Tachycardia
at the bedside
- full vitals, cardiac monitor
- definition → HR > 100 bpm; a rhythm itself rarely causes instability below 150 bpm
- confirm → recheck the rate, 12-lead ECG, compare with baseline
- sinus tachycardia from sepsis, pain, hypovolemia, hypoxia or anxiety → treat the cause, not the rate
- tachyarrhythmia → rhythm-directed plan in treat
escalate now if: unstable from the rhythm, any of
- hypotension or shock
- acutely altered mental status
- ischemic chest discomfort
- acute heart failure / pulmonary edema
- any of these → synchronized cardioversion; stable → SVT, VT, AF
focused check
- symptoms → palpitations, chest pain, dyspnea, presyncope
- triggers → pain, anxiety, hypovolemia, bleeding, caffeine, new drugs, withdrawal
- arrhythmia history; drug chart
- infection → fever, cough, dysuria, diarrhea, wounds, lines, devices → fever
- tachypnea or desaturation → think PE → Wells’ criteria for PE · MDCalc ↗︎
send now
- ECG
- narrow QRS < 0.12 s or wide ≥ 0.12 s; regular or irregular
- P waves and their relation to QRS; QTc, ischemia, pre-excitation
- common patterns
- narrow regular → sinus tachycardia, SVT, atrial flutter with fixed conduction
- narrow irregular → AF, flutter with variable block, MAT
- wide regular → treat as VT unless proven otherwise; SVT with aberrancy or pre-existing BBB possible
- wide irregular → pre-excited AF or polymorphic VT; avoid adenosine and AV-nodal blockers
- K, Mg, Ca; CBC; VBG with lactate if unwell; troponin if chest pain or ischemic ECG; TSH if suspected
- infection suspected → CRP, blood cultures, urinalysis, CXR
treat
sinus tachycardia
- treat the cause → sepsis, hypovolemia, pain, anxiety, drugs; correct K and Mg
- hypovolemic → balanced crystalloid 250–500 mL IV bolus, reassess before repeating
unstable from the rhythm → synchronized cardioversion
- cardiovert only when the rhythm itself is causing the instability, not sinus tachycardia from sepsis or hypovolemia
- call for help; pads on; IV access
- sedate if time allows; never delay the shock for sedation
- shock, sync confirmed before every shock
- atrial fibrillation → 200 J synchronized
- atrial flutter → 200 J synchronized
- regular narrow-complex tachycardia → 100 J synchronized
- monomorphic VT with a pulse → 100 J synchronized
- polymorphic VT → unsynchronized high-energy shock (defibrillation); torsades → magnesium sulfate 2 g IV over 10–15 min
- no success → resynchronise, increase the energy
stable narrow-complex regular (likely SVT)
- vagal maneuvers first → modified Valsalva: strain for 15 s, then lie flat with legs raised (Lancet video, 2 min ↗︎)
- adenosine
- adenosine 6 mg rapid IV push with an immediate saline flush; no response → 12 mg
- run a rhythm strip while giving it
- regular rhythms only; avoid in irregular wide-complex tachycardia and severe asthma
- lower dose through a central line or in a transplanted heart
stable regular monomorphic wide-complex (presumed VT)
- treat as VT unless proven otherwise; cardiology early
- adenosine only if regular, monomorphic and the rhythm is unclear; never in irregular or polymorphic wide-complex
- amiodarone 150 mg IV over 10 min, repeat if VT recurs; then 1 mg/min for 6 h, then 0.5 mg/min for 18 h
- can cause hypotension and bradycardia; not in pre-excited AF
atrial fibrillation
- cardiology; unstable → synchronized cardioversion
- rate control, target < 110 bpm at rest, on continuous ECG and BP monitoring
- metoprolol 2.5–5 mg IV over 2 min, up to 3 doses; not in decompensated HF
- verapamil 0.075–0.15 mg/kg IV over 2 min, may repeat after 30 min (diltiazem not stocked); narrow-complex only; not in wide-complex, pre-excited AF, hypotension, AV block or HFrEF
- digoxin in HFrEF or when the above are contraindicated
- becomes unstable → cardiovert
- rhythm control → treat the trigger first (sepsis); cardiology decision if rate control fails
- pre-excited AF (WPW), wide irregular → no adenosine, beta-blocker, verapamil, digoxin or IV amiodarone (AV-nodal block can precipitate VF); cardiology now, cardiovert if unstable
- anticoagulation
- AF ≥ 48 h or unknown duration → anticoagulate or TEE before elective cardioversion; < 48 h alone does not make it safe
- never delay urgent cardioversion for the anticoagulation decision
- long term → CHA₂DS₂-VASc · MDCalc ↗︎ · HAS-BLED · MDCalc ↗︎ flags modifiable bleeding risks, it does not by itself withhold anticoagulation
- hand over → rhythm, rate trend, drugs given, escalation trigger
evidence
| source | type |
|---|---|
| 2025 AHA Adult Advanced Life Support | international guideline |
| 2026 Surviving Sepsis Campaign | international guideline |
Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.
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reviewed 17 Aug 2026updated Oct 2026file vital/heart-rate-tachycardia