click below
click below
Normal Size Small Size show me how
CC1 Unit 1&2
Coronary Care I
Question | Answer |
---|---|
Where does the right ventricle pump blood to? | pulmonary system (aka lungs) |
does the right ventricle deliver oxygenated or un-oxygenated blood? | un-oxygenated blood from the body to the lungs |
what is the approximate thickness of the walls of the right ventricle? | 4-5mm in thickness, relatively thin |
what are the names of the 2 valves attached to the right ventricle? | tricuspid and pulmonic valves |
Where does the left ventricle pump blood to? | systemic circulation (aka the body) |
does the left ventricle deliver oxygenated or un-oxygenated blood? | oxygenated blood received from the lungs to the body |
what is the approximate thickness of the walls of the left ventricle? | 8-15mm thickness, 2-3x that of the right ventricle |
what are the names of the 2 valves attached to the left ventricle? | mitral and aortic valves |
which rib numbers does the heart lie behind? | between the 2nd and the 6th ribs |
what is the name of the broad portion of the heart (upper right area)? | the base |
what is the name of the pointed end of the heart (lower left area)? | the apex |
where is the point of maximum (PMI) impulse heard best at? | the apex |
what are the names of the 3 inner layers of cardiac tissue? | epicardium, myocardium, endocardium |
what is the name for the outermost cardiac tissue surrounding the heart? | pericardium |
where is the pericardial sac located? | between the fibrous and serous pericardia |
what are the 2 types of pericardial tissue and describe their structure? | fibrous pericardium (tough fibrous outer layer) and serous pericardium (thin delicate smooth lining) |
which muscle layer forms most of the heart's wall? | myocardium |
where is an AV (atrio-ventricular) valve located? | between an atrium and a ventricle |
where is a semilunar valve located? | leading from a ventricle to a great vessel |
which valve only has 2 cusps? | mitral (bicuspid) valve |
what is the name of the left sided AV valve? | mitral valve |
what is the name of the right sided AV valve? | tricuspid |
what is the name of the valve that leads out of the left ventricle? | aortic valve |
what is the name of the valve that leads out of the right ventricle? | pulmonic |
what are the chordae tendoneae? | valve leaflets that open and close; strong cords of fibrous tendinous tissue; attached to the cusps of the AV valves and connect to the papillary muscles |
what are the papillary muscles? | muscles that attach to the ventricles and project into the ventricular cavities; continuous extensions of the chordae tendoneae |
what can dysfunction or rupture of a papillary muscle or chordae tendoneae lead to? | regurgitation |
what is the function of the chordae tendonaea and papillary muscles with respect to blood flow? | prevents valves from being pushed backwards, allows the valve to open in the correct position and propel blood in the right direction |
what are the 2 phases of the cardiac cycle? | diastole and systole |
what is another term for diastole? | relaxation phase |
what is another term for systole? | contraction phase |
what happens during diastole? | chambers are relaxed, filling with blood, tricuspid and mitral valves are open, blood flows from atrium to ventricle |
what percentage of ventricular filling occurs during the diastolic phase? | 80% |
what happens during systole? | hearts contracting phase occurs when enough blood has entered the individual chambers to propel blood volume |
what are the 2 phases of systole? | atrial systole and ventricular systole |
what is atrial systole? | ventricles are relaxed, atria contract pushing more blood into ventricles |
what is the atrial kick? | last 20% of blood volume being pushed into the ventricles |
what is ventricular systole? | ventricles contract and push blood out to the lungs and body |
which valves close during ventricular systole? why? | tricuspid and mitral valves close to prevent blood flow back into the atria |
which valves close after ventricular systole? why? | pulmonic and aortic valves close to prevent blood flow back into the ventricles |
what does automaticity mean? | the ability to initiate electrical impulses |
what does conductivity mean? | the ability to pass, conduct the impulses along to other cells |
what does contractility mean? | the ability to cause shortening of cardiac fibers |
where do electrical impulses original for normal heart beats? | SA node |
where is the SA node located? | on the endocardial surface of the right atrium |
