Heart failure resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mahmoud Sakr, M.D. [2]; Ayokunle Olubaniyi, M.B,B.S [3]

Acute Heart Failure Resident Survival Guide Microchapters
Overview
Classification
Causes
FIRE
Diagnosis
Treatment Stage C Stage D Diuretic Therapy Medications
Prevention Stage A & B
Do's
Don'ts

Overview

Heart failure is a complex syndrome in which there is inadequate forward cardiac output to meet the metabolic demands of the body. Acute heart failure can be either the first presentation of new heart failure or as an exacerbation of chronic heart failure. The clinical presentation may include dyspnea, swelling of the legs, fatigue, and rales on physical examination. The diagnosis is mainly clinical, coupled with laboratory evaluations such as chest X-ray, EKG, echocardiography, and the measurement of the B-type natriuretic peptide (BNP). The aim of the treatment is relief of symptoms through the administration of oxygen, diuresis and morphine as well as the reduction of morbidity and mortality through the administration of ACE inhibitors or angiotensin II receptor blockers, beta blockers, aldosterone antagonists, and hydralazine/nitrate.

Classification

Based on the Severity of Congestive Heart Failure

The New york Heart Association (NYHA) assessment of heart failure severity is often used to guide treatment:

NYHA classification	Description
I	No limitation of physical activity. Ordinary physical activity does not cause symptoms of heart failure (HF)
II	Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in symptoms of HF
III	Marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes symptoms of HF
IV	Unable to carry on any physical activity without symptoms of HF, or symptoms of HF at rest

NYHA - New York Heart Association

Based on the Stage of Heart Failure

ACCF/AHA Stages	Description
A	At high risk for heart failure (HF) but without structural heart disease or symptoms of HF
B	Structural heart disease but without signs or symptoms of HF
C	Structural heart disease with prior or current symptoms of HF
D	Refractory HF requiring specialized interventions

ACCF - American College of Cardiology Foundation; AHA - American Heart Association

Based on Left Ventricular Ejection Fraction (LVEF)

• Heart failure with preserved ejection fraction (HFpEF) or diastolic heart failure: ejection fraction ≥ 50%
• Heart failure with reduced ejection fraction (HFrEF) or systolic heart failure: ejection fraction ≤ 40%

Causes

Life Threatening Causes

Acute decompensated heart failure is life threatening and should be treated as such irrespective of the underlying cause.

Common Causes

• Acute coronary syndrome
• Acute kidney injury
• Acute severe myocarditis
• Cardiac arrhythmias
• Cardiomyopathy
• Cardiotoxic agents - alcohol, cocaine
• Decompensation of an underlying chronic heart failure
• Hypertensive crisis
• Pulmonary embolus
• Systemic Inflammatory response syndrome
• Valvular heart disease

Click here for the complete list of causes.

FIRE: Focused Initial Rapid Evaluation

A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention.

Boxes in red signify that an urgent management is needed.

Abbreviations: MAP: Mean arterial pressure; NYHA: New York Heart Association; SBP: Systolic blood pressure;

Identify cardinal signs and symptoms that increase the pretest probability of acute heart failure ❑ Past medical history of heart failure ❑ History of orthopnea and paroxysmal nocturnal dyspnea ❑ Symptoms ❑ Dyspnea ❑ Chest pain ❑ Signs ❑ Pulmonary crepitations/rales/crackles ❑ Cool extremities ❑ Peripheral edema ❑ Third heart sound (S3)

Does the patient have any of the following findings that require urgent management? ❑ Hypotension (SBP < 90 mmHg or drop in MAP >30 mmHg) ❑ Altered mental status ❑ Cold and clammy extremities ❑ Oliguria (urine output <0.5mL/kg/hr) ❑ Metabolic acidosis

Yes

No

Treat cardiogenic shock ❑ Admit to intensive care unit (ICU) or coronary care unit (CCU) for closer monitoring ❑ Initiate oxygen therapy ❑ For SBP 85 - 100 mm Hg ❑ Consider dobutamine or milrinone ❑ For SBP < 85 mm Hg ❑ Consider dopamine and norepinephrine ❑ Consider intra-aortic balloon pump, if hypotension persists ❑ Consider left ventricular assist devices Click here for cardiogenic shock resident survival guide

