1) Welcome to a 🆕#accred...
Highlights
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- Welcome to a 🆕#accredited #tweetorial & another opportunity to earn 🆓CE/#CME! Just follow this 🧵as returning expert author Ph.Gabriel Steg @gabrielsteg 🇫🇷 discusses the basics of #HCM along with special considerations for the #interventionalist.
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- This program is intended for #HCPs & is supported by an unrestricted educational grant from Bristol Myers Squibb. Statement of accreditation and faculty disclosures at https://t.co/gvXca4G9Xm.
FOLLOW US for expert-authored #cardiometabolic programs for 🆓CE/#CME (View Tweet)
- 3a) So let's get this party started! 🎉🥳
When should we think of #HCM?
🫀 In pts with cardiac symptoms (chest pain, dyspnea, #arrhythmia)
🫀 In pts with a heart #murmur
🫀 When evaluating an athlete (View Tweet)
- 3b)
🫀 When dealing with a complication of potential #HCM (stroke or SE, arrhythmia, sudden cardiac death #SCD)
🫀 When evaluating a relative from a case with HCM
🫀 When detecting ECG or echo signs of #LVH, particularly with Q waves or repolarization abnormalities (View Tweet)
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- What defines HCM ?
LV thickness > 15 mm (particularly in the septum, can be 13 mm in 1st degree relative)
LVH can be septal asymmetric, but also apical or global concentric
How frequent is HCM ?
Est~ 1/200 - 1/500 adults, but only 25% are diagnosed.
🔓https://t.co/24tQHQZ75p (View Tweet)
- 5a) What is the cause of HCM ?
It is a disease of the #sarcomere, the basic contractile unit of the myocardial fiber.
(View Tweet)
- 5b) The main abnormality is excess #actin-#myosin cross bridging which leads to
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- Diagnostic pitfalls
🫀 False tendons mimicking septal LVH
🫀 Subaortic membrane creating obstruction
🫀 Antero basal or apical hypertrophy may be missed by TTE; contrast TTE can help
🫀 Athlete’s heart can mimic HCM
When in doubt, #strain on #TTE and #MRI can be very useful (View Tweet)
- 7a) Obstruction
Dx
🫀 Obstruction not always present; in 70% #HCM patients, obstruction +at rest (1/3) or can be provoked (1/3).
🫀 Defined: max gradient >/= 30 mmHg
🫀 Hemodynamically significant if gradient >/= 50 mmHg
🫀 If absent at rest, always seek using >/= 2 methods (View Tweet)
- 7b) Obstruction
Triggers:
🫀 exertion (stress or exercise echo using a bicycle or a treadmill) or post exertion
🫀 #Valsalva maneuver (may be used when stress echo is not feasible or when there is concern with comorbidities). Typically will trigger lower gradients than exercise. (View Tweet)
- 7c) Tests can be sensitized in the post-prandial period or the standing position
🫀 Obstruction is correlated to functional impairment & prognosis, predicts risk of #SCD
🫀 Obstruction predicts functional impairment (#NYHA class III & IV)
X 2⃣if provoked
X 5⃣ if present at rest (View Tweet)
- 7d) More on obstruction predicts functional impairment:
🫀 30% of pts have no obstruction or < 30 mm Hg, NYHA class III/IV = 1.6%
🫀 35% of pts have obstruction > 30 provoked, NYHA class III/IV = 3.2%
🫀 35% of pts have obstruction at rest, NYHA class III/IV = 7.4%
(Maron 2022)
(View Tweet)
- 7e) Causes of obstruction
🫀 Systolic anterior motion (#SAM) of mitral valve leaflet due to subaortic acceleration in a narrowed #LVOT & LV hypercontractility
🫀 Due to anteposition of mitral valve in #LV & excess valvular tissue
🫀 Enhanced after exertion, after meal, after 🍸
(View Tweet)
- 7f) Consequences of obstruction
🫀 Mitral regurgitation
🫀 LV relaxation impairment, resulting in enlargement of the left atrium and the risk for atrial #arrhythmia
🫀 Reduction of #LV stroke volume (View Tweet)
- 8a) Diagnosing #HCM
Symptoms:
🫀 May be none, may be mild and nonspecific , which ➡️ #underdiagnosis. Dx often made in middle age but some forms express early & some late in life
🔓https://t.co/mkhMu3Hqzl
https://t.co/EysZpoeq1k (View Tweet)
- 8b) Common symptoms include
🫀 #Dyspnea
🫀 Chest pain
🫀 #Palpitations
🫀 #Syncope
🫀 Fatigue
🔓 https://t.co/RglMNfeXtx (View Tweet)
- 8c) Clinical examination can uncover a #systolic ejection murmur #SEM, but absence does not exclude #HCM. The systolic ejection murmur is reduced when squatting compared to standing
🔊 <skip ad!> https://t.co/yvMe0KpdwA (View Tweet)
- 8d) #EKG abnormalities are common (90% of cases) but nonspecific . . . may see
🫀 ST-T waves changes
🫀 Deep Q waves
🫀 #LVH (View Tweet)
- 8e) Diagnostic suspicion will be confirmed with cardiac #imaging: #echocardiography or cardiac MRI #CMR with a diagnostic threshold of 13 mm #LV wall thickness (View Tweet)
- 9a) #Echocardiography should
- establish #hypertrophy (and in all myocardial segments as #LVH can be localized to any segment) with additional apical views, describing maximal wall thickness, pattern severity, & distribution of hypertrophy (View Tweet)
- 9b) Patterns can be
Sigmoidal 40-50%
Apical 10%
reverse 30-40%
concentric (neutral) 10%
(View Tweet)
- 9c) The use of ultrasound enhancing agents can aid in the detection of apical #LVH, #aneurysm, & thrombus in cases where LV apex is suboptimally visualized
🔓https://t.co/Rjq6llrI2r
🔑 In all cases that remain uncertain or difficult, #CMR should be performed (View Tweet)
- 9d) #Echocardiography should
2. assess systolic (#LVEF) and diastolic function (LV filling pressures)
3. assess obstruction:
🫀 #Pulsed #Doppler assesses location
CW doppler assesses severity (peak LVOT gradient); see 🔓 https://t.co/FeHym2EE4F
(View Tweet)
- 9e) More #Echocardiography
🫀 should show #LVOTO if present; if resting gradient is < 50 mmHg, upon provocation (Valsalva or more effectively with effort)
🫀 #SAM
🫀 Secondary MR (View Tweet)
- 9f) And a little math 🧮:
🫀 LVOT gradient can be estimated using MR and SBP:
🫀 LVOT gradient ≈ LV pressure - SBP
🫀 LV pressure ≈ 4 x (VelocityPeak MR)^2 + LA pressure (View Tweet)
- 10a) Screening for #HCM
🫀 Subclinical forms, esp during cascade screening, can have milder abnormalities
🫀 Phenotype can vary enormously, even within a given family & over time in a given individual. In a given family, there is also variable #penetrance. (View Tweet)
- 10b) Dx thus based on #phenotype, not genetics. In individuals who are genotype-positive or phenotype-negative, serial echo rec'd at periodic intervals by age (1-2y in children, adolescents; 3-5y in adults) and change in clinical status.
