Cardiomyopathies

Diseases with mechanical and/or electrical dysfunction of the myocardium

Dilated Cardiomyopathy (DCMP)

Definition and epidemiology (Ore 2006:113:1807)

• Ventricular dilatation, normal to i wall thickness, and i contractility

• Incidence: 5-8 cases/100,000 population per y, prevalence: 1 in 2500

Etiologies (nejm 1994331 1564 ft 2000342:1077)

• Ischemia: systolic dysfxn & dilation out of proportion to CAD (poor r«nod«img po«-Mi)

• Valvular disease: systolic dysfxn due to chronic volume overload in MR & Al

• Familial ( 25%): mutations in cytoskeletal, nuclear, and filament proteins

• Idiopathic ( 25% of DCMP, ? undiagnosed infectious, alcoholic, or genetic cause)

• Infectious myocarditis (10-15%, often due to immune rxn to infxn: nejm 2000.343:1388)

Viruses (coxsackie, adeno. echovirus. CMV): subacute (dilated LV w/ mod dysfxn) to fulminant (nondilated. thickened, edematous LV w/ severe dysfxn) Bacterial, fungal, rickettsial,TB. Lyme (mild myocarditis, often with AVB) HIV: 8% of asx HIV ©;due to HIV vs. other viruses vs. meds (nejm 1998:339:1093) Chagas: apical aneurysm • thrombus. RBBB. megaesophagus or colon (nejm 1993:329:639)

Alcohol (5%) typically 7-8 drinks/d < >5 y. but much interindividual variability Anthracyclines (risk t as dose >550 mg/m:. may manifest late); cyclophosphamide Cocaine, antiretrovirals. lead. CO. radiation

• Infiltrative (5%): often mix of DCMP • RCMP (qv) with thickened wall.

amyloidosis, sarcoidosis, hemochromatosis

• Autoimmune

Collagen vascular disease (3%): polymyositis. SLE. scleroderma. PAN. RA. Wegener's Peripartum (last month 5 mos postpartum): 0.1% of preg.; t risk w/ multiparity &

! age; -50% will improve; ? T risk w/ next preg. (jama 2000:283:1183) Idiopathic giant cell: avg age 42 y. fulminant myocarditis.VT (nejm 1997:336:1860) Eosinophilic (variable peripheral eosinophilia): hypersensitivity (mild CHF) or acute necrotizing (STE. effusion, severe CHF)

• Stress-induced ("Takotsubo." apical ballooning): mimics Ml with pain, - STE. • T Tn;

deep TWI & f QT; mid/apical dyskinesis; usually improve over 1-2 wks (Ntyw 2005:351539)

• Tachycardia-induced: likelihood proportional to rate and duration

• Metabolic & other: hypothyroidism, acromegaly, pheo, thiamine, sleep apnea Clinical manifestations

• Heart failure: both congestive & poor forward flow sx; signs of L- & R-sided HF

diffuse, lat.-displaced PMI. Sj. • MR or TR (annular dilat, displaced pap. muscle)

• Embolic events (10%), arrhythmias & palpitations

• Chest pain on exertion seen in up to one-third (even with no CAD) Diagnostic studies and workup

• CXR: moderate to marked cardiomegaly. • pulmonary edema & pleural effusions

• ECG: may see PRWP. Q waves, or BBB; low voltage; AF (20%)

• Echocardiogram: LV dilatation, I EF. regional or global LV HK. • RV HK. - mural thrombi

• Laboratory evaluation:TFTs, iron studies. HIV. SPEP.ANA; others per clinical suspicion

• Stress test: completely 0 test useful to r/o ischemic etiology (low false © rate), but s © test does not rule in ischemic etiology (high false © rate, even wI imaging)

• Coronary angiography to r/o CAD if risk factors, hlo angina. Qw Ml on ECG. equivocal ETT

• ? Endomyocardial biopsy (Oc 1989:79:971; On Ret Card 2006:95:569)

yield 10% (of these. 75% show myocarditis. 25% show evidence of systemic disease) 40% false © rate (patchy disease) and false © (necrosis inflammation) no proven Rx for myocarditis;.. biopsy for prognosis or if suspect systemic disease

