Cardiovascular

Sustained ventricular tachycardia: management and ICD indications

Clinical Overview and When to Suspect Sustained VT

— Sustained VT: lasts ≥30 seconds OR causes hemodynamic compromise requiring termination sooner

— Nonsustained VT (NSVT): ≥3 beats but <30 sec, self-terminating, no compromise

— Wide-complex tachycardia in any patient with structural heart disease (prior MI, cardiomyopathy, HF) — assume VT until proven otherwise (>90% probability)

— Syncope or presyncope in a patient with reduced LVEF

— Palpitations + ICD shock

— Cardiac arrest survivor with shockable rhythm

— New wide-complex tachycardia in post-MI patient (especially >48 hrs out)

— Ischemic VT (most common): scar-mediated reentry around old infarct

— Nonischemic cardiomyopathy: dilated, hypertrophic, ARVC, sarcoidosis, Chagas

— Channelopathies with structurally normal heart: long QT, Brugada, CPVT, short QT

— Idiopathic VT: RVOT (LBBB+inferior axis), fascicular (verapamil-sensitive)

— Reversible triggers: electrolyte derangement, ischemia, drug toxicity (digoxin, QT-prolongers)

Board pearl: In any patient over 50 with prior MI presenting with wide-complex tachycardia, the default diagnosis is monomorphic VT — do not be misled by hemodynamic stability. Hemodynamic stability does NOT exclude VT; young hearts tolerate VT well for minutes.

Step 3 management: Your first triage question is always: pulse or no pulse? Pulseless VT = defibrillation (unsynchronized). VT with pulse = synchronized cardioversion if unstable, IV antiarrhythmic if stable.

Definition: Ventricular tachycardia (VT) is ≥3 consecutive beats at rate >100 bpm originating below the AV node with wide QRS (≥120 ms).

When to suspect on Step 3:

Etiologic categories:

Epidemiology framing: Sudden cardiac death claims ~300,000 US adults/year; the majority involve VT degenerating into VF. Most occur in patients with LVEF ≤35% and prior MI.

Presentation Patterns and Key History

— Asymptomatic (incidental telemetry capture)

— Palpitations, lightheadedness, dyspnea

— Presyncope or syncope (especially exertional → think structural or CPVT)

— Angina or HF decompensation from tachycardia-induced ischemia

— Cardiac arrest — VT degenerating into VF

— ICD shock — appropriate (VT/VF detected) or inappropriate (AF, lead noise, SVT)

— Prior MI, CABG, or PCI → ischemic substrate; ask year of MI

— Heart failure — current LVEF, ICD/CRT status, NYHA class

— Family history of sudden death <50 yo → channelopathy, HCM, ARVC

— Syncope during exertion or emotion → CPVT, LQTS type 1, HCM

— Syncope while sleeping or febrile → Brugada

— Medications: QT-prolongers (azithromycin, fluoroquinolones, methadone, ondansetron, antipsychotics), digoxin, diuretic-induced hypoK/hypoMg

— Substance use: cocaine, methamphetamine, energy drinks

— Recent diarrhea/vomiting → electrolyte disturbance

— Peri-MI VT (<48 h): ischemia-driven, treat ischemia, ICD usually NOT indicated based on this episode

— Late post-MI VT (>48 h, >40 days): scar-mediated, ICD candidacy

— VT during dialysis runs → electrolyte shifts

— Ask exactly: number of shocks, single vs multiple, what patient was doing, any preceding palpitations

— Multiple shocks = electrical storm (≥3 episodes in 24 h) — emergent admission

Key distinction: VT in the first 48 hours after MI is a marker of the ischemic event itself and does not confer long-term SCD risk if revascularization is adequate — so it does NOT independently qualify the patient for an ICD. VT occurring >48 hours after MI, particularly with persistent LVEF ≤35%, is the substrate-driven form that drives ICD decisions.

