SAM Cardio Baller Flashcards
How does the SNS respond to a decrease in CO?
- Increase contractility ( +inotrope)
- Increase HR (+chronotrope)
- Veno/Arterio constriction
How is the RAAS activated?
Decreased Renal Blood flow
Functionality of the RAAS System?
- Angiotension 2 ===> Peripheral vasoCONSTRICTION of arteries/veins
- Aldosterone ===> Increased Na & H2O retention
- OVERALL ======> INCREASE venous return to heart
Brief description of DCM?
- Pump FAILURE
2. Ventricular walls become thinner & SYSTOLIC force is decreased ====> Lowered CO
Brief description of chronic valve dz?
- MITRAL valves thickened & contracted ===> Mitral regurg
- L-Ventricle contracts ===> 70% SV regurgs through faulty mitral valve into the LA==========»> Decreased CO
Effects of sustained activity on HF?
- INCREASE peripheral resistance ===> DECREASED flow + signs of HYPOtension
- +chronotrope effect increases heart O2 demand
- Since HR is INCREASED = Time in Diastole is DECREASED ===> reduced coronary perfusion
- Can cause arrhythmias b/c coronary vasospasm & myocardial damage
Animals with HF have elevated levels of ________ which shortens their survival time
Norepinephrine
Problem with long term stimulation of RAAS system?
- Failing heart Frank starling curve = LESS steep and the increase in CO is NOT as pronounced as normal heart
- Increased PRELOAD ===> Pulmonary Edema
- Chronic vasoCONSTRICTION increases AFTERLOAD ====> Hypotension
- Aldosterone causes
- myocardial fibrosis
- direct vasculature damage
- BARORECEPTOR dysfunction
Cause of Eccentric Hypertrophy?
- Chronic INCREASED diastolic pressure
2. VOLUME Overload
Characteristics of Eccentric Hypertrophy?
- Addition of sarcomeres ===> Cells elongating
- Large ventricle w/ INCREASING chamber size but walls of NORMAL thickness
- Results in INCREASED end Diastolic volume & afterload
Describe afterload
The ventricular RESISTANCE encountered as it tries to eject blood during systole
Describe preload
After Diastole (filling) occurs ===> MAXIMUM ventricular volume/pressure that occurs
Characteristics of Concentric Hypertrophy
- Sarcomeres replicate side by side resulting in WIDER cells & THICKER/STIFFER ventricular wall
Cause of Concentric Hypertrophy
- Response to INCREASED Systolic Ventricular Pressure
- Aortic Stenosis or Systemic Hypertension
- “PRESSURE OVERLOAD”
Physiology responsible for the clinical signs of HF?
- Chronic compensatory mechanisms occurring
- Cause INCREASED Preload ===> Edema
- Vasoconstriction increases workload of heart
- Results in cardiac hypertrophy ===> increased MVO2 requirement
- Eventually cannot compensate enough ===> DECREASED efficiency of heart muscle contraction
- Leads to arrhythmias
Why does increased preload cause pulmonary edema in the failing heart?
- Increase in preload causes drastic INCREASE in Systolic volume
- Dz’ed heart cannot compensate so SV is only slightly elevated
- Causes high pressure buildup in the vessels filling the heart forcing fluid into interstital space ===> Interstitial Edema
Signs of excessive LEFT Ventricular Preload?
- Pulmonary Edema
- Hypoxemia/Cyanosis
- Excessive RIGHT Ventricular Preload
Signs of excessive RIGHT Ventricular Preload?
- Jugular & peripheral vein distension
- Pleural effusion
- Hepatomegaly
- Ascites
- SC Edema
What are the general signs of HF?
- Low CO, weakness/syncope, dyspnea, severe hypotension (cardiogenic shock)
Physiology behind LEFT HF?
DECREASED forward Stroke Volume ===> Hypotension & high End Diastolic pressure