Case report patient A
This female patient was diagnosed with left ventricular non-compaction, left ventricular ejection fraction (LVEF 0.52) and frequent (30%) premature ventricular contractions (PVC) at the age of 37years. The MRI did not show any scar nor late enhancement. An electrophysiological study was performed, and the major origin site of the PVC was identified near the aortic valve and was successfully ablated. Nine years later, at the age of 46years, she presented with EF 0.47, frequent episodes of non-sustained ventricular tachycardia, together with frequent and highly symptomatic paroxysmal atrial fibrillation. The patient underwent pulmonary vein isolation and prophylactic ICD implantation. One year later a redo procedure for multiple left atrial flutters was unsuccessful, as contact mapping could not localize the irregular atrial activation patterns. An antiarrhythmic treatment with flecainide was successful, but stopped after 2 years because of decrease in EF to 0.35. Then at the age of 50years a noncontact mapping system (AcQmap®, Acutus Medical) became available for a redo proceure. The system has been described elsewhere (1)11. Briefly a beat to beat analysis of the electrical charge (Coulomb/area) is obtained simultaneously in the entire atrium by signal processing from 48 noncontact electrodes. The system has been validated against contact mapping in sinus rhythm and atrial fibrillation(2).
There was no activity in any pulmonary vein. A left atrial map showed a flutter with changing activation sequence originating from the interatrial septum region with a cycle length of 270ms. (Figure 2 upper panel left) Therefore also a right atrial map was performed, which showed the trigger at the corresponding site in the right atrial septum. During RFA at a site with very discrete electrograms (Figure 2 panel A) the flutter slowed to 365msec and converted to Sinus Rhythm only in the right atrium, while the left atrium continued in the arrhythmia (Figure 2 panel B). An additional left atrial map showed again the earliest triggers in the septum and further ablation there led to conversion to Sinus Rhythm (Figure 2 panel C). Afterwards a very long interatrial conduction time of 200ms was observed.
During follow up of 3 years the patient remained free of atrial arrhythmias longer than 2 minutes according to the ICD interrogation, in the absence of any antiarrhythmic drug. After discontinuation of flecainide and in sinus rhythm, the EF remained stable at 0.35. However, she experienced during follow-up repeated stroke despite anticoagulation with VKA, which were attributed to thromboembolism from the non-compacted ventricular myocardium. Therefore the anticoagulation was combined with Aspirin.