Spectrum of presentation (mild → severe):

High-yield history elements:

Symptom timing clues:

ICD interrogation history:

Physical Exam Findings and Hemodynamic Assessment

— Unstable VT: hypotension (SBP <90), altered mental status, ischemic chest pain, acute HF, shock

— Stable VT: awake, perfusing, tolerating rhythm

— Diaphoresis, pallor, anxiety, cool extremities → low cardiac output

— Cannon A waves in jugular venous pulse → AV dissociation (highly specific for VT vs SVT with aberrancy)

— Variable intensity of S1 → also from AV dissociation

— Beat-to-beat variability in pulse and BP

— Rales, S3 → tachycardia-induced or pre-existing HF

— Murmur of HCM (harsh systolic, increases with Valsalva) if outflow obstruction is substrate

— Displaced PMI → dilated cardiomyopathy

— Healed sternotomy (CABG history)

— Subclavian ICD/PPM pocket — palpate and inspect for erythema or erosion

— Stigmata of long-standing HF (elevated JVP, edema, hepatomegaly)

— SBP <90 with end-organ signs → immediate synchronized cardioversion (100 J biphasic, escalate)

— Pulseless → unsynchronized defibrillation (200 J biphasic), ACLS

— Stable + monomorphic VT → IV antiarrhythmic trial reasonable

Board pearl: Three classic physical findings of AV dissociation that distinguish VT from SVT with aberrancy: cannon A waves, variable S1 intensity, beat-to-beat systolic BP variability. These are essentially pathognomonic when present.

Step 3 management: If a wide-complex tachycardia patient becomes unstable at any point during your workup, abandon further diagnostic effort and cardiovert. Do not chase the ECG distinction at the cost of perfusion. After return of sinus rhythm, then reassess substrate, electrolytes, and trigger.

Primary survey first — ABCs and pulse check. Define stability immediately:

General appearance:

Cardiac/pulmonary:

Signs of underlying substrate to look for after termination:

Hemodynamic assessment thresholds for action:

Diagnostic Workup — Initial ECG and Labs

— Wide QRS (≥120 ms), regular, rate typically 140–220

— Monomorphic VT: single QRS morphology — scar reentry

— Polymorphic VT: changing morphology — ischemia, drug-induced

— Torsades de pointes: polymorphic VT with twisting axis on long QT background

— AV dissociation → VT

— Capture/fusion beats → VT (pathognomonic)

— QRS >140 ms (RBBB pattern) or >160 ms (LBBB pattern) → favors VT

— Concordance across precordial leads (all positive or all negative) → VT

— Northwest axis (-90° to ±180°) → VT

— History of MI alone → ~95% VT predictive

— CBC, BMP — focus on K (goal >4.0) and Mg (goal >2.0)

— Troponin — both as cause (ischemic VT) and consequence (demand)

— TSH — thyrotoxicosis as trigger

— Drug screen — cocaine, meth, sympathomimetics

— Digoxin level if applicable; QT-prolonging drug review

— BNP, lactate for HF and perfusion assessment

Board pearl: The presence of fusion beats or capture beats on the rhythm strip is essentially pathognomonic for VT. A fusion beat is a hybrid QRS from simultaneous supraventricular and ventricular activation; a capture beat is a normal-width sinus beat that "captures" the ventricles between VT beats — both prove independent atrial and ventricular activity (AV dissociation).

12-lead ECG during tachycardia — obtain whenever possible before terminating (if stable):

VT vs SVT-with-aberrancy criteria (Brugada algorithm highlights):

Post-conversion ECG: Q waves (prior MI), epsilon wave (ARVC), delta wave (WPW), prolonged QT, Brugada pattern (coved ST in V1–V2), HCM features (deep septal Q, LVH)

Initial labs:

Continuous telemetry while in ED and admission

Diagnostic Workup — Advanced and Substrate Studies

— Quantify LVEF (the single most important number for ICD decisions)

— Wall motion abnormalities (ischemic scar territory)

— Chamber dimensions, LV thickness (HCM if septum ≥15 mm)

— RV dilation/dysfunction (ARVC, sarcoidosis)

— Valvular disease, intracardiac thrombus (especially LV apex)

— Left heart catheterization or coronary CTA — most patients with new VT and risk factors need to exclude CAD as substrate or trigger

— Stress testing if low pretest probability

— Gold standard for scar characterization and substrate mapping

— Detects late gadolinium enhancement (LGE) — predicts arrhythmia risk

— Diagnostic for ARVC, myocarditis, sarcoidosis, HCM, amyloid

— Programmed ventricular stimulation to induce VT

— Map circuit for ablation candidacy

— Risk stratify selected patients (e.g., post-MI with intermediate EF, syncope of unknown origin)

— Holter (24–48 h) or extended patch monitor (14–30 days)

— Implantable loop recorder for infrequent symptoms

Step 3 management: Workflow after stabilization of monomorphic VT in an adult with cardiac risk factors: TTE → coronary angiography → cardiac MRI if EF reduced or nonischemic features → EP consult for ICD/ablation decision. This is the standard substrate evaluation pathway and is frequently the correct "next step" answer.

