Cardiomyopathy & Pericarditis

Introduction

Primary cardiomyopathies

• HOCM is second most common cause of sudden cardiac death in adolescents and leading cause of sudden death in competitive athletes
• Cardiomyopathy is the third most common form of cardiac disease after ischaemic and hypertensive heart disease
• Divided into primary and secondary cardiomyopathies

• Genetic
  • HOCM
  • Arrhythmogenic right ventricular dysplasia
  • Left ventricular non-compaction
  • Conduction system disease
    • Long QT syndrome
    • Brugada syndrome
    • Catecholaminergic polymorphic VT
    • Short QT syndrome
    • Idiopathic VF
  • Mixed (genetic and non-genetic)
    • Dilated cardiomyopathy
    • Primary restrictive non-hypertrophied cardiomyopathy
  • Acquired
    • Myocarditis (inflammatory)
    • Takotsubo
    • Peripartum cardiomyopathy

Secondary cardiomyopathies

• Toxins
  • Ethanol, chemotherapeutics (doxorubicin), antiretrovirals (zidovudine, didanosine), phenothiazines, cocaine, methamphetamine
• Infiltrative
  • Amyloidosis
• Storage
  • Haemochromatosis
• Autoimmune
  • Scleroderma, SLE, RA, dermatomyositis
• Metabolic
  • Nutritional (thiamine, selenium deficiency)
  • Endocrine (diabetes mellitus, hypothyroidism, hyperthyroidism)
  • Electrolyte (hypophosphataemia, hypocalcaemia)
• Neuromuscular
  • Muscular dystrophy
  • Freiderich’s ataxia

Features of cardiomyopathies

Dilated cardiomyopathy

• Idiopathic dilated cardiomyopathy makes up 25% of heart failure cases and is primary indication for cardiac transplant
• Mostly diagnosed between 20-50yo
• Systolic and diastolic dysfunction seen, often with reduced LVEF and RVEF
• LV and often RV dilatation with normal LV wall thickness is hallmark
• Clinical features
  • May present with congestive heart failure, embolic phenomonen from mural thrombi or chest pain (due to limited coronary reserve vs. atherosclerosis)
  • Often holosystolic murmurs at mitral and tricuspid areas heard due to impaired complete closure due to dilation

• Diagnosis
  • Typical CCF CXR
  • ECG: LV hypertrophy and LA enlargement. Rarely normal.
  • Q or QS waves and poor R wave progression may produce pseudoinfarction pattern
  • AF and ventricular ectopy are common
  • Echo is diagnostic
• Treatment
  • Diuretics and digoxin improve symptoms but not survival
  • ACEi (carvedilol) improves survival
  • Some patients will benefit from cardiac resynchronisation therapy
  • Complex ventricular ectopy may be at risk of sudden death and may benefit from amiodarone and/or ICD
  • LVAD’s can be used as a bridge to heart transplantation

• Left ventricular assist devices (LVAD)
  • Implanted pump transfers blood from apex of LV to proximal aorta
  • Mostly continuous flow maintaining a normal MAP in the absence of palpable pulse
    • If some cardiac contractility remains, the LVAD assists (and does nto replace) normal CO and a pulse may be present
  • Still rely on RV function to perform lung perfusion
  • Can be in VF and clinically stable
  • Clinical features
    • ECG show have discernible QRS complexes

• LVAD – management
  • If unstable
    • Never perform chest compressions as can dislodge leading to intractable haemorrhage
    • Auscultate the praecordium – If whirr is heard, the LVAD is functioning. If silent, search for mechanical LVAD failure – check and/or change battery but DO NOT DISCONNECT anything
    • For hypotension, give bolus crystalloids and assess for haemorrhage
    • Initiate IV pressors if this fails – Dopamine is reasonable first-line
    • Obtain ECG to rule out RV infarct/strain pattern
    • Bedside USS may show cardiac tamponade or RV failure (consider PE, RV infarct or pulmonary HTN)
    • Give heparin if PE or device thrombosis is suspected
    • VF or VT requires defibrillation as per standard protocols. Do not place pads over the driveline
    • If pulsatile VT, give amiodarone

