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What can increase contractility?
- Increased sympathetic stimuli
- Hormones - Epinephrine and Thyroxine
- Ca2+ and some drugs
- Intra- and extracellular ion concentrations must be maintained for normal heart function
Sympathetic stimulation of contractility releases what and initiates what system?
- Releases Norepinephrine
- Initiates a cAMP second-messenger system
What cells release Renin?
Where is Angiotensinogen released from?
Where does ACE come from?
Is Angiotensin II a vasoconstrictor or vasodilator?
What does Angiotensin II help release?
- Argenine Vasopressin (ADH)
What does Aldosterone do?
Na and Water Retention
What does ADH do?
- Water Retention
What 4 things determine cardiac function?
- Contractile state of the heart muscle
- Preload (end-diastolic volume and the resulting length of the cardiomyofibers prior to the onset of contraction)
- Afterload (resistance to the ventricular ejection of blood)
- Heart rate
What are the cardiac characteristics of a Left Sided Heart Failure?
- Ineffective left ventricular contractility
- Decreased LV pump
- Decreased SV
- Decreased CO
- Increased HR
- Back up of volume in LA and back to lungs
What are the symptoms of left sided heart failure?
- Paroxysmal Nocturnal Dyspnea - can't sleep at night when lying flat
- Elevated Pulmonary Capillary Wedge Pressure
- Pulmonary congestion (Cough, Crackles, Wheezes, Blood-Tinged Sputum, Tachypnea)
- Pulmonary edema
- Exertional Dyspnea
What are the cardiac characteristics of a Right Sided Heart Failure?
- Ineffective right ventricular contractility
- Decreased RV pump
- Decreased SV
- Decreased CO
- Increased HR
- Back up of volume on venous side
What are the symptoms of Right Sided Heart Failure?
- Weight gain
- Back up to vital organs - liver, spleen
- ↑ Peripheral Venous Pressure
- May be secondary to chronic pulmonary problems
- Distended Jugular Veins
- Anorexia and Complaints of GI Distress
- Dependent Edema
What is a systolic dysfunction?
- Ventricular Chambers are large
- Lack of good Starling Effect, won't pump with good contractile force
What is a diastolic dysfunction?
- Problem with filling of stiffened ventricles
- Due to remodeling became stiffened
What are the causes of Systolic Dysfunction?
- Coronary Artery Disease (CAD)
- Dilated cardiomyopathy
What are the causes of Diastolic Dysfunction?
- Ventricular Hypertrophy
- Restrictive Cardiomyopathy
- Coronary Artery Disease
What is preload?
Volume of blood in ventricles at end of diastole (end diastolic pressure)
When is preload increased?
- Regurgitation of cardiac valves
- Heart failure
What is afterload?
Resistance left ventricle must overcome to circulate blood
When is afterload increased?
What are 3 causes of CHF?
- Decreased contractility
- Increased afterload
- Decreased preload
What drugs do you give to increase contractility and how does it work?
- Inhibits Na/K ATPase Pump
What are the symptoms for Digitalis Toxicity?
- Irregular pulse
- Loss of appetite
- Nausea, vomiting, diarrhea
- Vision changes (unusual), including blind spots, blurred vision, changes in how colors look, or seeing spots. Halos of white and green colors
What happens if you slow down the Na/ K ATPase Pump?
- Metabolic alkalosis
How do you decrease preload?
- ↓ Salt intake
- ↓ water intake (1200 mls/day)
- Give diuretics to decrease edema. Give K+ sparing (over K+ wasting) due to possibility of hypokalemia
How do you decrease afterload?
- Give β-blockers - reduces BP caused by body trying to ↑ CO
- Will ↓ BP
- Give ACE inhibitors to ↓ angiotensin II formation
- Give diuretics to ↓ BP
What do you give when CHP is due to Coronary Artery Disease and how does it work?
- Vasodilate the coronary arteries and ↑ oxygenation to the myocardium which will ↑ contractility and ↓ preload and afterload
What is an acronym to treat CHF?
- Upright Position
- ACE inhibitors
- Fluids (↓)
- Afterload (↓)
- Sodium Restriction
- Test (Dig level, ABGs, K+ levels)
What are symptoms of late stages of CHF?
- Dilated pupils
- Skin pale, gray, or cyanotic
- Dyspnea, Orthopnea, Crackles, wheeze, cough
- ↓ BP
- Nausea and vomiting
- Dependent, pitting edema
- Anxiety, Confusion
- Falling O2 saturation
- Jugular vein distention
- S3 gallop, tachycardia
- Enlarged spleen and liver
- Decreased urine output
- Weak pulse
- Cool, moist skin
Why does the heart hypertrophy during CHF?
- According to the Law of Laplace, best way to ↓ LVP is to ↑ the wall thickness
- Denominator is ↓ the LVP value
- ↓ Radius helps offset the effects of an ↑ LVP