of prognostic. The presence of complex ventricular arrhythmias during the exercise is indicative of a more regular follow-up.