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)

  • 

• 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.

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

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.

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

  •         

• 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

  • For Details see TASK FORCE 2010 RECOMMENDATIONS
• 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.