Echocardiography (TTE) — every patient with VT:

Ischemic evaluation:

Cardiac MRI with gadolinium:

FDG-PET: suspected cardiac sarcoidosis (patchy uptake) — VT in middle-aged patient with AV block, especially Black or Scandinavian descent

Electrophysiology (EP) study:

Genetic testing: if clinical phenotype suggests channelopathy (LQTS, Brugada, CPVT, ARVC) — family screening implications

Ambulatory monitoring after discharge for NSVT burden:

Risk Stratification and Acute Management Logic

— No pulse (VT/VF arrest): Unsynchronized defibrillation (200 J biphasic), CPR, ACLS algorithm. Epinephrine 1 mg IV q3–5 min. Amiodarone 300 mg IV bolus after 3rd shock (or lidocaine 1–1.5 mg/kg).

— Pulse present: proceed to step 2

— Unstable (hypotension, altered mentation, chest pain, acute HF): synchronized cardioversion at 100 J biphasic, escalate to 200 J. Sedate with etomidate or midazolam if conscious.

— Stable: medical therapy attempt

— IV amiodarone 150 mg over 10 min, may repeat, then 1 mg/min infusion x 6 h, then 0.5 mg/min

— Alternative: IV procainamide (preferred in some guidelines for stable monomorphic VT — superior conversion in PROCAMIO trial); avoid in HF/long QT

— Alternative: IV lidocaine 1–1.5 mg/kg bolus, especially in ischemic VT

— If drugs fail or hemodynamics worsen → cardiovert

— Normal baseline QT: treat as ischemia — emergent angiography, beta-blocker, amiodarone, defibrillate when sustained

— Long QT (torsades): IV magnesium 2 g first-line regardless of Mg level; correct K to >4.5; overdrive pacing or isoproterenol if recurrent; stop offending drugs

— IV beta-blocker (propranolol, esmolol) — sympathetic blockade is crucial

— Amiodarone load

— Sedation/intubation may be needed

— Consider stellate ganglion block, urgent VT ablation, mechanical circulatory support

CCS pearl: In CCS cases of stable monomorphic VT, order: continuous cardiac monitor, IV access x2, defibrillator pads on patient, amiodarone IV, cardiology consult, BMP/Mg/troponin, 12-lead ECG, and admit to telemetry/CCU. Reassess clock frequently — escalate to cardioversion if BP drops.

Step 1 — Is there a pulse?

Step 2 — Is the patient stable?

Step 3 — For stable monomorphic VT:

Step 4 — For polymorphic VT:

Electrical storm (≥3 sustained VT episodes in 24 h):

Pharmacotherapy — Acute and Chronic Antiarrhythmics

— Amiodarone — workhorse. 150 mg IV over 10 min, repeat PRN; maintenance 1 mg/min x 6 h then 0.5 mg/min. Safe in HF and reduced EF. Watch hypotension (give slowly), bradycardia.

— Procainamide — 20–50 mg/min IV until VT terminates, QRS widens >50%, hypotension, or 17 mg/kg total. Maintenance 1–4 mg/min. Avoid in HFrEF, prolonged QT, renal failure.

— Lidocaine — 1–1.5 mg/kg IV bolus, then 1–4 mg/min. Best for ischemic VT. Watch CNS toxicity (seizure, confusion).

— Magnesium — torsades regardless of level

— Beta-blockers (esmolol, propranolol) — electrical storm, CPVT, LQTS, sympathetic-driven VT

— Beta-blockers — foundation for nearly all VT substrates (post-MI, HF, LQTS, CPVT)

— Amiodarone PO — most effective at reducing VT recurrence; does NOT reduce mortality and has substantial long-term toxicity → reserve for ICD shock reduction or non-ablation candidates

— Sotalol — class III; effective for VT; requires QTc monitoring, contraindicated in CrCl <40, severe HF

— Mexiletine — oral lidocaine analog; adjunct for refractory ischemic VT or LQT3

— Pulmonary fibrosis — baseline + annual CXR, PFTs if symptomatic

— Thyroid — TSH q6 months (hypo- or hyperthyroid)

— Hepatic — LFTs q6 months

— Ocular — corneal deposits (common, benign); optic neuropathy (rare)

— Dermatologic — blue-gray discoloration, photosensitivity

— Neurologic — tremor, neuropathy

Board pearl: Antiarrhythmic drugs suppress VT but do not improve survival; only ICDs and beta-blockers reduce SCD mortality in eligible substrates. Never use antiarrhythmics as a substitute for an indicated ICD.

