Clinical and imaging description of the Maron subtypes of hypertrophic cardiomyopathy

Specific alterations of regional myocardial work in strength-trained athletes using anabolic steroids compared to athletes with genetic hypertrophic cardiomyopathy

PURPOSE

Strength-trained athletes using anabolic androgenic steroids (AAS) have left ventricular (LV) hypertrophy and myocardial fibrosis that can lead to sudden cardiac death. A similar feature was described in athletes with hypertrophic cardiomyopathy (HCM), which complicates the diagnosis for clinicians. In this context, we aimed to compare the LV function of the 2 populations by measuring global and regional strain and myocardial work using speckle-tracking imaging.

METHODS

Twenty-four strength-trained asymptomatic athletes using AAS (AAS-Athletes), 22 athletes diagnosed with HCM (HCM-Athletes), and 20 healthy control athletes (Ctrl-Athletes) underwent a resting echocardiography to assess LV function. We evaluated LV global and regional strains and myocardial work, with an evaluation of the constructive work (CW), wasted work, and work efficiency (WE).

RESULTS

Compared to Ctrl-Athletes, both AAS-Athletes and HCM-Athletes had a thicker interventricular septum, with majored values in HCM-Athletes. LV strain was reduced in AAS-Athletes and even more in HCM-Athletes. Consequently, global WE was significantly diminished in both AAS and HCM-Athletes (93% ± 2% in Ctrl-Athletes, 90% ± 4% in AAS-Athletes, and 90% ± 5% in HCM-Athletes (mean ± SD); p < 0.05). Constructive work and WE regional analysis showed specific alterations, with the basal septal segments preferentially affected in AAS-Athletes, and both septal and apical segments affected in HCM-Athletes.

CONCLUSION

The regional evaluation of myocardial work reported specific alterations of the major LV hypertrophy induced by the regular use of AAS compared to the LV hypertrophy due to HCM. This finding could help clinicians to differentiate between these 2 forms of pathological hypertrophy.

Strain Analysis of Left Ventricular Function in the Association of Hypertrophic Cardiomyopathy and Systemic Arterial Hypertension

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most common heart disease of genetic origin in the world population, with a prevalence of at least 1/500. The association with systemic arterial hypertension (SAH) is not uncommon, as it affects approximately 25% of the world population. Most studies aim at the differential diagnosis between these diseases, but little is known about the magnitude of this association.

OBJECTIVE

To compare left ventricular global longitudinal strain (GLS) in HCM patients with and without associated SAH.

METHODS

Retrospective cross-sectional study that included 45 patients with HCM and preserved ejection fraction, with diagnosis confirmed by magnetic resonance imaging, including 14 hypertensive patients. Transthoracic echocardiography was performed, with emphasis on left ventricular myocardial strain analysis using GLS. In this study, p < 0.05 was considered statistically significant.

RESULTS

Left ventricular strain was significantly lower in hypertensive individuals compared to normotensive individuals (-10.29 ± 2.46 vs. -12.35% ± 3.55%, p = 0.0303), indicating greater impairment of ventricular function in that group. Mean age was also significantly higher in hypertensive patients (56.1 ± 13.9 vs. 40.2 ± 12.7 years, p = 0.0001). Diastolic dysfunction was better characterized in hypertensive patients (p = 0.0242).

CONCLUSION

Myocardial strain was significantly lower in the group of patients with HCM and SAH, suggesting greater impairment of ventricular function. This finding may be related to a worse prognosis with early evolution to heart failure. Prospective studies are required to confirm this hypothesis.

Ventricular Arrhythmias and Sudden Cardiac Death

Ventricular arrhythmias remain a significant cause of sudden cardiac death (SCD), and knowledge of their cause and high-risk features is important. SCD occurs when the interaction between vulnerable substrates and acute triggers results in sustained ventricular tachycardia progressing to ventricular fibrillation. Here, the authors aim to review the role of ventricular arrhythmias in SCD, first by approaching the substrates that support ventricular arrhythmias, and then by exploring features of these substrates and the acute triggers that may lead to SCD.

Heterogeneity of longitudinal and circumferential contraction in relation to late gadolinium enhancement in hypertrophic cardiomyopathy patients with preserved left ventricular ejection fraction

PURPOSE

To evaluate heterogeneity of myocardial contraction in relation to extensive late gadolinium enhancement (LGE) in hypertrophic cardiomyopathy (HCM) patients with preserved left ventricular ejection fraction, using fast strain-encoded magnetic resonance imaging.

MATERIALS AND METHODS

Twenty-two HCM patients and 24 age-matched control subjects were included in this retrospective study. The regional and global peak values of longitudinal and circumferential strain (LS_regional, LS_global, CS_regional, CS_global), and their regional heterogeneities were evaluated using coefficients of variation (LS_CoV, CS_CoV) in relation to LGE. Receiver operating characteristic curve analysis was performed to identify patients with a total left ventricular myocardial LGE ≥ 15%.

RESULTS

LS_global in HCM patients was significantly decreased compared to that in controls (- 14.4 ± 2.4% vs - 17.2 ± 2.0%; p = 0.0004), while CS_global was not (p = 1.0). Negative LGE segments demonstrated decreased LS_regional in HCM patients compared to in controls (p < 0.0001), while CS_regional was not decreased. CS_CoV demonstrated the largest area under the curve (AUC) (0.91), with high sensitivity (83%) and specificity (94%) for detection of HCM patients with extensive LGE, while the AUC of LS_CoV was low (0.49).

