a pt with a tricuspid valve disorder will have impaired blood flow
between the right atrium and right ventricle
a pt has a severe blockage in his right coronary artery. which cardiac structure is most likely to be affected by this
AV node
if the purkinje system is damaged, conduction of the electrical impulse is impaired through the
ventricles
the portion of the vascular system responsible for hemostasis is the
endothelial layer of the arteries
characteristics of 2nd degree AV block, mobitz 11
artial: usually normal & regular, ventricular: slower & regular or irregular; more P waves than QRS complexes; PR interval normal or prolonged; widened QRS, preceded by 2 or more P waves, with nonconducted(blocked) QRS complex
characteristics of 2nd degree AV block, Mobitz 1, wenchkebach
atrial: normal & regular, ventricular: slower & irregular; normal P wave; PR interval progressive lengthening; normal QRS width, with pattern of one nonconducted(blocked) QRS complex
characteristics of 1st degree AV block
normal & regular; normal P wave; >0.2 sec PR interval; normal QRS complex
charaterisitics of atrial fibrillation
artial: 350-600bpm, ventricular: ><100bpm & irregular; fibrillatory waves; PR interval not measurable; QRS complex normal
charaterisitics of Atrial flutter
atrial: 200-350bpm & regular; ventricular: ><100bpm & may be regular or irregular; sawtoothed pattern, more flutter waves than QRS complexes; may occur in 2:1, 3:1 or 4:1, etc pattern; PR interval not measurable; QRS complex normal
what are the charaterisitics of paroxysmal supraventricular tachycardia
150-220bpm & regular; abnormal shaped P wave, may be hidden in preceeding T wave; normal or shortened PR interval; normal QRS complex
what are the charaterisitics of premature atrial contraction
usually 60-100 bpm & regular; abnormal shaped P wave; normal PR interval & QRS complex
what are the charateristics of sinus tachycardia
101-200bpm & regular; normal P wave, PR interval & QRS complex
what are the charateristics of sinus bradycardia
<60bpm & regular; normal P wave; normal PR interval; normal QRS complex
what are the charateristics of normal sinus rhythm
60-100bpm & regular; normal P wave; normal PR interval; normal QRS complex
how many sec does each small box represent on a ECG strip
0.04 seconds
what is a normal duration of a P wave
0.06-0.12
what is a normal PR interval
0.12-0.2
what is a normal QRS interval
<0.12
what is a normal ST segment
0.12
what is a normal T wave
0.16
what is a normal QT wave
0.34-0.43
what is the relative refractory phase
period occurs slightly later in the cycle, & excitability is more likely
explain the flow of blood thru the heart
right atrium receives venous blood from the IFC, SVC & the coronary sinus; blood passes thru the tricuspid valve into the right ventricle; from the right ventricle thru the pulmonic valve into the pulmonary artery to the lungs; oxygenated blood flows from the lungs to the left atrium by way of the pulmonary veins; it then passes thru the mitral valve & into the left ventricle; blood is then passed through the aortic valve into the aorta which enters the systemic circulation
at what rate do the SA node, AV node & purkinje fibers fire
SA - 60-100bpm
AV - 40-60bpm
purkinje - 20-40bpm
what are the electrical charges associated with action potential
resting cell(polarized) (contraction of atrium) - positive outside, negative inside
stimulated cell(depolarized) (resting of atrium, contraction of ventricle, systole) - negative outside, positive inside
recovered cell(repolarized) (resting of ventricle, contraction of atrium, dialstole) - positive outside, negative inside
what are the non-modifiable risk factors for cardiac dx
positive family hx for heart problems; increasing age; gender until women reach menopause; race
what are the modifiable risk factors for cardiac dx
elevated BP; elevated blood cholesterol; cigarette smoking; elevated blood glucose(DM); obesity; physical inactivity; stress; use of oral contraceptives
Normal & abnormal with heart and JVD
jugular veins are frequently distended while the patient lies supine. as the patient's head is elevated, the distention of the veins will disappear. obvious distention of the veins indicate an abnormal increase in the volume of the venous system, cause by right-sided heart failure.
describe the location within the heart where the valves are
tricuspid valve - between right atrium & right ventricle; mitral valve - between left atrium & left ventricle; pulmonic valve - between right ventricle & pulmonary artery leading to the lungs; aortic valve - between the left ventricle to the aorta leading to systemic circulation
what do the heart sounds S1 & S2 represent
S1 = "Lub", systole, AV valves closed
S2 = "Dub", diastole, SV valves closed
Where is S1 best heard at
mitral (apical area) which is the apex of heart, left midclavical at the 5th ICS
where is S2 best heard at
2nd ICS just to the right or left of the sternum which is the base of the heart
what are LDL, HDL & triglycerides & what do they do
LDL - transport cholesterol to the peripheral cells, WNL=<130
HDL - takes cholesterol from the peripheral cells & brings it to liver, WNL=35-65men, 35-85women
triglycerides - source of energy, WNL=40-150
what does ECG stand for
electrocardiography
what is the difference between CVP & PA lines
CVP measures right ventricle pressure, as PA measures left ventricle pressure. CVP can use internal jugular or subclavian veins
how do you place the different limb leads for an ECG
Lead 1 - positive over left nipple, negative over right nipple
Lead 2 -positive midclavicular top of left abdominal quad, negative,right midclavicular just above the clavical
Lead 3 - just the opposite of Lead 2
aVr - inside the right shoulder; unipolar
aVl - inside the left shoulder; unipolar
aVf - just above the umbilicus; unipolar
V1 - 4th ICS right of sternal border; unipolar
V2 - 4th ICS left of sternal border; unipolar
V3 - half way between V2&V4 unipolar
V4 - 5th ICS left midclavicular line; unipolar
V5 - 5th ICS left of anterior axillary line; unipolar
V6 - 5th ICS left midaxillary line; unipolar
what should the nurse include in discharge teaching for a pt with a new permanent pacemaker
take & record a daily pulse rate; obtain & wear a medic alert id or bracelet at all time; avoid lifting arm on the side of the pacemaker above shoulder; but air travel is not restricted
a pt with a sinus node dysfunction has a permanent pacemaker inserted. before discharge, the nurse teaches the pt to
avoid high-voltage electrical generators; but air travel is not restricted
what is a sodium channel blocker & what is it used for
class 1A: procainamide(Pronestyl, ProcanSR) used for supraventricular & ventricular tachycardias
class 1B: lidocaine(Xylocaine) used for PVCs and ventricular tachycardia
what is a beta-blocker and what is it used for
propranolol(INderal) & metoprolol(Toprol) - decrease automaticity and conduction through the AV node. they also reduce the heart rate & myocardial contractility. they are used to treat supraventricular tachycardia and to slow the ventricular rate to atrial fibrillation, contraindicated for asthmatic pt r/t bronchospasm