Cardiomyopathies

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    Cardiomyopathies

    • Restrictive Cardiomyopathy (RCM)
    • Hypertrophic Cardiomyopathy (HCM)
    • Dilated Cardiomyopathy (DCM)
    • ArrythmogenicRight Ventricular Cardiomyopathy (ARVC)
     

    Restrictive Cardiomyopathy (RCM)

    • Infiltration or fibrosis of the myocardium causing impaired ventricular filling with preserved systolic function.
      • Reduced or normal diastolic ventricular cavity volume + stiff ventricular myocardium.
      • Causing high filling pressures with small amounts of volume.
      • Early in course biventricular systolic function is normal, but can deteriorate later in disease.
    • Systolic function may diminish in end-stage disease
    • Typical have RAPID early diastolic filling on echo (and JVP - Prominent x/y descents)
    • NOTE: Constrictive pericarditis vs. restrictive cardiomyopathy --> RV and LV share same space in constrictive pericarditis.  Relative increase in filling of RV, which restricts LV filling and vice versa.  Look for this ventricular interaction on echo.
      • Also restrictive cardiomyopathy have higher BNP levels than constrictive pericarditis. (>800)
    • Causes:
      • Infiltrative (rule these out!)
        • Amyoidosis
        • Sarcoidosis
        • Hemochromatosis
      • Non-Infiltrative
        • Scleroderma
        • Radiation
        • Fibrosis following cardiac surgery
        • Myocardial Storage Conditions
        • anthracyclines (doxorubicin, donorubicin)
    • Symptoms:
      • Dyspnea, fatigue, peripheral edema
    • Exam:
      • Elevated JVP (increases with inspiration - Kussmaul's Sign)
      • Normal LV impulse
      • If advanced: Heptosplenomegaly + Ascites
    • DDx:
      • Hypertrophic cardiomyopathy, Dilated cardiomyopathy
      • Constrictive pericarditis: Clinical presentation and physical exam may yield findings identical to RCM.
        • MRI shows pericardial thickening(>5mm), and right heart catheterization demonstrates equalization of diastolic pressures in contrictive pericarditis.
    • Diagnosis:
      1. ECG
        • Conduction System Disease
        • Low QRS voltage
        • Nonspecific ST-T wave changes
      2. Echocardiography
        • Restrictive filling pattern (preserved systolic function)
        • (If infiltrative, myocadium can look granular)
        • Biatrial enlargement
      3. R-Heart Catheterization
        • Dip & plateau vetnricular filling ("Square root sign")
        • Pulmonary hypertension
        • Respiratory concordance of ventricles
      4. Myocardial Biopsy
        • Detects infiltrative disease (amyoidosis & sarcoidosis)
    • Treatment
      • Treat underlying disease
      • Diuretics
        • Can improve symptoms, but hard b/c overdiuresis causes hypotension (preload dependence, no cardiac index)
      • B-Blockers & CCB
        • Can improve diastolic function early in disease. (slow heart rate & increase filling time)
        • Caution: can drop cardiac output
        • CCB: careful in amyloid (causes negative inotropy & conduction problems)
      • Cardiac transplant
        • If no systemic disease

     

    Hypertrophic Cardiomyopathy (HCM)

    • Autosomal-dominant disorder of myocardial structural proteins that causes premature, severe LVH
      • A subset of HCM can cause asymmetrical septal hypertrophy causing dynamic outflow tract obstruction (HOCM!)
    • Symptoms:
      • Syncope, chest pain, dyspnea
    • Exam:
      • If LVOT Obstruction:
        • Systolic crescendo-decrescendo murmur that
          • intensivies with reduction of LV volume (Standing, valsalva)
          • Decreases with increase LV volume (handgrip, raising legs when supine, stand to sit)
      • S4 and sustained apical impulse are characteristic
      • Carotid upstrokes bifid (mid-systolic obstruction)
    • Treatment:
      • Agents that DECREASE LV VOLUME (preload) such as nitrates & diuretics increase LVOT obstruction --> contraindicated in HCM!
      •  

    Notes on Specific Types

    Amyoidosis

    • Heart failure, hepatomegaly, proteinuria, bruising
    • Low voltage ECG (despite increased wall thickness on echo)
    • Diagnose with: sPEP, uPEP, abdominal fat pad or gingival biopsy
    • Cardiac involvement = BAD prognosis

