ECG tracings

electrophysiology study (EPS)

procedure used to identify the cause/site of life-threatening cardiac arrhythmias by mapping the heart's conduction system in a patient with an arrhythmia

when to defibrillate

pulseless VT, VF, arrest

Second Degree Heart Block Type I (Wenckebach)

PR interval gradually lengthens as AV conduction time increases until a QRS is dropped. P-P is constant. Atrial rate is greater than ventricular rate. R-R is irregular. - usually a result of an MI or a warning sign of more serious AV disturbance (like a type 3)

3rd Degree Heart Block (Complete Heart Block)

- Impulses are completely disassociated - QRS & P-waves (atrial rate 60-100) seen, but irregular w/ no correlation btwn the two - Ventricular rate is slow and this impairs cardiac output. Can progress to ventricular standstill - complications: SCD

SVT treatment

- Mild (P150s-170, BP stable): vasovagal maneuver - Moderate (P170s-190+ BP unstable/SBP90): Adenosine given in antecubital vein nearest to heart on a 3-way stop cock w/ 20 ml flush immediately after - Severe (P190-230+, hypotensive/SBP<90): synchronized cardioversion

Symptoms & tx of Afib

- SX: SOB, palpitations, irregular pulses TX: goal is to decrease the ventricular response, prevent stroke, and convert to sinus rhythm - anticoags if >48hrs - antidysrhythmics to control ventricular rate (Cardizem, Amiodarone, Digoxin) - cardiovert if <48hrs w/ amiodarone - synchronized cardioversion w/ 50-100 joules, pt must be sedated - radiofrequency ablation if meds unsuccessful

Causes & clinical significance of v-fib

- VT deteriorates into VF within 3 mins - seen w/ myocardial ischemia, bradycardia, metabolic abnormalities, antidysrhythmic drugs, digoxin

Atrial Flutter Treatment

- anticoagulants if >48hrs - antidysrhythmics - CCB and b-blockers if <48hrs - electrocardioversion if unstable & <48hrs - may need radiofrequency catheter ablation

Adenosine ECG changes

- asystole may be seen following the administration of adenosine

Atrial Fibrillation

- disorganized atrial electrical activity (350-600 bpm) - ventricles either normal or in RVR (>100) - normal rhythmic atrial contractions are replaced by rapid irregular twitching of the muscular heart wall - associated w/ CAD, valvular dz, myopathy, HTN, HF, thyroid storm, EtOH toxicity, caffeine, stress) - results in decreased CO from ineffective atrial contraction & clots form causing stroke, MI, PE, & DVT

TX if Wenckebach

- if symptomatic, atropine can be used to increase HR & placed on temorary pacemaker - if asymptomatic, keep a transcutaneous pacer nearby

Cardioversion considerations

- pt w/ a-fib of unknown duration (>48hrs) must receive adequate anticoagulation for 4-6 wks prior to prevent thrombi dislodgement - hold digoxin 48hrs prior

Sinus Tachycardia

-HR 100-180 bpm -Normal equal P and QRS in all the leads, as well as normal PR intervals

Heart Block Poem

-If the R is far from the P then you have a first degree -Longer, longer, longer drop then you have a Wenkebach -if some Ps don't get through then you have a Mobitz II -If Ps and Qs don't agree then you have a third degree

1 small box

0.04 sec (40 ms) lateral/time 0.1mv vertical/amplitude

Normal QRS interval

0.06 - 0.1 sec (generally <.2 sec) 1 - 3 small boxes

Normal PR interval

0.12-0.20 seconds

1 large box

0.2 sec (200ms) 0.5 mv

Normal QT interval

0.34-0.44 represents time between electrical depolarization and repolarization of ventricles - as HR ↑, QT interval ↓

Paroxysmal Supraventricular Tachycardia (PSVT)

A dysrhythmia originating in an ectopic focus anywhere above the bifurcation of the bundle of His. starts & ends suddenly - P wave is often hidden in the preceding T wave, but if seen may have an abnormal shape. - The PR interval may be shortened or normal, and QRS is usually normal.

R on T phenomenon

A premature ventricular QRS complex in the ECG interrupting the T wave of the preceding beat; often predisposes to serious ventricular arrhythmias .

Ventricular tachycardia (VT)

A rapid heart rhythm in which the electrical impulse begins in the ventricle (instead of the atrium), which may result in inadequate blood flow and eventually deteriorate into cardiac arrest. - rate 150-250 bpm - exists when 3 or more PVCs occur in a row - may occurs w/ or without pulses

Sinus Arrhythmia

A sinus rhythm in which the rate varies with respiration, causing an irregular rhythm, HR increases slightly w/ inspiration & decreases w/ expiration. - remains 60-100 bpm

Torsades de pointes

A type of ventricular tachycardia in which depolarization impulses move from one ventricle to the other, resulting in a "twisted ribbon" appearance on the ECG tracing

Tx of monomorphic VT

Amiodarone IV

radiofrequency catheter ablation

An invasive procedure that uses radiofrequency waves to abolish an irritable focus that is causing a supraventricular or ventricular tachydysrhythmia.

