EMGuideWire's Radiology Reading Room: Hypertrophic Cardiomyopathy

Ashley Moore-Gibbs, DNP, Claire Lawson, NP,
Laszlo Littmann, MD, John Symanski, MD
Departments of Emergency Medicine & Internal Medicine
Sanger Heart & Vascular Institute
Carolinas Medical Center
Michael A. Gibbs, MD, Lead Editor
Carolinas Medical Center Imaging Mastery Project
Hypertrophic Cardiomyopathy

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Amyloid
Dilated
• Ischemic
• Peripartum
• Hypertensive
• Iron overload
Genetic
• Hypertrophic
• LV Noncompaction
• ARVC1
Inflammatory (Myocarditis)
• Viral
• Giant cell
• Eosinophilic
• Chagas
• COVID-19
Metabolic
• Diabetic
• Hypothyroid
• Acromegalic
• Cardiac Sarcoid
Stress-Induced (Takotsubo)
Tachycardia-Induced
Toxic
• Alcoholic
• Chemotherapy-induced
• Cocaine-induced
• Other drug related
1Arrhythmogenic Right Ventricular Cardiomyopathy
Classification Of Cardiomyopathies

Embedded References
Ommen SR. 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients with Hypertrophic
Cardiomyopathy. Journal of the American College of Cardiology. Article In Press.
Maron BJ. Clinical Course and Management of Hypertrophic Cardiomyopathy. New England Journal
of Medicine. 2018. Volume 379, Number 7.
Geske JB. Hypertrophic Cardiomyopathy: Clinical Update. Journal of the American College of
Cardiology. 2018. Volume 6, Number 5.

See Appendix 1 For AHA/ACC Top Ten Hypertrophic Cardiomyopathy Recommendations.

Hypertrophic Cardiomyopathy (HCM)
Cases Studies From Carolinas Medical Center

HCM: Imaging Essentials
• The cardiac silhouette may or may not be enlarged on chest X-ray
• Thickening of the interventricular septum is seen on cardiac
ultrasound and cardiac MRI (CMR)
• On CMR “late phase gadolinium enhancement” is seen on T1 images

Gadolinium Enhancement
• Gadolinium containing contrast is widely used in cardiac MRI to
assess the integrity of the myocardium
• Gadolinium is typically taken up and rapidly washed out from healthy
myocardial cells
• In the presence of disease (e.g.: acute and chronic ischemia, prior
infarct, myocarditis, cardiomyopathies) gadolinium remains in
abnormal cardiomyocytes, thus causing late phase enhancement
gadolinium enhancement (LGE) on T1 images
• In hypertrophic cardiomyopathy, LGE is most prominent in the
septum (or apex in patients with apical variant HCM)

Case #1
Asymmetric Septal Hypertrophy
Septum
Cardiac MRI (CMR)
Cardiac Apex

Case #1
26 mm
25 mm
Septum

Case #1
T1 Images: Late Phase Gadolinium Enhancement
Areas Of Gadolinium Enhancement (Arrow) Represent Tissue Fibrosis & Scaring
Cardiac Apex

Case #2
Septum
Cardiac Apex

T1 Images: Late Phase Gadolinium Enhancement

“Ace of Spade” LV Chamber Geometry
Case #3
Cardiac MRI

“Ace of Spade” LV Chamber Geometry
Case #3
Apical Variant HCM
Cardiac Apex

Case #3 T1 Images: Late Phase Gadolinium Enhancement
Cardiac Apex

Prominent Apical Hypertrophy
Case #3
Cardiac Apex
Apical Variant HCM

Apical Scarring (Late Gadolinium Enhancement)
Case #3 T1 Images: Late Phase Gadolinium Enhancement

Definition
• Hypertrophied, nondilated left ventricle – in the absence of another
cardiac, systemic, or syndromic disease state as an explanation
• A wall thickness of ≥15 mm by echocardiogram, CT, or CMR suggests HCM
• Extensive late phase gadolinium enhancement on CMR is diagnostic

Epidemiology
• Prevalence of 1 in 200 - 500 persons
• Reported in 122 countries on all continents
• Highly variable penetrance, disease expression, and clinical course
• Under recognition disproportionately affects women and underserved
minorities

Genetics
• Autosomal dominant mutation of the cardiac sarcomere
• To date, mutations of 11(+) genes have been identified
• Offspring of an affected person have a 50% risk of developing HCM
• Genetic testing is typically limited to next-generation (cascade) family
screening

2020 ACC/AHA Genetic Screening Guidelines
• Clinical screening (with or without genetic testing) recommended in
first-degree relatives of patients with HCM (Class I, LOE: B)
• Genetic testing reasonable in index patient to facilitate identification
of first-degree relatives at risk for developing HCM (Class IIA, LOE: B)
• Two or more mutations identified in < 5%
Journal Of The American College of Cardiology. 2020. Article In Press.