• LVAD – Medical complications
  • Haemolytic anaemia
  • Bleeding (usually on warfarin INR 2-3)
  • Thromboembolism
    • At risk of PE, stroke and mesenteric ischaemia, especially if INR subtherapeutic
    • Heparin is safe once bleeding ruled out
  • Infection
    • Especially the driveline exit site
    • Treat as for sepsis

Myocarditis

• Common cause of dilated cardiomyopathy
• Commonly associated with pericarditis
• Viral
  • Coxsackie B virus, echovirus, influenza virus, parainfluenza, EBV, Hep B, HIV
• Bacterial
  • Corynebacterium diphtheriae, N. meningitidis, Mycoplasma, beta-haemolytic strep (Rheumatic fever) and Lyme disease
• Presentation
  • Fever, myalgias, headache, sinus tachycardia (out of proportion to fever) and chest pain (often angina-type chest pain and usually due to myopericarditis)
  • Heart failure symptoms if severe
  • Pericardial friction rub is often heard

• Diagnosis
  • ECG: Non-specific ST/T wave changes, ST elevation or PR depression (pericarditis), AV block and QRS interval prolongation
  • May have raised troponin
  • Echo shows myocardial depression and wall motion abnormalities in severe cases
  • Cardiac MRI can be used
• Treatment
  • Supportive
  • Antibiotics if suspected rheumatic fever, diphtheria, meningococcaemia
  • Immunosuppression in select patients (usually for severe cases only)

Hypertrophic cardiomyopathy

• LV and/or RV hypertrophy that is usually asymmetric and involves primarily the interventricular septum
• Hallmark is IV septal hypertrophy associated with myocardial fibre disarray
• Familial (autosomal dominant) or sporadic
• No apparent sex or ethnic predilection
• Particular genotypes have more rapid progression
• 1/500 prevalence in general population
• Annual mortality rate is 1% per annum (4-6% per annum in childhood and adolescence)

• Haemodynamics
  • Abnormal LV diastolic function due to reduced compliance
  • Increased LV filling pressures with often normal CO, ejection fraction and end-systolic and end-diastolic volumes
  • Systolic pressure gradient between LV and subvalvular outflow tract can be recorded at rest or with provocation
• Clinical features
  • The older the patient, the more severe the symptoms
  • Dysnpoea on exertion is most common
    • Exercise-induced sinus tachycardia leads to abrupt rise in LV diastolic pressure and pulmonary venous hypertension
    • +- chest pain, palpitations and syncope
  • FHx of death due to cardiac disease is not uncommon
  • Chest pain is due to coronary flow/demand mismatch
    • May be exacerbated by atherosclerosis in older patients
  • AF is poorly tolerated due to loss of atrial kick in diastolic failure

• Examination
  • Upstroke of carotid pulse is rapid. May have pulsus bisferiens
  • S1, S2 + S4 in most
  • Systolic ejection murmur heard best at lower left sternal border or at apex and rarely radiates to the carotids
  • Interventions that decrease LV filling and distending pressure of LV outflow tract or that increase force of myocardial contraction accentuate the murmur
    • Valsalva, standing
  • Interventions that increase LV filling reduce the murmur intensity
    • Squatting, passive leg raise and hand grip

HCM vs. mitral valve prolapse

• Diagnosis
  • CXR often unremarkable
  • ECG: LV hypertrophy + LA enlargement. Septal Q waves >0.3mV may be seen in anterior, lateral and inferior leads
    • Pseudoinfarction pattern of Q waves can be seen
    • Typically get upright T waves in leads with QS or QR complexes in HCM vs. TWI in leads with Q waves suggests ischaemic heart disease
  • Echo
    • Characteristic disproportionate septal hypertrophy, reduced LV end-diastolic dimensions, systolic anterior motion of the mitral valve and mid-systolic closure of the aortic valve
  • Cardiac MRI for inconclusive cases
  • Genetic testing

• Treatment
  • Hospitalise for Ix
  • Syncope in HCM may presage death
  • Beta-blockers are the mainstay of therapy for chest pain
    • Slows heart rate, reduces LV-LV outflow tract pressure gradient, reduces myocardial demand

Restrictive cardiomyopathy

• Most cases idiopathic (sometimes autosomal dominant)
• Other causes include amyloidosis, sarcoidosis, haemochromatosis, scleroderma, carcinoid heart disease, endomyocardial fibrosis or hypereosinophilic syndrome
• Results in restricted ventricular filling and subsequent diastolic failure of one or both ventricles
• Systolic function usually normal with normal or increased ventricular wall thickness

