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
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 assessed by the MRI and echocardiogram 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. Dilated cardiomyopathy is treated the same way that congestive heart failure is.

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

FIRE: Focused Initial Rapid Evaluation

A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients with signs and symptoms of severe acute decompensated heart failure who require immediate intervention.

Boxes in red signify that an urgent management is needed.

Abbreviations: BU: Blood urea nitrogen; COPD: Chronic obstructive pulmonary disease; D5W: 5% dextrose solution in water ; HF: Heart failure; IV: Intravenous; MAP: Mean arterial pressure; Na: Sodium; NSAID: Non steroidal anti-inflammatory drug; SBP: Systolic blood pressure; S3: Third heart sound;

Identify cardinal findings that increase the pretest probability of acute decompensated heart failure ❑ Dyspnea ❑ Cool extremities ❑ Peripheral edema ❑ Decreased urine output ❑ Past medical history of heart failure ❑ History of orthopnea and paroxysmal nocturnal dyspnea ❑ Pulmonary crepitations/rales/crackles ❑ Third heart sound (S3)

Does the patient have any of the following findings that require hospitalization and urgent management? ❑ Severe decompendated HF: ❑ Hypotension (either SBP < 90 mmHg or drop in MAP >30 mmHg) and/or cardiogenic shock ❑ Altered mental status ❑ Cold and clammy extremities ❑ Urine output <0.5mL/kg/hr ❑ Dyspnea at rest manifested by tachypnea or oxygen saturation <90% ❑ Atrial fibrillation with a rapid ventricular response resulting in hypotension ❑ Acute coronary syndrome ❑ Chest pain or chest discomfort ❑ Sudden onset ❑ Sensation of heaviness, tightness, pressure, or squeezing ❑ Duration> 20 minutes ❑ Radiation to the left arm, jaw, neck, right arm, back or epigastrium ❑ No relief with medications ❑ No relief with rest ❑ Worse with time ❑ Worse with exertion ❑ Palpitations ❑ Nausea ❑ Vomiting ❑ Sweating

Yes

No

Admit to a level of care that allows for constant ECG monitoring

Proceed to complete diagnostic approach

Initial Stabilization: ❑ Assess the airway ❑ Position the patient upright at an angle of 45 degrees, with legs dangling off the bedside (decrease preload) ❑ Monitor heart failure and blood pressure continuously ❑ Monitor oxygen saturation continuously ❑ If hypoxemia is present (Sa02 < 90% or Pa02 <60 mmHg), administer oxygen with/without noninvasive ventilation ❑ Secure intravenous access with 18 gauge cannula ❑ Monitor fluid intake and urine output carefully to guide diuretic dose titration)

Assess Congestion and Perfusion: Congestion at rest (dry vs. wet) "Wet" suggested by orthopnea, ↑JVP, rales, S3, pedal edema Low perfusion at rest (warm vs. cold) "Cold" suggested by narrow pulse pressure, cool extremities, hypotension The patient is: ❑ Warm and dry, OR ❑ Warm and wet, OR ❑ Cold and dry, OR ❑ Cold and wet

Identify precipitating factor and treat accordingly: Click on the precipitating factor for more details on the management ❑ Acute coronary syndrome ❑ Myocarditis ❑ Renal failure ❑ Hypertensive crisis ❑ Non adherence to medications ❑ Worsening Aortic stenosis ❑ Drugs (NSAIDS, thiazides, calcium channel blocker, beta blockers) ❑ Toxins (alcohol, anthracyclines) ❑ Atrial fibrillation Rate control of atrial fibrillation is the mainstay of arrhythmia therapy. Avoid the use of drugs with negative inotropic effects such as beta blockers and non-dihydropyridine calcium channel blockers e.g., verapamil in the treatment of acute decompensated systolic heart failure Consider cardioversion if the patient is in cardiogenic shock or if new onset atrial fibrillation is the clear precipitant of the hemodynamic decompensation ❑ COPD ❑ Pulmonary embolism ❑ Anemia ❑ Thyroid abnormalities ❑ Systemic infection

