Comparison of cardiac morphological and functional changes according to magnetic resonance imaging with the genetic testing data in patients with hypertrophic cardiomyopathy

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Aim. To analyze the data of cardiac magnetic resonance imaging (MRI) of patients with hypertrophic cardiomyopathy (HCM) depending on the results of genetic testing. Material and methods. The study included 83 patients with a diagnosis of HCM (39 men, 44 women, mean age 50,4±14,9 years) who had no contraindications to MRI. Cardiac MRI was performed on 1,5 T and 3 T MRI systems using a standard protocol. T1 and T2 mapping was performed in 41 patients, and the extracellular volume fraction was estimated. All patients underwent genetic testing with assessment of sarcomeric genes, two non-sarcomeric genes associated with HCM, and genes of syndromic diseases (HCM phenocopies). Results. Positive results of genetic testing were obtained in 49 (59%) of 83 patients: MYBPC3 29%, MYH7 17%, TPM1 5%, FLNC 4%, MYL2 2%, TNNC1 1%, TNNI3 1% (genotype-positive group (G+)). Negative results of genetic testing were obtained in 34 (41%) patients (genotype-negative group (G-)). In the G-group, patients were significantly older than in G+ (57,7±12,9 vs 45,3±14,2 years, p<0,05), with a smaller left ventricular (LV) wall thickness (18,9±4,2 vs 21,3±5,9 mm, p<0,05), and a higher LV ejection fraction (70,5±10,7 vs 64,7±10,4%, p<0,05). Comparison of myocardial fibrosis parameters between the groups showed a significantly lower incidence of delayed contrast enhancement in the G-group, and in its presence, the fibrosis severity, which was assessed as the fibrosis percentage from the total LV mass, was significantly lower than in the G+ group (71% vs 92%; 5,0±8,0% vs 11,4±9,0%, respectively, p<0,05). When analyzing G+ patients depending on the identified mutations, no significant difference in the severity of fibrosis was found between the groups. Conclusion. In patients with HCM, a positive genetic analysis, regardless of the affected gene, is associated with a greater severity of fibrosis according to MRI data, which indicates a less favorable prognosis.

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