Does the patient have severe symptoms of heart failure? ❑ NYHA class III ❑ Marked limitation of physical activity ❑ Comfortable at rest, but less than ordinary activity causes symptoms of HF ❑ NYHA class IV ❑ Unable to carry on any physical activity without symptoms of HF, or symptoms of HF at rest

Yes

No

Urgent treatment ❑ Diuretic therapy (click for details) ❑ Administer IV morphine ❑ Administer oxygen by: ❑ Non-rebreather face masks ❑ Continuous positive airway pressure ❑ Noninvasive positive pressure ventilation (NPPV) ❑ Mechanical ventilation (PEEP) ❑ Administer IV vasodilators e.g.,nitroglycerin, nesiritide

Continue with the complete diagnostic approach below

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.

Abbreviations: ARDS: Acute respiratory distress syndrome; BNP: B-type natriuretic peptide; BUN: Blood urea nitrogen; CAD: Coronary artery disease; CBC: Complete blood count; CCB: Calcium channel blocker; CT: Computed tomography; CXR: Chest x-ray; DM: Diabetes mellitus; EKG: Electrocardiogram; HTN: Hypertension; LVEF: Left ventricular ejection fraction; LVH: Left ventricular hypertrophy; MI: Myocardial infarction; MRI: Magnetic resonance imaging; NT-pro BNP: N-terminal pro-brain natriuretic peptide; OCPs: Oral contraceptive pills; PAWP: Pulmonary artery wedge pressure TSH: Thyroid stimulating hormone

Characterize the symptoms: Symptoms of fluid accumulation ❑ Dyspnea ❑ At rest ❑ Exertional ❑ Paroxysmal nocturnal dyspnea ❑ Orthopnea ❑ Cough ❑ Peripheral edema ❑ Ascites Symptoms of reduced cardiac output ❑ Fatigue ❑ Oliguria ❑ Dizziness ❑ Syncope ❑ Altered mental status ❑ Cyanosis ❑ Abdominal pain (suggestive of mesenteric ischemia) Symptoms suggestive of precipitating events ❑ Chest pain (if myocardial ischemia is present) ❑ Palpitations (suggestive of arrhythmias) ❑ Fever (suggestive of sepsis) Nonspecific symptoms ❑ Anorexia ❑ Bloating ❑ Nausea ❑ Weight loss Obtain a detailed history: ❑ Past medical history ❑ Atrial fibrillation ❑ Cardiomyopathy ❑ Diabetes mellitus ❑ Hypertension ❑ Myocarditis ❑ Previous myocardial infarction ❑ Prior heart failure ❑ Sleep apnea ❑ Thyroid disease ❑ Valvular heart disease ❑ Medication history ❑ Noncompliance with previously prescribed medications for heart failure ❑ Intake of the following drugs: ❑ Alcohol ❑ Beta blockers ❑ Calcium channel blockers like verapamil which can exacerbate CHF or diltiazem which can cause peripheral edema ❑ Chemotherapy drugs - anthracyclines ❑ NSAIDs wchich should not be given in CHF ❑ Thiazolidinedione ❑ Family history ❑ History of dilated cardiomyopathy ❑ Radiation to the chest

