NPTE - ECGs

P wave

Atrial depol

<.12s (3 small boxes)

PR Interval

AV node delay

.12-.2s

QRS Complex

Ventricular depol

<.1s

Wide QRS = ventricular origin

Narrow QRS = supraventricular origin

ST Segment

Beginning of ventricular repol

Should be isoelectric

T wave

Ventricular repol

Rounded, upright (usually)

QT interval

Full ventricular depol + repol

.35-.44s (rate-dependent)

Paper speed

25mm/s

1 small box

.04s

1 large box (5 small boxes)

.2s

5 large boxes

1s

calculate HR (quick method)

Count large boxes btw R waves:

• 1 box = 300bpm

• 2 boxes = 150bpm

• 3 boxes = 100bpm

• 4 boxes = 75bpm

• 5 boxes = 60bpm

• 6 boxes = 50bpm

Normal Sinus Rhythm

Regular rhythm, P wave before every QRS

HR 60-100bpm

Normal PR and QRS intervals

Safe to tx

Monitor normally

Sinus Bradycardia

HR < 60bpm

Common in athletes, Beta-blocker use

If symptomatic (lightheadedness, fatigue): may need to hold PT

Sinus Tachycardia

HR > 100bpm

Often from p!, fever, anxiety, hypoxia

OK to treat if stable and asymptomatic

AFib

No P waves, irregularly irregular rhythm

Can result in decreased CO

If HR > 100bpm (rapid AFib) —> check with RN/MD before mobilizing

A Flutter

“Sawtooth” P waves

Atrial rate ~250-350bpm, with variable AV conduction

Treat similarly to AFib - monitor hemodynamic stability

PVCs

Wide QRS, no P wave before it

Occasional unifocal PVCs = often benign in healthy pts

PVC Red Flag

>6 PVCs/min, multifocal, or couplets —> may progress to VTach

VTach

3+ PVCs in a row

HR >100-250bpm

Wide QRS, regular rhythm, NO P waves

Medical emergency

Stop tx, call code if unresponsive

VFib

Chaotic, no organized QRS

No CO

Defibrillation required immediately

Asystole

Flatline

No electrical activity

Confirm in 2 leads

Start CPR, notify medical team

ST Depression

Ischemia

ST Elevation

Acute MI

If a pt develops new ST changes during exercise testing —> STOP IMMEDIATELY

T wave inversion

Ischemia/evolving infarct

Q wave

Old MI (>1 small box wide, deep)

Pacemaker rhythm

Look for a pacing spike before P/QRS

Ventricular pacemaker —> spike before wide QRS

Dual chamber —> spike before P and QRS

Stable rhythm = OK to tx, avoid electromagnetic interference (TENS near chest)

Controlled AFib

Safe to tx

Monitor rate and fatigue

Occasional PVC

Safe to tx

Monitor; stop if >6/min or symptomatic

Boards Tips

Wide QRS = ventricular origin

Irregular rhythm with no P waves = AFib

3 PVCs in a row = VTach

ST elevation = emergency (MI)

Know when to stop tx:

• new arrhythmia

• HR > 130bpm at rest

• Drop in BP >10mmHg with exertion

• lightheadedness, SOB, chest p!