Tx of Asystole

CPR and Epi This will NOT be defibrillated.

Premature Atrial Contraction

Contraction originating from ectopic focus in atrium in location other than SA node causing an early contraction - pt describes the feeling as palpitations or "heart skipped a beat"

Sinus Bradycardia

HR is less than 60 beats/min and rhythm is regular. - The P wave precedes each QRS complex and has a normal shape and duration. - The PR interval is normal. - The QRS complex has a normal shape and duration.

causes of PVCs

Hypokalemia, hypomagnesemia, excess caffeine, chemical imbalance, illegal drugs, alcohol.

Tx of polymorphic VT

IV phenytoin or IV Magnesium

TX of v-fib

Immediate defibrillation, CPR, intubation, ACLS, and medications (epi & amiodarone)

Polymorphic Ventricular Tachycardia

Occurs when the QRS complexes arise from multiple ectopic sites and gradually change back and forth from one shape, size, and direction to another over a series of beats.

Monomorphic Ventricular Tachycardia

QRS complexes that arise from the same ectopic site and are the same shape, size, and direction.

Atrial flutter

Rate:Atrial 250-350 Ventricular: 100 -175 P-wave: Irregular or absent, often "saw tooth" QRS: Normal Conduction: AV Block (2:1 > 3:1, 4:1) Rhythm: Regular (usually) - Often d/t underlying cardiac disease (CAD, HTN, valve disorder, lung dz, myopathy, hyperthyroid) - Results in CO and HF w/ increased risk of clotting

Tx of complete heart block

Requires emergency treatment. - temporary pacemaker used as bridge to permanent pacemaker. Atropine is NOT effective

First degree heart block

Slowed conduction through the AV node. PR interval prolonged (>0.20). Not life threatening. - normal HR & rhythm, normal P wave and QRS complex

Second Degree Heart Block

Some P waves are not conducted through the AV node; hence more P than QRS waves are seen. Dropped p waves are not preceded by prolonged PR. The ratio of P waves to QRS waves can be 2:1, 3:1 etc. - This AV block is more serious because more of the SA node impulses are not conducted to the ventricles and this is associated with rheumatic heart dx, CAD, anterior MI, & drug toxicity. Can progress into 3rd degree heart block

Asystole

Total absence of cardiac activity (Flat line).- no ventricular rate or rhythm, no pulse, no CO. - may occur d/t extensive myocardial damage, hypoxia, K+ imbalance, hypothermia, acidosis, OD, ARF.

Tx of Mobitz type I

Transcutaneous pacing until permanent pacer is placed. Atropine does NOT work

Couplet PVC

Two PVC's occurring together without any pause in between

Ventricular fibrillation (V-fib)

Uncoordinated depolarization of ventricles causing an irregularly irregular rate. Ventricles quiver, resulting in ineffective contraction -> no pulse or CO. - pt is unresponsive, apneic & pulseless • fine waves <3mm • coarse waves >3mm

Causes of PACs

Usually harmless -Excessive caffeine, alcohol, or tobacco, lack of sleep, medications -Myocardial ischemia or injury -Hypokalemia -Digitalis toxicity -CHF, COPD

When to use defibrillation

V-fib or pulseless VT

Pulseless Electrical Activity (PEA)

a condition in which the heart's electrical rhythm remains relatively normal, yet the mechanical pumping activity fails to follow the electrical activity, causing cardiac arrest

P-wave asystole

asystole with only p waves

1 mv

equal to 2 large squares on EKG grid, 10 mm high

Bigeminy PVC

every other beat is a PVC

Trigeminy PVC

every third beat is a PVC

Three or more consecutive PVCs

indicate Vtach

Premature Atrial Contraction (PAC)

irregular heart rhythm characterized by atrial contractions occurring before the expected time

Normal sinus rhythm (NSR)

regular rhythm of the heart cycle stimulated by the SA node (average rate of 60-100 beats/minute) - The P wave is normal, precedes each QRS complex, and has a normal shape and duration. - The PR interval is normal. The QRS complex has a normal shape and duration

sustained vs nonsustained vtach

sustained: lasts >30 seconds unsustained: last <30 sec

Premature Ventricular Contraction

ventricular contraction that occurs early and independently in the cardiac cycle before the sinoatrial node initiates an electrical impulse. -Early QRS with no P wave (large!), usually opposite the polarity of normal QRSs

When to use cardioversion

when a pt is unstable in VTw/pulse, PSVT, AFIB or AFlutter