what is the normally the primary pacemaker of the heart? | the SA (Sino-Atrial) node |
which cells in the heart have automaticity in a normal heart beat? | SA node |
what is the normal rate of impulses per minute from the SA node? | 60-100 times/minute |
when would the SA node stop initiating impulses? | if another area of the heart originates impulses at a rate more rapid than that of the SA node |
where are the intermodal tracts located? | between the SA node and the AV node |
what is the main role of the intermodal tracts? | the main role of the intermodal tracts is to transmit the impulse that has originated in the SA node and conduct it through the RA allowing the RA to contract |
where is the inter-atrial tract located? | between the two atria |
what is the main role of the inter-atrial tract? | conducts the impulse from the SA node to the left atria so that the LA can contract |
what is another name for the inter-atrial tract? | Bachman's Bundle |
where is the AV node located? | located in the lower right atrium |
what is the main property of the AV node? why is this important? | its ability to slow/delay the impulse before it reaches the ventricles allowing the atria the time they need to fully contract to fill the ventricles to capacity |
what is the AV junction? | the pathway that the impulse travels through on its route to reaching the ventricles |
what can serve as a backup pacemaker if the SA node were to become ischemic to fail? | the AV junction has automaticity meaning that if can initiate impulses if the SA node fails |
what is the impulse rate of conduction of the AV junction? | 40-60 impulses/minute |
what is the pathway of the electrical impulses? | SA node -> AV node -> AV junction -> bundle of HIS -> two bundle branches -> Purkinje Fibers |
where would electrical impulses be initiated if the SA node and AV junction were to both fail? | impulses would be initiated within the ventricles |
what would the rate of electrical impulses be if they were initiated in the ventricles? | 20-40 impulses/minute |
what is the cardiac output? | the volume of blood ejected by the left ventricle each minute |
what is the normal cardiac output? | 3.6-10 litres |
what is the equation to determine cardiac output? | heart rate x stroke volume |
what is the normal stroke volume in ml? | 60-100ml |
what influences the stroke volume? | preload, contractility, afterload |
what influences the heart rate? | the autonomous nervous system (sympathetic and parasympathetic) |
what is another name for preoad (LVEDP)? | left ventricular end diastolic pressure |
what is left ventricular end diastolic pressure? | the amount of stretch, tension, pressure within the LV at the end of diastole aka the amount of wall stretch, caused by the blood volume within the ventricules at the end of distaole |
what is preload? | the load of blood that establishes the initial muscle length of the cardiac fibers just prior to contraction |
what happens if not enough blood is in the left ventricle at the end of diastole before the LV contracts? | not enough blood will be ejected by the LV, thereby leading to a decrease in the cardiac output |
what influences preload? | venous return, status of the LV, atrial kick, status of the mitral valve |
how does the status of the mitral valve influence preload? | preload decreases with mitral stenosis as blood has difficulty leaving the LA, causing less LV stretch |
what is contractility? | the muocardial muscles ability to contract which reflect speeds and muscle shortening capacity of the myocardial fibers |
what are the major factors affecting contractility? | the ability of the muscle fibers to shorten |
what happens if the fibers cannot contract effectively? | less than optimum amounts of blood are ejected |
what is afterload? | the amount of stretch, tension, pressure against the LV during peak systole |
what influences afterload? | status of the aortic valve, blood viscosity, systemic vascular resistance |
how does blood viscosity affect afterload? | thin blood ejects with more ease than thicker blood |
how does vasoconstriction affect afterload? | increases afterload as the LV needs more push, energy or pressure to propel its blood volume into the constricted arteries |
how does vasodilation affect afterload? | afterload is reduced with vasodilatation as blood is easily propelled into the dilated vessels |
what influences the heart rate? | HR is influenced by the autonomic nervous systems (SNS and PSNS) |
