Chest Pain ILA Flashcards
What is myocardial perfusion?
Blood flow to the muscles of the heart, it occurs all the time due to the pressure gradient.
What will a blockage to the LAD do?
LAD - ‘widow maker’
because it supplies the entire front wall of the heart and most of the side wall, blockage = MI
What are the risk factors for coronary artery disease?
Risk factors for CAD often include:
Smoking
High LDL cholesterol, high triglycerides levels, and low HDL cholesterol
High blood pressure (hypertension)
Physical inactivity
Obesity
High saturated fat diet
Diabetes
What is coronary artery disease?
Coronary heart disease, or coronary artery disease (CAD), is characterized by the accumulation of fatty deposits along the innermost layer of the coronary arteries. The fatty deposits may develop in childhood and continue to thicken and enlarge throughout the life span. This thickening, called atherosclerosis, narrows the arteries and can decrease or block the flow of blood to the heart.
What are the heart sounds?
S1 - Lub - closure of AV valve (mitral and tricuspid)
S2 - Dub - opening of semi lumar valves (aortic and pulmon)
S3 - Lub - closure of semi lumar valves (aortic and pulmon)
S4 - Dub -opening of AV valves
Why may a heart murmur be heard?
- Regurgitation through the mitral valve is by far the most common
- Stenosis of the aortic valve is typically the next most common heart murmur, a systolic ejection murmur.
- Regurgitation through the aortic valve
- Stenosis of the mitral valve
What is cardiac output?
CO (ml/min) = HR X SV
Cardiac output is the Heart rate (number of beats per minute) multiplied by the Stroke volume (ml of blood pumped out of the heart with each beat)
What affects heart rate?
Heart rate can be slowed by parasympathetic activity and increased by sympathetic activity
What is stroke volume, and what affects it?
Stroke volume is the amount of blood ejected by the left ventricle in one contraction.
-Stroke volume is affected by preload and afterload. 1)Preload is the load, or stretch, put on the ventricle by the amount of entering blood volume. (EDV)
As preload increases it increases the strength of the contraction, thus increasing the stroke volume.
2) Afterload is the resistance the ventricle must pump against to eject the stroke volume. Now factor in numerous diseases or shock that increase afterload. An example is cardiogenic shock. There is impaired cardiac function along with increased vasopressin secretion leading to high afterload by the constricting vessels. This makes it difficult for the ventricle to pump against a tight vascular in an already impaired state, thus reducing the stroke volume.
- Prolonged aerobic exercise training may also increase stroke volume, which frequently results in a lower (resting) heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.
What is starling law of the heart?
As diastolic volume of blood increases (EDV), stroke volume increases and therefore there is a more forceful pump
What are the mechanisms of heart failure?
- damage to the left ventricle reduces LDV
- therefore there is reduced stroke volume
- the heart cannot keep up with the demands of the body
What are the symptoms of heart failure?
- Shortness of breath
- Feeling weak
- ankle swelling
- weight loss
What is the treatment of MI/Heart failure
- Weight loss = reduces strain
- Smoking cessation = reduces bp and damage
- Exercise = weight loss, reduces strain and also
- Low salt diet
- Limit alcohol
- statins
- ACE inhibitors - less aldosterone, less Na+ reabsorption, lowers plasma levels
- Beta blockers - slow heart rate
- Diuretics - reduce swelling
What is a myocardial infarction?
When the supply of blood to the coronary arteries is blocked, ischemia causes heart tissue death
What are the symptoms are heart attack?
- Crushing heart pain, may spread to arms and neck
- anxiety
- shortness of breath
- dizziness