Examine the patient: General appearance: ❑ Ill-looking ❑ In respiratory distress ❑ Usually in upright sitting position Vitals: ❑ Temperature ❑ Fever (suggestive of underlying infection) ❑ Pulse ❑ Tachycardia ❑ Narrow pulse pressure (<25 mmHg) ❑ Blood pressure ❑ Hypotension (suggestive of circulatory collapse) ❑ Hypertension ❑ Respiration ❑ Tachypnea (commonest symptom) ❑ Pulse oximetry assure sat is > 90% Weight: ❑ Subtract 'dry weight' from current weight to quantitate extent of volume overload and edema Skin ❑ Cool and clammy, in hypoperfusion or cardiogenic shock ❑ Cyanosis, in severe hypoxemia ❑ Anasarca Neck examination: ❑ Jugular vein distention is often present Respiratory examination ❑ Tachypnea ❑ Wheeze (suggestive of cardiac asthma) ❑ Dullness at lung bases, suggestive of pleural effusion ❑ Crackles/crepitations/rales Cardiovascular examination ❑ Displaced apex beat (suggestive of enlarged left ventricle) ❑ Parasternal heave (suggestive of elevated right ventricular pressure) ❑ S3 (typical) or S4 or both ❑ New or changed murmur (suggestive of an underlying valvular heart diseases) ❑ Mitral regurgitation - Holosystolic murmur ❑ Aortic regurgitation - Decrescendo diastolic murmur ❑ Aortic stenosis - Crescendo-decrescendo systolic ejection murmur with ejection click Abdominal examination The following suggest volume overload and / or poor forward cardiac output: ❑ Hepatojugular reflux ❑ Hepatomegaly ❑ Ascites Extremity examination ❑ Pedal edema Neurological examination ❑ Altered mental status ❑ Syncope (suggestive of aortic stenosis or pulmonary embolism)

Order tests: Routine (Class I, level of evidence C) ❑ CBC (rule out anemia) ❑ Troponin ❑ Elevated in myocardial ischemia and acute cardiogenic pulmonary edema, particularly if CrCl is reduced ❑ Troponin T ≥0.1 ng/mL (associated with poor survival) ❑ Electrolytes ❑ Dilutional hyponatremia (with the presence of edema) ❑ Serum calcium ❑ Serum magnesium ❑ BUN, creatinine may be elevated due to poor renal perfusion ❑ Urinalysis ❑ Fasting blood sugar ❑ Fasting lipid profile ❑ Liver function tests ❑ TSH ❑ BNP or NT-pro BNP (if diagnosis is uncertain) Heart failure is unlikely if: ❑ BNP ≤ 100 pg/mL, or ❑ NT-pro BNP ≤ 300 pg/mL ❑ Chest X-ray (Class I, level of evidence C) ❑ Cardiomegaly (cardiothoracic ratio >50%) ❑ Cardiogenic pulmonary edema ❑ Kerley B lines ❑ Peribronchial cuffing ❑ Cephalization Chest X-ray findings in a patient with acute heart failure ❑ EKG ❑ Low QRS voltage due to electrically inert myocardium ❑ Arrhythmia (usually atrial fibrillation which carries a poor prognosis and requires slowing to improve filling & cardiac output) ❑ Poor R wave progression (suggestive of a prior MI) ❑ Left ventricular hypertrophy (consistent with a history of hypertension) ❑ Left bundle branch block (LBBB) due to prior MI, may result in dysynchrony ❑ Left atrial enlargement due to valvular dz or hypertension ❑ Non-specific ST segment and T wave changes may suggest ischemia ❑ 2-D echocardiography with Doppler (Class I, level of evidence C) ❑ Assess ventricular size, function, wall thickness, wall motion, and valve function ❑ Radionuclide ventriculography or MRI ❑ To assess LVEF and volume when echocardiography is inadequate ❑ To assess myocardial infiltrative processes or scar burden (MRI) ❑ Coronary angiography (in settings of ischemia) ❑ Pulmonary artery catheterization in respiratory distress or shock or to definitively assess volume status and tailor therapy Order additional tests to rule out other etiologies: ❑ ANA, rheumatoid factor (for rheumatologic diseases) ❑ Diagnostic tests for hemochromatosis, pheochromocytoma ❑ Endomyocardial biopsy (when myocarditis is suspected)

Consider alternative diagnoses: Alternative diagnoses Features Acute asthma ❑ Wheeze ❑ Reversal of symptoms following administration of bronchodilators ARDS ❑ Severe hypoxia ❑ Bilateral opacities on chest X-ray ❑ PCWP < 15 mmHg Pneumonia ❑ Fever, cough, sputum ❑ Consolidation on chest X-ray Pulmonary embolism ❑ Pleuritic chest pain, cough, S4 ❑ Risk factors: trauma, immobilization, smoking, OCPs ❑ Clot in pulmonary artery on CT pulmonary angiography

Assess the stage of heart failure using the ACCF/AHA staging system to guide chronic therapy

