Discussion:
These are the first case reports of complex irregular atrial flutters mapped with a novel noncontact mapping system (AcQmap®, Acutus Medical) in Lamin heart disease. Contact mapping had not been successful because of irregular and varying atrial conduction patterns. Instead beat to beat analysis of the simultaneous activation in the entire heart chamber by the Acutus system showed the origin of arrhythmias without annotation. The electrograms at target sites showed minimal amplitudes at maximum gain, further illustrating the limitations of contact mapping by filtering and subtraction for bipolar EGM. But the visualization of activation wavefronts repeatedly arising from the same regions by AcQmap indicated the true focal origin of these unusual atrial arrhythmias in the absence of any pulmonary vein activity. They arose from the interatrial septum, close to the regions of interatrial and atrioventricular block in otherwise healthy young patients, which is typical for Lamin heart disease (3-5). During follow up of 2 and 3 years no major recurrences have been demonstrated in PM and ICD interrogation, which illustrates the successful mapping and ablation strategy using this novel technology.
Interestingly these two sisters with Lamin A/C mutation demonstrate two unusual morphological features, which have not been described previously in this context: noncompacted left ventricular myocardium leading to recurrent strokes and a vertical vein connection from the LSPV to the SVC. This adds to the clinical spectrum of Lamin heart disease and the diagnosis by genetic testing is important because of worse prognosis and prophylactic ICD implantation has been recommended in many cases (5, 6).