Flashcards in CVS Deck (53)
What is starling's law?
the greater the stretch, the greater the contraction
Identify 4 unique functional properties of cardiac cells.
automaticity - independent electrical activity and initiation
excitability - ability to respond to external stimuli (chemical, mechanical, or electrical)
conductivity - conducting electrical activity from cell to cell
contractility - contraction in response to stimulus
What happens when Beta 1 sympathetic receptors are stimulated?
increased heart rate, increased force of contraction, increased speed of conduction via the AV Node, increased oxygen consumption
What happens when beta 2 adrenergic receptors are stimulated?
affects the heart, lungs, and skeletal muscle by dilation, and increased organ perfusion
What is the inherent rates of the SA node?
What is the intrinsic rate of the av junction?
What is the intrinsic pacemaker rate of the purkinje fibres?
What does PQRST mean?
P - Precipitating factors
Q - Quality and Quantitative
R - Radiating
S - Signs and Symptoms
T - Timing and Treatment
What are the characteristics of S3?
end diastolic sound, normal in pregnancy, children, and YA due to rapid ventricular feeling, abnormal after 40 years. Causes are acute MI, heart failure, valve disease, systematic or pulmonary hypertension
Why are hemoglobin, WBC and platelets so important when assessing your adult cardiac patient?
Hemoglobin oxygen carrying capacity not below 90
WBC inflammation, infection
Platelets - risk of coronary artery disease - increased clotting factors
How does magnesium affect the heart?
affects AV node conduction
How does creatine kinase show cardiovascular function?
-enzyme specific to brain, myocardium, skeletal muscle
-followed to determine timeline of the injury
-level rises 4 - 8 hours, peaks in 24 hours, decreases in 48-72 hours
-CK - MB enzyme more specific to myocardium
How does troponin show cardiac function?
released into the circulation with cellular damage
specific to myocardial cells - most sensitive indicator of myocardial damage
rises in 4 to 6 hours; remains detectable for 7 - 15 days (is undetectable by 2 weeks)
How does BNP indicate cardiac function?
brain natriuretic peptide
hormone secreted from the ventricles of the heart
secreted in response to changes in pressure (stretch) occurring when heart failure develops and worsens
How does CRP indicate cardiac function?
indicates acute inflammation
trend more beneficial
increased CRP levels correlate with increased cardiac risk
-threeford increase in risk of acute MI
How does HbgA1c indicate cardiac function?
minor component of hemoglobin to which glucose is bound
higher the glucose concentration in blood, higher the level of HbA1c
not influenced by daily fluctuations in blood glucose; reflects average glucose levels over prior six to eight weeks
What is the formula for figuring out MAP?
SBP + 2 DBP divided by 3
What are the characteristics of central venous pressure?
reflects preload - end diastolic volume
normal 2 - 6mmHg
mean reading used
obtained through CVC
What is the normal ejection fraction?
the amount of resistance to flow the ventricles must overcome to eject blood from the heart
increased afterload means an increased workload of the heart
What are the steps to troubleshooting a pacemaker?
1. find pacemaker rate
2. should it have fired? if there is an intrinsic beat between pacer beats it shouldn't fire
3. is it sensing?
hardening of the arteries
chronic inflammatory disorder
formation of plaque with fibrous cap
define coronary artery disease
progressive atheroslerotic disoder, narrowing to complete occlusion of coronary arteries.
What are the three types of angina?
stable - predictable, specific triggers, responds to treatment
unstable - unpredictable, increased frequency, increased duration, no response to treatment
variant - prinzmetal angina, coronary artery spasm, occurs with or without atherosclerotic lesions
What are the immediate treatments for a suspected MI?
initiate medications such as ASA and clopidigrel
What do beta blockers do?
decreases cardiac workload, myocardial O2 demand, decreases risk for tachyarrythmias
What do ACE inhibitors do?
blocks conversion of angiotensin I to angiotensin II
prevents Na and water reabsorption
What are the considerations to unfractionated heparin?
response to medication unpredictable
narrow therapeutic window
closely monitor PTT
acts within minutes of administration