Cardiovascular function Flashcards
acute coronary syndrome
a constellation of signs and symptoms due to the rupture of atherosclerotic plaque and resultant partial or complete thrombosis within a diseased coronary artery; leads to unstable angina or acute myocardial infarction
afterload
the amount of resistance to ejection of blood from the ventricle
apical impulse
impulse normally palpated at the fifth intercostal space, left midclavicular line; caused by contraction of the left ventricle; also called the point of maximal impulse
atrioventricular (AV) node
secondary pacemaker of the heart, located in the right atrial wall near the tricuspid valve
baroreceptors
nerve fibers located in the aortic arch and carotid arteries that are responsible for control of the blood pressure
cardiac catheterization
an invasive procedure used to measure cardiac chamber pressures and assess patency of the coronary arteries
cardiac conduction system
specialized heart cells strategically located throughout the heart that are responsible for methodically generating and coordinating the transmission of electrical impulses to the myocardial cells
cardiac output
amount of blood pumped by each ventricle in liters per minute
cardiac stress test
a test used to evaluate the functioning of the heart during a period of increased oxygen demand; test may be initiated by exercise or medications
contractility
ability of the cardiac muscle to shorten in response to an electrical impulse
depolarization
electrical activation of a cell caused by the influx of sodium into the cell while potassium exits the cell
diastole
period of ventricular relaxation resulting in ventricular filling
ejection fraction
percentage of the end-diastolic blood volume ejected from the ventricle with each heartbeat
hemodynamic monitoring
the use of pressure monitoring devices to directly measure cardiovascular function
hypertension
blood pressure that is persistently greater than 140/90 mm Hg
hypotension
a decrease in blood pressure to less than 100/60 mm Hg that compromises systemic perfusion
murmurs
sounds created by abnormal, turbulent flow of blood in the heart
myocardial ischemia
condition in which heart muscle cells receive less oxygen than needed
myocardium
muscle layer of the heart responsible for the pumping action of the heart
normal heart sounds
sounds produced when the valves close; normal heart sounds are S1 (atrioventricular valves) and S2 (semilunar valves)
opening snaps
abnormal diastolic sound generated during opening of a rigid atrioventricular valve leaflet
postural (orthostatic) hypotension
a significant drop in blood pressure (20 mm Hg systolic or more or 10 mm Hg diastolic or more) after an upright posture is assumed
preload
degree of stretch of the cardiac muscle fibers at the end of diastole
pulmonary vascular resistance
resistance to blood flow out of the right ventricle created by the pulmonary circulatory system
pulse deficit
the difference between the apical and radial pulse rates
radioisotopes
unstable atoms that give off small amounts of energy in the form of gamma rays as they decay; used in cardiac nuclear medicine studies
repolarization
return of the cell to resting state, caused by reentry of potassium into the cell while sodium exits the cell
S1
The first heart sound produced by the closure of the atrioventricular (mitral and tricuspid) valves
S2
The second heart sound produced by the closure of the semilunar (aortic and pulmonic) valves
S3
an abnormal heart sound detected early in diastole as resistance in met to blood entering either ventricle; most often due to volume overload associated with heart failure
S4
an abnormal heart sound detected late in diastole as resistance is met to blood entering either ventricle during atrial contraction; most often caused by hypertrophy of the ventricle
sinoatrial (SA) node
primary pacemaker of the heart, located in the right atrium
stroke volume
amount of blood ejected from one of the ventricles per beat
summation gallop
abnormal sounds created by the presence of an S3 and S4 during periods of tachycardia
systemic vascular resistance
resistance to blood flow out of the left ventricle created by the systemic circulatory system
systole
period of ventricular contraction resulting in ejection of blood from the ventricles into the pulmonary artery and aorta
systolic click
abnormal systolic sound created by the opening of a calcified aortic or pulmonic valve during ventricular contraction
telemetry
the process of continuous electrocardiographic monitoring by the transmission of radio waves from a battery-operated transmitter worn by the patient
The cardiac action potential has how many phases?
5
Cardiac action phase 0
Cellular depolarization is initiated as positive ions influx into the cell. During this phase, the atrial and ventricular myocytes rapidly depolarize as sodium moves into the cells through sodium fast channels. The myocytes have a fast response action potential.
Cardiac action Phase 1
Early cellular repolarization begins during this phase as potassium exits the intracellular space.
Cardiac action Phase 2
This phase is called the plateau phase because the rate of repolarization slows. Calcium ions enter the intracellular space.
Cardiac action Phase 3
This phase marks the completion of repolarization and return of the cell to its resting state.
Cardiac action Phase 4
This phase is considered the resting phase before the next depolarization.
Frank-Starling Law
the greater the initial length or stretch of the cardiac muscle cells (sarcomeres), the greater the degree of shortening that occurs.
What are the 5 locations to listen to the heart?
Right midclavicular 2nd intercostal space (atrial), left midclavicular 2nd intercostal space(pulmonary), left sternal boarder 3rd intercostal space (ERB’s Point), left sternal boarder 4th intercostal space (tricuspid), left midclavicular 5th intercostal space (mitral/apex),
What is the BP & heart rate for a patient with postural hypertension (supine)?
BP 120/70 mm Hg, heart rate 70 bpm
What is the BP & heart rate for a patient with postural hypertension (sitting)?
BP 100/55 mm Hg, heart rate 90 bpm
What is the BP & heart rate for a patient with postural hypertension (standing)?
BP 98/52 mm Hg, heart rate 94 bpm
How is a murmur graded?
Grade 1: Very faint and difficult for the inexperienced clinician to hear
Grade 2: Quiet but readily perceived by the experienced clinician
Grade 3: Moderately loud
Grade 4: Loud and may be associated with a thrill
Grade 5: Very loud; heard when stethoscope is partially off the chest; associated with a thrill
Grade 6: Extremely loud; detected with the stethoscope off the chest; associated with a thrill
What happens to gerontological patients’ apex if they develop kyphoscoliosis?
The cardiac apex moves downward so the palpation of the apical impulse is obscured
How are cardiac biomarkers used to diagnose myocardial infarction?
Myocardial cells become necrotic from prolonged ischemia/trauma. creatine kinase [CK], CK isoenzymes CK-MB, and proteins (myoglobin, troponin T, and troponin I). These leak into the interstitial spaces of myocardium, carried by lymphatic system into general circulation. As a result, abnormally high levels can be detected in serum blood samples.
What is hemodynamic monitoring?
continuous assessment of cardiovascular system that is used to diagnose and monitor medical conditions. Direct pressure monitoring: CVP, pulmonary artery pressure and intra-arterial BP.
What is normal CVP (Central Venous Pressure)?
2-6 mmHG
What are the most common causes of elevated CVP (over 6 mm HG)?
Hypervolemia or right-sided HF
Intra-arterial BP monitoring is used for what
obtain direct and continuous BP measurements in critically ill patients who have severe hypertension or hypotension.