🔓 https://t.co/Rjq6llrI2r
(View Tweet)
- 11a) New #imaging methods such as Diffusion Tensor Imaging can be useful to identify cardiomyocyte disarray in hypertrophied and even non hypertrophied segments.
🔓 https://t.co/fOdqUbmUoc
🔓 https://t.co/L7c7U1PvwP
(View Tweet)
- 11b) Very striking focal & dense perfusion defects can be observed even in the absence of any #LVH or scarring and typically occur in areas such as the interventricular #septum or right ventricular insertion points, where early LVH or scarring is commonly detected in overt #HCM (View Tweet)
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- Because of prevalence of #HCM #phenocopies, #DDx should always include non-sarcomeric causes of #LVH, eg:
🫀 Hypertension
🫀 Aortic stenosis
🫀 Cardiac #amyloid
🫀 Fabry dz
🫀 Mitochondrial cardiomyopathy
All HCM pts should undergo #CMR at least once at the time of diagnosis (View Tweet)
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- Complications of # HCM
🫀 #HeartFailure
🫀 #Arrhythmias
🫀 #Stroke
🫀 Sudden cardiac death #SCD ☠️ (View Tweet)
- 14a) So, about #SCD in #HCM:
Sudden Cardiac Death
🧮#Risk assessment for #SCD required in all patients
🫀 #RF for SCD may differ in weight among children vs adults, & problems & complications of #ICDs also differ
🫀 Risk of SCD is approximately 1% per year in adults (View Tweet)
- 14b) @ACCinTouch / @American_Heart #guidelines recommend #SCD risk assessment & #ICD indications:
For adult pts w/HCM & ≥1 major risk factors for SCD, it is reasonable to offer an ICD (class 2a). Major RFs include: (View Tweet)
- 14c) (cont)
1⃣ #SCD judged definitively/likely attributable to #HCM in ≥1 first-degree or close relatives ≤50 years of age
2⃣ Massive #LVH ≥30 mm in any LV segment (View Tweet)
- 14d) (cont)
3⃣ ≥1 Recent episodes of syncope suspected by clinical history to be arrhythmic (i.e., unlikely to be of neurocardiogenic vasovagal, etiology, or related to #LVOTO)
4⃣ LV apical aneurysm, independent of size
5⃣ LV systolic dysfunction (EF<50%) (View Tweet)
- 14e) (cont)
6⃣ Extensive LGE on CMR
7⃣ #NSVT on Holter
(View Tweet)
- 14f) @escardio guidelines #RiskStratification: use a specific score estimating the risk of #SCD at 5 years in adults.
Formula based on
o Age
o Max wall thickness
o Max #LVOT gradient
o Left atrial diameter
o Family hx of #ICD
o Hx of unexplained #syncope
o Hx of #NSVT (View Tweet)
- 14g) Free web calculator for @escardio score at https://t.co/ZJvgcOjauR
or
get out your calculator:
(View Tweet)
- 14h) Based on the #ESC #SCD score,
- in pts w/5yr risk of SCD <4%, an ICD is generally not indicated,
- in pts w/risk of 4 to < 6%, an ICD may be considered
- in pts w/risk ≥6%, an ICD should be considered.
🔓 https://t.co/CoylVkuQa0 (View Tweet)
- 15a) Let's pause and do a quick knowledge ✔️.
Which of the following is NOT a major #riskfactor for #SCD in the #ACC/#AHA #HCM guidelines?
a. Massive #LVH ≥30 mm in any LV segment
b. LV systolic dysfunction (EF<50%)
c. #atrialfibrillation
d. #NSVT on Holter (View Tweet)
- 15b) Mark your best answer and COME BACK TOMORROW for the correct response & more teaching from @gabrielsteg !
#FOAMed #CardioTwitter @MedTweetorials @AntonioBarros_ @SeguraCardio @drvishalg @SABOURETCardio @GiuseppeGalati_ @AJamilTajik @HanCardiomd @JasonKatzMD @SrihariNaiduMD (View Tweet)