Cardiomyopathies

    .

     

    Introduction

    • 3 Morphologic Categories:
      • Dilated Cardiomyopathy (DCM) (MOST COMMON)
        • Ventricular Dilation
        • Contractile Dysfunction
      • Hypertrophic Cardiomyopathy (HCM)
        • Inappropriate LV Hypertrophy
        • Impaired contractility
      • Restrictive Cardiomyopathy (RCM)
        • Impaired diastolic filling
      • Arrhythmogenic Right Ventricular CM (ARVD)
      • CardiomyopathyClasses1.png

    • Multiple Etiologies for each morphologic change
      • Only diagnose condition 25% of the time
    • Hazebroek et al JACC 2015 - Registry of all cardiomyopathies
      • Found cause in 75%

     

    • Common Exam Question:
      • Constructive Pericarditis vs. Restrictive CMPY vs. Cardiac Tamponade
    • Entity History ECG Physical Exam CXR

      Constrictive 

      Pericarditis

      TB, CV surgery,

      radiation, CTD

      trauma, prior 

      pericarditis

      non-specific

      Pulsus Paradoxus

      JVP: (prominent X and Y descents)

              + Kussmaul's

      Heart Sounds: Pericardial knock

                               No Murmurs

      Pericardial

      Calcification

      Restrictive 

      Cardiomyopathy

      Amyloidosis, 

      Sarcoidosis, 

      Hemochromatosis

      RAE or LAE

      AV delay, BBB

      JVP: prominent X and Y descents 

               +Kussmaul's

      Heart sounds: Prominent S4

      Pulsus Paradoxus - RARE

      Non-Specific

      Cardiac 

      Tamponade

      Prior effusion, 

      CV surgery, 

      malignancy 

      (breast ca) 

      recent MI

      Low voltage, 

      electrical alternans

      JVP: Absent or diminished Y descent

            "lose your Y before you die"

      Heart Sounds: Muffled

                              No Murmurs

      Cardiomegaly

      (globular heart?)

     

     

     

    • Entity Echo Hemodynamics

      Constrictive 

      Pericarditis

      Pericardial thickening

      Pericardial effusion (maybe)

      Ventricular septal flattening with inspiration

      Equalization of Diastolic Pressures:

               YES

      Dip-And-Plateau Sign ("Square Root Sign"):

               YES (restricts at end)

      LV/RV Respiratory Variation:  

               Discordant peak  RV/LV pressures

      Restrictive 

      Cardiomyopathy

      Atrial enlargement

      Mod-to-Severe Diastolic Dysfunction

      Equalization of Diastolic Pressures: 

               L-sided higher (more restricted on L)

      Dip-And-Plateau Sign ("Square Root Sign"):

               YES (restricts at end)

      LV/RV Respiratory Variation:  

               Concordant peak RV/LV pressures

               (septum restricts too!)

      Cardiac 

      Tamponade

      Pericardial Effusion Present

      RV Collapse in Diastole

      Equalization of Diastolic Pressures: 

               YES

      Dip-And-Plateau Sign ("Square Root Sign"):

               NO!! (restricted throughout cycle)

      LV/RV Respiratory Variation:  

               Variable (more discordant likely)