• Haemodynamics
  • Elevated LV and RV end-diastolic pressures
  • Normal LV EF
  • Marked decreased followed by rapid rise and plateau in early diastolic ventricular pressure
    • = Square root sign” due to increased myocardial stiffness
    • Also seen in constrictive pericarditis (main differential)
• Clinical
  • LV and/or RV failure symptoms
  • Non-specific St/T wave changes
  • Cardiac conduction disturbances are common in sarcoid and amyloidosis
  • Low-voltage QRS often seen in amyloidosis and haemochromatosis
• Diagnosis
  • Echo and angio based to rule out ischaemic diastolic dysfunction
• Treatment
  • CT and MRI can differentiate constrictive pericarditis vs. restrictive cardiomyopathy
  • Diuretics and ACEi provide symptom relief
  • Corticosteroids for sarcoidosis
  • Chelation therapy for haemochromatosis

Acute pericarditis

• Typically sharp or stabbing precordial or retrosternal chest pain
• Sudden or gradual onset, radiates to back, neck, left shoulder or arm and may be pleuritic or worse with movement
• Referral to the left trapezial ridge (due to inflammation of the diaphragmatic pleura) is a particular distinguishing feature
• Typically worse when supine and relieved by sitting up and forward
• Associated symptoms
  • Fever, dyspnoea (due to pleurisy) and dysphagia (if oesophageal irritation from posterior pericardium)
• Pericardial friction rub is the most common and important physical finding but can be hard to hear
  • Best heard at apex or left lower sternal edge, sitting forward. Typically intermittent
  • Classicaly triphasic: Systolic component due to ventricular contraction, early diastolic component during early phase of ventricular filling and presystolic component synchronous with atrial systole
  • Less commonly biphasic: Systolic + early diastolic or presystolic component
  • Rarely monophasic systolic component

• Causes
  • Idiopathic
  • Viral: Coxsackie, echovirus, HIV
  • Bacterial: Staph, strep pneumoniae, beta-haemolytic strep (Rheumatic fever), TB
  • Fungal (Histoplasma capsulatum)
  • Malignancy: Leukaemia, lymphoma, metastatic breast/lung Ca, melanoma
  • Drug-induced: Procainamide, hydralazine
  • Rheumatic: SLE, RA, scleroderma, PAN, dermatomyositis
  • Post-MI: Dressler’s
  • Radiation-induced
  • Uraemia
  • Myxoedema

• ECG
  • Four stages over several weeks
    • I (acute)
      • PR depression II, aVF, V4-6; 
      • ST elevation I, V5/6; 
      • ST:T >0.25 (pericarditis vs. BER)
      • Knuckle sign – Reciprocal PR elevation and ST depression in aVR
    • II
      • PR isoelectric or depressed
      • ST segments isoelectric
      • T wave amplitude decreases; inversion rare
    • III
      • PR isolectric or depressed
      • ST segments isoelectric
      • T wave inversion I, V5, V6
    • IV
      • All normal

• Sensitivity of ST:T wave amplitude >0.25 is >85% and specificity >80%
• Echo
  • Ech0-free fluid in anterior or posterior space is always pathological
  • Normally 50mL of fluid only and not visible on bedside echo
  • Quantification of the size is arbitrary but mild thought to be only posterior and only in systole
  • CT is equally sensitive as echo in diagnosing effusion
  • Can diagnose tamponade with echo though
• Troponin rise indicates associated myocarditis or alternative diagnosis

• Treatment
  • Idiopathic or presumed viral
    • Benign course 1-2 weeks usually
    • Symptoms respond well to NSAID’s for 7 days to 3 weeks
      • Ibuprofen 400mg TDS preferred
    • Colchicine 0.5mg BD may be a beneficial adjuvant and prevent recurrent episodes
    • Hospitalisation only necessary for associated myocarditis and follow-up echo is not required unless symptoms fail to resolve or reappear
    • Indicators of poor prognosis
      • Fever >38
      • Subacute onset over weeks
      • Imunosupression
      • Previous oral anticoagulant use
      • Associated myocarditis (trop leak or CCF)
      • Large pericardial effusion (echo-free space >20mm)

