Role of multimodality cardiac imaging in the management of patients with hypertrophic cardiomyopathy: an expert consensus of the European Association of Cardiovascular Imaging Endorsed by the Saudi Heart Association

ESC sudden-death risk model in hypertrophic cardiomyopathy: Incremental value of quantitative contrast-enhanced CMR in intermediate-risk patients

BACKGROUND

Hypertrophic cardiomyopathy (HCM) remains the most common cause of sudden cardiac death (SCD) in the young; however, current strategies do not identify all HCM patients at risk. A novel validated algorithm was proposed by the last European Society of Cardiology guidelines to guide implantable cardioverter-defibrillator (ICD) therapy. Recently, extensive myocardial fibrosis was independently associated with increased risk of SCD events. This study aimed to establish the relation between myocardial fibrosis (late gadolinium enhancement [LGE] extension) and the novel SCD risk-prediction model in a real population of HCM to evaluate its potential additional value in the different risk groups.

HYPOTHESIS

There is a significant association between LGE extension and the novel SCD risk calculator that may help conflicting ICD decisions.

METHODS

Seventy-seven patients with HCM underwent routine clinical evaluation, echocardiography, and cardiac magnetic resonance study. Their SCD risk at 5 years was calculated using the new model.

RESULTS

Extension of LGE positively correlated with SCD risk prediction (r = 0.7, P < 0.001). Low-, intermediate-, and high-risk groups according to the model showed significantly different extent of LGE (5% ± 6% vs 18% ± 9% vs 17% ± 4%; P < 0.001). Four patients (6%) in the low-risk group and 5 (62%) in the intermediate-risk group showed extensive areas of LGE. All patients except 1 (86%) at highest risk (n = 6) showed extensive areas of LGE.

CONCLUSIONS

LGE extension is concordant with the novel SCD-risk model defining low- and high-risk groups; it may provide additional information, allowing better discrimination to support implantable cardioverter-defibrillator decision. LGE quantification holds promise for SCD stratification in HCM.

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.

Usefulness of Cardiac Magnetic Resonance Imaging to Measure Left Ventricular Wall Thickness for Determining Risk Scores for Sudden Cardiac Death in Patients With Hypertrophic Cardiomyopathy

Echocardiography-derived measurements of maximum left ventricular (LV) wall thickness are important for both the diagnosis and risk stratification of hypertrophic cardiomyopathy (HC). Cardiac magnetic resonance (CMR) imaging is increasingly being used in the assessment of HC; however, little is known about the relation between wall thickness measurements made by the 2 modalities. We sought to compare measurements made with echocardiography and CMR and to assess the impact of any differences on risk stratification using the current European Society of Cardiology guidelines. Maximum LV wall thickness measurements were recorded on 50 consecutive patients with HC. Sixty-nine percent of LV wall thickness measurements were recorded with echocardiography, compared with 69% from CMR (p <0.001). There was poor agreement on the location of maximum LV wall thickness; weighted-Cohen's κ 0.14 (p = 0.036) and maximum LV wall thicknesses were systematically higher with echocardiography than with CMR (mean 19.1 ± 0.4 mm vs 16.5 ± 0.3 mm, p <0.01, respectively); Bland-Altman bias 2.6 mm (95% confidence interval -9.8 to 4.6). Interobserver variability was lower for CMR (R² 0.67 echocardiography, R² 0.93 CMR). The mean difference in 5-year sudden cardiac death (SCD) risk between echocardiography and CMR was 0.49 ± 0.45% (p = 0.37). When classifying patients (low, intermediate, or high risk), 6 patients were reclassified when CMR was used instead of echocardiography to assess maximum LV wall thickness. These findings suggest that CMR measurements of maximum LV wall thickness can be cautiously used in the current European Society of Cardiology risk score calculations, although further long-term studies are needed to confirm this.