Clinical Manifestations
• Patients may be asymptomatic
• 1 in 5 patients have atrial fibrillation - high stroke risk if undetected
Symptoms include:
• Dyspnea on exertion
• Chest pain
• Fatigue
• Syncope or presyncope

Systematic Literature Review Assessing The Use Of Different Bedside
Maneuvers To Discern The Likelihood That A HCM Murmur Is Present.
Intensity decreased with passive leg elevation [+] LR 8.0 (95% CI 3-21)
No change in intensity with leg elevation [-] LR 0.22(95% CI 0.06-0.77)
Decreased from standing to squatting [+] LR 4.5 (95% CI 2.3-8.6)
Increased from standing to squatting [-] LR 0.13 (95% CI 0.02.81)
JAMA. 1997; 277:564-571.
Does This Patient Have An Abnormal Systolic Murmur?
JAMA: The Rational Clinical Examination

ECG Hallmarks
• Left ventricular hypertrophy
• Deep Q waves in the inferior and anterolateral leads
See Appendix 1 at the end of this presentation:
“Hypertrophic Cardiomyopathy ECG Case Studies.”
Created by the master ECG educator, Dr. Laszlo Littmann.

A 34-YO HEALTHY, PHYSICALLY ACTIVE WOMAN PRESENTED
WITH THREE RECENT EPISODES OF EXERTIONAL SYNCOPE

ECG DIAGNOSIS
 Sinus bradycardia, left axis deviation
 Left ventricular hypertrophy (aVL = 13 mm)
 Deep Q waves in the inferior and anterolateral leads

Echocardiography
• Left ventricular hypertrophy:
• LV wall thickness 13-15mm = mild; > 15mm = severe
• Diffuse LV wall thickening evident in ~50% patients
• 10%-20% will have segmental hypertrophy
• Truly symmetrical LVH is rare
• Mild right ventricular hypertrophy
• Mitral valve systolic anterior motion
• Hyper-dynamic left ventricle

Echocardiography
Class I:
• TTE recommended in the initial evaluation of all patients with suspected HCM
(LOE: B)
• TTE recommended in screening of all family members of patients with HCM
unless the family member is genotype negative in a family with known
definitive mutations (LOE: B)
• Repeat TTE recommended with a change in clinical status or new
cardiovascular event (LOE: B)

Cardiac Magnetic Resonance
Class I:
• Indicated in patients with suspected HCM when echocardiography is
inconclusive for the diagnosis (LOE: B)
• Indicated in patients with known HCM when additional information impacting
decision-making regarding invasive management is not adequately defined by
echocardiography (LOE: B)
Class IIa:
• CMR imaging is reasonable in HCM patients to define apical hypertrophy
and/or aneurysm if echocardiography is inconclusive (LOE: B)

Therapies: Reduction OF LVOT Obstruction
𝛽 -blockers are the mainstay of therapy for symptomatic patients:
• Negative inotropy reduced left ventricular outflow track obstruction
• Negative chronotropy prolongs diastole (which improves filling
hemodynamics) and blunts adrenergic-mediated tachycardia
Calcium channel blockers can be used if 𝛽-blockers are ineffective or not
well tolerated
Disopyramide and a 𝛽 -blockers is an alternative approach

Therapies: Treatment Of Atrial Fibrillation
• Up to 20% of patients with HCM will develop atrial fibrillation (AF)
• Silent cases are common, increasing the risk of stroke

Sudden Cardiac Death Risk Stratification
• The incidence of sudden cardiac death (SCD) is ∼1% per year
• The highest risks include a history of prior SCD, ventricular fibrillation,
or sustained ventricular tachycardia. These are associated with an
annual risk of SCD ∼10%
• Massive hypertrophy (>30 mm), a family history of SCD, and
unexplained syncope also important risk factors

European
Society Of
Cardiology

Lifestyle Modifications
• 2020 ACC/AHA guidelines encourage moderate-intensity aerobic exercise
to increase overall cardiovascular health
• Avoidance of alcohol, dehydration, and temperature extremes, e.g.: hot
tubs, saunas
• Avoidance of drugs that worsen left ventricular outflow track (LVOT)
obstruction: diuretics, digitalis, phosphodiesterase inhibitors

Improved Outcomes Over The Last 50 Years

APPENDIX 1: Top 10 Take Home Points

2020 AHA/ACC Guidelines: Top 10 Take-Home Points
1. Shared decision-making, a dialogue between patients and their care team that
includes full disclosure of all testing and treatment options, discussion of the risks and
benefits of those options and, importantly engagement of the patient to express their
own goals is particularly relevant.
2. Although the primary cardiology team can initiate evaluation, treatment, and
longitudinal care, referral to multidisciplinary HCM centers with graduated levels of
expertise can be important to optimizing care for patients with HCM. Challenging
treatment decisions – where reasonable alternatives exist, where the strength of the
evidence or is particularly nuanced, and for invasive procedures that are specific to
patients with HCM – represent crucial opportunities to refer patients to HCM center.