Non-traumatic cardiac tamponade

• If fluid accumulates to degree that intrapericardial pressure rises above right heart filling pressures, cardiac tamponade results
• Point at which this occurs depends on pericardial fluid accumulation rate, pericardial compliance and intravascular volume
• Causes
  • Metastatic malignancy (40%)
  • Acute idiopathic pericarditis (15%)
  • Uraemia (10%)
  • Bacterial/TB pericarditis (10%)
  • Chronic idiopathic pericarditis (10%)
  • Haemorrhage (anticoagulants) (5%)
  • Other – SLE, post-radiotherapy, myxoedema (10%)

• Clinical features
  • Non-specific; dyspnoea on exertion or at rest
  • Symptoms of underlying cause
  • Examination
    • Sinus tachycardia, low BP, narrow pulse pressure
    • Pulsus paradoxus (dropped beats with inspiration)
      • <10mmHg drop in SBP during inspiration in supine position suggests restricted cardiac filling
      • If >10mmHg drop suggests true tamponade
    • Distended neck veins
    • Apical impulse may be indistinct or tapping
    • Distant or soft heart sounds
    • Pulmonary rales usually absent
    • RUQ tenderness from hepatic venous congestion may occur
    • Beck’s triad: Soft heart sounds, distended neck veins, hypotension
• Low-pressure pericardial tamponade
  • Haemodynamically significant effusion with intrapericardial pressure lower than expected
  • Classically chronic effusions with superimposed hypovolaemia
  • Respond well to fluid bolus
  • Don’t show typical neck distension but will show echocardiographic evidence of tamponade physiology

• Diagnosis
  • ECG:
    • Low voltage QRS <0.7mV and ST elevation (due to epicardial inflammation) with PR depressions as in pericarditis
    • Electrical alternans is classic but uncommon
    • Echo
      • Large pericardial fluid volume
        • <10mm = Small
        • 10-20mm = Moderate
        • >20mm = Large
      • Diastolic RA compression (highly specific and sensitive)
      • Diastolic RV collapse (highly specific but less sensitive)
      • LA collapse (highly specific)
      • Small, slit-like LV
      • Abnormal respiratory variation in mitral and tricuspid flow velocities
      • Dilated IVC with lack of inspiratory collapse
      • Swinging heart
• Treatment
  • Volume expansion temporising measure
  • Pericardiocentesis

Constrictive pericarditis

• Pericardial inflammation with fibrous thickening, which prevents passive diastolic filling of cardiac chambers
• Causes
  • Post-cardiac trauma, pericardial haemorrhage, pericardiotomy (as in CABG), fungal/TB pericarditis and in chronic renal failure
  • Most cases idiopathic
• Clinical features
  • May mimic CCF with restrictive cardiomyopathy
  • If pericardial effusion arises, may have sudden effusive constrictive pericarditis
  • JVP distension, rapid ‘y’ descent, Kussmaul sign (inspiratory neck vein distension), paradoxical pulse is occasionally seen
  • Early diastolic pericardial ‘knock’ may be heard (may mimic S3 of CCF)
• ECG
  • Low-voltage QRS <0.7mV, inverted T waves are common
• Echo may show thickened pericardium, effusion and abnormal ventricualr septal motion
• Cardiac CT and MRI preferred
• Cardiac cath with intraventricular pressure measurement is diagnostic with square root sign of dip and rapid rise/plateau of RV pressure trace
• Pericardiectomy is the surgical treatment of choice

Takotsubo cardiomyopathy

• First described in Japan in 1980’s
• Acute reversible LV dysfunction triggered by emotional or physical stress
• Classically transient apical akinesis/hypokinesis and basal hyperkinesis that resolves over days to weeks
• Name derived from Japanese octopus trap appearance of LV on echocardiogram
• 90% of cases are in women
• 2% of all troponin-positive patients presenting with suspected ACS
• Reverse takotsubo
  • Basal hypokinesis with apical hyperkinesis
  • Associated with younger age, less reduction in EF
• ECG abnormalities
  • ST elevation minicking STEMI
  • TWI
  • New BBB
  • Prolonged QT
• Diagnosis of exclusion once angiogram performed and myocarditis ruled out
• Supportive treatment only
• Recurs in 10% of patients
• Complications may include pleural effusion, pericardial effusion and LV thrombi

Last Updated on May 14, 2024 by Andrew Crofton