Delayed and decreased LV untwist and unstrain rate in mutation carriers for hypertrophic cardiomyopathy

Background

The echocardiographic focus to detect abnormalities in genetically hypertrophic cardiomyopathy (HCM) affected subjects without left ventricular (LV) hypertrophy (G+/LVH-) has been on diastolic abnormalities in transmitral flow and longitudinal myocardial function with tissue Doppler imaging. The aim of this study was to assess diastolic LV unstrain and untwist.

Methods and results

Forty-one consecutive genotyped family members of HCM patients (mean age 37 ± 11 years, 16 men) and 41 age- and gender-matched healthy volunteers underwent speckle-tracking echocardiography to measure untwist and unstrain. No significant differences between G+/LVH- and control subjects were seen in maximal systolic twist and global longitudinal strain. In diastole, the early peak untwist rate was significantly lower in G+/LVH- subjects compared with control subjects (62 ± 19°s - 1 vs. 76 ± 30°s - 1, P <0.05), whereas the late peak untwist rate tended to be higher. Untwist from maximal twist until the first 20% of diastole was delayed in G+/LVH- subjects (39.3 ± 12.9% vs. 51.3 ± 15.6%, P <0.005). Late diastolic unstrain rate was significantly higher in G+/LVH- subjects in the inferoseptal wall (111 ± 33 s - 1 vs. 94 ± 32 s - 1, P = 0.024), the inferolateral wall (105 ± 42 vs. 75 ± 35 s - 1, P = 0.007) and the anteroseptal wall (97 ± 26 vs. 80 ± 23 s - 1, P = 0.010). Unstrain from maximal twist until the first 20% of diastole was delayed in G+/LVH- subjects in the inferoseptal (18.9 ± 14.0% vs. 30.1 ± 17.7%, P = 0.005), inferolateral (27.1 ± 16.3% vs. 39.2 ± 18.0%, P = 0.015) and anteroseptal (19.1 ± 14.7% vs. 35.8 ± 18.5%, P = 0.0003) segments.

Conclusions

In mutation carriers, for HCM LV, untwist and unstrain are delayed and untwist rate and unstrain rate are decreased.

Hypertrophic obstructive cardiomyopathy

Hypertrophic obstructive cardiomyopathy is an inherited myocardial disease defined by cardiac hypertrophy (wall thickness ≥15 mm) that is not explained by abnormal loading conditions, and left ventricular obstruction greater than or equal to 30 mm Hg. Typical symptoms include dyspnoea, chest pain, palpitations, and syncope. The diagnosis is usually suspected on clinical examination and confirmed by imaging. Some patients are at increased risk of sudden cardiac death, heart failure, and atrial fibrillation. Patients with an increased risk of sudden cardiac death undergo cardioverter-defibrillator implantation; in patients with severe symptoms related to ventricular obstruction, septal reduction therapy (myectomy or alcohol septal ablation) is recommended. Life-long anticoagulation is indicated after the first episode of atrial fibrillation.

Hypertrophic Cardiomyopathy from A to Z: Genetics, Pathophysiology, Imaging, and Management

Hypertrophic cardiomyopathy (HCM) is a heterogeneous group of diseases related to sarcomere gene mutations exhibiting heterogeneous phenotypes with an autosomal dominant mendelian pattern of inheritance. The disorder is characterized by diverse phenotypic expressions and variable natural progression, which may range from dyspnea and/or syncope to sudden cardiac death. It is found across all racial groups and is associated with left ventricular hypertrophy in the absence of another systemic or cardiac disease. The management of HCM is based on a thorough understanding of the underlying morphology, pathophysiology, and clinical course. Imaging findings of HCM mirror the variable expressivity and penetrance heterogeneity, with the added advantage of diagnosis even in cases where a specific mutation may not yet be found. The diagnostic information obtained from imaging varies depending on the specific stage of HCM-phenotype manifestation, including the prehypertrophic, hypertrophic, and later stages of adverse remodeling into the burned-out phase of overt heart failure. However, subtle or obvious, these imaging findings become critical components in diagnosis, management, and follow-up of HCM patients. Although diagnosis of HCM traditionally relies on clinical assessment and transthoracic echocardiography, recent studies have demonstrated increased utility of multidetector computed tomography (CT) and particularly cardiac magnetic resonance (MR) imaging in diagnosis, phenotype differentiation, therapeutic planning, and prognostication. In this article, we provide an overview of the genetics, pathophysiology, and clinical manifestations of HCM, with the spectrum of imaging findings at MR imaging and CT and their contribution in diagnosis, risk stratification, and therapy.