Stage A ❑ At high risk for heart failure ❑ Patients with HTN, DM, obesity, CAD, metabolic syndrome ❑ Family history of cardiomyopathy ❑ Patients using cardiotoxins AND ❑ No structural heart disease AND ❑ No symptom of heart failure

Stage B ❑ Patients with structural heart disease ❑ Previous MI ❑ LV remodelling LVH + low EF ❑ Family history of cardiomyopathy ❑ Asymptomatic valvular disease AND ❑ No sign or symptom of heart failure

Stage C ❑ Patients with structural heart disease AND ❑ Signs or symptoms of heart failure

Stage D ❑ Refractory heart failure ❑ Marked symptoms at rest ❑ Recurrent hospitalizations

Treatment

Initial stabilization: ❑ Assess the airway ❑ Position the patient upright at an angle of 45 degrees ❑ Check pulse oximetry ❑ If hypoxemia is present (Sa02 < 90% or Pa02 <60 mmHg) ❑ Give oxygen by: ❑ Non-rebreather face masks ❑ Continuous positive airway pressure ❑ Give IV morphine - no mortality benefit and generally not advisable, may relieve refractory symptoms though ❑ Continuous cardiac monitoring ❑ Intravenous access with 18 gauge IV ❑ Monitor vitals signs ❑ Monitor fluid intake and urine output

Consider admission if the following is present: ❑ Hypotension and/or cardiogenic shock ❑ Poor end-organ perfusion - worsening renal function, cold clammy extremities, altered mental status ❑ Hypoxemia - Sa02 ↓90% ❑ Atrial fibrillation with a rapid ventricular response resulting in hypotension ❑ Presence of an acute coronary syndrome

Treat precipitating causes/co-morbidities Click for detailed management ❑ Acute aortic/mitral regurgitation ❑ Acute coronary syndrome ❑ Anemia ❑ Aortic dissection ❑ Atrial fibrillation ❑ Hypertensive crisis ❑ Renal failure ❑ Sepsis

Assess hemodynamic and volume status ❑ 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

Warm & Dry ❑ Consider outpatient treatment ❑ Dietary sodium restriction (2-3 g daily) ❑ Smoking cessation ❑ Alcohol abstinence (≤2 standard drinks per day for men; ≤1 for women) ❑ ACE inhibitors or (ARBs) if LVEF is ≤ 40% ❑ Beta blockers ❑ Encourage exercise/physical activity

Warm & Wet ❑ Diuretic therapy ❑ Treat co-morbidities HTN, DM, CAD, AF

Cold & Wet ❑ CCU admission ❑ Invasive hemodynamic monitoring (arterial line, consider pulmonary catheter if volume status unclear) ❑ Intravenous inotropic drugs (e.g., dobutamine) ❑ Diuretic therapy while monitoring blood pressure ❑ IV vasodilators

Cold & Dry ❑ CCU admission ❑ Intravenous inotropic drugs (e.g., dobutamine) ❑ Persistent organ hypoperfusion (e.g., low urine output or persistent low SBP<85) ❑ Norepinephrine 0.2–1.0 mcg/kg/min, titrate for best response

General measures ❑ Low sodium diet ❑ Monitor blood pressure, congestion, oxygenation ❑ Ensure daily weights ❑ Intake and output charts ❑ Convert all IV diuretic to oral forms in anticipation of discharge ❑ Continue or initiate ❑ ACE inhibitors ❑ Beta blockers ❑ Omega-3 fatty acid ❑ Daily serum electrolytes, urea & creatinine ❑ DVT prophylaxis ❑ Influenza & pneumococcal vaccination ❑ Encourage physical activity in stable patients

Discharge and follow-Up ❑ Patient and family education ❑ Prior to discharge, ensure: ❑ Low salt diet ❑ Oral medication plan is stable for 24 hours ❑ No IV vasodilator or inotropic drugs for 24 hours ❑ Weighing scale is present in patient's home ❑ Smoking cessation counseling ❑ Follow-up clinic visit scheduled within 7 to 10 days ❑ Ambulation prior to discharge to assess functional capacity ❑ Telephone follow-up call usually 3 days post discharge

Diuretic Therapy Details

Evidence of volume overload

❑ Low sodium diet (<2 g daily) ❑ Free water restriction to <2 L/day if the Na is < 130 meq/L, and < 1 L/day or more if the Na is < 125 meq/L ❑ Initiate IV diuretics due to poor absorption from gut ❑ Frusemide 40 mg, or ❑ Torsemide 20 mg, or ❑ Bumetanide 1 mg Contraindications to IV Diuresis ❑ Hypotension and cardiogenic shock Note - Give a higher dose of IV diuretic in patients chronically on diuretic therapy (e.g., 2.5x their maintenance dose)

Symptomatic improvement?

