Objective To explore the clinical characteristics, prevention, and treatment strategy for SCN5A A1180V mutation carriers by following up a family displaying dilated cardiomyopathy (DCM) and atrioventricular block (AVB).
Methods According to the first discovery of the family in 2007 and the follow-up data in 2012, the medical history of 6 A1180V mutation carriers and 7 non mutation carriers in the family were followed up by medical history inquiring in 2021, and 12-lead electrocardiogram and echocardiography were performed. Clinical data of 10 mutation carriers (including 3 dead mutation carriers and 1 person who did not participate in the follow-up), 7 non mutation carriers and 1 dead member with unknown genotype were analyzed.
Results In this family, the first symptom of SCN5A A1180V mutation carrier was usually degree Ⅰ AVB (mean age at diagnosis was 36±4.42years), and most gradually progressed to degree Ⅲ AVB and DCM. After 2012, one old carrier had suffered sudden cardiac death, and four carriers had progressed to degree Ⅲ AVB from degree Ⅰ AVB. Three children of the proband had implanted pacemaker because of degree Ⅲ AVB, but they had no cardiac dysfunction even though they were at the age when their father had DCM, indicating the phenotype of DCM in mutation carriers was delayed. The three daughters of the proband's younger brother manifested normal ECG and echocardiography in 2012. However, two had degree Ⅰ AVB and one had degree Ⅲ AVB in 2021, the exacerbation might be related to heavy physical labour.
Conclusions A1180V mutation of SCN5A, genetic background, and environmental factors play a mutual role in the phenotype of DCM, and the prevention and treatment strategy of controlling heart rate and reducing physical labor could delay the appearance and progression of the disease phenotype for A1180V mutation carriers in this family.
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