EKG (All lectures) Flashcards
(42 cards)
How is the heart’s current measured?
An electrical current causes the heart to contract & the current spreads in the surrounding tissues. Some of this current goes to the surface of the body, which is measured by the electrodes placed on the body.
Look @ my EKG diagram, isoelectric diagram, & EKG Illnesses sheet.
-
The QRS complex is produced by the ____ of all the ventricular action potentials.
The plateau phase (phase 2) corresponds to the _____ segment of the ECG.
The ___ wave is produced by ventricular repolarization (phase 3).
The ____ segment corresponds to ventricular diastole, at the end of which atrial depolarization produces the P wave of the ECG.
The QRS complex is produced by the sodium upstrokes (phase 0) of all the ventricular action potentials.
The plateau phase (phase 2) corresponds to the ST segment of the ECG.
The T wave is produced by ventricular repolarization (phase 3).
The TP segment corresponds to ventricular diastole, at the end of which atrial depolarization produces the P wave of the ECG.
See pg. 120 of notes 3
Diastole begins at the dichrotic notch (drop in pressure & flow reversal) when the _____ valve closes.
The trampoline effect & flow reversal of the aortic valve @ the dichronic notch is what perfuses the _______ located @ the base of the aorta.
Diastole begins at the dichrotic notch (drop in pressure & flow reversal) when the aortic valve closes.
The trampoline effect & flow reversal of the aortic valve @ the dichronic notch is what perfuses the coronary arteries located @ the base of the aorta.
Does atrial contraction cause the blood to go into the ventricles?
No, the atrial contraction does not put any blood into the heart. This is why people with atrial arrhythmias do not lose any signifiant CO since CO is due to the action to the left ventricle.
The atrium does not contract until the ventricle is full, it contracts @ the very end.
First heart sound S1 is closure of the ____ (lub), & the second heart sound S2 is the closure of the _____ valves (dub).
S3 ________ & S4 ________.
First heart sound is closure of the AV valves (lub), & the second heart sound is the closure of the aortic & pulmonary valves (dub).
S3 diastolic filling of ventricles (evident in children) & S4 atrial contraction (pathologic).
P wave & Q wave _____ atrial & ventricular contraction respectively because depolarizations occur ______ contractions.
P wave & Q wave precede atrial & ventricular contraction respectively because depolarizations occur before contractions.
Jugular pulse follows _______ atrial pressure.
A wave follows _____ contraction
C wave follows closure of the ______
V wave is _____ filling & emptying
Jugular pulse follows right atrial pressure.
A wave follows atrial contraction
C wave follows closure of the tricuspid valve
V wave is atrial filling & emptying
Right atrium contracts _____ left atrium (due to proximity to SA node where wave starts), although they contract very close to one another.
Left ventricle contracts _____ right ventricle since AP starts @ SA but the current goes diagonally from upper right to lower left.
Right atrium contracts before left atrium (due to proximity to SA node where wave starts), although they contract very close to one another.
Left ventricle contracts before right ventricle since AP starts @ SA but the current goes diagonally from upper right to lower left.
Valve openings are right side _____ left side for the atrium & left side _____ right side for the ventricles.
Pressure in the pulmonary system (pulmonary artery) is _____ than in the systemic system (aorta) so the aortic valve closes ______ the pulmonary valve.
Valve openings are right side before left side for the atrium & left before right for the ventricles.
Pressure in the pulmonary system (pulmonary artery) is less than in the systemic system (aorta) so the aortic valve closes before the pulmonary valve.
Left ventricular contraction is before right ventricular contraction. Hence mitral valve closes before tricuspid valve closes. But pulmonary artery pressure is less than aortic pressure. Hence, pulmonic valve opens before aortic valve opens.
Aortic pressure is higher than pulmonary artery pressure. Hence, aortic valve closes before
pulmonary valve closes. Also, the drop in pressure in the left ventricle is larger and takes longer
than in the right ventricle. Hence the tricuspid valve opens before the mitral valve opens.
Analyze the Wiggers diagram on pg. 124 & watch YouTube video on Wiggers diagram.
-
Watch the pressure volume loop from handwritten tutorials & watch the 3 ECG/ EKG video from handwritten tutorials!
-
Describe the basic ECG features necessary for the recognition of cardiac arrhythmias.
-
Explain and classify the various forms of heart block.
-
Describe the diagnostic features of premature beats and the tachyarrhythmias.
-
What are the 3 things you look for in every EKG?
Rhythm
Conduction
Wave form
Where can rhythym originate & what is normal, fast, & slow? How do we name arrhythmia’s?
It can originate in SA, AV node-AV & AV junction, or ventricles.
60-100 B/min = normal
100 = tachycardia
So there is sinus bradycardia, AV node tachy, all we do is combine the top origin & the rate = arrhythmia etc.
1) What is the standard paper speed on an EKG?
2) How is EKG paper organized?
3) Each large square is ___ sec, so 1 sec is _____ squares?
4) Each small box is ___ sec & there are _____ in 1 min. There are ___ small boxes width wise in 1 large box.
1) 25mm/sec
2) Large (dark) & small (light) squares. In each big box, there are 5 smaller boxes.
3) 1/5 sec = .2 sec, so 1 second is 5 large squares
4) .2/5 = .04 sec. There are 1500 small boxes in 1 min. There are 5 small boxes width wise in 1 large box.
On an EKG, how do we calculate heart rate?
1) (# beats in 6 sec) x 10 = beat/min
2) 1500/ # small boxes between R-R interval **EASIEST METHOD
Typically, the HR is given on the top of the EKG.
see pg. 163
1) How do we measure AV conduction? What does it measure? Normal PR interval time?
2) How do we measure I-V conduction? What does it measure? Normal QRS complex time?
3) How do we measure QT interval? What does it measure? Normal QT interval time?
4) Which measurements are most important of arrhythmias?
1) PR interval is the time it takes for the current to get from the atrium into the ventricle. Normal is ≤ .2 sec (1 big box). Measures from onset of P wave to onset of QRS.
2) IV conduction is the time it takes for the ventricle to depolarize it is the duration of the QRS complex. Normal is ≤ .1 sec.
3) Onset of QRS to end of T wave (it has nothing to do with arrhythmias). It is the time it takes for depolarization & depolarization of the ventricles. It varies with HR so corrected form is QTc = square root of R-R interval. Normal ≤ .45 sec. “c” means corrected.
4) AV & IV conduction
1) What is the time of the PR interval on pg. 165?
2) What about QRS?
1) .2 - .04 = .16 sec
2) .08 sec = 2x(.04)
What doesn’t show up on EKG?
SA, AV node, bundle of his, bundle branches, purkinje volatages are so low that they do not show up on EKG. QRS complex covers up atrial repolarization.
Leads 1, 2, & 3 will show positive displacement on the ____ wave. This means that there is normal _____ rhythm & that the current comes from the ____node.
Leads 1, 2, & 3 will show positive displacement (upright) on the P wave. This means that there is normal sinus rhythm & that the current comes from the SA node.
You will always see an upright P wave in lead 2, if this is not occurring & it is inverted, then the current cannot be coming from the SA node & coming from somewhere else in a lower direction.
See pg. 166
Discuss normal conduction of the heart
SA node–>Atrium–>AV node–>AV junction–>His bundle–>Purkinje system–> Ventricles
