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).