ECG - visuals Flashcards
Name this rhythm?
sinus bradycardia
HR < 60 bpm (here, about 30 bpm)
pacemaker: SA node
P waves, QRS complexes and PR intervals appear normal
Name this rhythm?
sinus bradycardia
HR < 60 bpm (here, about 40 bpm)
pacemaker: SA node
P waves, QRS complexes and PR intervals appear normal
Name this rhythm?
sinus tachycardia
HR > 100 bpm (but under 180-200, as SA can only go to about 200 as a pacemaker)
HR > 100 bpm healthy in kids and exercising adults
otherwise normal
BONUS: Name some causes of sinus tachycardia?
- naturally high in children
- normally high in adults during exercise
- normally high in adults during emotional event
- could be due to volume depletion (ex. dehydration, blood loss, etc)
- could be due to increased energy demands (hyperthyroid, pheochromocytoma, hyperthermia)
- impaired cardiac filling (pericardial tamponade, tension pneumothorax)
- decreased afterload (septic shock, anaphylaxis)
Name this rhythm?
sinus tachycardia
HR >100 bpm
pacemaker: SA node
Name this rhythm?
First Degree Heart Block
hallmark: wide PR interval, but all P waves conducted
(slow conduction in the AV node, delay in AV node, SA function normal)
possible causes: ischemia, firbrosis
Name this rhythm?
First Degree Heart Block (here with sinus bradycardia)
hallmark: wide PR interval, but all P waves conducted
(slow conduction in the AV node, delay in AV node, SA function normal)
possible causes: ischemia, firbrosis
Name this rhythm?
Second Degree Heart Block Type I (Wenckebach)
Hallmarks: irregular rhythm with pattern
P appearing at regular interval, with some “missing” QRS complexes ( P> QRS)
PR intervals increase, then reset; repeat
Some but not all P waves are conducted to ventricles
As PR intervals increase, they become so long they can no longer “reach” ventricle -> depolarization stops at AV node , thus QRS does not happen. After a “dropped” beat, the AV node “restarts” and QRS complexes re-appear until PR is too long again.
Name this rhythm?
Second Degree Heart Block Type I (Wenckebach)
Hallmarks: irregular rhythm with pattern
P appearing at regular interval, with some “missing” QRS complexes ( P> QRS)
PR intervals increase, then reset; repeat
Some but not all P waves are conducted to ventricles
As PR intervals increase, they become so long they can no longer “reach” ventricle -> depolarization stops at AV node , thus QRS does not happen. After a “dropped” beat, the AV node “restarts” and QRS complexes re-appear until PR is too long again.
Name this rthythm?
Second Degree Heart Block Type II
Hallmarks: More Ps than QRS complexes (regular Ps with some “dropped” QRS complexes). Consistent with type I block, some but not all P waves make it to ventricles
Unline second degree heart block type I, type II has constant PR intervals.
2nd degree block Type II is more dangerous, as it is more likely to progress to 3rd degree block.
Name this rhythm?
Third Degree Heart Block
Hallmarks: P waves and QRS complexes completely dissociated from each other: atrial rate is different from ventricular rate
Complete P wave block, no P waves make it to ventricules
Wide QRS complexes (usually)
Pacemaker for atria: SA node
Pacemaker for ventricles: usually ventricular ectopic (non AV) -> slow travel time for electrical impulses (travelling through myocardium and not through “normal” electrical conducting system -> wide QRS
Pacemaker for ventricles can be low AV (rarely), in which case QRS complexes will be normal
Name this rhythm?
Third Degree Heart Block (complete)
Hallmarks: P waves and QRS complexes completely dissociated from each other: atrial rate is different from ventricular rate
Complete P wave block, no P waves make it to ventricles
Wide QRS complexes (usually)
Pacemaker for atria: SA node
Pacemaker for ventricles: usually ventricular ectopic (non AV) -> slow travel time for electrical impulses (travelling through myocardium and not through “normal” electrical conducting system -> wide QRS
Pacemaker for ventricles can be low AV (rarely), in which case QRS complexes will be normal
Name this rhythm?
Atrial Flutter
“sawtooth” pattern of P waves, many more P waves than QRS complexes
= extreme atrial tachycardia, atrial rates of 300 (much higher than AV node can pick up and conduct) -> AV node blocks every X number of atrial impulses. If AV blocks 1 out of every 2 atrial impulses, 2:1 block (common), there is also 3:1, 4:1 etc
Since atrial contraction can reach 300, sometimes P waves may not be obvious at all. Suspect atrial flutter anytime ventricular rates are above 150.
Name this rhythm?
Atrial Flutter
“sawtooth” pattern of P waves, many more P waves than QRS complexes
= extreme atrial tachycardia, atrial rates of 300 (much higher than AV node can pick up and conduct) -> AV node blocks every X number of atrial impulses. If AV blocks 1 out of every 2 atrial impulses, 2:1 block (common), there is also 3:1, 4:1 etc
Since atrial contraction can reach 300, sometimes P waves may not be obvious at all. Suspect atrial flutter anytime ventricular rates are above 150.
Here atrial flutter with 2:1 block, P waves difficult to see because of high rate.
Name this rhythm?
Atrial Fibrillation (a.fib or AF)
Hallmarks: HR> 80 (but not required), no P waves, very “noisy” patterns
Atrial has multiple “pacemakers” with multidirectional electrical activity quivering, loss of P waves. This uncoordinated electrical activity keeps stimulating AV node until it is out of refractory period and responds with signal propagation - > pattern is irregular and often tachycardic (since so many electrical impulses present in atria)
Be very careful about blood clots! Atria are fibrillating, NOT contracting - > blood is not moving well and can easily form clots -> danger of emboli in other parts of the body (brain, kidneys, …) -> put patient on anti-coagulants & control heart rate