Acute IV agents for sustained VT:

Chronic oral antiarrhythmic suppression:

Amiodarone long-term toxicity surveillance (high yield):

Drug interactions: amiodarone potentiates warfarin (reduce dose ~30%) and digoxin (reduce ~50%); raises statin levels

Procedural Therapy — ICD, Ablation, and Mechanical Support

— Transvenous ICD — standard; provides antitachycardia pacing (ATP), cardioversion, defibrillation, and bradycardia pacing

— Subcutaneous ICD (S-ICD): no transvenous lead; for patients without pacing need, with vascular access issues, or at high infection risk (dialysis, young, congenital). Cannot provide ATP or bradycardia pacing.

— Wearable cardioverter-defibrillator (LifeVest): bridge therapy for patients with temporarily reduced EF (recent MI <40 days, new nonischemic CM <90 days post-GDMT) where ICD not yet indicated

— Indications: recurrent monomorphic VT despite drugs, ICD shocks, electrical storm, idiopathic VT (RVOT, fascicular — often curative)

— VANISH and PAUSE-SCD trials: ablation reduces VT recurrence and ICD shocks vs escalation of antiarrhythmics

— Endocardial ± epicardial approach; substrate mapping to scar

— Add when LVEF ≤35%, NYHA II–IV (ambulatory), QRS ≥150 ms with LBBB morphology, sinus rhythm

— IABP, Impella, VA-ECMO as bridge to ablation or recovery

— Ischemic CM: LVEF ≤35%, NYHA II–III, ≥40 days post-MI, ≥90 days post-revascularization, on GDMT ≥3 months, life expectancy >1 year

— Nonischemic CM: LVEF ≤35%, NYHA II–III, on GDMT ≥3 months (DANISH tempered enthusiasm but guideline indication remains class IIa)

— HCM: risk score ≥6% 5-year SCD risk, or major risk factors (massive LVH ≥30 mm, syncope, family SCD, NSVT, apical aneurysm)

Step 3 management: Secondary prevention ICD is indicated for any survivor of cardiac arrest due to VT/VF or sustained VT with structural heart disease, regardless of EF, after reversible causes are excluded.

Implantable cardioverter-defibrillator (ICD):

VT ablation — catheter-based:

Cardiac resynchronization therapy (CRT-D):

Mechanical circulatory support for refractory VT/electrical storm:

Cardiac sympathetic denervation (stellate ganglion block acutely, surgical left cardiac sympathetic denervation chronically) for refractory storm or CPVT/LQTS

Primary prevention ICD (no prior sustained VT/SCD but high risk):

Special Populations — Elderly and Renal/Hepatic Impairment

— ICD decision-making must integrate life expectancy — guideline floor of >1 year meaningful survival, but in practice frailty, multimorbidity, and goals of care dominate

— Higher procedural complications: pneumothorax, lead dislodgement, infection, bleeding (anticoagulation prevalence)

— Shared decision-making is mandatory (CMS requirement before primary prevention ICD) — discuss shock burden, end-of-life deactivation, quality of life

— Subcutaneous ICD may reduce infection risk in select elderly

— Higher risk of inappropriate shocks from AF — program with longer detection intervals, higher rate cutoffs

— Dose adjustments:

— Sotalol — contraindicated CrCl <40 mL/min (board favorite); accumulates → torsades

— Procainamide and NAPA metabolite — accumulate in renal failure; reduce dose, monitor levels, watch QT

— Dofetilide — strict CrCl-based dosing; contraindicated <20 mL/min

— Amiodarone — no renal adjustment (hepatic metabolism)

— Lidocaine — no acute renal adjustment but reduce in prolonged infusions

— Dialysis patients: electrolyte shifts during HD precipitate VT — keep K bath ≥2.0, time meds around sessions; high SCD rate

— ICD infection risk higher in HD patients → S-ICD often preferred

— Amiodarone, mexiletine, lidocaine — hepatic clearance; reduce dose, monitor LFTs

— Baseline LFTs before amiodarone initiation; discontinue if AST/ALT >3x baseline

— Avoid class Ic (flecainide, propafenone) and procainamide in structural heart disease/HFrEF — pro-arrhythmic mortality (CAST trial legacy)

— Amiodarone and dofetilide are the structurally-safe oral options

Board pearl: Sotalol in renal impairment is a classic Step 3 trap — accumulation prolongs QT and triggers torsades. Always check CrCl before initiating or continuing sotalol, and recheck QTc within 2–4 hours of each dose change during loading.