Stress echo 2020: the international stress echo study in ischemic and non-ischemic heart disease

BACKGROUND

Stress echocardiography (SE) has an established role in evidence-based guidelines, but recently its breadth and variety of applications have extended well beyond coronary artery disease (CAD). We lack a prospective research study of SE applications, in and beyond CAD, also considering a variety of signs in addition to regional wall motion abnormalities.

METHODS

In a prospective, multicenter, international, observational study design, > 100 certified high-volume SE labs (initially from Italy, Brazil, Hungary, and Serbia) will be networked with an organized system of clinical, laboratory and imaging data collection at the time of physical or pharmacological SE, with structured follow-up information. The study is endorsed by the Italian Society of Cardiovascular Echography and organized in 10 subprojects focusing on: contractile reserve for prediction of cardiac resynchronization or medical therapy response; stress B-lines in heart failure; hypertrophic cardiomyopathy; heart failure with preserved ejection fraction; mitral regurgitation after either transcatheter or surgical aortic valve replacement; outdoor SE in extreme physiology; right ventricular contractile reserve in repaired Tetralogy of Fallot; suspected or initial pulmonary arterial hypertension; coronary flow velocity, left ventricular elastance reserve and B-lines in known or suspected CAD; identification of subclinical familial disease in genotype-positive, phenotype- negative healthy relatives of inherited disease (such as hypertrophic cardiomyopathy).

RESULTS

We expect to recruit about 10,000 patients over a 5-year period (2016-2020), with sample sizes ranging from 5,000 for coronary flow velocity/ left ventricular elastance/ B-lines in CAD to around 250 for hypertrophic cardiomyopathy or repaired Tetralogy of Fallot. This data-base will allow to investigate technical questions such as feasibility and reproducibility of various SE parameters and to assess their prognostic value in different clinical scenarios.

CONCLUSIONS

The study will create the cultural, informatic and scientific infrastructure connecting high-volume, accredited SE labs, sharing common criteria of indication, execution, reporting and image storage of SE to obtain original safety, feasibility, and outcome data in evidence-poor diagnostic fields, also outside the established core application of SE in CAD based on regional wall motion abnormalities. The study will standardize procedures, validate emerging signs, and integrate the new information with established knowledge, helping to build a next-generation SE lab without inner walls.

Diagnostic and prognostic roles of echocardiography and cardiac magnetic resonance

Accurate prediction of sudden cardiac death due to ventricular arrhythmia remains challenging. Left ventricular ejection fraction has shown an association with increased risk of ventricular arrhythmias and is included in the recommendations for implantable cardioverter defibrillator as primary prevention. However, left ventricular ejection fraction may be normal in a large number of patients who are at risk of ventricular arrhythmias. Echocardiography remains the imaging technique of first choice to rule out the presence of structural heart disease and assess left and right ventricular function. Advances in strain echocardiography and cardiac magnetic resonance have provided important insights into the mechanisms of ventricular arrhythmias, and will be summarized in this review.