    Hypertrophic Cardiomyopathy

    • Primary myocardial diesease: Diffuse or focal LV hypertrophy in the absence of afterload-increasing conditions (AS, HTN, etc.)
    • Prevalence: 0.02%.  50% have familial origin.
    • Most common pattern:
      • ASH (Asymmetric Septal Hypertrophy)
        • Some cause asymmetrical septal hypertrophy and dynamic LVOT obstruction
    • Symptoms:
      • Syncope, Chest Pain, Dyspnea
    • Annual mortality: 3-6%.
    • Suspicions:
      • Often sent for screening when family members found this.
      • Often have angina, dyspnea, palpitations, fatigue, dizziness, true syncope.
        • Diastolic dysfunction.
        • Myocardial ischemia
        • LV outflow tract obstruction
        • AFib
    • On Exam:
      • If LVOT obstruction present:
        • Mid-systolic murmur caused by LVOT obstruction.
        • Valsalva or Squat-to-Stand manouvres, decrease preload, shrinks chamber, more opposition of hypertrophic muscles, murmur becomes louder (40% sensitivity, quite poor)
        • Opposite maneuver to increase LV volume decreases murmur:
          • Lift Legs (pt supine)
          • Hand Grip
      • Independent of obstruction:
        • S4
        • Sustained apical impulse
        • Carotid upstrokes are bifid (mid-systolic obstruction)
      • Typical Exam Question: Distinguish HCM from AS:
        • Murmur of AS radiates to neck, weak and delayed carotid pulse (bifid in HCM)
      • Typical Exam Question: Distinguish HCM from Hypertensive Disease
        • Not LVOT obstruction
        • No asymmetric septal hypertrophy
    • NOTE: There are other causes LVOT obstruction (HOCM is a dynamic obstruction).
    • Investigations:
      • EKG:
        • LVH
        • LAE
        • Increased QRS voltage, ST abnormalities (repolarization abnormalities). (many have normal EKG).
        • Prominent Q-waves (i.e. infero-lateral - precordial and leads I and II) are not due to infarcts (pseudoinfarction pattern), but due to septal hypertrophy
        • T-waves upright in leads with Q-waves
        • Can cause giant anterior T-wave inversions
      • Echocardiography (≥15mm septum).
        • LVH
        • Systolic Anterior Motion of mitral valve (SAM)
        • Maybe asymmetric septum and LV outflow obstruction (depends on type)
        • LVEF is usually ok
        • LV cavity is SMALL and HYPERCONTRACTILE --> diastolic dysfunction present
      • Often need Stress Echocardiogram!!!
          • 40-50% of patients have provokable obstruction on exercise
          • Or any other afterload reduction agent (like amyl nitrite, dobutamine).
          • Diagnosis of HCM on Echo:

            • Resting gradient >30mmHg or provokable gradient of >50mmHg is diagnostic.
    • SAM (Systolic anterior  motion of the mitral valves)
      • Most common mechanism of dynamic outflow tract obstruction.
      • Anterior leaflet of the mitral valve is pushed into the hypertrophied basal septum causing obstruction.
      • The anterior leaflet is then separated from posterior leaflet during systole (should be coapting) --> causing MR that is often directed posterior into the atrium.

    HOCMwaveforms.png

     

    Continuous-wave Doppler after exercise stress testing in a pt with hypertrophic cardiomyopathy (left panel) demonstrates a high-velocity late-peaking systolic waveform (arrow) across the LVOT from an exercise-provoked dynamic obstruction. Peak velocity is 4.48 M/sec, indicative of a peak gradient of 80 mm Hg. For comparison, the right panel shows pulsed Doppler echocardiography across the left ventricular outflow tract in a patient without hypertrophic cardiomyopathy. There is an earlier-peaking systolic waveform (arrow) with a normal velocity of 0.9 M/sec, indicative of no outflow gradient. Note the difference in velocity scales.

     

     

    • Genetic Testing:
      • Not routinely done for diagnosis
      • Used to identify genotype (for prognosis)
      • Screen family members

     

    HCM Mimics

    • Athlete's Heart
      • The athlete is trained in exercise with aerobic and anaerobic demands develops LVH.
      • Lesser degree of hypertrophy (<15mm of any wall thickness), cavity volume enlarged due to high volume state (rather than reduced in HCM)...  Also no LA enlargement.
    • Infiltrative causes (Sarcoid, Amyloid) --> often symmetric and concentric wall thickening (HCM is asymmetric)
      • Cardiac MRI or PET helps separate them from HCM (delayed hyper-enhancement).
    • Fabrey's Disease (alpha-galactosidase enzyme deficiency)

     

    Complications

    • High risk of atrial fibrillation (need atrial kick), may precipirate heart failure and stroke.
    • Some patients can progress to dilated CMTHY with impaired systolic function.
    • Sudden death, heart failure, stroke.
    • Sudden death is infrequent --> more common in young (15-35yo).
      • High risk if :
        • Prev cardiac arrest
        • VTach
        • 1st deg family member with sudden cardiac death with known HCM
        • Recurrent unexplained loss of consciousness (hard to separate from obstructive)
        • Extreme increased wall thickness (>30mm [normal <10mm])
        • Abnormal blunted BP response during exercise, if BP fails to rise during exercise.
        • NSVT (even if asymptomatic on ambulatory ECG).