• Cardiac MRI: detect myocarditis or infiltrative disease, but nonspecific (ehj 2005:26:1461) Treatment

• Standard HF therapy (see "Heart Failure")

• Implantation of devices may be tempered by possibility of reversibility of CMP

• Immunosuppression: used for giant-cell myocarditis (prednisone • AZA), collagen vascular disease, peripartum (? IVIg). and eosinophilic; no proven benefit for viral myocarditis

Hypertrophic Cardiomyopathy (HCMP)

Definition and epidemiology

• LV (usually mm) and/or RV hypertrophy disproportionate to hemodynamic load

• Prevalence: 1 case/500 population; 50% sporadic. 50% familial

• Differentiate from 2° LVH: hypertension (espec. elderly women; nejm 1985:312.277).AS, elite athletes (wall thickness usually <13 mm & symmetric and nl/T rates of tissue Doppler diastolic relaxation; NEjM 1991:324:295) Pathology

• Autosomal dominant mutations in genes encoding cardiac sarcomere proteins

• Myocardial fiber disarray with hypertrophy

• Morphologic hypertrophy variants: asymmetric septal; concentric; mid-cavity; apical Pathophysiology

• Subaortic outflow obstruction: narrowed tract 2° hypertrophied septum ♦ systolic anterior motion (SAM) of ant. MV leaflet V Venturi forces (may be fixed, variable, or nonexistent) and papillary muscle displacement. Gradient (V) worse w/ i contractility (digoxin, 0-agonists), i preload, or i afterload.

• Mitral regurgitation: due to SAM (mid-to-late, post-directed regurg. jet) and abnormal mitral leaflets and papillary muscles (pansystolic, ant-directed regurg. jet)

• Diastolic dysfunction: * chamber stiffness -» impaired relaxation

• Ischemia: small vessel dz. perforating artery compression (bridging). 1 coronary perfusion

• Syncope: As in load-dependent CO. arrhythmias

Clinical manifestations (70% are asymptomatic at dx)

• Dyspnea (90%): due to T LVEDP. MR. and diastolic dysfunction

• Angina (25%) even in absence of epicardial CAD; microvasc. dysfxn (NE/m 2003:349:1027)

• Arrhythmias (AF in 20-25%;VT/VF) — palpitations, syncope, sudden cardiac death Physical exam

• Sustained PMI. $2 paradox, split if severe outflow obstruction. © Sa (occ. palpable)

• Systolic crescendo-decrescendo murmur at LLSB: 1 w/Valsalva & standing

• • mid-to-late or holosystolic murmur of MR at apex

• Bisferiens carotid pulse (brisk rise, decline, then 2nd rise); JVP w/ prominent a wave

• Contrast to AS. which has murmur that i w/Valsalva and I carotid pulses

Diagnostic studies

• ECG: LVH. anterolateral and inferior pseudo-Qw. _t apical giant TWI (apical variant)

• Echocardiogram: no absolute cutoffs for degree of LVH but sePtum ^1,3 suggestive post wall as is septum >15 mm; other findings include dynamic outflow obstruction. SAM. MR

• Cardiac cath: subaortic pressure V; ftrockenbrough sign I pulse press, postextrasystole

(in contrast to AS. in which pulse pressure I postextrasystole)

• Annual echo. 48-h Holter. & exercise testing for risk stratification once dx is made

Treatment (Nejm 2004.350:1320)

• Heart failure

G inotropes/chronotropes: (i-blockers, CCB (verapamil), disopyramide. Careful use of diuretics. Vasodilators only if systolic dysfxn. Avoid digoxin. If refractory to drug therapy and there is obstructive physiology (V >50 mmHg):

a) Alcohol septal ablation (NijM 2002:347.1326)

triphasic V response: acute i — = partial 1 back to 50% of baseline i over mos by 6-12 mos achieve resting V -16 mmHg & stress-induced V 45 mmHg complications: RBBB; transient 3° AVB w/ 10-20% req. PPM: VT

b) Surgical myotomy-myectomy: long-term sx improvement in 90% (Ore 2005:112:482) cj ? Dual-chamber pacing, but large placebo effect (jacc 1997:29:435: Ore 1999:99 2927)

If refractory to drug therapy and there is nonobstructive pathophysiology: transplant

• AF: rate control with {J-blockers. maintain SR with disopyramide. amiodarone. sotalol

• Sudden cardiac death: ICD tfACC 2003:42:1687). Major risk factors include history of VT/VF.