Characteristic systolic waveform of left ventricular longitudinal strain rate in patients with hypertrophic cardiomyopathy

We analyzed the waveform of systolic strain and strain-rate curves to find a characteristic left ventricular (LV) myocardial contraction pattern in patients with hypertrophic cardiomyopathy (HCM), and evaluated the utility of these parameters for the differentiation of HCM and LV hypertrophy secondary to hypertension (HT). From global strain and strain-rate curves in the longitudinal and circumferential directions, the time from mitral valve closure to the peak strains (T-LS and T-CS, respectively) and the peak systolic strain rates (T-LSSR and T-CSSR, respectively) were measured in 34 patients with HCM, 30 patients with HT, and 25 control subjects. The systolic strain-rate waveform was classified into 3 patterns ("V", "W", and "√" pattern). In the HCM group, T-LS was prolonged, but T-LSSR was shortened; consequently, T-LSSR/T-LS ratio was distinctly lower than in the HT and control groups. The "√" pattern of longitudinal strain-rate waveform was more frequently seen in the HCM group (74 %) than in the control (4 %) and HT (20 %) groups. Similar but less distinct results were obtained in the circumferential direction. To differentiate HCM from HT, the sensitivity and specificity of the T-LSSR/T-LS ratio <0.34 and the "√"-shaped longitudinal strain-rate waveform were 85 and 63 %, and 74 and 80 %, respectively. In conclusion, in patients with HCM, a reduced T-LSSR/T-LS ratio and a characteristic "√"-shaped waveform of LV systolic strain rate was seen, especially in the longitudinal direction. The timing and waveform analyses of systolic strain rate may be useful to distinguish between HCM and HT.

Left ventricular mechanical dispersion is associated with nonsustained ventricular tachycardia in hypertrophic cardiomyopathy

OBJECTIVE

We assessed the value of speckle tracking two-dimensional (2D) strain echocardiography (2DSE) measured mechanical dispersion (MD) with other imaging and electrocardiographic parameters in differentiating hypertrophic cardiomyopathy (HCM) patients with and without nonsustained ventricular tachycardia (NSVT) on 24-h ambulatory ECG monitoring.

METHODS AND RESULTS

We studied 31 patients with HCM caused by the Finnish founder mutation MYBPC3-Q1061X and 20 control subjects with comprehensive 2DSE echocardiography and cardiac magnetic resonance imaging (CMRI). The presence of NSVT was assessed from ambulatory 24-h ECG monitoring. NSVT episodes were recorded in 11 (35%) patients with HCM. MD was significantly higher in HCM patients with NSVT (93 ± 41 ms) compared to HCM patients without NSVT (50 ± 18 ms, p = 0.012) and control subjects (41 ± 16 ms, p < 0.001). MD was the only variable independently associated with the presence of NSVT (OR: 1.60, 95% CI: 1.05-2.45, p = 0.030). Assessed by ROC curves, MD performed best in differentiating between HCM patients with and without NSVT (AUC = 0.81).

CONCLUSIONS

Increased mechanical dispersion was associated with NSVT in HCM patients on 24-h ambulatory ECG monitoring. Key messages The prediction of sudden cardiac death in hypertrophic cardiomyopathy remains a challenge and novel imaging methods are required to identify individuals at risk of malignant ventricular arrhythmias. Mechanical dispersion by speckle tracking echocardiography is associated with NSVT on 24-h ambulatory ECG monitoring in patients with hypertrophic cardiomyopathy.

Computed tomography imaging to quantify the area of the endocardial subvalvular apparatus in hypertrophic cardiomyopathy - Relationship to outflow tract obstruction and symptoms

BACKGROUND

Abnormalities of the endocardial subvalvular apparatus (SVA), which includes the papillary muscles directly attached to the mitral leaflet and left ventricular apical-basal muscle bundles, are occasionally identified in hypertrophic cardiomyopathy (HCM). Their associations with left ventricular outflow tract (LVOT) obstruction are unknown.

METHODS

We retrospectively reviewed cardiac computed tomography image data sets of 107 consecutive patients with HCM [56 obstructive (HOCM) and 51 non-obstructive (HNOCM)] as well as 53 controls. We evaluated anomalies of the SVA, measured the cross-sectional area of the SVA at the level of the LVOT, and subsequently assessed its correlation with the LVOT pressure gradient with and without medication.

