PMC10328153_01
(a) ECG of the proband; (b) TTE showed left and right atria; (c) TTE showed the presence of peak E-wave and the loss of A-wave; (d) TDI at the MV annulus further supported left AS; (e) coronary artery CT showed thrombosis of left atrial appendage.. TEE: transthoracic echocardiography; TDI: tissue Doppler imaging; MV: mitral valve.
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The ECG showed a regular junctional rhythm of 43 beats/min (Figure 1(a)). In addition, the same exam showed 40 mm for the left atrial diameter, 44 mm for the RA diameter, 37 mm for the right ventricular diameter, left ventricular ejection fraction (LVEF) 33%, and no atrial mechanical contraction (Figure 1(b)). Atrial and ventricular systolic spectra and tissue Doppler imaging (TDI) at the mitral valve annulus showed the absence of a' at the annulus (Figure 1(c) and (d)). However, thrombosis was seen in the left atrial appendage unexpected (Figure 1(e)).
(a) Electrocardiogram of RA, Koch triangle and CS were recorded without waves, HRA in the intracavitary electrogram showed the potential of RA and Koch triangle and (b) 10 V electrical stimulation in RA and CS could not capture the atrium. The intracavitary electrogram showed that CS 3,4 was stimulated.
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No A-wave appeared in the high RA, the middle RA, the Koch triangular, or all CS domain (Figure 2(a)). Electrical stimulation (10 V) at a frequency of 60 times/min was performed on the high RA, the middle RA, the Koch triangular domain, and the CS, but the right and left atria were not captured (Figure 2(b)).
PMC10328153_02
(a)-(e) Sanger sequencing showing the c.1567dupG pathogenic heterozygous variant in the proband, the proband's younger brother, elder sister, younger sister, and her son. (f) Family tree. Pedigree showing the pathogenic people with black box and the nonpathogenic person in blue box.
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The amino acid frameshift insert mutation of asparagine to glutamic acid at the 524 locus and early termination after the latter 28 amino acids (p.Asn524Glufs*28) was due to a double-G insertion c.1567 within the LMNA gene (Figure 3(a)). The heterozygous mutation of the LMNA gene was also detected in the patient's younger brother and her older sister (Figure 3(b) and (c)). The patient's younger sister and son did not carry the gene mutation (Figure 3(d) and (e)). The family tree was showed as Figure 3(f).