     

    Sarcoidosis

    • Patchy involvement of the myocardium (inflammation & fibrosis due to granuloma formation)
    • Myocardium is not replaced or displaced hence ECG = normal!  (not low voltages like Amyoid)
    • Systemic Symptoms:
      • Pulmonary Involvement
      • Skin involvement

     

     

    Myocarditis

    Giant Cell Myocarditis

    • Presents with heart failure & cardiogenic shock within several days (can be up to months) of onset.
      • Often refractory ventricular arrhythmias
    • High mortality rate
    • Does not have systemic symptoms (unlike amyloid)

     

     

    Constrictive vs. Restrictive vs. Tamponade

     

    Condition History ECG Physical Exam CXR ECHO

    Constrictive

    Pericarditis

    TB, Cardiac Surgery,

    Radiation,

    CTD, Trauma,

    Prior Pericarditis

    Nonspecific

    Pulsus Par. - may have

    JVP (prominent x/y descents,

            Kussmauls)

    Heart Sounds (pericardial

                              Knock)

    Pericardial

    Calcification

    Pericardial Thickening

    Pericardial Effusion

        (Sometimes)

    Ventricular septal flattening

    with inspiration

    Restrictive CM

    Amyoid, Sarcoid,

    Hemochromatosis, etc..

    - R or L Atrial

    Enlargement

    - AV Delay, BBB

    Pulsus Par. - RARE

    JVP - Prominent x/y

              descents

            - Kussmaul's

    Heart Sounds - S4

    Murmurs - MR, TR

    ----

    - Atrial Enlargement

    - Mod/Severe Diastolic

      Dysfunction

    Cardiac

    Tamponade

    Prior effusion,

    cardiac surgery,

    malignancy (i.e. breast Ca),

    recent MI

    Low Voltage,

    Electrical Alternans

    Pulsus Par. - Frequent

    JVP - Abscent/diminished

              y-descent

    Heart Sounds - muffled

    Murmurs - NONE

    Cardiomegaly

    Globular Heart

    - Pericardial Effusion

    - RV collapse during

      systole

     

    Hemodynamics

     

    Constrictive

    Pericarditis

    Restrictive

    CM

    Cardiac Tamponade

    Equalization of diastolic pressures YES

    L-side is higher

    (LV more restricted)

    YES
    Dip & Plateau (Square Root Sign)

    YES

    (restricts at end)

    YES

    (Restricts at end)

    NO

    (restricts entire cycle)

    Respiratory Variation in LV/RV

      Pressures

    Discordant peak

    RV and LV pressures

    (outline restricts/pulsus)

    Concordant peak 

    RV and LV pressures

    (septum restricts too!)

    Variable,

    likely discordant

    (Outline restricts/pulsus)

     

    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.

     

    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 patern: ASH (Asymmetric Septal Hypertrophy)
    • Often benign
    • Complications:
      • Syncope
      • Arrhythmia
      • Ischemia
      • HF
      • Stroke.
    • 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:
      • Mid-systolic murmur caused by LVOT obstruction.
      • Valsalva or Squat-to-Standmanouvres, decrease preload, shrinks chamber, more opposition of hypertrophic muscles, murmur becomes louder (40% sensitivity, quite poor)
      • If lift legs, increasepreload, murmur gets quieter.
    • NOTE: Other causes LVOT obstruction (HOCM is a dynamic obstruction).
    • EKG:
      • Increased QRS voltage, ST abnormalities (repolarization abnormalities). (many have normal EKG).
      • Prominent Q-waves (i.e. infero-lateral) are not due to infarcts, due to septal hypertrophy (T-waves upright in leads with Q-waves).
    • Diagnosis:
      • On Echocardiography (≥15mm septum).
        • Often LVEF ok, but diastolic dysfunction and L-atrial enlargement.
        • Often hyperdynamic LV with small cavity.
      • 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.
      • In HCM, SAM is prolonged

    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.

     

     

    HCM Mimics

    • Athlete's Heart
      • Athlete is elitely 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.
      • Beta-Blockers - reduce HR, diastolic filling, LV contarctility, 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
        • All HCM patients should receive ICD regardless of presence of symptoms.
        • Primary prevention of sudden cardiac death for HCM and multiple RFs for sudden 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 cases, 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.

    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.
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