Congestive Heart Failure (CHF)

Dr Yograj Khinchi

Congestive Heart Failure (CHF/CCF)

Heart failure is the state in which the heart can not produce the Cardiac Output (CO) required to sustain the metabolic needs of the body without evoking certain compensatory mechanisms (cardiac reserve).

Cardiac reserve →Compensated CHF

When these mechanisms becomes ineffective there is cardiac decompensation (decompensated CHF).

Congestive Heart Failure (CHF/CCF)Pathophysiology:

Cardiac Output (CO) = Heart rate X Stroke volume

Heart is a pump with an output: • Proportional to its filling volume and• Inversely proportional to the resistance against

which it pumps

As ventricular end diastolic volume increases a healthy heart increases CO until a maximum is reached and CO can no longer be augmented.

(Frank -Starling principle)

FRANK-STARLING CURVE

Pathophysiological factors causing CHF:1. Preload (volume work): Volume to be ejected = End diastolic volume (↑)2. Afterload (pressure work) : Impedance against ejection ( ↑ )3. Myocardial contractility : Ionotropic state (myocardial dysfunction)4. Frequency of ejection : Heart rate (dysrrhythmia)

Myocardial Dysfunction

↓ Cardiac output

Systemic over reactions:↑ E, NE (sympathetic system )↑AVP-Aldosterone(antidiuretic sys)↑Renin-Angiotensin(renin-angio sys)

Anti diuresisNa & fluid retention

↑ Pre load

Peripheralvasoconstriction

↑ After load

Pathophysiology: Vicious Circle

Etiology of CHF according to Pathophysiological factors :

1. Excessive volume load (Preload)• Large L→R shunt: VSD, PDA• Large valvular insufficiency: MR, AR• Endocardial cushion defect (ECD)• TGA with VSD, TGA with Tricuspid atresia• Secundum ASD• Excessive blood or fluid transfusion (fluid overload)

2. Pressure load (Afterload)• Severe Aortic stenosis, coarctation of aorta, mitral atresia• Systemic hypertension• Severe pulmonary hypertension• Total anomalous venous connections (TAPVC)

Etiology of CHF according to Pathophysiological factors :

3. Myocardial dysfunction• Myocarditis: Rheumatic, Viral• Cardiomyopathy, Endocardial fibroelastosis, Myocardial

ischemia• Non-structural causes: Hypoglycemia, Hypocalcemia,

Hypoxia

4. Dysrrythmias: Tachyarrhythmia, Heart blocks

5. High out put failures: Severe anemia, Thyrotoxicosis, Arteriovenous (AV) Fistula

Etiology of CHF according to age of onset:

1. Fetal: Severe anemia, Dysrrythmias

2. Premature neonate:• Fluid overload, Hypertension, Cor pulmonale (broncho

pulmonary dysplasia)• PDA, VSD

3. Full term neonate:• Asphyxial cardiomyopathy, viral myocarditis• Left sided obstructive lesions: Coarctation of aorta• Arteriovenous Malformations• Large mixing defects: single ventricle, Truncus arteriosus

Etiology of CHF according to age of onset…

4. Infant- Toddler:• L→R shunts: VSD• Hemangiomas (Arterio-Venous Malformations)• Metabolic cardiomyopathy, viral myocarditis, Supraventricular tachycardia (SVT) • Acute hypertension (Hemolyic uremic synddrome), Kawasaki disease

5. Child-Adolescent:• Rheumatic fever, RHD• Acute hypertension (Post streptococcal glomerulonephritis)• Viral myocarditis, Cardiomyopathy, Endocarditis• Cor pulmonale, • Misc: Hemo-chromatosis, Thyrotoxocosis

• Infants become dyspneic while feeding with profuse sweating

• Becomes exhausted with less volume/feed• Irritable infant, poor weight gain, weak cry• Tachypnea with respiratory distress, persistent

cough/wheeze• Puffiness of face, pedal edema • Deep coloring / cyanosis• Fatigue• Effort intolerance • Anorexia, pain abdomen(GIT cogestion)• Orthopnea / nocturnal dyspnea

Clinical features:

NYHA Classification

• Class I– Symptoms with greater than ordinary activity

• Class II– Symptoms with ordinary physical activity

• Class III– Symptoms with minimal physical activity

• Class IV– Symptoms at rest

Left sided failure:• Tachycardia • Tachypnea• Wheeze / cough• Acute pulmonary edema in severe CHF

Right sided failure:• Hepatomegaly• Neck vein distension / Increased JVP• Edema

Failure of either side:• Cardiomegaly• Gallop rhythm• Cyanosis• Small volume pulse

» Other clinical features of basic lesion responsible for CHF

JVP• JVP – Measurement

HEIGHT

InvestigationsX-ray chest:• Cardiomegaly• Lungs- Fluffy pulmonary markings / Acute pulmonary edema

ECG:• Specific chamber enlargement / ischemic / inflammatory disease • Rhythm disorders

Echocardiography : To assess ventricular function

Investigations for primary cause responsible for CHF

Cardio-Thoracic Ratio

<50%

the cardio-thoracic ratio which is the widest diameter of the heart compared to the widest

internal diameter of the rib cage, normal <50%

the cardio-thoracic ratio which is the widest diameter of the heart compared to the widest

internal diameter of the rib cage, normal <50%

Cardiomegaly on chest X-rayCauses• CHF (causes of CHF)• Pericardial effusion: Transudate: Hypoproteinemia Exudate : Infectious, inflammatory, autoimmune, malignancy

Management of CHF1.General management:• Rest , Mild sedation, Propped up position• Humidified oxygen• Salt restriction, fluid restriction2.Pre load reducing agents: Diuretics (and Venodilators )• Furosemide• Chlorthiazide• Spironolactone

3.Positive ionotropic agents:• Glycosides: Digitalis• Catecholamine like non glycoside agents

• Dopamine/ Dobutamine • Non catecholamine non glycoside agents

• Amrinone , Milrinone

4. After load reducing agents and ACE inhibitors:» Vasodilators which decrease Peripheral Vescular Resistance (PVR)» Arterial dilators, Venodilators (also ↓ preload) & arterio-venodilators• Hydralazine(A) • Nitropruside (A+V) • Prazocine (A+V)

► ACE (Angiotensin Converting Enzyme) inhibitors: Captopril (A+V)

5. Other drugs:• Beta-blockers (used in cardiomyopathy): metoprolol, carvedilol

6. Treatment of precipitating and aggravating factors:• i.e. infection, anemia

7. Treatment of pathological cause of CHF

Management of CHF…

Digitalis: DigoxinDigitalization:

►Rapid Digitalization: IV / Oral (IV dose is 75% of oral dose)• Total Digitalizing Dose(TDD): Oral dose

• Newborn = 0.02-0.03mg/kg• Infant/child = 0.04mg/kg (max 0.5mg); Adolescent = 0.5- 1mg(TDD)

♦ TDD is divided as follows (given in 16 hours):• Half dose stat• One fourth dose after 8 hours• One fourth dose after next 8 hours

♦Maintenance dose: 1/4th dose of TDD (i.e. 0.01mg/kg/day in infant) ♦Maintenance dose started after 12 hours of last dose of TDD (3rd

dose) ►Slow Digitalization: Oral Dose is maintenance daily dose only without loading dosage & will achieve digitalization in 7-10 days

» Monitoring during digitalis: ECG, S. Electrolytes» Digitalis toxicity, Hypokalemia / Hypercalcemia