© FHx SCD. unexplained syncope. NSVT, hypotension w/ exercise, LV wall -30 mm; V ^30 mmHg; high-risk mutations

• Counsel to avoid dehydration, extreme exertion

• Endocarditis prophylaxis

• First-degree relatives: periodic screening w/ echo (as timing of HCMP onset variable)

Restrictive Cardiomyopathy (RCMP)

Definition

• Impaired ventricular filling due to 1 compliance

Etiology (NE}M 1997:336:267)

• Myocardial processes autoimmune (scleroderma, polymyositis-dermatomyositis) infiltrative diseases (see primary entries for extracardiac manifestations. Dx. Rx) amyloidosis: age at present. 60 y; male:female 3:2

AL (MM. light-chain disease. WM); familial (transthyretin.TTR); senile (TTR. ANP) ECG: 1 QRS amplitude (70%). pseudoinfarction pattern (Qw). AVB (10-20%). hemiblock (20%). BBB (5-20%) Echo: biventricular hypertrophy, granular sparkling texture (65%), biatrial enlargement, valve thickening (65%). small effusion normal voltage & normal septal thickness has NPV 90% sarcoidosis: age at present. 30 y, more common in blacks. N. Europeans, women 5% of those with sarcoid w/ overt cardiac involvement; cardiac w/o systemic in 10% ECG: AVB (75%). RBBB (20-60%), VT

Echo: regional WMA (particularly basal septum) with thinning or mild hypertrophy nuclear imaging: gallium uptake in areas of sestaMIBI perfusion defects hemochromatosis: presents in middle-aged men (particularly N. European) storage diseases (Gaucher's. Fabry's, Hurler's, glycogen storage diseases) diabetes mellitus idiopathic fibrosis

• Endomyocardial processes chronic eosinophilic: Loffler's endocarditis (temperate climates; t eos.; mural thrombi that embolize); endomyocardial fibrosis (tropical climates; var. eos.: mural thrombi) toxins (radiation, anthracyclines) serotonin (carcinoid, serotonin agonists, ergot alkaloids) metastatic cancer

Pathology & pathophysiology

• Normal or 1 wall thickness * infiltration or abnormal deposition

• I myocardial compliance -» nl EDV but i EDP -»* systemic & pulm. venous pressures

• A ventricular cavity size -♦ 1 SV and I CO Clinical manifestations

• Right-sided > left-sided heart failure with peripheral edema dyspnea

• Diuretic "refractoriness"

• Thromboembolic events

• Poorly tolerated tachyarrhythmias

Physical exam

• T JVP, • Kussmaul's sign (classically seen in constrictive pericarditis)

• Congestive hepatomegaly, r ascites and jaundice, peripheral edema Diagnostic studies

• CXR: normal ventricular chamber size, enlarged atria. • pulmonary congestion

• ECG: low voltage, pseudoinfarction pattern (Qw). i arrhythmias

• Echo: symmetric wall thickening, biatrial enlarge., ± mural thrombi. • cavity obliteration diastolic dysfxn: t early diastolic (E) and J late atrial (A) filling. T E/A ratio. I decel. time

• Cardiac MRI: may reveal inflammation or evidence of infiltration (although nonspecific)

• Cardiac catheterization atria: M's or W's (prominent x and y descents)

ventricles: dip & plateau (rapid 1 pressure at onset of diastole, rapid * to eariy plateau) concordance of LV and RV pressure peaks during respiratory cycle (vs. discordance in constrictive pericarditis; Ok 1996.93 2007)

• Endomyocardial biopsy if suspect infiltrative process

• Restrictive cardiomyopathy vs. constrictive pericarditis: see "Pericardial Disease"

Treatment (in addition to Rx'ing underlying disease)

• Gentle diuresis

• Control HR and maintain SR (important for filling). Dig pro-arrhythmic in amyloid.

• Anticoagulation (particularly with AF or low CO)

• Transplantation for refractory cases

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