49&50: Cardiac Function 2 Flashcards
Define cor pulmonale
Pulmonary and arterial hypertension resulting from disease affecting lung structure/function. It leads to RV enlargement and in time RHS heart failure.
What are causes of pulmonary hypertension?
- Loss of capillary beds
- Vasoconstriction caused by hypoxia, hypercapnia, both
- Increased alveolar pressure
- Medical hypertrophy in arterioles
Why is the second heart sound split enhanced with inspiration?
Reduced intrathoracic pressures lead to increased right heart filling, delaying pulmonary closure
Why is the IV septum displaced leftward during diastole in a patient with pulmonary hypertension
- RV diastolic pressures increased
- Pressure gradient across IV septum during diastole pushes it into LV cavity
Why does a patient experience SOB with mitral valve stenosis?
- Inc. back pressure in pulmonary vasculature
(engorgement)
Why is 1st HS enhanced in patients with mitral stenosis?
Mobile but stiff mitral leaflets open more due to elevated pressure
What causes an opening snap in mitral stenosis?
- High pressure gradient
- Abnormal valves billow into LV and are rapidly arrested by chordae tendineae, causing vibrations
Why are patients with mitral stenosis at risk of atrial arrhythmia?
- LA enlargement inc. path length and distention, inc. probability of ectopic activation
- Inflammation and fibrosis cause activation delays, facilitate unstable electrical activity
- Regionally varying ANS remodelling
What is the spectrum of AF?
- Paroxysomal
- Persistent
- Permanent
Explain the pathophysiology of aortic stenosis
- Endothelial cell damage from mechanical stress
- Inflammation of deposition of LDL cholesterol and lipoproteins occurs
- Valve thickens and becomes calcified
Why does a patient with aortic stenosis feel dizzy when exercising
- Vasodilation in skeletal muscle
- Heart cannot deliver extra flow rate
- Overall fall in MAP causes reduced brain perfusion
What electrical abnormality do you need to be aware of in a patient with aortic stenosis?
- LBBB
- Calcium deposits can occur on myocardium and block conduction