    Management

    • Lifestyle changes
      • Level of exercise (Moderate level of exercise - not competitive or strenuous.  Avoid activities that require sudden intense bursts of energy such as full court basketball, soccer, football).  These are considered high risk for provoking sudden death.
    • Medical therapy warranted if symptomatic.
      • Nitrates and diuretics are contraindicated (increase LVOT obstruction, incrase murmur intensity)
      • Reduce HR and increase diastolic filling time!!
        • Beta-Blockers - reduce HR, diastolic filling, LV contractility, dynamic LVOT obstruction.
        • CCB (verapamil) - can use if don't tolerate BB
          • Do not combine with BB due to negative inotropy (severe bradycardia).
          • Vasodilatory effect can cause worse LVOT obstruction, severe symptoms.
        • Disopyramide
          • Very old antiarrhythmic.  
          • Very negative inotropic agent, used in addition to BB therapy.
          • Can prolong QT interval / QRS duration.  
    • Avoid worsening outflow gradient
      • Exercissive diuresis, vasodilators, digoxin.
    • Device therapy
      • Pacemaker
        • For those with bradycardia during medical titration
        • Not used to reduce LVOT obstruction.
      • ICD
        • Some say all HCM patients should receive ICD regardless of presence of symptoms.
        • Other guidelines: Indications for ICD in HCM patients:
           
          (ACCF/AHA Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy)  
        •  
    1. Massive myocardial hypertrophy (wall thickness ≥30 mm);
    2. Previous cardiac arrest due to ventricular arrhythmia;
    3. Blunted blood pressure response or hypotension during exercise;
    4. Unexplained syncope;
    5. Nonsustained ventricular tachycardia on ambulatory electrocardiography;
    6. Family history of sudden death due to HCM
    • Remember: EP study and/or ICD placement indicated in pts with syncope and family history of sudden cardiac death.
    • Indicated for LV systolic dysfunction with LVEF <35%.
    • Heart transplant
      • For refractory symptoms that cannot be managed medically 
        OR
      • Progressive systolic dysfunction
        OR
      • Refractory ventricular arrhythmias
    • Atrial Fibrillation
      • Same rules for anticoagulation, but rhythm control may be preferred to maintain ventricular filling.
      • AFib ablation, amiodarone are options.
    • Septal Reduction therapy
      • Reduce thickness of basal septum to reduce systolic anterior motion of mitral valves => greater forward flow / (stroke volume).  Very significant surgery!
      • Only for medically-refractory symptoms, and severe cases.
      • However, operativive mortality is quite low (<1%), improves symptoms, quite effective for LVOT.
      • NEW: Alcohol Septal Ablation
        • Catheter passed into septal perforator artery that supplies the hypertrophied part of ventricle with blood.
        • Alcohol injected into that area, causing therapeutic infarction.
        • Initially area remains thick, but over time will thin, reducing LVOT.
        • No trials comparing these two therapies.  
        • Concern about scar causing future arrhythmias.
    • Genetic counselling. (autosomal dominant) --> screen family members.
      • Many genes in effect.  (Sarcomeric proteins).
      • Negative echo in family member does not rule out HCM...
        • 1st degree relatives should undergy q5y echo screening in adulthood to ensure no late-onset HCM.
        • In adolescence echo q1year.