what affect does a dominant sympathetic nervous system have on heart rate and CO? | HR >100; ventricles have less time to fill because they are contracting too rapidly, preload is decreased = CO decreased |
what affect does a dominant parasympathetic nervous system have on heart rate and CO? | HR <60; the slow rate allows time to fill but the SV reaches a max and cannot increase more volume = decreased CO |
what is the function of coronary arteries? | to bring oxygen-rich blood to the myocardium |
what are the 2 main coronary arteries? | Right and Left coronary arteries |
how does coronary artery blood flow through the layers of the heart? | from the outside (pericardium) to the inside (endocardium) |
what is the pathway of the right coronary artery (RCA)? | originates anteriorly off the aorta, lies between the RA and RV then travels posteriorly and descends inferiorly behind the heart |
which cardiac muscles are supplied by the RCA? | the right atrium, large portion of the RV, most of the inferior wall of the LV, part of the posterior wall of the LV, posterior 1/3 of interventricular septum |
what electrical structures are supplies by the RCA? | SA node (in about 55% of people), AV node and AV junction (in 90% of people), Bundle of His |
what is the pathway of the left coronary artery (LCA)? | originates anteriorly off the aorta, divides into 2 braches (LAD artery and circumflex artery) |
what are the names of the two branches of the left coronary artery (LCA)? | left anterior descending artery (LAD) and the circumflex artery |
what is the pathway of the left anterior descending artery (LAD)? | travels anteriorly over the interventricular septum, circles around the apex at the bottom of the heart, terminates in the inferior aspect of the cardiac apex |
which cardiac muscles are supplies by the LAD artery? | anterior walls of both ventricles, anterior 2/3 of interventricular septum |
which electrical structures are supplies by the LAD artery? | both bundle braches |
what is the pathway of the circumflex artery? | arises anteriorly from LCA, lies anteriorly between LA and LV, travels posteriorly around to the L side of the heart |
which cardiac muscles are supplied by the circumflex artery? | LA, lateral wall of LV, part of the posterior wall of LV |
which electrical structures are supplied by the circumflex artery? | SA node (45% of people), AV node and AV junction (10% of population), proximal bundle branches |
what are 6 parts of the assessment of chest pain? | location, severity, description, provoking/alleviating factors, type of onset, occurrence and duration |
what are other conditions that can cause chest pain that are not cardiac? | esophageal asps, hiatus hernia, cholecystitis, peptic ulcer, endocarditis, myocarditis, chest trauma |
what are palpitations? | awareness or sense of feelings ones own heartbeat |
where can palpitations be felt? | over the precordium or in the throat |
what often causes palpitations? | caffeine, alcohol, nicotine, bronchodilators, nasal decongestants |
what determines the urgency of treatment for palpitations? | the presenting clinical picture; can be a symptom of an arrhythmia or can be insignificant |
what is syncope? | a transient brief loss of consciousness due to cerebral anoxia |
what are accompanying symptoms to syncope? | pallor, nausea, diaphoresis, slow and shallow respirations, slow and weak peripheral pulses, hypotension |
what usually causes syncope? | vasodilation or overactivity of the parasympathetic nervous system (PSNS) which results in a slow HR |
what is peripheral edema? | an abnormal accumulation of fluids in interstitial issues, in the periphery |
how does gravity and ambulation affect peripheral edema? | ambulatory patients experience edema in legs and feet, bedridden pts develop edema over sacrum |
what areas can peripheral edema extend to? | abdomen (ascites), torso and face (anasarca) |
what is the likely cause of edema of the arm? | superior vena cava syndrome or thrombophlebitis |
what is the likely cause of edema that develops in one leg only? | thrombophlebitis or venous insufficiency |
what are some common signs and symptoms that occur with chest pain? | dyspnea, cough, decreased breath sounds, diaphoresis, changes in skin colour, weakness/fatigue, dizziness/headache, anxiety/sense of impending doom, nausea, vomiting |
what should you examine the chest for on a normal cardiac assessment? | symmetry of respiratory movement, presence of intercostal retractions, heaves, pulsations |
what are heaves? | strong outward thrusts of the chest wall |