RESULTS

The area of the SVA was greater in HOCM than in HNOCM patients and in the control group (2.5 ± 1.3 cm(2), 1.4 ± 0.8 cm(2), and 0.9 ± 0.6 cm(2), respectively; p < 0.0001). Anomalies in the SVA were more often observed in the HOCM group than in the HNOCM patients and controls (abnormal papillary muscles, 14%, 8%, and 0%, respectively; P = 0.010; LV apical-basal muscle bundles, 73%, 65%, and 45%, respectively; P = 0.0094). Among HOCM patients, logistic regression analysis demonstrated that an SVA area of 2.2 cm(2) was an independent risk factor of residual severe LVOT obstruction (≥50 mmHg) after medication (odds ratio, 10.1; 95% confidence interval, 2.05-49.80).

CONCLUSION

An increased area of the endocardial subvalvular apparatus could be an independent risk factor for clinically relevant LVOT obstruction refractory to medication.

Myocardial Dimensions in Children With Hypertrophic Cardiomyopathy: A Comparison Between Echocardiography and Cardiac Magnetic Resonance Imaging

BACKGROUND

The primary mode of imaging in hypertrophic cardiomyopathy (HCM) is transthoracic echocardiography (TTE). However, in adults inadequate acoustic windows lead to poor quantification of myocardial thickness compared with cardiac magnetic resonance (CMR) imaging. In comparison, children have better acoustic windows and TTE measurements of wall thickness might be more accurate. The aim of this study was to assess the performance of TTE compared with CMR for the assessment of myocardial thickness in children with HCM.

METHODS

Nineteen children (median age, 12.7 years; range, 8.4-18.4 years) with known HCM were studied using TTE and CMR imaging on the same day. The left ventricle was measured off-line using the standard 16-segment model.

RESULTS

With CMR imaging 304 (19 × 16) segments were analyzable whereas only 263 were analyzable using echocardiography. Wall thickness measurements according to TTE were greater than those according to CMR imaging in the basal anterolateral, midventricular anterior and anterolateral and apical inferior, lateral and septal segments and smaller for the midventricular inferior and inferoseptal segments. Reproducibility of CMR and TTE measurements was assessed using the intraclass correlation coefficient (ICC). CMR measurements showed excellent intrareader (ICC, 0.929-0.991) and moderate inter-reader (ICC range, 0.512-0.991) reproducibility. TTE measurements revealed moderate intrareader (ICC, 0.575-0.942) and poor inter-reader (ICC range, -1.02 to 0.939) reproducibility.

CONCLUSIONS

Echocardiography incompletely assesses circumferential myocardial thickness in a proportion of pediatric patients with HCM. Echocardiography under- and overestimates maximum wall thickness compared with CMR, depending on the location. Measurements using CMR are more reproducible than those obtained using echocardiography.

Prognostic role of stress echocardiography in hypertrophic cardiomyopathy: The International Stress Echo Registry

BACKGROUND

Stress echo (SE) may have a role in the outcome in patients with hypertrophic cardiomyopathy (HCM).

OBJECTIVES

The aim was to assess the prognostic value of SE in a retrospective multicenter study in HCM.

METHODS

We enrolled 706 HCM patients. The employed stress was exercise (n=608) and/or vasodilator (n=146, dipyridamole in 98 and adenosine in 48). We defined SE positivity according to clinical/hemodynamic criteria including: symptoms (all stress modalities), exercise-induced hypotension (failure to increase or fall >20mmHg, exercise) and exercise-induced left ventricular outflow tract obstruction (left ventricular outflow tract obstruction >50mmHg); and ischemic criteria, such as new wall motion abnormalities (new wall motion abnormality) and/or reduction of coronary flow reserve velocity (CFVR≤2.0) on left anterior descending coronary artery with vasodilator stress assessed in 116 patients. All patients completed the clinical follow-up.

