Snapshot A 60-year-old man presents to his cardiologist for worsening shortness of breath and easy fatigability. He began developing symptoms a few months prior to presentation. His shortness of breath is most significant with exertion and he notes having swollen feet. His medical history includes hypertension, hyperlipidemia, alcohol use disorder. He currently takes hydrochlorothiazide and atorvastatin. On physical exam, an S3 heart sound and a systolic regurgitant murmur is appreciated on cardiac auscultation. An echocardiogram shows markedly dilated ventricles with a reduced ejection fraction. Summary Dilated cardiomyopathy (DCM) is the most common type of cardiomyopathy. It is caused by cardiac chamber dilation and systolic dysfunction. The condition typically presents in adults with symptoms of fatigue, dyspnea, edema, and decreased exercise tolerance. Diagnosis is made based on assessment of ventricular dilation and systolic dysfunction while ruling out other causes. Echocardiography can confirm diagnosis by visualizing ventricular changes. Treatment usually consists of addressing the underlying cause of DCM. In severe cases, operative treatment including cardioverter defibrillator, ventricular assist devices, and heart transplantation are considered. Epidemiology Incidence most common cardiomyopathy 90% of all cardiomyopathies common 6/100,000 Demographics 1.5:1 male:female overall DCM 3:1 male:female idiopathic DCM Location cardiac chambers Risk Factors heavy alcohol consumption toxins cocaine amphetamine doxurubicin autoimmune disease systemic lupus erythematosus sarcoidosis stress Takutsubo cardiomyopathy or broken heart syndrome infectious viral parvovirus B19 HSV 6 coxsackievirus influenza virus adenovirus echovirus cytomegalovirus HIV Chagas disease Lyme disease inherited syndromes hemochromatosis pregnancy obstructive sleep apnea Etiology Pathogenesis eccentric hypertrophy underlying causative disease process reduces the contractility of myocardium myocardium stretches and results in left ventricle (LV) dilation ↑ end-diastolic volume (EDV) (preload) results in ↓ EF ↓ ejection fraction (EF) dilation leads to decreased LV contractility leads to left heart failure over time this results in right heart failure Pathoanatomy sarcomeres are added in series results in thinning and stretching of myocardium primarily affects LV and atria Anatomy Cardiac walls are stretched and thinned results in enlarged ventricles Presentation Symptoms progressive congestive heart failure dyspnea on exertion orthopnea paroxysmal nocturnal dyspnea fatigue pulmonary edema Physical exam inspection jugular venous distention peripheral edema ascites auscultation S3 gallop systolic regurgitant murmur secondary to mitral valve regurgitation or tricuspid valve regurgitation pulmonary rales Imaging Radiography chest x-ray indications for all patients with clinical suspicion findings cardiomegaly heart looks like a balloon pulmonary congestion Echocardiogram indications for all patients best initial test to assess ejection fraction findings ventricular dilation with of without atrial dilation reduced ejection fraction can see wall motion abnormalities in cases with underlying pathologies Cardiac MRI indications suspicion of infiltrative DCM evaluation of cardiac function and morphology findings myocardial edema disease-specific pattern of gadolinium enhancement Studies Electrocardiography (ECG) indications for all patients screen first-degree relatives of patients with familial DCM findings may have bundle branch block may have widened QRS Labs CBC, CRP, ESR indications evaluate for signs of infection or inflammation findings elevated in cases of infection or pericarditis cardiac enzymes indications to assess for myocardial damage findings elevated in cases of myocardial infarction Genetics indications suspected familial or idiopathic DCM family members of DCM patients with an identified genetic etiology findings discovery of underlying disease Diagnosis Based on LV dilation and reduce EF as demonstrated by echocardiography. Differential Restrictive cardiomyopathy distinguishing factors Kussmaul sign on physical exam electrocardiogram with low voltages Hypertrophic cardiomyopathy distinguishing factors echocardiogram with normal ejection fraction S4 gallop on physical exam Treatment Goals treat underlying cause of DCM treat CHF if present Medical drugs that lower mortality angiotensin converting enzyme inhibitors (ACE inhibitors) indication for all patients β-blockers indication for all patients drugs with mortality benefits metoprolol carvedilol bisoprolol spironolactone or eplerenone indications for all patients decreases work of the heart cessation of alcohol indications for all patients Operative automatic implantable cardioverter/defibrillator (AICD) indications ejection fraction < 35% biventricular pacemaker indications QRS > 120 ms with a widened QRS, the 2 ventricles are not in synchrony a biventricular pacemaker will resynchronize the 2 ventricles heart transplant indications the only definitive treatment Techniques automatic implantable cardioverter/defibrillator (AICD) approach evaluate patient suitability, select appropriate candidates, and address underlying heart conditions technique insert leads into the heart chambers via veins position the device in a subcutaneous pocket confirm proper lead placement and device functionality complications infection lead-related issues bleeding pneumothoraxarrhythmias, allergic reactions, device malfunction, and potential migration of the device or leads arrhythmias potential migration of the device or leads biventricular pacemaker approach assess patient suitability, select appropriate candidates, and address the specific heart condition and conduction abnormalities technique position leads in the right atrium, right ventricle, and coronary sinus synchronize to optimize ventricular contraction and improve cardiac output complications infection lead-related issues bleeding pneumothorax arrhythmias potential for migration of leads, as well as the need for ongoing device monitoring and adjustments heart transplant approach meticulous patient evaluation, donor organ matching, and comprehensive preoperative preparation to ensure optimal outcomes technique remove the recipient's diseased heart and implant a healthy donor heart connect major blood vessels and ensuring proper blood flowmeticulous postoperative care meticulous postoperative care complications graft rejection infection organ failure complications related to immunosuppressive medications vascular issues need for ongoing post-transplant monitoring and management Complications Heart failure Thromboembolism Prognosis Around 50% of patients die within 2 years from heart failure or arrhythmias