Elderly (>75 years):

Renal impairment:

Hepatic impairment:

Heart failure overlap:

Special Populations — Pregnancy, Pediatrics, Channelopathies

— Most VT in pregnancy occurs in structurally normal hearts (often RVOT VT); incidence rises in 3rd trimester due to volume and catecholamine surge

— Peripartum cardiomyopathy is a key substrate — develops in last month of pregnancy or first 5 months postpartum

— Acute management: cardioversion is safe in all trimesters; place pads avoiding gravid uterus, left lateral tilt to relieve IVC compression

— Drug safety:

— Beta-blockers (metoprolol, propranolol) — preferred for chronic suppression; avoid atenolol (IUGR)

— Lidocaine, procainamide — generally safe acutely

— Amiodarone — fetal hypothyroidism, neurodevelopmental concerns — reserve for life-threatening refractory VT

— Sotalol — used in selected cases

— ICD is not contraindicated; can be implanted with abdominal shielding if needed during pregnancy, but defer if possible

— Think channelopathies and inherited cardiomyopathies first — LQTS, CPVT, Brugada, HCM, ARVC

— CPVT — exercise/emotion-triggered bidirectional or polymorphic VT; structurally normal heart; treat with high-dose nonselective beta-blocker (nadolol), flecainide add-on, left cardiac sympathetic denervation, ICD if syncope on therapy

— LQTS — beta-blockers (propranolol, nadolol); avoid QT-prolonging drugs; ICD for survivors of arrest or syncope on therapy

— Brugada — ICD for symptomatic patients (syncope, arrest); quinidine for storm; avoid sodium channel blockers, treat fevers aggressively

— Sudden death screening — family history, syncope, murmur; ECG screening per AHA judgment

— HCM and ARVC are leading causes of athletic SCD

— Restrict competitive athletics after VT diagnosis pending workup

Key distinction: CPVT vs LQTS: both present with exertional syncope, but CPVT has a normal resting ECG and reveals bidirectional VT on exercise testing, whereas LQTS shows prolonged QT at rest. Both treated initially with beta-blockers; CPVT specifically responds to nonselective beta-blockade (nadolol).

Pregnancy:

Pediatric and young adult VT:

Athletes:

Complications and Adverse Outcomes

— Degeneration to VF and sudden cardiac death — the dominant feared outcome

— Tachycardia-induced cardiomyopathy — incessant VT (often slow VT or RVOT) over weeks-months reduces EF; reversible with arrhythmia control

— Hemodynamic collapse, shock, end-organ hypoperfusion — AKI, hepatic injury, anoxic brain injury

— Demand ischemia and type 2 MI during sustained tachycardia

— Inappropriate shocks — most often from AF/SVT, T-wave oversensing, lead noise/fracture; reduce with proper programming (longer detection, higher rate cutoffs — MADIT-RIT)

— Appropriate but recurrent shocks → psychological distress, PTSD, depression

— Lead complications: dislodgement, fracture, perforation (tamponade), venous thrombosis, tricuspid regurgitation

— Device infection: pocket erythema, fever, bacteremia — device extraction required, IV antibiotics 2–6 weeks

— Pneumothorax/hemothorax during implant

— Twiddler syndrome — patient manipulation causing lead displacement

— Pro-arrhythmia: torsades from QT prolongers (sotalol, dofetilide, ibutilide); incessant VT from class Ic in structural disease

— Amiodarone organ toxicity (pulmonary, thyroid, hepatic, ocular, dermatologic, neurologic)

— Bradycardia, heart block from beta-blockade + amiodarone

— Cardiac perforation/tamponade, AV block, stroke (LV access), coronary injury, phrenic nerve injury, vascular access complications

— Driving restrictions, occupational impact, anxiety, depression

Board pearl: A patient with frequent appropriate ICD shocks has high short-term mortality — recurrent shocks are themselves a marker of progressive disease and an indication for VT ablation referral, not just more antiarrhythmics. Each shock also confers myocardial injury.

