Heart Faliure Flashcards
Describe the 3 adaptive mechanisms used by the body to compensate for reduced cardiac function & their time frames.
- Frank starling = short term (see notes)
- Neuro/ Hormonal & Renal = intermediate
- Norepi symp stimulation - Hypertrophy = long term
- Remember that hypertrophy is an increase in the size of the cells (myocytes), not the number of cells.
Describe how each of these mechanisms to compensate for reduced cardiac function becomes maladaptive.
- Frank starling = With increasingly severe LV dysfunction the LV filling pressure reaches 25mmHg, where the oncotic pressure of the plasma is exceeded and fluid crosses the alveolar membrane and enters the pulmonary alveoli.
- Neuro/ Hormonal & Renal = Heart begins to produce Norepi instead of just consuming it. Increasing norepi positivley correlates with degree of severity of disease. Also, decreased renal function.
- If ventricular hypertrophy lasts long enough, it will make patient worse because contractility DECREASES (although their is an increase in muscle both eccentric & concentric hypertophy).
Define heart faliure
Inability of the heart to meet the metabolic needs of the body
What are some causes of heart faliure
Decreased circulatory supply to the body
Increased circulatory demand from the body
See pg. 141
Read the notes fully
-
Ejection fraction
SV/EDV = (EDV-ESV)/EDV
It is a measure of cardiac contractility
Concentric hypertrophy comes from _____ overload. The sarcromeres are in ____ & the myocardium _____ & the lumen size ______.
Concentric hypertrophy comes from pressure overload. The sarcromeres are in parallel & the myocardium & the lumen size decreases.
Eccentric hypertrophy comes from _____ overload. The sarcromeres are in _____ & the myocardium becomes ______ & the lumen size increases.
Eccentric hypertrophy comes from volume overload. The sarcromeres are in series & the myocardium becomes longer & the lumen size increases.
Concentric hypertrophy (fat muscle, small lumen) comes from pressure overload, which increases sytolic wall stress, which forms parallel sarcomeres.
Eccentric hypertrophy (thin long muscle, large lumen) comes from volume overload, which increases diasytolic wall stress, which forms series sarcomeres.
See pg. 153 - 155
Frank starling curve is shifted toward the ____ in heart failure.
Frank starling curve is shifted toward the pressure axis (down and to the right) in heart failure.
See pg. 142
Pressure and volume overload induce _____ increase in cardiac mass in ventricular hypertrophy.
Pressure and volume overload induce nearly the same increase in cardiac mass in ventricular hypertrophy.
The normal PR interval extends from the ____ of the P wave to the _____ of the QRS.
The normal PR interval extends from the beginning of the P wave to the beginning of the QRS.
3rd degree A-V block is always associated with an _______.
3rd degree A-V block is always associated with an escape rhythm.
A ventricular escape beat is a self-generated electrical discharge initiated by, and causing contraction of, the ventricles of the heart; normally the heart rhythm is begun in the atria of the heart and is subsequently transmitted to the ventricles.
The ventricular escape beat follows a long pause in ventricular rhythm and acts to prevent cardiac arrest. It indicates a failure of the electrical conduction system of the heart to stimulate the ventricles (which would lead to the absence of heartbeats, unless ventricular escape beats occur).
Premature Atrial Contractions usually reset the ________ node.
Premature Atrial Contractions usually reset the sinus node.
Atrial fibrillation is associated with _______ atrial contraction.
Atrial fibrillation is associated with no coordinated atrial contraction.
The contraction of the ventricles lasts almost from the beginning of the ____ wave and continues to the end of the _____ wave. This interval is called the _____ interval and ordinarily last about ______.
The contraction of the ventricles lasts almost from the beginning of the Q wave and continues to the end of the T wave. This interval is called the Q-T interval and ordinarily last about 0.35 sec.