Echocardiography in the Diagnosis and Management of Hypertrophic Cardiomyopathy

Hypertrophic, Dilated, and Arrhythmogenic Cardiomyopathy: Where Are We?

Cardiomyopathies are a heterogeneous group of structural, mechanical, and electrical heart muscle disorders which often correlate with life-threatening arrhythmias and progressive heart failure accounting for significant cardiovascular morbidity and mortality. Currently, cardiomyopathies still represent a leading reason for heart transplantation worldwide. The last years have brought remarkable advances in the field of cardiomyopathies especially in terms of understanding the molecular basis as well as the diagnostic evaluation and management. Although most cardiomyopathy treatments had long focused on symptom management, much of the current research efforts aim to identify and act on the disease-driving mechanisms. Regarding risk assessment and primary prevention of sudden cardiac death, additional data are still pending in order to pave the way for a more refined and early patient selection for defibrillator implantation. This review summarizes the current knowledge of hypertrophic, dilated and arrhythmogenic cardiomyopathy with a particular emphasis on their pathophysiology, clinical features, and diagnostic approach. Furthermore, the relevant ongoing studies investigating novel management approaches and main gaps in knowledge are highlighted.

Right atrial function assessed by volume-derived values and speckle tracking echocardiography in patients with hypertrophic cardiomyopathy

Background

To detect the right atrial (RA) functions in hypertrophic cardiomyopathy (HCM) patients by using volume-derived values and two-dimensional strain.

Methods

Thirty-two HCM patients and 34 age and gender matched normal controls were enrolled for this study. RA volume-derived values were measured by using 2D ultrasonic images. RA strain (S-reservoir, S-conduit, S-booster pump) and strain rate (SR-reservoir, SR-conduit, SR-booster pump), representing the reservoir, conduit and booster pump functions, respectively, were measured by EchoPAC.

Results

Total RA emptying fraction (RAEF) and RA expansion index in HCM patients were significantly lower than normal controls (p < 0.05). The values of S-reservoir, S-conduit, Sr-reservoir and Sr-conduit in HCM patients were significantly lower than normal controls (p < 0.001). Although there were no significant differences in S-booster pump and Sr-booster pump between HCM patients and normal controls, the absolute values in HCM patients were lower than normal controls.

Conclusions

In this study, we concluded that RA dysfunctions, including the reservoir and conduit functions were impaired in HCM patients.

Screening of MYH7 gene mutation sites in hypertrophic cardiomyopathy and its significance

BACKGROUND

There have been few reports of mutations in the beta-myosin heavy chain (MYH7) gene in hypertrophic cardiomyopathy (HCM), which is associated with sudden cardiac death caused by HCM. This study aimed to screen the mutation sites in the sarcomeric gene MYH7 in Chinese patients with HCM. We also planned to analyze the pathogenicity of the mutation site as well as its significance in clinical and forensic medicine.

METHODS

From January 2006 to June 2017, autopsy cases were collected from the Department of Pathology, the Affiliated Hospital of Qingdao University. The experiment was to detect MYH7 gene status in formalin-fixed paraffin-embedded tissues from 18 independent autopsy cases who suffered HCM related sudden death (fatal HCM) and 20 cases without cardiomyopathy. Common mutation exon fragments of MYH7 gene were amplified by polymerase chain reaction. The end-of-deoxygenation method and gene cloning method were further performed to analyze the mutation sites. Homologous comparison among mutant sites was conducted using BLAST online database.

RESULTS

The 1336th nucleotide of MYH7 gene at exon 14 was converted from T to G in one HCM case, resulting in the conversion of threonine (Thr) at position 446 to proline (Pro). In another case, the 1402th nucleotide at exon 14 was converted from T to C, resulting in the conversion of phenylalanine (Phe) at position 468 to leucine (Leu). Homologous comparison results showed that the two amino acid residues of Thr446 and Phe468 are highly conserved among different species.

CONCLUSIONS

Our results showed fatal HCM harbored mutations of Thr446Pro and Phe468Leu in the MYH7 gene. It is significant for clinical and forensic medicine to further explore the functions and detailed mechanisms of these mutations.