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cardio.post-arrest.tca-overdose.v1

Post-cardiac-arrest care — tricyclic antidepressant (TCA) overdose

cardiologyacuteadultacuteinpatienttransitionoutpatient
Start encounter →Print handoutPRODUCTION

Phase E variant of cardio.post-arrest.core.v1 — narrowed to TCA-overdose-induced cardiac arrest cohort. Multi-mechanism toxidrome: Na-channel blockade → QRS widening → R-on-T → VF; K-channel blockade → QT prolongation; α-adrenergic blockade → vasodilation; anticholinergic + serotonergic + CNS toxicity (seizures 10-20%). Implicated agents: amitriptyline, nortriptyline, doxepin, imipramine, clomipramine, desipramine, protriptyline, trimipramine. Lethal dose ≥10x daily therapeutic dose. ECG predictors (Liebelt 1995 PMID 7775314): QRS >100 ms predicts arrhythmia; QRS >160 ms predicts seizures + VF; terminal R-wave in aVR specific for TCA toxicity. DEFINITIVE therapy: SODIUM BICARBONATE 1-2 mEq/kg IV BOLUS for QRS widening or hypotension; infusion 150 mEq/L D5W at 250 mL/h targeting arterial pH 7.45-7.55 + QRS <100 ms; reverses Na-channel blockade by both alkalosis and sodium loading. AVOID Class IA (procainamide, quinidine, disopyramide), Class IC (flecainide, propafenone), Class III (amiodarone, sotalol) antiarrhythmics — all additive Na-channel or QT effects. AVOID phenytoin for seizures (Class IB additive). Lidocaine acceptable adjunct after bicarbonate. AVOID phenylephrine (pure α-agonist) — use norepinephrine. Refractory cardiac arrest unresponsive to bicarbonate → lipid emulsion 20% bolus + infusion (ACMT 2017); VA-ECMO bridge (INCEPTION extrapolation PMID 36720130) — lipophilic large Vd allows 24-48 h drug elimination during ECMO run. Mandatory co-ingestant screen: acetaminophen + salicylate + ethanol levels — TCA + APAP common combination for self-harm; missed APAP → fulminant hepatic failure 2-4 d later requiring NAC. Suicide risk evaluation MANDATORY (TCA OD nearly always intentional self-harm in adult population); 1:1 sitter throughout; psychiatry consult from ED; psychiatric admission required; means restriction counseling; SSRI/SNRI substitution discussion (TCAs no longer first-line for depression). Inherits manifest + design-brief pointer from parent. 5 setting playbooks (ed, icu, inpatient, transition, outpatient). 4 severity triggers: QRS >160 ms predicts seizures + VF, refractory VF unresponsive to bicarbonate + lipid, seizures with rhabdomyolysis, suicide risk with repeated OD or substance use co-morbidity. Status INTEGRATED. Authored 2026-05-15 by shard-06-cardio-acute Phase E wave 18 TCA-overdose post-arrest variant.

Entry points (4)

  • symptom
    ROSC after TCA-overdose cardiac arrest — wide-complex VT / VF rhythm reflecting Na-channel blockade with R-on-T phenomenon
    rosc_after_tca_overdose_arrest
  • imaging
    Wide QRS >160 ms with terminal R wave in aVR predicts impending VF / seizures in TCA OD (Liebelt 1995 PMID 7775314)
    wide_qrs_above_160_ms_pre_arrest
  • history
    Witnessed TCA ingestion (amitriptyline, nortriptyline, doxepin, imipramine, clomipramine, desipramine) with cardiac arrest — typically intentional self-harm in adult
    witnessed_tca_ingestion_with_arrest
  • history
    Patient with depression history found collapsed with empty TCA pill bottle / suicide note → suspect TCA OD with high lethality
    depressed_patient_with_collapse_pill_bottle_at_scene

Required inputs (22)