Manage the patient's acute symptoms Chest Pain ❑ Administer morphine IV to reduce symptom severity. ❑ Initial dose 4-8 mg ❑ 2-8 mg every 5 to 15 minutes, as needed Congestiona and Volume Status Diuretics ❑ Administer IV loop diuretics as intermittent boluses or continuous infusion (I-B) ❑ If patient is already on loop diuretics: Rule of thumb: Administer IV dose with total daily dose = 2.5 x usual daily PO dose ❑ Generally, administer IV furosemide bolus dose 40 mg IV for patients with normal renal function. ❑ If patient is not already on loop diuretics, administer IV starting dose: Furosemide 20 to 40 mg (most common), OR Torsemide 5 to 10 mg, OR Bumetanide 0.5 to 1 mg ❑ Evaluate adequacy of diuresis. For furosemide, adequate diuresis is defined as urine output > 1L/2hours following IV administration. ❑ If not adequate, increase furosemide IV dose to 80 mg. Re-evaluate diuresis adequacy in the following 2 hours post-administration. ❑ Titrate dose until adequate diuresis is achieved. Once achieved, administer the dose at a twice daily rate. ❑ Perform serial assessment of fluid input and output, vital signs, daily body weight (measured every day, with the same scale, at the same time, after first void) and symptoms ❑ Order daily electrolytes, BUN, creatinine (I-C) ❑ Low sodium diet (<2 g daily) ❑ In case of persistent symptoms: ❑ Add a second diuretics, such as thiazide (preferably metolazone) (I-B) ❑ Metolazone PO dose: 2.5 - 10 mg once daily (there is no IV preparation for metolazone) ❑ Reassess diuresis adequacy several hours (2 to 9) following metolazone administration. ❑ Consider low dose dopamine infusion for improved diuresis and renal blood flow (IIb-B) ❑ Consider renal replacement therapy/ultrafiltration in obvious volume overload (IIb-B) refractory to higher dose/combination of IV diuretics Maintenance of Diuresis ❑ Consider continuous infusion of furosemide following bolus administration. Infusion dose and rate vary according to the patient's creatinine clearance: ❑ CrCl > 75 ml/min: Administer furosemide infusion 100 mg loading dose with an initial infusion rate of 10 mg/hour. Maximum daily infusion rate is 240-360 mg/hour in non-elderly adults (170 mg/hour in elderly). ❑ CrCl= 25-75 ml/min: Administer furosemide infusion 100-200 mg loading dose with an initial infusion rate of 10-20 mg/hour. Maximum daily infusion rate is 240-360 mg/hour in non-elderly adults (170 mg/hour in elderly). ❑ CrCl < 25 ml/min: Administer furosemide infusion 200 mg loading dose with an initial infusion rate of 20-40 mg/hour. Maximum daily infusion rate is 240-360 mg/hour in non-elderly adults (170 mg/hour in elderly). ❑ Monitor urine output to achieve goal urine output > 100 mL/hour. Administer Venodilators ❑ Consider administration of IV nitroglycerin, nitroprusside, or nesiritide as add-on to diuretics to relieve dyspnes (IIb-A) Do not administer vesodilators among patients with hypotension. Manage Low Perfusion ❑ Administer inotropic agents (click here for details). If the patient is total body and intravascular volume overloaded in normotensive, then diuresis alone should be undertaken. If the patient is volume overloaded but hypotensive, then inotropes must be administered in addition to diuretics. Invasive Hemodynamic Monitoring ❑ Consider pulmonary artery catheterization in case of failure to respond to medical therapy, respiratory distress, shock, uncertainty regarding volume status, or increase in creatinine; assess the following parameters: ❑ PCWP ❑ Cardiac output ❑ Systemic vascular resistance Management of Hyponatremia ❑ Water restriction ❑ <2 L/day if Na is < 130 meq/L ❑ < 1 L/day or more if the Na is < 125 meq/L

Hospital Care Thromboprophylaxis ❑ Anticoagulation in the absence of contraindications (I-B) Hold Home Administered Chronic Medical Therapy ❑ Chronic ACE inhibitor: Hold if patient is hemodynamically unstable ❑ Chronic beta blocker: ❑ Hold if patient is hemodynamically unstable and/or in need or inotropes ❑ Decrease dose by ≥ half if patient is in moderate heart failure ❑ DO NOT INITIATE ACEI/ARBs during an acute decompensation ❑ DO NOT INITIATE BETA BLOCKER during an acute decompensation; initiate beta blockers at a low dose in stable patients following optimization of volume status and D/C of IV diuretics and inotropes (I-B) Monitor Laboratory Tests ❑ BUN daily ❑ Creatinine daily ❑ Creatinine daily

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 (at least 3 generations of 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 (S4; S3 associated with adverse prognosis, valvular heart disease?) ❑  Carvallo's sign (augmented murmurs of TR on inspiration) is frequently absent ❑  Orthostatic changes in blood pressure and heart rate (volume status/vasodilation?) ❑  Jugular venous pressure at rest and following abdominal compression (to identify congestion) ❑  ± Prominent V wave with brisk Y descent (suggestive of tricuspid regurgitation) ❑  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: nonspecific repolarization or conduction abnormalities, poor R wave progression, and LVH ❑  Chest x-ray: cardiomegaly, pulmonary venous redistribution, and pulmonary congestion ❑  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

Do's

• The initial diagnostic approach should aim to identify potentially reversible causes of left ventricular dysfunction. Pertinent history includes alcohol consumption, recent viral illness, coronary risk factors, and family history.

Dont's

• Endomyocardial biopsy should not be performed in the routine evaluation of patients with HF. Optimal timing of endomyocardial biopsy for patients unresponsive to medical therapy remains unclear.
• Nondihydropyridine calcium channel blockers with negative inotropic effects may be harmful in asymptomatic patients with low LVEF and no symptoms of HF after MI.

References