PMC10285104_01
Standard 12-lead surface ECG (A), with a very low voltage atrial activity and irregularly irregular (with no pattern to the RR intervals) ventricular response with a rate of 92 beats/mi. QRS width of 100 msec; QTc 463 msec. Magnification of leads DII and V1 (B), showing almost undetectable atrial electrical activity.
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F1
The surface ECG presented atrial fibrillation:with a very low voltage (Figure 1) -and the transthoracic echocardiography estimated the LV ejection fraction to be 65%.
Left atrial CT scan segmentation. Cardiac computed tomography, with a left atrial volume of 70 ml and a left pulmonary venous drainage pattern R2a/L1.
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F2
Voltage map of the right (A) and the left atrium (B), depicting extensive areas of low voltage (red) (cut-off 0.20-0.50 mV). (A1 and B1) Antero-Posterior view; (A2 and B2) posteroanterior view.
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F3
The right and left atrial maps revealed extensive LVAs (Figure 3).
Visualization of next-generation sequencing results, showing the variant c.449G > A, p.(Arg150Gln) in the NPPA gene as homozygous in the index case.
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F4
A targeted panel for the inherited cardiac disease were analysed (in Supplementary Material), which revealed the variant c.449G > A, p.(Arg150Gln) in homozygosity in NPPA gene (Figure 4) classified as pathogenic, according to guidelines ACMG/ACGS 2020 (P:PM3_vstr, PP1_str).
Sanger sequencing showing the variant c.449G > A, p.(Arg150Gln) in NPPA gene, identified in heterozygosity both in the father and the mother of the patient. Black arrows indicate the point mutation.
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F5
Familiar segregation studies reveal the consanguinity of the parents, and the presence of the variant in heterozygosity (Figure 5) in both parents was confirmed.
Images from late gadolinium enhancement (LGE) MRI. Fibrosis assessment with the ADAS 3 D software. The three-dimensional LA model from MRI shows extensive areas of fibrosis (dense scar) involving the posterior wall and the anterior and septal walls. LAA, left atrial appendage; RSVP, right superior pulmonary vein; RIPV, right inferior pulmonary vein.
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F6
In addition, cardiac magnetic resonance imaging was performed (Figure 6), where extensive areas of fibrosis could be identified.