  • agerequired
    demographic • used at CONTEXT
    Older patients have higher mortality; informs prognosis discussion + ICU-care intensity
  • tca_agent_and_doserequired
    history • used at CONTEXT
    Agent identification (amitriptyline vs doxepin vs nortriptyline) and estimated dose (≥10× daily dose lethal); informs duration of monitoring given Vd
  • time_since_ingestionrequired
    history • used at CONTEXT
    Activated charcoal candidacy (<2 h post-ingestion + airway protected); peak toxicity 4–6 h; redistribution from tissues 24–72 h
  • co_ingestantsrequired
    history • used at CONTEXT
    Mixed OD common — acetaminophen (TCA + APAP common combo for self-harm) → check serum APAP level; benzodiazepine → augments sedation; alcohol → augments cardiotoxicity; SSRI → serotonin syndrome layered
  • suicide_intentrequired
    history • used at CONTEXT
    TCA OD is nearly always intentional self-harm in adult population; mandates psychiatry consultation + 1:1 sitter + means restriction counseling
  • down_time_minrequired
    history • used at CONTEXT
    Prolonged down-time → rhabdomyolysis from positional injury + seizure + worse hypoxic-ischemic encephalopathy + lower ROSC sustainability
  • arrest_witnessedrequired
    history • used at CONTEXT
    Witnessed + bystander CPR + low-flow time → favorable neuro prognosis; CAHP/OHCA score inputs
  • initial_rhythmrequired
    history • used at CONTEXT
    VF / wide-complex VT most common with TCA OD (Na-channel blockade + R-on-T); pulseless asystole reflects late terminal phase
  • low_flow_time_minrequired
    history • used at CONTEXT
    CPR duration → ECPR eligibility (INCEPTION PMID 36720130); neuro prognosis weighting
  • sbprequired
    vital • used at TREATMENT
    MAP ≥65 target post-ROSC; hypotension common from α-adrenergic blockade + cardiogenic depression
  • core_temprequired
    vital • used at TREATMENT
    TTM target 33–37.5 °C × 24h; anticholinergic toxicity may produce hyperthermia requiring active cooling
  • spo2required
    vital • used at TREATMENT
    Avoid hyperoxia: SpO2 92–98%; aspiration risk from AMS
  • ecg_12_leadrequired
    imaging • used at INITIAL_WORKUP
    QRS width is the central decision variable: >100 ms = bicarbonate indicated; >160 ms predicts seizures + VF; terminal R-wave in aVR specific for TCA toxicity (Bradberry); QTc for torsades risk; serial ECG q15-30 min initially then q4-6 h × 48 h for redistribution
  • troponinrequired
    lab • used at INITIAL_WORKUP
    Hypoxic myocardial injury post-arrest produces troponin elevation; rule out concurrent type-1 MI
  • tca_serum_level
    lab • used at INITIAL_WORKUP
    Confirms TCA exposure; not always available; not used to guide therapy (clinical + ECG drives); elevated levels >1000 ng/mL high lethality marker
  • acetaminophen_salicylate_ethanolrequired
    lab • used at INITIAL_WORKUP
    Mandatory co-ingestant screen in any intentional OD; TCA + APAP very common combination; missed APAP OD → fulminant hepatic failure 2-4 d later
  • ck_with_mbrequired
    lab • used at INITIAL_WORKUP
    Down-time + seizures → rhabdomyolysis → myoglobinuric AKI; CK >5000 high-risk threshold (Bosch 2009 PMID 19571284)
  • lactaterequired
    lab • used at INITIAL_WORKUP
    Tissue hypoperfusion + post-arrest perfusion debt; clearance trajectory drives prognosis (SCAI 2022 PMID 35718438)
  • creatininerequired
    lab • used at CONTEXT
    AKI risk from rhabdomyolysis + hypoperfusion; KDIGO 2012 staging
  • abgrequired
    lab • used at INITIAL_WORKUP
    Severe metabolic acidosis common; bicarbonate therapy targets pH 7.45-7.55 — ABG-driven
  • cxr_post_tca_arrestrequired
    imaging • used at INITIAL_WORKUP
    Aspiration pneumonitis from AMS; pneumothorax from CPR; baseline for ARDS evolution
  • echo_post_rosc
    imaging • used at INITIAL_WORKUP
    LV/RV function for post-arrest stunning; rule out concurrent ischemic precipitant if ECG concern

12-phase flow (12)

