What is the definition of heart failure (HF)?
CLINICAL SYNDROME wherein the heart pumps an inadequate volume of blood to meet O2 demands of tissue and prevent fluid accumulation
HF occurs in the face of _____ venous return (as distinguished from shock).
adequate/high
What type of diagnosis is HF?
Common end result of many different cardiac diseases - it is NOT a primary diagnosis
What factors determine CO?
HR x SV
What factors determine SV?
Preload, afterload, inotropy
What is preload?
Amount of blood coming back into heart during diastole
What is afterload?
All forces that resist ejection from the heart in systole
What are potential causes for L-HF due to too much afterload?
Systemic hypertension, congenital SAS
What are potential causes for L-HF due to too much preload?
Valvular disease (mitral, aortic)
Congenital - PDA, VSD, ASD
What are potential causes of L-HF due to not enough contractility?
DCM, myocarditis
What are potential causes of L-HF due to not enough relaxation/filling?
HCM
What are potential causes of R-HF due to too much afterload?
Pumonary hypertension, congenital PS
What are potential causes of R-HF due to too much preload?
valvular disease (tricuspid), congenital tricuspid dysplasia
What are potential causes of R-HF due to not enough contractility?
DCM, myocarditis
What are potential causes of R-HF due to not enough relaxation/filling?
Pericardial disease (tamponade), neoplasia
What are the clinical signs of forward (low output) HF?
Syncope, pallor, cyanosis, hypokinetic pulses, azotemia
(Heart is not pumping enough blood to meet demands)
What are the clinical signs of backward (congestive) HF?
Pulmonary edema, pleural effusion, ascites/hepatomegaly, pericardial effusion, peripheral edema
(This is the most common manifestation of HF in animals)
What role does the LV play in congestive HF?
Blood comes into LV from LA, which came from the lungs –>
Fluid accumulates in lungs –> pulmonary edema
What role does the RV play in congestive heart failure?
Blood comes into RV from RA, which came from systemic circ (vena cavae) –>
Cavitary effusions –> pleural eff, ascites, pericardial eff, peripheral edema
Where does the fluid go in DOGS with L-CHF?
Pulmonary edema
Where does the fluid go in DOGS with R-CHF?
Ascites = major
Occ = pleural effusion, pericardial effusion, peripheral edema
Where does the fluid go in CATS with L-CHF?
Pulmonary edema, pleural effusion, pericardial effusion
Where does the fluid go in CATS with R-CHF?
Ascites = major
(Also pleural effusion and pericardial effusion)
A cat with pulmonary edema only and no other issues is _____ likely to have L-CHF.
not
Which of the body’s neurohormonal compensatory systems respond to HF?
RAAS, sympathetic system
What activates RAAS?
Juxtaglomerular apparatus senses decrease in renal perfusion;
Also increased SNS tone
What are the short-term effects of RAAS?
Na+/H2O retention –> increased preload
Vasoconstriction –> increased preload and afterload
What are the long-term effects of RAAS?
Myocardial remodeling and fibrosis, renal and arteriolar sclerosis, cytokine activation
What activates the SNS?
Baroreceptors sense a decrease in BP
What are the short-term effects of the SNS?
Increased HR, increased contractility, vasconstriction –> increased preload and afterload
What are the long-term effects of the SNS?
Myocardial remodeling and fibrosis, cytokein activation
What pathophysiologic parameters can we alter pharmacologically to treat HF?
Increase inotropy, decrease preload, decrease afterload, optimize HR, blunt RAAS, blunt SNS