RESULTS

Positive SE showed more frequently CFVR reduction, exercise-induced hypotension, left ventricular outflow tract obstruction, and symptoms (38, 23, 20 and 15% respectively), but new wall motion abnormality only in 6%. During a median follow-up of 49months 180 events were observed, including 40 deaths. Clinical/hemodynamic criteria did not predict outcome (X2 0.599, p=0.598), whereas ischemia-related SE criteria (X2: 111.120, p<0.0001) was significantly related to outcome. Similarly, mortality was predicted with SE ischemic-criteria (X2 16.645, p<0.0001).

CONCLUSIONS

SE has an important prognostic significance in HCM patients, with ischemia-related end-points showing greater predictive accuracy than hemodynamic endpoints. New wall motion abnormalities and impairment of CFVR should be specifically included in SE protocols for HCM.

Differentiating hypertrophic cardiomyopathy from athlete's heart: An electrocardiographic and echocardiographic approach

Differential diagnosis of hypertrophic cardiomyopathy (HCM) vs athlete's heart is challenging in individuals with mild-moderate left-ventricular hypertrophy. This study aimed to assess ECG and echocardiographic parameters proposed for the differential diagnosis of HCM. The study included 75 men in three groups: control (n=30), "gray zone" athletes with interventricular septum (IVS) measuring 13-15mm (n=25) and HCM patients with IVS of 13-18mm (n=20). The most significant differences were found in relative septal thickness (RST), calculated as the ratio of 2 x IVS to left ventricle end-diastolic diameter (LV-EDD) (0.37, 0.51, 0.71, respectively; p<0.01) and in spatial QRS-T angle as visually estimated (9.8, 33.6, 66.2, respectively; p<0.01). The capacity for differential HCM diagnosis of each of the 5 criteria was assessed using the area under the curve (AUC), as follows: LV-EDD<54 (0.60), family history (0.61), T-wave inversion (TWI) (0.67), spatial QRS-T angle>45 (0.75) and RST>0.54 (0.92). Pearson correlation between spatial QRS-T angle>45 and TWI was 0.76 (p 0.01). The combination of spatial QRS-T angle>45 and RST>0.54 for diagnosis of HCM had an AUC of 0.79. The best diagnostic criteria for HCM was RST>0.54. The spatial QRS-T angle>45 did not add sensitivity if TWI was present. No additional improvement in differential diagnosis was obtained by combining parameters.

Strain echocardiography is related to fibrosis and ventricular arrhythmias in hypertrophic cardiomyopathy

Aims

Hypertrophic cardiomyopathy (HCM) patients are at risk of ventricular arrhythmias (VAs). We aimed to explore whether systolic function by strain echocardiography is related to VAs and to the extent of fibrosis by cardiac magnetic resonance imaging (CMR).

Methods and results

We included 150 HCM patients and 50 healthy individuals. VAs were defined as non-sustained and sustained ventricular tachycardia and aborted cardiac arrest. Left ventricular function was assessed by ejection fraction (EF) and by global longitudinal strain (GLS) assessed by speckle tracking echocardiography. Mechanical dispersion was calculated as standard deviation (SD) of time from Q/R on ECG to peak longitudinal strain in 16 left ventricular segments. Late gadolinium enhancement (LGE) was assessed by CMR. HCM patients had similar EF (61 ± 5% vs. 61 ± 8%, P = 0.77), but worse GLS (−15.7 ± 3.6% vs. −21.1 ± 1.9%, P < 0.001) and more pronounced mechanical dispersion (64 ± 22 vs. 36 ± 13 ms, P < 0.001) compared with healthy individuals. VAs were documented in 37 (25%) HCM patients. Patients with VAs had worse GLS (−14.1 ± 3.6% vs. −16.3 ± 3.4%, P < 0.01), more pronounced mechanical dispersion (79 ± 27 vs. 59 ± 16 ms, P < 0.001), and higher %LGE (6.1 ± 7.8% vs. 0.5 ± 1.4%, P < 0.001) than patients without VAs. Mechanical dispersion correlated with %LGE (R = 0.52, P < 0.001) and was independently associated with VAs (OR 1.6, 95% CI 1.1–2.3, P = 0.02) and improved risk stratification for VAs.