3. Counseling patients with HCM regarding the potential for genetic transmission of HCM
is one of the cornerstones of care. Screen first-degree family members of patients with
HCM, using either genetic testing of an imaging electrocardiographic surveillance
protocol can begin at any age and can be influenced by specifics of the patient/family
history and family preference. As screening recommendations for family members
hinge on the pathogenicity of any detected variants, the reported pathogenicity should
be reconfirmed every 2 to 3 year.

4. Optimal care for patients with HCM requires cardiac imaging to confirm the diagnosis,
characterize the pathophysiology for the individual, and identify risk markers that may
inform decisions regarding interventions for left ventricular outflow tract obstruction
and sudden cardiac death (SCD) prevention. Echocardiography continues to be the
foundational imaging modality for patients with HCM. Cardiovascular magnetic
resonance imaging will also be helpful in many patients, especially those in whom
there is diagnostic uncertainty, poor echocardiographic imaging windows, or where
uncertainty persists regarding decisions around implantable cardioverter-defibrillator
(ICD) placement.

5. Assessment of an individual patient’s risk for SCD continues to evolve as new markers
emerge (e.g.: apical aneurysm, decreased left ventricular systolic function, and
extensive gadolinium enhancement). In addition to a full accounting of an individual’s
risk markers, communication with patient’s regarding not just the presence of risk
markers but also the magnitude of the individual’s risk is key. This enables the
informed patient to fully participate in the decision-making regarding ICD placement,
which incorporates their own level of risk tolerance and treatment goals.

6. The risk factors for SCD in children with HCM carry different weights than those
observed in adult patients, they vary with age and must account for different body
sizes. Coupled with the complexity of placing ICDs in young patients with anticipated
growth and a higher risk of device complications, the threshold for ICD implantation in
children often differs from adults. These differences are best addressed at primary or
comprehensive HCM centers with expertise in children with HCM.

7. Septal reduction therapies (surgical myectomy and alcohol septal ablation), when
performed by experience HCM teams at dedicated centers, continue to improve in
safety and efficacy such that earlier intervention my be possible in select patients with
drug-refractory or severe outflow tract obstruction causing signs of cardiac
decompensation. Given the data on the significantly improved outcomes at
comprehensive HCM centers, these decisions represent an optimal referral
opportunity.
8. Patients with HCM and persistent or paroxysmal atrial fibrillation have a sufficiently
increased risk of stroke such that oral anticoagulants should be considered as default
treatment options independent of the CHA2DS2VASc score. As rapid atrial fibrillation is
often poorly tolerated in patients with HCM, maintenance of sinus rhythm and rate
control are key pursuits in successful treatment.

9. Heart failure symptoms in patients with HCM, in the absence of left ventricular
outflow tract obstruction should be treated similarly to other patients with heart
failure symptoms, including consideration of advanced treatment options (e.g.: cardiac
resynchronization therapy, left ventricular assist device, transplantation). In patients
with HCM, an ejection fraction <50% connotes significantly impaired systolic function
and identifies individuals with poor prognosis and who are at increased risk for SCD.

10. Increasingly, data affirm that the beneficial effects of exercise on general health can
be extended to patients with HCM. Healthy recreational exercise (moderate intensity)
has not been associated with increased risk of ventricular arrhythmia events in recent
studies. Whether an individual patient with HCM wises to pursue more rigorous
exercise/training is dependent on a comprehensive shared discussion between that
patient and their expert HCM care team regarding the potential risks of that level of
training/participation but with the understanding that exercise-related risk cannot be
individualized for any given patient.

