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

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.