Cardiac Muscle Dysfunction Flashcards
Describe the key features of CMD (4)
- Results from abnormality of structure or function
- Impairs the heart’s ability to pump or receive blood
- Exercise tolerance/funtional ability mild/mod reduced
- Decreased QoL
Term: Resistance the ventricle feels as it empties
Afterload
Define chronic heart failure?
When the congestion or edema causing CHF is controlled
List Ejection fraction for the following conditions:
- Normal
- CMD
- CHF
- 60-70%
- 30-40%
- < 30%
List seconday issues due to CMD (6)
- Angina and myocardial ischemia (inad O2 supply/demand)
- Cardiac arrhythmia (decreased myocardial function)
- HTN (places strain on the L ventricle)
- Ventricle hypertrophy (due to HTN)
- Myocardial stiffness (due to HTN)
- Renal insufficiency
List the most common cause of CMD and its effect on the heart
- MI
An MI can be due to artery spasm, ebolism, injury. Once an MI occurs there is subsequent scar formation. The scar tissue in the heart leads to decreased stretch with filling and decreased/altered line of squeeze with contraction. Overall the heart has decreased contractility
Describe the effect on HTN on EE
With HTN there is increased resistance for the heart. This requires increased EE due to the increased work of the heart mm to maintain/pump adequate cardiac output
Describe the difference in heart hypertrophy due to pathology vs. athletic conditioning
Pathologic: tissue is laid down on the inside of the ventricle, taking up space for filling and stiffening the heart
Athletic training: tissue laid down on the outside of the ventricle; pumping is more effeicient, SV is larger
Describe how ventricular hypertrophy progresses
With prolonged HTN the heart has increased EE > the ventricle hypertrophy > Myocardium stiffens > the ventricle weakens/deteriorates > the ventricle dilates (can’t squeeze) > CHF
Describe the tx options for HTN (2)
- Medications (ACE inhibitors, Ca blockers, beta blockers, diruetics)
- Regular exercise (Stimulate vasodilation at rest; Drop: SBP by 10; DPB by 6-8)
List the tx options for cardiac arrhythmia (4)
- Medication
- Pacemaker
- Ablation (removing arrhythmatic cells)
- ICD (implantatble cardiac defibrillator)
Describe the effect of renal insufficiency on the heart
Fluid retention/overload increases the pressure the heart must overcome
**Side note: Goal of tx is to decrease reabsorption as opposed to just removing the excess fluid
List the tx options for renal insufficiency (3)
- Lasix (diuretic)
- Monitor electrolyte levels (Na and K)
- Dialysis (severe cases)
Term: a disorder affecting heart muscle; inadequate pumping of the heart
Cardiomyopathy
Condition: enlarged heart
Cardiomyopathy