CONCLUSION

The heterogeneity in CS_regional has a high diagnostic value for detection of HCM patients with extensive LGE.

The Remarkable 50 Years of Imaging in HCM and How it Has Changed Diagnosis and Management: From M-Mode Echocardiography to CMR

The almost 50-year odyssey of cardiac imaging in hypertrophic cardiomyopathy (HCM), revisited and described here, has been remarkable, particularly when viewed in the timeline of advances that occurred during a single generation of investigators. At each step along the way, from M-mode to 2-dimensional echocardiography to Doppler imaging, and finally over the last 10 years with the emergence of high-resolution tomographic cardiac magnetic resonance (CMR), evolution of the images generated by each new technology constituted a paradigm change over what was previously available. Together, these advances have transformed the noninvasive diagnosis and management of HCM in a number of important clinical respects. These changes include a more complete definition of the phenotype, resulting in more reliable clinical identification of patients and family members, defining mechanisms (and magnitude) of left ventricular outflow obstruction, and novel myocardial tissue characterization (including in vivo detection of fibrosis/scarring); notably, these advances afford more precise recognition of at-risk patients who are potential candidates for life-saving primary prevention defibrillator therapy. This evolution in imaging as applied to HCM has indelibly changed cardiovascular practice for this morphologically and clinically complex genetic disease.

The systolic paradox in hypertrophic cardiomyopathy

Objective

We explored cardiac volumes and the effects on systolic function in hypertrophic cardiomyopathy (HCM) patients with left ventricular hypertrophy (HCM LVH+) and genotype-positive patients without left ventricular hypertrophy (HCM LVH−).

Methods

We included 180 HCM LVH+, 100 HCM LVH− patients and 80 healthy individuals. End-Diastolic Volume Index (EDVI), End-Systolic Volume Index (ESVI) and ejection fraction (EF) were assessed by echocardiography. Left ventricular (LV) global longitudinal strain (GLS) was measured by speckle tracking echocardiography.

Results

EDVI and ESVI were significantly smaller in HCM LVH+ compared with HCM LVH− patients (41±14 mL/m² vs 49±13 mL/m² and 16±7 mL/m² vs 19±6 mL/m², respectively, both p<0.001) and in healthy individuals (41±14 mL/m² vs 57±14 mL/m² and 16±7 mL/m² vs 23±9 mL/m², respectively, both p<0.001). HCM LVH− patients had significantly lower EDVI and ESVI compared with healthy individuals (49±13 mL/m² vs 57±14 mL/m² and 19±6 mL/m² vs 23±9 mL/m², both p<0.001). EF was similar (61%±7% vs 60%±8% vs 61%±6%, p=0.43) in the HCM LVH+, HCM LVH– and healthy individuals, despite significantly worse GLS in the HCM LVH+ (−16.4%±3.7% vs −21.3%±2.4% vs −22.3%±3.7%, p<0.001). GLS was worse in the HCM LVH− compared with healthy individuals in pairwise comparison (p=0.001). Decrease in ESVI was closely related to EF in HCM LVH+ and HCM LVH− (R=0.45, p<0.001 and R=0.43, p<0.001) as expected, but there was no relationship with GLS (R=0.02, p=0.77 and R=0.11, p=0.31). Increased maximal wall thickness (MWT) correlated significantly with worse GLS (R=0.58, p<0.001), but not with EF (R=0.018, p=0.30) in the HCM LVH+ patients.

Conclusion

HCM LVH+ had smaller cardiac volumes that could explain the preserved EF, despite worse GLS that was closely related to MWT. HCM LVH− had reduced cardiac volumes and subtle changes in GLS compared with healthy individuals, indicating a continuum of both volumetric and systolic changes present before increased MWT.

Echocardiographic diagnosis of the different phenotypes of hypertrophic cardiomyopathy

Hypertrophic Cardiomyopathy (HCM) is an inherited cardiovascular disorder of great genetic heterogeneity and has a prevalence of 0.1 – 0.2 % in the general population. Several hundred mutations in more than 27 genes, most of which encode sarcomeric structures, are associated with the HCM phenotype. Then, HCM is an extremely heterogeneous disease and several phenotypes have been described over the years. Originally only two phenotypes were considered, a more common, obstructive type (HOCM, 70 %) and a less common, non-obstructive type (HNCM, 30 %) (Maron BJ, et al. Am J Cardiol 48:418 –28, 1981). Wigle et al. (Circ 92:1680–92, 1995) considered three types of functional phenotypes: subaortic obstruction, midventricular obstruction and cavity obliteration. A leader american working group suggested that HCM should be defined genetically and not morphologically (Maron BJ, et al. Circ 113:1807–16, 2006). The European Society of Cardiology Working Group on Myocardial and Pericardial Diseases recommended otherwise a morphological classification (Elliott P, et al. Eur Heart J 29:270–6, 2008). Echocardiography is still the principal tool for the diagnosis, prognosis and clinical management of HCM. It is well known that the echocardiographic picture may have a clinical and prognostic impact. For this reason, in this article, we summarize the state of the art regarding the echocardiographic pattern of the HCM phenotypes and its impact on clinical course and prognosis.