1.3k likes | 2.16k Views
Heart failure. Laszlo L. Tornoci Inst. Pathophysiology Semmelweis University. Definition.
E N D
Heart failure Laszlo L. Tornoci Inst. Pathophysiology Semmelweis University
Definition A clinical syndrome characterized by progressive weakening of the heart as a pump, causing complex changes in processes at systemic, organ and cellular levels, finally leading to premature myocardial cell death.
Demography • Prevalence of symptomatic HF 0.4-2.0%, 6-10% in people over 65 years • Disease of the elderly (mean age > 70 years) • Prevalence is rising • Bad prognosis: 5-year survival rate < 50% • Mortality (even if age adjusted) is increasing
Classification • Acute/chronic HF • Forward/backward failure • Systolic/diastolic dysfunction • Left/right sided HF
Complaints • Left heart, backward failure • dyspnea • orthopnea • paroxysmal nocturnal dyspnea • Left heart, forward failure • weakness, fatigue • nycturia
Physical findings • Right heart, backward failure • edema, hydrothorax • congestive hepatomegaly • distension of neck veins • Left heart, backward failure • pulmonary rales • Miscellaneous • cyanosis • S3 gallop
Causes of heart failure • Underlying (true) causes • Precipitating causes (which make the clinical condition worse, ‘decompensate’ the patient)
Underlying causes • Ischemic heart disease • Hypertension • Valvular heart disease • Cardiomyopathies • Other
Precipitating causes 1. Increased workload • Increased cardiac output • metabolic need (fever, infection, hyperthyroidism) • volume overload (renal failure, high sodium intake) • Pressure overload • high BP • pulmonary embolism
Precipitating causes 2. • Cardiac ischemia • Decreased efficiency (arrhythmias) • Drug effect • Endocarditis, myocarditis Same workload, but weaker heart
Terms • Inotropy (contractility) • Lusitropy (capability to relax or be filled) • Preload • Afterload
Frank-Starling law isometric contractions
sympathetic stimulation hypertrophy ischemia, AMI valvular heart disease high BP parasympathetic stimulation sympathetic inhibition myocarditis Some of the factors affecting contractility increase decrease
Neurohormonal response to HF Overview • Hemodynamic defense reaction • Salt and water retention • Vasoconstriction • Cardiac stimulation • Inflammatory reaction • Hypertrophic response
torlasz: more examples are needed Neurohormonal response Effects by levels • Systemic • Organ • Cellular Fluid retention, fatigue, cachexia Hypertrophy, remodeling Change of myosin isoforms, Ca++
Neurohormonal response to HF Overview • Hemodynamic defense reaction • Salt and water retention • Vasoconstriction • Cardiac stimulation • Inflammatory reaction • Hypertrophic response
Hemodynamic defense reaction Effects: • Salt and water retention • Vasoconstriction • Cardiac stimulation: contractility , faster relaxation, HR • Cell growth and proliferation Mediators: Stimulatory Inhibitory catecholamines (per. eff.) angiotensin II ADH endothelin ANP NO bradykinin dopamine cathecolamines (central eff.)
Hemodynamicdefense reaction Adaptive (beneficial), short term responses
Hemodynamicdefense reaction Maladaptive (not beneficial), long term responses
Neurohormonal response to HF Overview • Hemodynamic defense reaction • Salt and water retention • Vasoconstriction • Cardiac stimulation • Inflammatory reaction • Hypertrophic response
Inflammatory reaction • Adaptive (beneficial), short term results • not known (heat shock proteins?) • Maladaptive (not beneficial), long term results • cardiac cachexia • apoptosis • necrosis
Neurohormonal response to HF Overview • Hemodynamic defense reaction • Salt and water retention • Vasoconstriction • Cardiac stimulation • Inflammatory reaction • Hypertrophic response
Hypertrophic response • Gene expression in myocardial cells will change as a result of: • cell stress • hemodynamic defense reaction • inflammatory reaction Changes of growth factor expressions: TGF- , IGF-1 , FGF adaptive hypertrophy maladaptive hypertrophy • sarcomere number • cardiac output • remodeling • energy demand • cell death
contradiction is possible! Therapy • Emergency setting • keep the patient alive! • Usual setting • alleviate symptoms (improve QOL) • prolong survival Goals of therapy in general
Classical approaches in drug therapy • Circulation • decrease fluid retention (diuretics) • decrease afterload, preload (vasodilators) • Heart • positive inotropic agents (digitalis)
Maladaptive features of the vasoconstrictor response vasoconstriction afterload myocardial energy expenditure arrhythmias, sudden death myocardial cell death cardiac output worse symptoms survival
Expected response to vasodilators vasoconstriction afterload myocardial energy expenditure arrhythmias, sudden death myocardial cell death cardiac output better symptoms survival
Actual response to vasodilators vasoconstriction BP afterload myocardial energy expenditure hemodynamic defense reaction arrhythmias, sudden death myocardial cell death cardiac output hypertrophy better symptoms survival
kallikrein, cathepsin G Renin-angiotensin system angiotensinogen (1-14) renin angiotensin I (1-10) ACE, chymase angiotensin II (1-8) peptidase angiotensin III (2-8) peptidase angiotensin IV (3-8) ACE: angiotensin converting enzyme
Actions of ACE • Converts angiotensin I to angiotensin II • Breaks down kinins (bradykinin) So ACE inhibitors not only decrease angiotensin II levels, but increase bradykinin concentration. This is beneficial, but may cause coughing as a side effect.
Summary of drug therapy *: long term effects are in parentheses
Availability The heart failure lectures (in .ppt file format) can be downloaded from inside the university local area network (e.g. Students’ Center) at this address: http://xenia.sote.hu/depts/pathophysiology