- •
Hypertrophic cardiomyopathy (HCM) is the leading cause of sudden death in young patients; although current risk factor strategy is very effective, not all high-risk patients are identified.
- •
Contrast-enhanced cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) can identify areas of myocardial fibrosis where potentially life-threatening ventricular arrhythmias originate.
- •
HCM patients with LGE have a 7-fold greater risk for nonsustained ventricular tachycardia compared
The Role of Cardiovascular Magnetic Resonance in Sudden Death Risk Stratification in Hypertrophic Cardiomyopathy
Section snippets
Key points
Current risk stratification strategy in hypertrophic cardiomyopathy
Sudden death remains the most devastating consequence of HCM and the most frequent cause of sudden death in competitive athletes in the United States.1, 2 Sudden death in HCM occurs most commonly in young patients and significantly less in patients of advanced ages (≥60 years), and is often the initial clinical manifestation of HCM.1 However, intense vigorous exertional activity, such as with most organized competitive sports, is also associated with an increased risk of sudden death in
Limitations of risk stratification in hypertrophic cardiomyopathy
Although the noninvasive clinical risk markers have proved to be highly effective in identifying many HCM patients at increased risk for sudden death who will benefit from primary prevention ICDs, the HCM risk algorithm is incomplete.14 For example, sudden death risk in patients without conventional risk markers is 0.5% per year, meaning that a minority of high-risk patients remains unrecognized with the current risk stratification algorithm.14 In addition, nearly half of clinically identified
Contrast-enhanced cardiovascular magnetic resonance
Following the intravenous injection of gadolinium, contrast-enhanced CMR images can detect areas of high signal intensity LGE in the LV myocardium (Fig. 2). Several observations support the principle that LGE represents the arrhythmogenic substrate of myocardial fibrosis in HCM. For example, in ventricular septal tissue removed from HCM patients at the time of surgical myectomy, there is a strong association between the extent of fibrosis assessed by histologic examination and LGE (as
Left Ventricular Apical Aneurysm
The ability with CMR to provide imaging of the distal LV chamber at high spatial resolution, not encumbered by thoracic and pulmonary parenchyma, has resulted in the increased recognition and visibility in clinical cardiovascular practice of a unique subgroup of HCM patients with LV apical aneurysm.24 The junction of scarred aneurysm rim and LV myocardium provides another nidus for the generation of ventricular tachyarrhythmias (in addition to an already myopathic ventricle),25 and a focus of
Summary
CMR with LGE has emerged as an important imaging technique to improve diagnosis and risk assessment in patients with HCM. Extensive areas of fibrosis are associated with increased risk for sudden death events, even in HCM patients without conventional risk factors, and may identify patients for potentially life-saving therapy with primary prevention ICD. In addition, for those patients in the “gray zone” of risk stratification, extensive LGE may arbitrate complex ICD decision making. The
References (26)
- et al.
Hypertrophic cardiomyopathy: present and future, with translation into contemporary cardiovascular medicine
J Am Coll Cardiol
(2014) - et al.
2011 ACCF/AHA guidelines for the diagnosis and treatment of hypertrophic cardiomyopathy
J Am Coll Cardiol
(2011) - et al.
Hypertrophic cardiomyopathy phenotype revisited after 50 years with cardiovascular magnetic resonance
J Am Coll Cardiol
(2009) - et al.
Hypertrophic cardiomyopathy: cardiac magnetic resonance imaging changes the paradigm
J Am Coll Cardiol
(2008) - et al.
Management implications of massive left ventricular hypertrophy in hypertrophic cardiomyopathy significantly underestimated by echocardiography but identified by cardiovascular magnetic resonance
Am J Cardiol
(2010) - et al.
Occurrence and frequency of arrhythmias in hypertrophic cardiomyopathy in relation to delayed enhancement on cardiovascular magnetic resonance
J Am Coll Cardiol
(2008) - et al.
Task Force 4: hypertrophic cardiomyopathy and other cardiomyopathies, mitral valve prolapse, myocarditis and Marfan syndrome
J Am Coll Cardiol
(2005) - et al.
Sudden death in hypertrophic cardiomyopathy: identification of high risk patients
J Am Coll Cardiol
(2000) - et al.
Risk of sudden death and outcome in patients with hypertrophic cardiomyopathy with benign clinical presentation and without risk factors
Am J Cardiol
(2014) - et al.
Myocardial fibrosis in hypertrophic cardiomyopathy: accurate reflection of histopathological findings by CMR
JACC Cardiovasc Imaging
(2013)
The histologic basis of late gadolinium enhancement cardiovascular magnetic resonance in hypertrophic cardiomyopathy
J Am Coll Cardiol
Prognostic significance of myocardial fibrosis in hypertrophic cardiomyopathy
J Am Coll Cardiol
Myocardial scar visualized by cardiovascular magnetic resonance imaging predicts major adverse events in patients with hypertrophic cardiomyopathy
J Am Coll Cardiol
Cited by (12)
Cardiac imaging and biomarkers for assessing myocardial fibrosis in children with hypertrophic cardiomyopathy
2023, American Heart JournalUsefulness of TI-scout images in the assessment of late gadolinium enhancement in children
2021, Journal of Cardiovascular Magnetic ResonanceACR Appropriateness Criteria® Nonischemic Myocardial Disease with Clinical Manifestations (Ischemic Cardiomyopathy Already Excluded)
2021, Journal of the American College of RadiologyCitation Excerpt :HCM patients with LGE have a 7-fold risk for nonsustained ventricular tachycardia, and extensive LGE >15% of LV mass is a marker for sudden death [39]. Apical aneurysm and massive hypertrophy >30 mm are also high-risk factors for sudden cardiac death [39]. Elevated native T1 and ECV measurements may be seen in HCM.
Invited Commentary
2018, Annals of Thoracic SurgeryThe First Operation for Apical Hypertrophic Cardiomyopathy—Dr Dwight McGoon, 1972
2017, Annals of Thoracic SurgeryExercise-QTc is associated with diffuse interstitial fibrosis reflected by lower approximated T1 relaxation time in hypertrophic cardiomyopathy patients
2017, Journal of ElectrocardiologyCitation Excerpt :A second possibility is microvascular ischemia, a frequent finding in HCM patients [28], which was not investigated in this study. Myocardial fibrosis has been associated with ventricular tachycardia, worsening heart failure and death in HCM [29]. CMR following gadolinium administration permits assessment of replacement and interstitial fibrosis.
The author has nothing to disclose.