Conclusion

GLS, mechanical dispersion, and LGE were markers of VAs in HCM patients. Mechanical dispersion was a strong independent predictor of VAs and related to the extent of fibrosis. Strain echocardiography may improve risk stratification of VAs in HCM.

The role of imaging in the diagnosis and management of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy, affecting approximately 1:500 people. As the yield of genetic testing is only about 35-60%, the diagnosis of HCM is still clinical and based on the demonstration of unexplained and usually asymmetric left ventricular (LV) hypertrophy by imaging modalities. In the past, echocardiography was the sole imaging modality used for the diagnosis and management of HCM. However, in recent years other imaging modalities such as cardiac magnetic resonance have played a major role in the diagnosis, management and risk stratification of HCM, particularly when the location of left ventricular hypertrophy is atypical (apex, lateral wall) and when the echocardiographic imaging is sub-optimal. However, the most unique contribution of cardiac magnetic resonance is the quantification of myocardial fibrosis. Exercise stress echocardiography is the preferred provocative test for the assessment of LV outflow tract obstruction, which is detected only on provocation in one-third of the patients.

Late gadolinium enhancement confined to the right ventricular insertion points in hypertrophic cardiomyopathy: an intermediate stage phenotype?

AIMS

To investigate whether hypertrophic cardiomyopathy (HCM) patients with late gadolinium enhancement (LGE) confined to the right ventricular insertion points (RVIP) differ phenotypically from patients without LGE or intramural LGE in the left ventricle (LV).

METHODS AND RESULTS

Sixty-two HCM patients underwent cardiac magnetic resonance for quantification of LGE (% LV mass) and were classified as group (i) no-LGE (n = 18), group (ii) LGE-RVIP (n = 19), and group (iii) intramural LGE (n = 25). All patients also underwent vasodilator N-13 ammonia PET to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR), and echocardiography to measure longitudinal LV strain. LGE extent (17 ± 11% vs. 4 ± 4% vs. 0%; P < 0.001) and LV thickness (21.7 ± 3.4 vs. 18.8 ± 3.9 vs. 16.3 ± 2.8 mm; P < 0.001) were significantly greater in group 3, intermediate in group 2, and lower in group 1. In contrast, stress MBF (1.62 ± 0.44 vs. 1.90 ± 0.37 vs. 2.22 ± 0.48 mL/min/g; P < 0.001); MFR (1.92 ± 0.47 vs. 2.15 ± 0.52 vs. 2.71 ± 0.52; P < 0.001), and longitudinal LV strain (-11.4 ± 3.8 vs. -12.6 ± 3.2 vs. -14.4 ± 4.1%; P = 0.04) were lower in group 3, intermediate in group 2, and higher in group 1.

CONCLUSIONS

From an imaging viewpoint, patients with LGE confined to only the RVIP appear to represent an intermediate-stage phenotype between patients with no LGE and intramural LGE in the LV.

Physiologic and pathophysiologic changes in the right heart in highly trained athletes

Exercise causes changes in the heart in response to the hemodynamic demands of increased systemic and pulmonary requirements during exercise. Understanding these adaptations is of great importance, since they may overlap with those caused by pathological conditions. Initial descriptions of athlete's heart focused mainly on chronic adaptation of the left heart to training. In recent years, the substantial structural and functional adaptations of the right heart have been documented, highlighting the complex interplay with left heart. Moreover, there is evolving evidence of acute and chronic cardiac damage, mainly involving the right heart, which may predispose subjects to atrial and ventricular arrhythmias, configuring an exercise-induced cardiomyopathy. The aim of this article is to review the current knowledge on the physiologic and pathophysiologic changes in the right heart in highly trained athletes.