    Restrictive Cardiomyopathy

    • Hallmarks:
      • Fibrosis/infiltration of myocardium
      • Impaired Ventricular Filling with PRESERVED systolic function
      • NOTE: In end-stage disease, systolic dysfunction may develop
    • Hemodynamics:
      • Reduced or normal diastolic ventricular cavity volume, but myocardium is stiff
      • Causing high filling pressures with small amounts of volume.
      • Early in course biventricular systolic function is normal but can deteriorate later in disease.
      • Characterized by RAPID early diastolic filling. 
    • Causes:  (but many idiopathic):
      • Non-infiltrative (Scleroderma, Radiation, Fibrosis after CV surgery)
      • Infiltrative (Amyloidosis, Sarcoidosis, Hemochromatosis)
      • Myocardial Storage Conditions
      • Endomyocardial Disorders
      • Drugs (anthracyclines - cause dilated or restricted dz)
    • R/O: amyloid, sarcoid, hemochromatosis, anthracycline use.
    • Symptoms:
      • Dyspnea, Fatigue, Peripheral Edema
    • Physical Exam
      • ↑ JVP (increases with inspiration = Kussmaul's Sign)
      • Normal LV impulse
      • HSM and ascites if advanced
      • DDx: Hypertrophic CMP, Dilated CMP, Constructive Pericarditis (identical to RCM on exam)

     

    • Investigations:
      • ECG: conductive system disease, low QRS voltage, non-specific ST-T wave changes.
      • Echo:
        • Restrictive filling pattern
        • Preserved EF
        • Bi-atrial enlargement
        • (If infiltrative = granular apperance of myocardium)      
      • R-Heart Cath:
        • Dip-and-plateau ventricular filling pressure ("square root sign")
        • Pulmonary HTN
        • Respiratory concordance of ventricles    
      • Myocardial Biopsy
        • Detects infiltrative causes (amyloid & sarcoid)

     

    • Common Exam Question:
      • Distinguish: Constrictive pericarditis vs. restrictive cardiomyopathy
        • Echo: RV and LV share same space in constrictive pericarditis.  Constrictive pericarditis = Relative increase in filling of RV, which restricts LV filling and vice versa.  Look for this ventricular interaction on echo.
        • MRI: Pericardial thickening > 5mm
        • Also restrictive cardiomyopathy has higher BNP levels than constrictive pericarditis. (>800)
        • R-heart cath: (constrictive pericarditis = equalization of diastolic pressures)

     

    • Management:
      • Prognosis is poor (surival is 64% at 5 years, 37% 10-years post-dx.).
      • Treat underlying cause
      • Pharmacotherapy:
        • None improve mortality (except heart transplant).
        • Diuretics (but very preload dependent, can lead to syncope)
        • B-Blockers & CCB:
          • improve diastolic function early in disease by increasing filling time. 
          • CAUTION: can cause drop in cardiac output
          • Avoid CCB in amyloid (can cause significant negative chronotropy due to conduction disease).
      • Transplant
        • Esp good candidates if no severe systemic disease. 

    Takotsubo Cardiomyopathy

    • Aka stress-induced cardiomyopathy
    • Transient cardiac dysfunction... apical ballooning triggered by emotional stress.  (in some cases no trigger identifiable).
    • Presenting picture looks like ACS:
      • Chest pain, troponin, ischemic ECG
      • Echo or ventriculogram make diagnosis.  (absence of CAD).
    • Treatment:
      • B-blocker therapy + supportive, but does not protect against recurrence.
      • Ejection fraction quickly normalizes, but small percentage take months to recover.

     

    Tachycardia-Induced Cardiomyopathy

    • Months to years of tachycardia.
      • Atrial or ventricular tachycardia.
      • Frequent PVCs can cause this (>1000 per day).
    • Rate control improves or resolves cardiomyopathy.
    • Recurrence occurs fast if tachycardia recurs.

     

    Acute Myocarditis

    • Inflammation of myocardium
      • Many causes: toxins, infections (most common: viral infections).
      • Pathophysiology is unkown.
    • Symptoms (range):
      • From minor symptoms to cardiogenic shock.
    • Treatment:
      • Immunosuppressives do not benefit.
      • Supportive care, and therapy for systolic HF for any cause.
      • Fulminant presentations (acute, cardiogenic shock), have higher recovery rates.