where is the point of maximum impulses located? | at the left 5th intercostal space, medial to the med-clavicular line |
what can displace the PMI? | can be displaced by lung or rib cage abnormalities (pneumothorax, thoracic scoliosis) |
where should the apical pulse be palpated? | over the PMI |
what can heaves indicate? | a hypertrophied left ventricle |
what are thrills? | vibrations that feel like the throat of a purring cat |
what do thrills indicate | a heart murmur |
what does a murmur result from? | turbulent blood flow across a valve |
which sounds are best heard using the diaphragm of the stethoscope? | used to hear high pitched sounds (S1 and S2) |
which sounds are best heard using the bell of the stethoscope? | low frequencies (S3, S4, murmurs) |
what produces the LUB DUB sounds of the heart? | closure of the valves |
where is the best place to auscultate the aortic valve? | 2nd right intercostal space |
where is the best place to auscultate the pulmonic valve? | 2nd left intercostal space |
where is the best place to auscultate the tricuspid valve? | lower left sternal border |
where is the best place to auscultate the mitral valve? | 5th left intercostal space, just medial to the midclavicular line |
what produces the S1 LUB sound? | the closure of the mitral and tricuspid valves after atrial contraction; the end of ventricular diastole and the onset of ventricular systole |
what produces the S2 DUB sound? | closure of the aortic and pulmonic valves that close at the end of ventricular systole |
where is S2 heard best? | over the base of the heart |
what are adventitious heart sounds? | vibration-like sounds that occur within the ventricles; S3 and S4 |
what produces adventitious (S3, S4) heart sounds? | these sounds are created by gushes of blood entering stiffened or resistant ventricles; not produced by valve closure |
what is another name for heart sounds S3? | ventricular gallop |
what produces the S3 (ventricular gallop) sound? | caused by ventricular filling during atrial diastole in the congested heart (heart failure, pulmonary edema) |
what is another name for heart sounds S4? | atrial gallop |
what produces the S4 (atrial gallop) sound? | heard with increased resistance to ventricular filling when the ventricles cannot accommodate the last 20% of blood from the atria |
which cardiac complication is commonly associated with the S4 sound? why? | commonly heard after MI, because the ventricular damage leads to altered ventricular expansion and compliance |
what is a bruit? | heard over an artery, usually caused by narrowing of the artery |
what is a friction rub? what does it usually indicate? | grating leathery sound heard loudest at the left sternal border, that usually indicates pericarditis |
what is the first chamber of the heart to receive unoxygenated blood from the body? | the internal jugular vein delivers blood into the right atrium |
what is used to determine the jugular venous pressure? | the pulsation level of the internal jugular vein |
what can affect the pulsations in the jugular vein? | positioning and breathing; normally the vein is only visible with the patient laying flat not sitting or standing |
does position or movement affect the pulsations in the carotid artery? | no |
how do you observe the JVP? | HOB 30-45 degrees, locate suprasternal notched, turn patients head away from examiner |
what are elevated JVP? what does this indicate? | pulsations visualized higher than 4-5cm above suprasternal notch; indicates distension of the venous system |
what cardiac complications are usually associated with elevated JVP? why? | right sided heart failure, right sided MI, cor pulmonale; because of higher right sided cardiac pressures as the venous blood is struggling to empty into the RA |
what is a systemic approach to assessing arterial pulses? | starting at the top of the body and working downward |
what is assessed when looking at arterial pulses? | compare both sides of the body for rate, rhythm, strength and character |
how long should the rate of arterial pulses be counter for? | 1 full minute |
how is strength of arterial pulses graded? | 4+ bounding, 3+ increased strength, 2+ normal, 1+ weak, 0 absent |
what can an absent pulse indicate? | aortic dissection, atherosclerosis |
what is pulsus alternans? what can this indicate? | alternating high and low volume beats; left sided heart failure |
what is pulsus paradoxuis? what can this indicate? | reduction of pulse pressure on inspiration; common in cardiac tamponade |