Yes

No

Maintain current IV diuretic dose

Double IV diuretic dose and titrate according to patient's response or when the maximum dose is reached

No symptomatic improvement

Add ❑ Another diuretic e.g., IV chlorothiazide or oral metolazone or ❑ An aldosterone antagonist e.g., spironolactone or eplerenone, in post MI patients

Adjuvants to diuretics ❑ Low dose dopamine to preserve renal function and renal blood flow ❑ IV nitroprusside, nitroglycerin, or nesiritide for hemodynamically stable patients to relieve dyspnea ❑ Vasopressin antagonists (e.g. tolvaptan; start with 15mg orally daily)

No symptomatic improvement (refractory edema)

Ultrafiltration or dialysis

General measures ❑ Monitor BP, volume status, congestion ❑ Daily weights ❑ Intake and output charts ❑ Convert all IV diuretic to oral ❑ Daily serum electrolytes, urea & creatinine ❑ DVT prophylaxis

Primary Prevention

Does the patient have stage A or stage B of heart failure according to the ACCF/AHA staging system?

Yes, the patient has stage A Therapeutic goals: ❑ Promote healthy lifestyle ❑ Prevent CAD and comorbidities ❑ Prevent LV structural abnormalities

Yes, the patient has stage B Therapeutic goal: ❑ Prevent symptoms of heart failure

No, the patient does not belong to any of the stages No preventive therapy is needed

❑ Control HTN and lipid disorders ❑ ACE inhibitors or (ARBs) in patients with vascular disease or DM ❑ Statins ❑ Minimize risk factors ❑ Dietary sodium restriction (2-3 g daily) ❑ Smoking cessation ❑ Alcohol abstinence (≤2 standard drinks per day for men; ≤1 for women) ❑ Encourage exercise/physical activity

❑ ACE inhibitors or (ARBs) ❑ History of MI (Class I, level of evidence A) ❑ All patients with LVEF ≤40% (Class I, level of evidence A) ❑ Beta blockers ❑ Patients with MI and LVEF ≤ 40% (Class I, level of evidence B) ❑ Statins ❑ Patients with MI (Class I, level of evidence A) ❑ Implantable cardioverter defibrillator (ICD) to prevent sudden death in: ❑ Asymptomatic ischemic cardiomyopathy (Class IIa, level of evidence B) ❑ ≥ 40 day post-MI ❑ LVEF ≤ 30% ❑ On GDMT ❑ The use of CCBs e.g., verapamil and diltiazem in patients with LVEF ≤ 30%

