Palpitations

at the bedside

five steps, in this order

stability, and an ECG while it is happening → ABC; vitals, glucose, temperature, SpO₂, monitor, IV access; is the patient perfusing. 12-lead now, compare with the old one; a strip during the symptoms if they come and go → ECG on call
rhythm and dangerous features → sinus or not (a P before every QRS, gradual on and off); narrow or wide (QRS ≥ 120 ms); regular or irregular; QT
- sinus tachycardia is a sign, not a diagnosis → treat the cause (sepsis, hypovolemia, bleeding, pain, hypoxia), never rate control
why tonight → why admitted, what changed; drug chart and MAR: beta-blocker or digoxin held or missed, QT-prolonging drugs, salbutamol; K and Mg trend; fever, pain, bleeding, hypovolemia, hypoxia; new central line
treat the rhythm you identified → by stability, LV function and local protocol; unstable first
reassess → rate, rhythm, symptoms, BP, recurrence → reassess

escalate now if

hypotension, chest pain, pulmonary edema or altered mental state caused by the rhythm → synchronized cardioversion, call for help
pulseless, or polymorphic and deteriorating → arrest call, defibrillate
regular wide complex → VT until proven otherwise
irregular wide complex, very fast → pre-excited AF, no AV-nodal drugs
syncope or presyncope with the palpitations → arrhythmic until proven otherwise → syncope
known structural heart disease or heart failure, long QT, or family history of sudden death → cardiology tonight

differentials

by the ECG → ECG patterns

sinus → a trigger until proven otherwise (step 3), PE and hyperthyroidism included
narrow, regular, not sinus → SVT (sudden on and off); atrial flutter with fixed block (often 150 bpm, hides as “sinus at 150”)
narrow, irregular → AF; flutter with variable block; multifocal atrial tachycardia (lung disease)
wide, regular → VT; SVT with bundle branch block only if proven
wide, irregular → pre-excited AF (WPW); polymorphic VT, torsades if long QT
pauses or dropped beats → ectopics with a compensatory pause (benign if isolated); sinus pauses, AV block → bradycardia

normal ECG at the time of review

intermittent arrhythmia → catch it on a strip or telemetry; one normal ECG excludes nothing
anxiety → a diagnosis of exclusion, after the ECG and electrolytes

focused check

character → fast vs skipping; sudden or gradual onset and offset; duration; can the patient tap the rhythm
symptoms → chest pain, dyspnea, presyncope or syncope, sweating
triggers → as step 3, plus caffeine, alcohol, thyroxine, withdrawal; recent procedure
history → known AF or SVT, ischemic or structural heart disease, heart failure, thyroid disease, anemia
drug chart and MAR → beta-blocker or digoxin held, missed or changed, QT-prolonging drugs, anticoagulant (which one, last dose)
exam → perfusion and mental state; pulse deficit against the monitor; murmur, JVP, crackles; dry mucosa or fever; goiter, tremor

send now

ECG → 12-lead now, a strip during any episode, repeat after conversion
K and Mg → always with an arrhythmia; add Ca and renal profile if replacing IV, on digoxin, or in CKD
by presentation → CBC if pallor, bleeding or sinus tachycardia without a trigger; TSH if thyroid disease is possible; troponin if chest pain or ischemic ECG → troponin
heart failure features → NT-proBNP, CXR → dyspnea
coagulation before starting anticoagulation; infection suspected → fever
echo → new AF, murmur or heart failure, by the treating team; ambulatory monitoring is for the treating team

treat

step 4 → stability first, then LV function and local protocol

unstable from the rhythm: synchronized cardioversion

call for help; pads on; IV access
sedate if time allows; never delay the shock for sedation
shock, sync confirmed before every shock → AF or flutter 200 J; regular narrow complex 100 J; monomorphic VT 100 J; polymorphic VT → unsynchronized defibrillation
no success → resynchronize, increase the energy

cardiovert only when the rhythm itself causes the instability, not sinus tachycardia from sepsis or hypovolemia
shock persists after the rhythm is corrected → cardiogenic shock

sinus tachycardia

treat the cause, not the rate → fever: paracetamol 1 g PO/IV q6h and fever; pain: analgesia; hypovolemia: balanced crystalloid 250–500 mL IV, reassess
no beta-blocker for a compensatory sinus tachycardia: slowing it removes the compensation
K or Mg low → correct the documented value, no fixed target for everyone; with an arrhythmia → monitored IV replacement, Mg alongside → potassium, magnesium

hyperthyroidism → beta-blocker for rate and symptoms; thionamide and endocrine once confirmed
anxiety → only after the above are excluded