  1. 1FRAME
    TCA-overdose cardiac arrest — Na-channel blockade → QRS widening → R-on-T → VF; multi-mechanism toxidrome (Na-block + K-block + α-block + anticholinergic + CNS); SODIUM BICARBONATE is DEFINITIVE for cardiotoxicity; AVOID Class IA/IC/III antiarrhythmics; route to parent cardio.post-arrest.core.v1 for TTM + neuroprog and integrate suicide risk + psychiatric care
    inputs: tca_agent_and_dose, initial_rhythm
    advance: TCA etiology + co-ingestant screen + initial rhythm documented
  2. 2ENTRY
    Standard ACLS for VF (defibrillation); SODIUM BICARBONATE 1-2 mEq/kg IV BOLUS for QRS >100 ms or hypotension; secure airway / ventilate; AVOID Class IA/IC/III antiarrhythmics; consider lipid emulsion for refractory VF; consider VA-ECMO bridge
    inputs: age, arrest_witnessed, down_time_min
    advance: ACLS + bicarbonate + airway secured
  3. 3CONTEXT
    TCA agent + dose + time since ingestion + co-ingestants (especially APAP) + suicide intent + witnessed status + down-time + social history (mental health treatment, prior attempts) + allergies + cardiac history
    inputs: co_ingestants, time_since_ingestion, suicide_intent, low_flow_time_min, sbp, core_temp, spo2, creatinine
    advance: context + GOC + family + psychiatric screening initiated
  4. 4RED_FLAGS
    Refractory VF unresponsive to bicarbonate; seizures (10-20% of severe TCA OD); hypotension refractory to bicarbonate + IVF + norepinephrine; rhabdomyolysis with rising CK; severe APAP co-ingestion (TCA+APAP common); aspiration pneumonitis with ARDS; QRS continues to widen despite bicarbonate (consider ECMO); persistent altered mental status post-ROSC requiring extended sedation
    inputs: ck_with_mb, creatinine, sbp, ecg_12_lead, cxr_post_tca_arrest
    actions: cardiogenic_shock, wide_complex_tach
    advance: red flags screened + escalations triggered
  5. 5INITIAL_WORKUP
    ECG (QRS width central) + serial troponin + CK ± myoglobin + BMP + ABG + lactate + CBC + coags + UA + UDS + serum TCA level if available + acetaminophen + salicylate + ethanol levels (mandatory co-ingestant screen) + CXR + bedside echo + CT head if AMS unresolved
    inputs: ecg_12_lead, troponin, acetaminophen_salicylate_ethanol, ck_with_mb, lactate, abg, cxr_post_tca_arrest
    actions: post_arrest_care, panel.cardiac, panel.renal
    advance: workup complete + AKI risk + cardiac injury + co-ingestion screened
  6. 6BRANCHING_WORKUP
    STEMI on post-ROSC ECG → cath (uncommon in pure TCA OD); severe APAP co-ingestion → NAC protocol; refractory VF → VA-ECMO; severe rhabdomyolysis → IVF + nephrology; severe seizures → status epilepticus protocol
    advance: cardiac vs metabolic vs neurologic vs ECMO branching decided
  7. 7DIFFERENTIAL
    Pure TCA arrest (Na-block VF) vs TCA + concurrent ACS (independent precipitant) vs other Na-channel-blocking toxin (cocaine, diphenhydramine, quetiapine, citalopram, propoxyphene) vs hyperkalemic cardiac arrest (BMP) vs other Na-channel-blocking toxin (e.g., bupropion, hydroxychloroquine)
    advance: primary mechanism + co-precipitants established
  8. 8RISK_STRATIFICATION
    CAHP/OHCA scores; QRS width trajectory; CK trend + AKI stage; SCAI shock stage; MAP-IT score for psychiatric risk; Columbia Suicide Severity Rating Scale; cumulative bicarbonate dose; lipid emulsion need
    inputs: initial_rhythm, low_flow_time_min, sbp, lactate, ck_with_mb, creatinine
    actions: calc.map, calc.heart, calc.ckd_epi_2021, calc.cha2ds2vasc
    advance: risk class + AKI + neuro prognosis + psychiatric risk documented
  9. 9TREATMENT
    Continue sodium bicarbonate infusion 150 mEq/L D5W at 250 mL/h targeting arterial pH 7.45-7.55 + QRS <100 ms; aggressive IVF + UOP target 1-2 mL/kg/h if rhabdo; NAC if APAP co-ingested per Rumack-Matthew; norepinephrine for refractory hypotension (NOT phenylephrine); benzodiazepines for seizures; TTM 33-37.5 °C × 24h once stable; standard post-ROSC bundle; lipid emulsion 20% bolus + infusion if refractory; VA-ECMO bridge if unresponsive
    inputs: sbp, core_temp, spo2, creatinine, ck_with_mb
    actions: protocol.cardiogenic_shock
    advance: bicarbonate strategy + post-ROSC bundle + psychiatric care plan documented
  10. 10DISPOSITION
    CICU vs MICU per predominant problem; psychiatric consult + 1:1 sitter from ED through psych admission; multidisciplinary team — psychiatry + critical care + cardiology + nephrology + social work + toxicology
    advance: unit + service-line ownership + psychiatry consult booked + 1:1 sitter in place
  11. 11MONITORING
    Continuous telemetry × 48 h (TCA redistribution from tissues over 24-72 h → late re-arrest risk); arterial line; central line; Foley with hourly UOP target 1-2 mL/kg/h; serial ECG q4-6 h × 48 h for QRS / QTc surveillance; CK q6h until peak documented + downtrending; serial troponin + ABG; multimodal neuroprog ≥72h post-rewarm (Sandroni 2021 PMID 33745427); 1:1 sitter throughout
    inputs: ck_with_mb, creatinine
    actions: panel.renal, panel.cardiac
    advance: monitoring + extended cardiac surveillance + psychiatric supervision documented
  12. 12FOLLOWUP
    Inpatient psychiatry admission for involuntary or voluntary commitment; outpatient psychiatry within 7 d of d/c; PCP follow-up for mental health; means restriction counseling (medication storage, lethal-means reduction); SSRI/SNRI substitution discussion if depression treatment ongoing (TCAs no longer first-line for depression given fatal-OD risk); cardiology only if residual structural concern
    advance: psychiatry + outpatient mental health + means restriction + family education + safety plan booked