Post on 05-Aug-2015
Heart Failure
Definition
• structural or functional CD• impairs the blood filling/ejecting ability
of ventricles• inability to maintain the metabolic needs
of the body
CausesHeart performance (CO) depends on:• Contractility• Preload• Afterload• Heart Rate
Causes:• Abnormal loading conditions• Abnormal muscle function• Conditions that limit
ventricular filling
Congenital defects Valvular heart diseases Septal defects Hypertension Myocardial infarction Myocarditis Cardiomyopathy Alcoholism Mitral or tricuspid stenosis Pericarditis Ischaemic heart disease Drugs Thyrotoxicosis
CO = SV x HR
Classifications
Backward Failure Forward Failure
High Output
Low Output
RSHF LSHF
Acute vs. ChronicAcute
• Develops rapidly • Can be immediately life
threatening• Dramatic drop in cardiac
output• May be new (e.g. acute MI,
sepsis) or an exacerbation of chronic disease
Chronic
• Long term• More insidious• Associated with the heart
undergoing adaptive responses (e.g. dilation, hypetrophy) to a precipitating cause
Symptoms
• Fatigue• Activity decrease• Cough (especially supine)• Edema• Shortness of breath
SymptomsRVF– Fatigue– Weakness– Lethargy– Weight gain– Anorexia – RUQ pain– Hepatomegaly– Neck vein pulsations– Jugular veinous
distension– Pitting edema
LVF– Fatigue – Anxiety– Insomnia– Tachycardia– Gallop heart sounds (S3,
S4)– Pulmonary crackles,
rales– Orthopnea PND– Cheyne Stokes– Cough
Pathophysiology
Compensatory mechanism:1. Hemodynamic alterations2. Neurohormonal responses (SNS, RAAS, Vasopressin) 3. Ventricular dilation 4. Ventricular hypertrophy
Response Short-Term Effects
Long-Term Effects
Salt and Water Retention Augments preload Pulmonary Congestion, Anasarca
Vasoconstriction Maintains BP for perfusion of vital organs
Exacerbates pump dysfunction (excessive afterload), increases cardiac energy expenditure
Simpathetic stimulation Increases HR and ejection Increases energy expenditure
Frank-Starling Mechanism
• The ability of the heart to change its force of contraction and therefore stroke volume in response to changes in venous return.
• In heart failure, there is a compensatory increase in venous return which is augmented by neurohormonal mechanisms.
• Due to increase in venous return, there is a temporary increase in stroke volume.
Diagnostic Studies
• X-ray (Kerley B lines)• ECG• Echocardiography (EF)• Laboratory data (cardiac enzymes, BNP, serum
chemistries ,liver function studies ,thyroid function studies and complete blood count)
• Stress testing (exercise or medicine)• Cardiac catheterization- determine heart
pressures ( inc.PAW )
ECG
ECG findings are not diagnostic, but:• Old MI or recent MI• Arrhythmia• Some forms of tachycardia related
cardiomyopathies• LBBB
Approach to the Patient with HF
• Diagnose– Etiology– Severity (LV dysfunction)
• Initiate– Diuretic/ACE inhibitor– -blocker– Spirololactone– Digoxin
• Educate– Diet– Exercise– Lifestyle– CV Risk
• Titrate– Optimize ACE inhibitor– Optimize -blocker