Bedside Telemetry and Rhythm-Strip Recognition
The daily IMCU/ICU skill — read a strip systematically with the normal intervals, name the rhythm and the AV blocks, recognize torsades, separate artifact from emergency, and respond to the patient not the monitor.
Learning Objectives
- 1.Read a rhythm strip with a repeatable system (rate, regularity, P waves, PR, QRS) and know the normal intervals.
- 2.Recognize the common rhythms, the AV blocks, and the lethal rhythms at the bedside.
- 3.Manage alarms safely — distinguish artifact, recognize torsades, and always assess the patient.
Overview
On a monitored unit you’ll look at telemetry all day. The goal isn’t formal 12-lead expertise — it’s a fast, reliable bedside read: name the rhythm, decide whether it’s benign or dangerous, and check it against the patient in front of you.
A repeatable system
- 1.Rate — fast, slow, or normal?
- 2.Regularity — regular, regularly irregular, or irregularly irregular?
- 3.P waves — present, absent, or abnormal? One before every QRS?
- 4.PR interval — normal, long, or variable?
- 5.QRS — narrow (supraventricular) or wide (ventricular until proven otherwise)?
Estimate rate and intervals
- •Rate: 300 ÷ the number of large boxes between QRS complexes (the 300-150-100-75-60-50 sequence), or count QRS complexes in a 6-second strip × 10 (best for irregular rhythms).
- •Normal PR interval: 120–200 ms (3–5 small boxes).
- •Normal QRS: <120 ms (under 3 small boxes); ≥120 ms is “wide.”
- •Watch the QTc — prolongation (especially >500 ms) raises torsades risk.
Common rhythms
- •Sinus rhythm / sinus tachycardia / sinus bradycardia — normal P-QRS relationship at varying rates.
- •Atrial fibrillation — irregularly irregular, no discrete P waves; atrial flutter — “sawtooth” flutter waves, often regular.
- •SVT — narrow-complex, regular, fast (often ~150–250).
- •PVCs — early wide beats; frequent/runs deserve attention.
- •Paced rhythms — look for pacer spikes; correlate with the clinical picture.
The AV blocks
- •First-degree: PR >200 ms but every P conducts — usually benign.
- •Mobitz I (Wenckebach): the PR progressively lengthens until a beat drops — usually benign and nodal.
- •Mobitz II: the PR stays constant, then a QRS suddenly drops — DANGEROUS (can progress to complete block); think pacing.
- •Third-degree (complete): P waves and QRS complexes march independently (AV dissociation) — an emergency; escalate for pacing.
Escalate
Mobitz II or complete (third-degree) heart block — especially with symptoms, hypotension, or a slow escape rhythm — needs urgent escalation and pacing readiness (transcutaneous pads ± transvenous pacing). Don’t wait it out.
The lethal rhythms
- •Ventricular tachycardia — wide-complex, regular, fast; treat a wide-complex tachycardia as VT until proven otherwise.
- •Ventricular fibrillation — chaotic, no organized complexes → pulseless → start CPR / activate the code.
- •Torsades de pointes — a polymorphic VT that “twists” around the baseline, tied to a long QT; treat with IV magnesium and correct the QT/cause.
- •Asystole — flat line; a significant pause/asystole on telemetry demands an immediate patient check.
Assess the patient first
For any lethal-appearing rhythm (VT, VF, torsades, asystole, long pause), go to the bedside and check the patient immediately — if pulseless, start CPR and call the code. The patient, not the monitor, drives the response.
Artifact vs the real thing
- •Motion, a loose/disconnected lead, shivering, or brushing teeth can mimic VT/VF on the screen.
- •The tell: a comfortable, talking patient with a “lethal” tracing is almost certainly artifact — but you verify by SEEING the patient, never by ignoring the alarm.
- •Fix lead placement and skin prep to cut nuisance alarms (and alarm fatigue).
Lead choice matters
- •Monitor a lead where the P waves and QRS are clearest — lead II is good for rhythm and P waves.
- •V1 (or MCL1) helps distinguish VT from SVT-with-aberrancy by QRS morphology.
- •Good skin prep and correct lead placement cut nuisance alarms and false rhythms.
Alarm management & QT
- •Respond to the patient, not just the alarm; set clinically appropriate alarm limits to reduce alarm fatigue without silencing real events.
- •Monitor the QT interval in patients on QT-prolonging drugs or with electrolyte derangements (torsades risk) — and replete K⁺/Mg²⁺.
- •When the rhythm is unclear or changes, get a 12-lead EKG to confirm.
Scope
In the ICU/IMCU, APPs work under physician/intensivist direction and unit protocol — recognizing the problem early, starting protocolized care, titrating drips to ordered goals, and escalating. Initiating advanced therapies and running the resuscitation are team decisions; know your institution’s scope and code roles.
Common beginner mistakes
- •Treating (or “shocking”) artifact instead of checking the patient.
- •Silencing alarms without assessing the patient (dangerous alarm fatigue).
- •Calling a wide-complex tachycardia “SVT with aberrancy” and under-reacting — assume VT until proven otherwise.
- •Missing Mobitz II / complete heart block, or not recognizing torsades (and forgetting IV magnesium).
- •Not getting a confirmatory 12-lead when the strip is ambiguous.
Nurse / MA workflow connection
- •Monitor techs and nurses catch and call telemetry changes and run the strips; you correlate the rhythm with the patient, decide on a 12-lead/treatment, and escalate lethal rhythms.
Mini cases
Telemetry alarms for a wide-complex, regular, fast rhythm at 180; the patient is pale, diaphoretic, and hypotensive.
Read and action?
Show answer
Treat as ventricular tachycardia (wide-complex tachycardia until proven otherwise). The patient is unstable → urgent synchronized cardioversion and escalation per ACLS. Get a 12-lead if it doesn’t delay treating the unstable patient.
The monitor shows a chaotic “VF-like” tracing, but the patient is sitting up brushing their teeth and feels fine.
Most likely, and what do you do?
Show answer
Most likely motion artifact — but you confirm by going to the bedside and checking the patient (pulse, appearance) rather than assuming. Never silence/ignore the alarm without laying eyes on the patient; then fix the leads.
A bradycardic patient has a strip where the PR interval is constant and then a QRS suddenly drops, with no progressive lengthening.
Which block, and why does it matter?
Show answer
Mobitz II second-degree AV block — dangerous because it can progress to complete heart block. Escalate, monitor closely, and have pacing (transcutaneous pads ± transvenous) ready, especially if symptomatic.
A patient on sotalol with a low magnesium develops a polymorphic VT that twists around the baseline; the QT was long beforehand.
Rhythm and first drug?
Show answer
Torsades de pointes. Give IV magnesium, stop QT-prolonging drugs, correct electrolytes (K⁺/Mg²⁺), and treat per ACLS (defibrillate if pulseless/unstable); overdrive pacing or isoproterenol may be needed for recurrent episodes.