ECG INTERPRETATION

Learning outcomes: An understanding of the principles of basic ECG interpretation and management of arrhythmias: Review of A&P of the conduction system To be able to recognize the normal & abnormal ECG Common arrhythmias -To identify the treatable causes.

Before starting….. Make sure leads are in the correct positioning (colour coded for a reason!) Clean skin (shave hair if required) Apply over bony parts Lead setting (II)

A&P of conduction system:

A&P continued:

What do I look for? Is it too fast? To slow? Regular? Erratic/ Irregular? Different shape/ size? Has it in any way changed?

What do I look for cont… -P wave: is there one present? The shape? Is there one before every QRS complex? -PR interval: is it between 0.12-0.2 secs (3-5 small squares)? Longer/shorter? -QRS complex: is there one after each P wave? Is it between 0.06-0.1 secs (1.5 squares)? Is it wide? Are they all the same shape? -ST segment: ST elevation? ST depression, T-wave inversion? -Rate: 1500 ÷ (number of small sq. between R-R waves) 300 ÷ (number of large sq. between R-R waves)

Examining the pt. -Check patient: AVPU?, clammy/sweaty, chest pain, confusion/agitation, SOB, feel unwell? -Is there any compromise to BP, CO,SpO2? -Set up a 12-lead ECG. -Possible underlying causes?

ECG Examples

Rhythms: SR, SB, ST.

Sinus Rhythm Rate : 60-100 Regular rhythm. P wave for every QRS complex; all P waves similar in size and shape. All QRS complexes similar in size and shape. Normal PR and QT intervals. Normal (upright and round) T waves.

Sinus bradycardia Rate <60 bpm -Causes: ? -Treatment: *full pt assessement & treat reversible cause *!!! , has regular rhythm, every P wave followed by QRS complex, normal PR interval. Is it a problem: If asymptomatic no probs ! HOWEVER can lead to further deterioration and decrese CO and further arrhythmias. Causes: Vagal stimulation, electrolyte imbalance, hypoxia, MI’s (inferior MI invoving RCA) sick sinus syndrome, post op (valve surgeries), hypothermia, drug toxicity ( digoxin, β-blockers, calcium channel blockers , amio). pacing if able, atropine, adrenaline , dopamine

Sinus tachycardia -HR > 100bpm Unlike SB , it is usually symptomatic. -Causes: -Treatment: full pt assessment & treat reversable causes regular rhythm, every P wave followed by a QRS complex. Causes: sepsis, hypovolaemia, pain, HF, cardiogenic shock, electrolyte imbalance, compensatory mechanism, hypoxia drugs… excersise. , identify if its atrial, supraventricular or ventricular. if atrial tachy(AF): dig, amio, β-blockers, DCCV. if SVT: adenosine, DCCV, verapamil if ventricular : electrolytes (Mg+), DCCV,

Ectopics:

Atrial ectopics (PAC’s) -PAC’s originate outside the SA node (irritable spot). -Causes: nicotine, caffeine, anxiety.. alcohol. -Monitor -Treat causes

Ventricular ectopics (PVC’s) -Unifocal /multifocal/ bigeminy/ trigeminy. -Causes: many -Why so serious ?: Causes: electrolyte imbalances, metabolic acidosis, hypoxia myocardial ischemia and infarction, drug intoxication, particularly cocaine, enlargement of the ventricular chambers, increased sympathetic stimulation, myocarditis, proarrhythmic effects of some antiarrhythmics. Seriousness: PVCs are significant for two reasons. First, they can lead to more serious arrhythmias, such as ventricular tachycardia or ventricu-lar fibrillation. The risk of developing a more serious arrhythmia increases in patients with ischemic or damaged hearts. PVCs also decrease cardiac output, especially if the ectopic beats are frequent or sustained. Decreased cardiac output is caused by reduced ventricular diastolic filling time and a loss of

Atrial arrhythmias

-Irregular firing from various points -Causes: ? - Treatment? Atrial fibrillation -Irregular firing from various points -Causes: ? - Treatment? -Loss of P waves -Decreased CO Causes, POST OP, MI, hypoxia, elect. imbalance, atrial enlargement, PE, valve issues. Treatment: rate control, cardioversion (either pharmalogical/ DCCV- whats the risk with this one), ablation, surgical procedure.

-Originates from one point, regular. Atrial flutter -Originates from one point, regular. Rate 200-300 bpm -P waves are ‘saw-toothed’ in apperiance -Causes: - If pt is unstable then rate control/ cardiovert, otherwise monitor and treat underlying cause.

SVT -Above the ventricles, many types (AVNRT, AVRT WPW). - Regular, R 150-200, P wave, ST. -Treatment: ? Treatment : cardiovertion DDCV/ drugs/ rule out any other causes

Life threatning arrythmias

….. -Wide complexes usually causes instability...CRASH TROLLEY!!! -ILS/ ALS protocol and think 4T’s or 4 H’s. - Requires cardioversion either by drugs/ electricity/ICD?

…… -Life threatening!!!!!!!!!!! -Immidiate action should be take, patient IS in full cardiac arrest. - Speedy response = speedy recover and good patient outcome.

…….. -A P wave may be seen however ventricles are not producing anything therefore NO ELECTRICAL ACTIVITY !!!! NO OUTPUT.. NOTHING! -Immediate ALS/ILS required.

Interventions and treatments -Oxygen (SpO2, PaO2) -Access (IV/CVC) -Replace electrolytes

Interventions and treatments cont.... -Cardioversion (special considerations) -Drugs - Assess effectiveness of treatment

Thank you