Dilated cardiomyopathy resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Steven Bellm, M.D. [2]

Dilated cardiomyopathy resident survival guide Microchapters
Overview
Causes
Diagnosis
Treatment
Do's
Dont's

Overview

Dilated cardiomyopathy (DCM) relates to a group of heterogeneous myocardial disorders and is characterized by dilatation and impaired contraction and systolic function of the left or both ventricles. Atrial and/or ventricular arrhythmias can occcur, and there is a risk for sudden death. The weight of the heart is increased but the maximal thicknesses of the left ventricular free wall and septum are usually normal as a result of the abnormally dilated chambers.

Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Life-threatening causes:

• Carbon monoxide poisoning

• Common causes:

• Idiopathic
• Myocarditis
• Ischemic heart disease
• Infiltrative disease
• Peripartum cardiomyopathy
• Hypertension
• Human immunodeficiency virus (HIV) infection
• Connective tissue disease
• Substance abuse
• Doxorubicin
• Other

Complete Diagnostic Approach

A complete diagnostic approach should be carried out after a focused initial rapid evaluation is conducted and following initiation of any urgent intervention.

Symptoms of heart failure

History and symptoms: ❑  Hints for etiology (family history, and others) ❑  Duration and onset of illness ❑  Severity and triggers of dyspnea and fatigue, presence of chest pain, exercise capacity, physical activity, sexual activity (NYHA?) ❑  Weight loss/weight gain (cachexia/volume overload?) ❑  Palpitations/(pre)syncope/ICD shocks(adverse prognosis) ❑  Symptoms of transient ischemic attack or thromboembolism (anticoagulation necessary?) ❑  Presence of peripheral edema or ascites (volume overload?) ❑  Problems with breathing at night/ sleep ❑  Medical history: ❑  Prior hospitalizations for HF (adverse prognosis?) ❑  Discontinuation of medications (reasons?) ❑  Medications that may exacerbate HF ❑  Diet (restriction of sodium and fluid intake?)

Physical examination: ❑  Vital signs: ❑  Pulse (strength and regularity?) ❑  Blood pressure (supine and upright) to reflect adequacy of cardiac output ❑  Respiratory rate ❑  General appearance: ❑  BMI(weight loss/weight gain) ❑  Peripheral edema ❑  Heart: ❑  Extra heart sounds and murmurs (S³ associated with adverse prognosis, valvular heart disease?) ❑  Orthostatic changes in blood pressure and heart rate (volume status/vasodilation?) ❑  Jugular venous pressure at rest and following abdominal compression (to identify congestion) ❑  Size and location of point of maximal impulse (ventricular enlargement?) ❑  Right ventricular heave (right ventricular dysfunction and/or pulmonary hypertension?) ❑  Lungs: ❑  Rales ❑  Pleural effusion ❑  Abdomen: ❑  Hepatomegaly and/or ascites (volume overload) ❑  Extremities: ❑  Temperature of lower extremities

Laboratory findings: ❑  Complete blood count ❑  Chemistry: ❑  Troponin, BNP or NT-proBNP ❑  Serum electrolytes (including calcium and magnesium) ❑  Blood urea nitrogen ❑  Serum creatinine ❑  Glucose ❑  Fasting lipid profile ❑  Liver function tests ❑  Thyroid-stimulating hormone ❑  Consider Screening for hemochromatosis, HIV, rheumatologic diseases, amyloidosis, or pheochromocytoma ❑  Urinalysis

Imaging and additional tests: ❑  Noninvasive imaging: ❑  ECG ❑  Chest x-ray (heart size, pulmonary congestion and alternative cardiac, pulmonary, and other diseases?) ❑  2-dimensional echocardiogram with Doppler (ventricular function, size, wall thickness, wall motion, and valve function?) ❑  Repeat measurement of EF and severity of structural remodeling (after significant change in clinical status, after clinical event, after treatment or if candidates for device therapy) ❑  Cardiac-MRI (ventricular size, wall/muscle thickness, valves, pericardium, wall motion, etc.) ❑  Consider check for myocardial ischemia and viability for patients with known CAD and no angina ❑  Viability assessment when planning revascularization in HF patients with CAD ❑  Radionuclide ventriculography or magnetic resonance imaging can be useful to assess LVEF and volume when echocardiography is inadequate ❑  Consider magnetic resonance imaging when assessing myocardial infiltrative processes or scar burden ❑  Invasive imaging: Consider invasive Imaging only in specific cases. ❑  Invasive hemodynamic monitoring with a pulmonary artery catheter to guide therapy in patients with respiratory distress or clinical evidence of impaired perfusion if the adequacy or excess of intracardiac filling pressures cannot be determined from clinical assessment ❑  Careful consideration of invasive hemodynamic monitoring for patients: ❑  With persistent symptoms despite empiric adjustment of standard therapies ❑  If fluid status, perfusion, or systemic or pulmonary vascular resistance is uncertain ❑  Systolic pressure remains low, or is associated with symptoms, despite initial therapy ❑  If renal function is worsening with therapy ❑  If parenteral vasoactive agents are required ❑  If consideration for MCS or transplantation ❑  If ischemia contributes to HF coronary arteriography for patients who are eligible for revascularization ❑  Endomyocardial biopsy: ❑  Consider if a specific diagnosis is suspected that would influence therapy ❑  Consider if rapidly progressive clinical HF or worsening ventricular dysfunction that persists despite appropriate medical therapy ❑  Consider if suspicion of an acute cardiac rejection status after heart transplantation or a myocardial infiltrative processes ❑  Coronary angiography: ❑  Consider for patients with HF and angina, or without angina but with LV dysfunction ❑  In patients with known CAD and angina or with significant ischemia diagnosed by ECG or noninvasive testing and impaired ventricular function ❑  CAD should be considered as a potential etiology of impaired LV function and should be excluded wherever possible among those without prior diagnosis

Examples for specific findings for dilated cardiomyopathy: ❑  Echo (dilated left and/or right ventricle, global hypokinesis with left ventricular ejection fraction under 40% ❑  no specific cause identified ❑  coronary angiography shows no severe disease

Rapidly progressive symptoms (within 1 month)? And/or new ventricular tachycardia? Or conduction abnormalities? And/or suspected myocarditis?

Yes

No

Consider endomyocardial biopsy

Treat with conventional heart failure medications

Clinical improvement after 1 week?

Yes

No

Continue conventional heart failure treatment

Consider endomyocardial biopsy

The timing of endomyocardial biopsyis if patients fail to improve on medical therapy is controversial.

Treatment

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Do's

Dont's

❑  Endomyocardial biopsy should not be performed in the routine evaluation of patients with HF

References