SVT: narrow, regular

modified Valsalva → strain for 15 s, then lie flat with legs raised (Lancet video, 2 min ↗︎)
adenosine 6 mg rapid IV push with an immediate flush, strip running; no response → 12 mg
not terminating → cardiology

regular rhythms only → never in AF or an irregular wide complex; lower dose through a central line or in a transplanted heart

AF: narrow, irregular

unstable from the rhythm → cardioversion, not a drug; fast from sepsis, bleeding, PE or pain → treat that first
rate control, target < 110 bpm at rest, on the monitor
- metoprolol 2.5–5 mg IV over 2 min, up to 3 doses, or bisoprolol 2.5–5 mg PO OD; not in decompensated heart failure
- beta-blocker not tolerated and LVEF > 40% → verapamil 0.075–0.15 mg/kg IV over 2 min (diltiazem not stocked); not in HFrEF, hypotension, AV block or wide complex
- HFrEF, or soft BP but perfusing → digoxin 0.25–0.5 mg IV/PO by weight, renal function and age (less if elderly, renal impairment or low weight); amiodarone only after cardiology
rhythm → recent-onset AF often converts once the trigger is treated; rhythm strategy and elective cardioversion are cardiology decisions
anticoagulation → never delays urgent cardioversion; AF ≥ 48 h or unknown onset → 3 weeks of anticoagulation or TEE before elective cardioversion, then at least 4 weeks after
- anticoagulate on the stroke risk, not the rhythm, whether or not sinus returns
- DOAC, unless mechanical valve or moderate to severe mitral stenosis → warfarin
- HAS-BLED fixes modifiable risks and books closer review; it never withholds anticoagulation

which score, and where the guidelines differ

2024 ESC → CHA₂DS₂-VA, sex dropped: anticoagulate at ≥ 2, consider at 1; early cardioversion without anticoagulation or TEE only if AF is clearly < 24 h
2023 ACC/AHA/ACCP/HRS → CHA₂DS₂-VASc, decision framed on annual stroke risk ≥ 2%; keeps the 48 h framework
either way the score prompts the decision, it is not the decision

calculator CHA₂DS₂-VASc · MDCalc ↗︎ · HAS-BLED · MDCalc ↗︎

VT: wide, regular

treat as VT unless proven otherwise; cardiology now; no verapamil, no diltiazem
unstable → synchronized cardioversion 100 J
stable monomorphic VT → amiodarone 150 mg IV over 10 min, repeat if VT recurs, then 1 mg/min for 6 h and 0.5 mg/min for 18 h; the only amiodarone use here → tachycardia
polymorphic → pulseless or deteriorating: defibrillate; long QT (torsades): magnesium sulfate 2 g IV over 10–15 min, stop QT-prolonging drugs, correct K and Mg → magnesium

pre-excited AF (WPW): wide, irregular

irregular, wide, often > 200 bpm → AF conducting down an accessory pathway
no AV-nodal block → no adenosine, verapamil, diltiazem, beta-blocker, digoxin or IV amiodarone: they can accelerate the pathway and cause VF
unstable → synchronized cardioversion; stable → cardiology or EP now before any drug; if drug conversion is chosen, procainamide or ibutilide

step 5 → reassess

when → on the monitor; 15 min after each IV dose, 30 min after oral, then hourly until rate and BP hold

what → rate, rhythm on a strip, symptoms, BP, perfusion, recurrence; 12-lead after any conversion; K and Mg after replacement
not working → still > 110 bpm after the ladder, recurring, or any new instability feature → cardiology now; unstable → cardioversion

shock develops → hypotension, vasopressors & inotropes
hand over → rhythm, drugs given and when, K and Mg, cardiology plan, escalation trigger, next review

evidence

source	type
2025 AHA Adult Tachycardia With a Pulse algorithm	international guideline
2023 ACC/AHA/ACCP/HRS atrial fibrillation guideline	international guideline
2024 ESC atrial fibrillation guideline	international guideline

Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.

see also, MOC+ Volume 2: Cardiopulmonary covers the new-arrhythmia workup: SVT, AF, ectopics. browse the library.

go deeper MOC+ Vol 2 · Cardiopulmonary covers this in the full reference, or the complete set.

free the on-call checklist covers the whole shift on one printable page.

reviewed Jul 2026updated Oct 2026file complaint/palpitations