     

    Giant-Cell Myocarditis

    • Form or acute myocarditis (often fatal), affecting those in 40's.
    • Characterized by: rapid onset of fulminant heart failure (days-months).
    • Refractory ventricular arrhythmias are common.
    • Mechanism unknown, thought to be autoimmune.  
    • Treatment:
      • Immunosuppressives (steroids etc..) do not change outcomes.
      • Often need mechanical support or transplant.

     

    Cardiac Tumors

    • Atrial Myxomas (L-atrial 80% of the time).
      • Atrial myxomas must be surgically removed (especially if L-sided) to avoid embolic phenomena even in asymptomatic patients.
    • Rhabdomyosarcomas (show up bright on echo)
    • Fibroelastoma (attached to heart valves or mitral cordal aparatus)
      • Can also present with stroke or another embolization phenomena.
    • Secondary tumors 20 times more common than primary.  Originate from lung or breast carcinomas + renal, hepatocellular etc.
    • Cardiac tumors often cause non-specific symptoms... often heart failure and pericardial constriction.
      • Occasionally syncope, stroke (embolization), heart block (invasion), Ventricular arrhythmias.
    • Echo is gold standard in identifying tumors.  TEE specifically is more effective.
    • Generally requires surgical removal, and sent for biopsy.
      • (can't biopsy in cath lab, high risk of embolization).
      • If not removed, very high risk of embolization despite anticoagulation.
    • Malignant tumors are not amenable to curative surgery.

     

     

    ARVC(D)

    • Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia
    • Genetic disorder leading to fibrofatty replacement of RV myocardium.
    • Early changes localized to one of 3 RV sites ("triangle of dysplasia")
      • Inflow Tract
      • Outflow Tract
      • Apex
    • Late in disease can affect most of RV myocardium and even posterolateral LV wall. 
    • Familial autosomal dominant disorder (recessive forms present)
    • Symptoms/Presentation:
      • YOUNG! and Adolescents 
      • Palpitations, Syncope, or aborted sudden death
    • Investigations:
      • ECG:
        • Baseline: TWI in V1-V3, PVCs of LBBB morphology
        • VT of LBBB morphology 
      • CXR
      • Other:
        • 24-hour ambulatory ECG
        • Signal Averaged ECG
        • Stress Test
        • 2D Echo
      • If inconclusive evaluation thus far:
        • MRI
        • Contrast Angiography
        • Endomyocardial biopsy
    •  
    • Diagnosis:
      • Task Force Criteria (created 1994, revised in 2010 to incorporate advanced imaging)
      • See criteria (attached) PART1  and   PART2

      • ARVCcriteria1.png        ARVCcriteria2.png

    • Categories:

       

      • Structural (Global or regional dysfunction and structural alterations)
        (Echo, MRI - late gadolinium enhancement)
      • Tissue
      • Repolarization Abnormalities
        (on surface ECG - i.e. inverted T-waves in precordial leads)
      • Depolarization/Conduction Abnormalities
        (Signal Averaged ECGs, surface ECGs - i.e. epsilon wave)
      • Arrhythmias 
        (RV origin)
      • Family History
        (1st Degree relative who meets task force criteria)

       

       

      • Definitive Diagnosis
        • 2 major criteria
        • 1 major plus 2 minor criteria 
        • 4 minor criteria from different categories. 
      • Borderline Diagnosis
        • 1 major and 1 minor
        • 3 minor criteria from different categories
      • Possible Diagnosis
        • 1 major
        • 2 minor criteria from different categories

       

    • Treatment
      • Low EF
        • Medical Therapy
      • Arrhythmias
        • Antiarrhythmics, ICD, etc...
        • Ablations (often temporary relief of arrhythmias b/c disease is progressive)
      • Transplant (rare)
        • If very severe symptoms.
        • Although heart transplant is rarely needed.
    Tag page (Edit tags)
    • No tags
    Pages that link here
    Page statistics
    23564 view(s), 20 edit(s) and 31258 character(s)

    Comments

    You must login to post a comment.