McCarthy EKG Flashcards by Paige Hamay

a normal P wave axis lies between what two degrees? (for adults and children)

0 and +70 for adults

0 and +90 for kids

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lead II’s positive electrode is at what degree?

+60

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what is the isoelectric line?

flat line between beats when there is no electrical activity

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beats originating in the SA node should generate what type of P wave?

upright (seen in lead II)

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what two arrhythmias are seen with a wide complex?

ventricular arrhythmia or SV arrhythmia aberrant

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BPM for SA node, atria, AV node, ventricles

SA- 60-100
Atria- 60-75
AV- 40-60
ventricles- 30-45

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how does the action potential spread from the SA node to left and right atria?

via the atrial internodal tracts

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why is conduction through the AV node slow?

to insure that the ventricles have enough time to fill before they are activated and contract (has a refractory period)

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what three things does increasing the conducting velocity of the AV node lead to?

decreased ventricular filling, stroke volume, and cardiac output

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what makes up the AV junction?

AV node and bundle of His

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junctional pacemaker cells = ?

AV node

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what makes up the ventricular conducting system?

right and left bundle branches plus purkinje system

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what is an ectopic pacemaker?

when failure of the SA node leads to another pacemaker taking over and setting the new rhythm

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besides SA node failure, how could other pacemaker cells (besides the SA node) take over?

altered automaticity- events that increase automaticity such as myocardial ischemia, increase sympathetic tone, HYPOkalemia

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describe escape or premature beats narrow complex VS wide complex

narrow complex escape/premature beats arise from above the bundle branches (AV node or atrium); wide complex beats are originating in the ventricles

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what is an escape beat?

rescue beats taking over rhythm from SA node (ALWAYS a pause before escape beat)

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is a P wave seen with an escape beat?

not usually since the pacemaker cell isn’t the SA node (and can hide within the QRS complex)

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narrow vs wide complex numbers?

narrow is less than 0.12 sec

wide is greater than 0.12 sec

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what is a premature beat?

a beat that occurs early within normal sinus rhythm

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atrial vs junctional premature beat

atrial p wave occurs early and ABNORMAL contour

junctional occurs early but usually doesn’t have p wave (sometimes retrograde, inverted)

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what are the three types of junctional rhythms?

1) . inverted p wave before QRS- atria depolarizing from bottom to top before ventricles depol
2) . atria and ventricles depolarizing at same time- p wave hidden in QRS
3) . inverted p wave after QRS- atria depolarizing bottom to top after ventricles depol

NSR PR interval and QRS complex

PR interval- 0.12-0.2 sec

QRS- NARROW (<0.12)

sinus tachy and sinus brady rates

tachy: 100-160
brady: 40-60

PSVT also called what two things?

AV nodal reentry tachycardia

Paroxysmal atrial tachycardia

PSVT: complex? rate? p waves?

narrow complex tachy, 150-250 bpm, usually no p waves seen (grouped with T wave)

what is PSVT usually initiated by?

a premature supraventricular beat (atrial or junctional)

atrial flutter: complex? rate? p wave? pattern?

narrow complex tachy, 250-350 rate, multiple p waves between QRS "sawtooth"- no flat baseline

three different types of conduction rates for atrial flutter?

variable- differing amounts of atrial vs ventricle rates 4: 1- 4 p waves to every 1 QRS 2: 1- 2 p waves for every 1 QRS

Afib: complex? rate? p waves? ventricle rate?

narrow complex tachy, >350 rate, no true p waves, ventricle rate is irregularly irregular (only occasional impulses passed from atria to ventricles)

what are the two main types of afib?

controlled rate (<100 BPM) vs uncontrolled rate (>100 BPM)

BBB- complex? rate? p wave?

WIDE complex, tachy rate, sinus p wave (if significant tachy, p waves might be buried in T wave)

PVC: complex? p wave? what is a PVC?

wide complex, usually no p wave seen | PVC: premature ventricular contraction

what is an escape ventricular beat?

PVC looking ventricular contraction that occurs after a pause (OCCURS LATE- compared to PVC)

should a ventricular escape rhythm be suppressed?

NO, could be life saving if its the only pacemaker the heart has left

what is ventricular tachy? complex? rate? p waves?

run of 3 or more PVC's in a row; WIDE complex tachy, 140-250 rate, no p waves

what is often seen in VT waves?

ST segment and T wave slope opposite direction than the deflected QRS

what is monomorphic vs polymorphic VT?

monomorphic- all the QRS complexes have the same appearance | polymorphic- varying amplitudes, shapes sizes

what is ventricular escape rhythm?

pause and then ventricles take over pacing

what three electrolyte imbalance can cause Torsades? why?

Hypocalcemia- because it prolongs the QT interval | hypokalemia and hypomagnesemia

what is torsades? how is it usually started?

it is polymorphic VT with prolonged QT interval; usually started by a premature PVC falling on a prolonged T wave

Vfib: complex? rate? p wave?

wide complex tachy, undistinguishable rhythm, NO p waves, QRS or T waves *NO ASSOCIATED PULSE*

first degree heart block: complex? special criteria?

``` narrow complex (unless BBB is present) **prolonged PR interval >0.2 seconds every p wave has a corresponding QRS ```

second degree heart block: two types? difference between the two?

Mobitz 1 "wenckebach" or Mobitz 2 - in both, a QRS is eventually dropped by PR interval in type 1 increases with every beat until QRS is gone (type 2= PR stays consistent)

Mobitz Type 1 complex? Type 2 complex? type 2 p waves?

type 1: narrow (unless BBB is present) type 2: narrow or wide depending on site of block type 2 p waves have multiple to every QRS

third degree heart block: complex? p waves?

narrow or wide; more p waves than QRS (looks like separation of p wave from t wave)

atrial vs ventricular rate for Type 1, 2nd degree heart block?

atrial- rate regular | ventricular- rate irregular

atrial vs ventricular rate for Type 2, 2nd degree block?

atrial- rate regular | ventricular- rate usually regular and a multiple of the atrial rate

atrial vs ventricular rate for 3rd degree block?

both rates usually regular (ventricular under 60 BPM)

what is asystole? what two ways can it present on EKG?

no ventricular activity, no QRS complexes EVER | presentation- as ONLY p waves or straight line

what is pulseless electrical activity (PEA)? what two things can it be due to?

an organized cardiac rhythm other than VT without a pulse | due to hypovolemia or hypoxia

what two things do you see with wolf Parkinson white?

PR interval less than 0.12 | delta wave

what happens in wolf Parkinson white?

an accessory pathway called "bundle of kent" is used to bypass slow conduction of AV node