Case report
A 36-year-old woman in whom a left anterior cruciate ligament repairment was planned, reported a history of 3 months of palpitations and dyspnea in the pre-anesthetic examination, where arrhythmic heart sounds were found, reason why she was referred for cardiologist evaluation.
An initial electrocardiogram (ECG) showed sinus rhythm without any abnormality and a normal echocardiogram was obtained. The 24 hours Holter-ECG showed frequent PVCs with an arrhythmic burden of 35% (Figure 1), so β-blocker therapy was prescribed. Ischemic substrate was ruled-out with a dobutamine stress-echocardiogram as well as Chagas disease and electrolyte disturbances. However, the CMR revealed prominent trabeculae and deep recesses in the left ventricle (LV) apex, as well as in the anterior, inferior and lateral wall of the LV. The right ventricle (RV) was normal without any myocardial or function disturbances (Figure 2). Therefore, the diagnosis of isolated LVNC cardiomyopathy was proposed.
Despite the prescription of highest-tolerated dose of β-blocker therapy, it was recorded a persistent high PVCs burden (22%) in a 24 hours Holter-ECG; reason why the patient was referred to the Electrophysiologist for ventricular ablation. On the procedure day, the baseline ECG of the patient showed a sinus rhythm with right ventricular outflow tract (RVOT) complexes in ventricular bigeminy. The preliminary electrophysiology study found normal sinus function test, normal atrioventricular conduction intervals and absence of accessory pathways. Then a Pentarray Biosense® catheter was used to obtain a RVOT-3D electroanatomic mapping with the CARTO-3 mapping system.
The activation map identified the PVCs origin in the anterolateral segment of the RVOT (Figure 3) where the topostimulation with pass mode and pattern-matching showed a correlation of the ninety five percent compared with the extrasystole. Then, radiofrequency ablation was performed. Afterwards, no tachycardia was induced with the programmed auricular and ventricular heart stimulation. No complications related to the procedure were reported and the patient was discharged from the hospital on the next day, with her previous antiarrhythmic medication. In the follow-up after 3 months of the ventricular ablation, remains asymptomatic and free of PVCs.