Medications

Drug Class	Drug	Daily doses, maximum daily dose
Loop diuretics	Furosemide	20 to 40 mg once or twice, 600 mg max daily dose In HF patients on loop diuretic, the initial IV dose should be greater or equal to their chronic oral daily dose.
	Bumetanide	0.5 to 1.0 mg once or twice, 10 mg
	Torsemide	10 to 20 mg once, 200 mg
Thiazide diuretics	Chlorothiazide	250 to 500 mg once or twice, 1000 mg
	Hydrochlorothiazide	25 mg once or twice, 200 mg
	Metolazone	2.5 mg once, 20 mg
K+- sparing diuretic	Amiloride	5 mg once, 20 mg
	Spironolactone	12.5 to 25.0 mg once, 50 mg
	Triamterene	50 to 75 mg twice, 200 mg
ACE inhibitors	Enalapril	2.5 mg twice, 10 to 20 mg twice
	Lisinopril	2.5 to 5 mg once, 20 to 40 mg once
	Ramipril	1.25 to 2.5 mg once, 10 mg once
ARBs	Candesartan	4 to 8 mg once, 32 mg once
	Losartan	25 to 50 mg once, 50 to 150 mg once
	Valsartan	20 to 40 mg twice, 160 mg twice
Beta blockers	Bisoprolol	1.25 mg once, 10 mg once
	Carvedilol	3.125 mg twice, 50 mg twice
	Metoprolol succinate	12.5 to 25.0 mg once, 200 mg once
Aldosterone antagonists	Spironolactone	12.5 to 25.0 mg once, 25 mg once or twice
	Eplerenone	25 mg once, 50 mg once
Inotropes	Dopamine	5 to 10 mcg/kg/min
	Dobutamine	2.5 to 5 mcg/kg/min
	Milrinone	0.125 to 0.75 mcg/kg/min
Vasodilators	Nitroglycerin	5 to 10 mcg/min, increase dose by 5-10mcg/min every 3-5 mins as tolerated, max is 400mcg/min
	Nitroprusside	5 to 10 mcg/min, increase dose by 5-10mcg/min every 5 mins as tolerated, max is 400mcg/min
	Nesiritide	2 mcg/kg bolus; then 0.01 mcg/kg/minute continuous infusion, maximum of 0.03 mcg/kg/minute
Hydralazine and isosorbide dinitrate	Fixed-dose combination	37.5 mg hydralazine/20 mg isosorbide dinitrate 3 times daily, 75 mg hydralazine/40 mg isosorbide dinitrate 3 times daily
	Individual doses	Hydralazine: 25 to 50 mg 3 or 4 times daily, 300 mg daily in divided doses Isosorbide dinitrate: 20 to 30 mg 3 or 4 times daily, 120 mg daily in divided doses
Digoxin		0.125 to 0.25 mg daily. There is no need for a loading dose in CHF. Drugs that increase the concentration of digoxin include amiodarone, quinidine and verapamil.|} Do's Guideline-directed medical therapy (GDMT) is a term which represents the optimal medical therapy in the management of heart failure as defined by ACCF/AHA. These are primarily the class 1 recommendations. It involves the use of ACE inhibitors or (ARBs), beta blockers, aldosterone antagonists, and hydralazine/nitrate medications. Order an echocardiogram as soon as possible in the absence of a recent one or if the patient's clinical status is deteriorating. Digoxin decreases hospitalization but not mortality in the RALES study. It can be used in CHF & afib to reduce the ventricular response. In the RALES study, a level of < 1 ng/ml was associated with efficacy. Levels > 1 ng/ml not associated with greater efficacy & associated with higher mortality. No need to load a CHF patient with dig. For majority of patients with normal Cr, a daily dose of 0.25 mg of digoxin is usually adequate. In the older patient or in those patients with renal impairment, a dose of 0.125 mg per day may be adequate. Drugs that increase the concentration of digoxin include amiodarone, quinidine and verapamil. Ensure DVT prophylaxis unless contraindicated. Consider adding another diuretic (e.g. metolazone or thiazides) for worsening congestion despite high doses of loop diuretics. Daily serum electrolytes, urea nitrogen, and creatinine concentrations should be measured during the use of IV diuretics or active titration of heart failure medications. Schedule an early follow-up visit (within 7 to 14 days) and early telephone follow-up (within 3 days) of hospital discharge . Don'ts Avoid, if possible, NSAIDs, sympathomimetics, tricyclic antidepressants, class I and III antiarrhythmics (except amiodarone), and nondihydropyridine calcium channel blockers (diltiazem, verapamil as they can cause harm in acute decompensated HF. Don't administer parenteral inotropes in normotensive patients with acute decompensated HF without evidence of decreased organ perfusion. Don't combine an ACEI, ARB, and aldosterone antagonist in patients with HFrEF unless otherwise indicated as this combination carries a risk of renal dysfunction and hyperkalemia. Don't use aldosterone receptor antagonists in patients with hyperkalemia or renal insufficiency when serum creatinine is more than 2.5 mg/dL in men or more than 2.0 mg/dL in women (or estimated glomerular filtration rate <30 mL/min/1.73 m2), and/or potassium more than 5.0 mEq/L. Don't continue nutritional supplements with no proven benefit. Don't use statins routinely without other indications. References Template:WikiDoc Sources