HYPERTROPHIC CARDIOMYOPATHY
ECG CASE STUDIES
Dr. Laszlo Littmann, MD
Department of Internal Medicine
Carolinas Medical Center
September 2020
APPENDIX 2

1. HYPERTROPHIC OBSTRUCTIVE
CARDIOMYOPATHY

A 34-YO HEALTHY, PHYSICALLY ACTIVE WOMAN PRESENTED
WITH THREE RECENT EPISODES OF EXERTIONAL SYNCOPE
EXERTIONAL SYNCOPE: PROBABLY NOT VASOVAGAL

 In a young, a normotensive patient, the causes of left axis deviation and
LVH are:
 Aortic stenosis
 HCM
 Causes of non-infarction Q waves:
 HCM
 Cardiac amyloidosis
 Scleroderma
 Pneumothorax
 WPW syndrome
 Hyperkalemia

Hypertrophic Cardiomyopathy
 In a young, normotensive patient, causes of left axis deviation and LVH:
 Aortic stenosis
 HCM
 Causes of non-infarction Q waves:
 HCM
 Cardiac amyloidosis
 Scleroderma
 Pneumothorax
 WPW syndrome
 Hyperkalemia
 The Q waves are usually narrow but deep
 As in this case, they are usually present in the inferior and
lateral leads
 Their etiology is uncertain:
 Myocardial fibrosis?
 Marked thickening of the base of the septum?
 Their clinical significance is also uncertain

ECG DIAGNOSIS
CLINICAL DIAGNOSIS: HOCM
 Sinus bradycardia, left axis deviation
 Left ventricular hypertrophy (aVL = 13 mm)
 Deep Q waves in the inferior and anterolateral leads

2. APICAL VARIANT OF

56-year-old with multiple hospitalizations over 5 years for chest pain and syncope. Most recent admission for
paroxysmal atrial fibrillation demonstrated: normal BP and cardiac examination. A 48-hour Holter demonstrated
brief episodes of ventricular tachycardia. 3 echocardiograms all showed LVH and abnormal relaxation. Coronary
angiogram was negative.

HYPERTROPHIC CARDIOMYOPATHY, APICAL VARIANT

 A rare form of hypertrophic cardiomyopathy; highest prevalence in Asia
 Typical presentation: chest pain, syncope, supraventricular and ventricular arrhythmias
 Despite normal BP and negative physical exam, there is LVH both in the ECG and echo
ECG: sharp, deep negative T waves in the chest leads

 Easy to miss by routine echocardiogram: the LV apex is frequently not well visualized
 Imaging studies show an “Ace of Spades” pattern
 Treatment is controversial

ECHO CONTRAST ECHO
ACE OF SPADES

3. HYPERTROPHIC CARDIOMYOPATHY,
MIDVENTRICULAR VARIANT WITH APICAL
ANEURYSM

A 66-YEAR-OLD MAN EXPERIENCED SUDDEN-ONSET
PALPITATION, SHORTNESS OF BREATH, DIZZINESS
AND ATYPICAL CHEST PAIN

VENTRICULAR TACHYCARDIA
FOLLOWING IV
PROCAINAMIDE, SINUS
RHYTHM WITH ST
ELEVATION IN THE
ANTEROLATERAL LEADS
 Heart rate: 200/min; ECG: wide-complex tachycardia
 200 mg procainamide IV: sinus rhythm and symptom resolution
 Subsequent ECG c/w anterolateral STEMI
 Emergent cardiac catherization: clean coronaries
 This was the patient’s third negative caths in the last 8 years

2007
2015
 STABLE ST ELEVATION
SPANNING 8 YEARS SUGGESTS
STRUCTURAL ABNORMALITY
 LVH SUGGESTS HYPERTROPHIC
CARDIOMYOPATHY
 ST ELEVATION SUGGESTS LV
APICAL ANEURYSM
 THIS COMBINATION IS MOST
FREQUENTLY SEEN IN HCM
WITH MIDVENTRICULAR
OBSTRUCTION
 FREQUENT COMPLICATIONS:
VENTRICULAR TACHYCARDIA,
THROMBOEMBOLIC EVENTS,
SUDDEN CARDIAC DEATH
 TREATMENT: BETA BLOCKER,
ICD, CATHETER ABLATION OF VT,
ANTICOAGULATION

THE ECG IN DIFFERENT TYPES OF
SUMMARY

 HCM
 Left axis deviation
 Abnormal Q waves
 Bizarre repolarization abnormalities
 Apical variant
 Deep symmetrical negative T waves in the chest leads
 Mid-ventricular variant with apical aneurysm
 Stable, persistent ST elevation in the anterolateral leads
II
V4
V4
HYPERTROPHIC CARDIOMYOPATHY AND THE ECG
LVH AND:

If You Have Interesting Cases Of Hypertrophic Cardiomyopathy, We Invite You
To Send A Set Of Digital PDF Images And A Brief Descriptive Clinical History To:
michael.gibbs@atriumhealth.org
Your De-Identified Case(s) Will Be Posted On Our Education Website And You
And Your Institution Will Be Recognized!

EMGuideWire's Radiology Reading Room: Hypertrophic Cardiomyopathy

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