Direct arrhythmia complications:

ICD-related complications:

Drug-related complications:

Ablation complications:

Psychosocial:

Escalation, Consults, and Triage

— Any sustained VT episode in the past 24 hours

— Post-arrest care (targeted temperature management 32–36°C x 24 h if comatose)

— Electrical storm

— Hemodynamic instability or shock

— Active ischemia driving VT

— IV antiarrhythmic infusions (amiodarone, lidocaine, procainamide)

— Post-ablation observation (first 24 h)

— Stable monomorphic VT that converted with single intervention, no ongoing ischemia, normal electrolytes corrected, observation for recurrence

— Electrophysiology — every sustained VT patient; for ICD candidacy, ablation, and programming

— Heart failure cardiology — if EF reduced; GDMT optimization is a prerequisite for ICD reassessment

— Interventional cardiology — if ischemia suspected

— Cardiothoracic surgery — refractory storm requiring sympathectomy or MCS, lead extraction for infection

— Genetics — channelopathies, ARVC, HCM with family screening implications

— Palliative care — recurrent shocks in end-stage HF, ICD deactivation discussions

— VT ablation, MCS, or advanced HF therapies (transplant, LVAD) needed

— Refractory electrical storm

— Suspected sarcoidosis or amyloid requiring PET/biopsy

CCS pearl: When managing sustained VT in CCS, advance the clock in short increments (5–15 min) early — frequent reassessment of rhythm, BP, and mental status earns credit. Order defibrillator at bedside, IV access x2, continuous telemetry, pulse oximetry, BMP/Mg/troponin, 12-lead ECG, cardiology consult, and admit to CCU before advancing the clock substantially.

Immediate ICU/CCU admission criteria:

Telemetry floor (step-down) admission:

Consults to mobilize early:

Transfer to tertiary center if:

Key Differentials — Wide-Complex Tachycardia Mimics

— Pre-existing or rate-related bundle branch block

— Favored by: younger age, no structural heart disease, identical QRS morphology to baseline, responsive to vagal/adenosine

— Adenosine challenge: can terminate AV-nodal-dependent SVTs and unmask atrial activity; safe in stable monomorphic wide-complex tachycardia if VT cannot be excluded (does NOT typically terminate VT but is generally safe); avoid in irregular wide-complex (AF + WPW)

— Irregular, wide, and very fast (often >250 bpm) with varying QRS morphology — "FBI" (fast, broad, irregular)

— Avoid AV nodal blockers (adenosine, beta-blockers, calcium channel blockers, digoxin) — accelerate conduction down accessory pathway, risk VF

— Treat with procainamide or ibutilide, or cardioversion

— Wide bizarre QRS, peaked T waves, sine-wave morphology

— Treat with calcium gluconate, insulin/dextrose, etc.

— Wide QRS, terminal R in aVR, prolonged QT

— Treat with sodium bicarbonate boluses

— Accelerated idioventricular rhythm (AIVR): 40–120 bpm, common in early reperfusion post-MI, usually benign, no treatment

— Nonsustained VT: <30 sec, clinically significant if symptomatic or in structural heart disease

— VF: chaotic, no organized QRS — defibrillate

Key distinction: Wide-complex tachycardia in a patient with known prior MI is VT in >95% of cases. Default to VT; treat as VT; do not delay therapy chasing aberrancy criteria when the substrate is obvious.

SVT with aberrant conduction:

SVT with pre-excitation (AF with WPW):

Antidromic AVRT — wide regular tachycardia via accessory pathway; rare; cardiovert or procainamide

Hyperkalemia:

Sodium channel blocker toxicity (TCAs, cocaine, flecainide):

Paced rhythm: look for pacer spikes

Other ventricular rhythms:

Key Differentials — Substrate and Cause Categorization

— Acute MI with peri-infarct VT (<48 h)

— Healed MI with scar-mediated reentry (>48 h, often years later)

— Demand ischemia from severe CAD

— Dilated cardiomyopathy — idiopathic, alcohol, chemotherapy (anthracyclines, trastuzumab), peripartum, tachycardia-induced

— HCM — septal hypertrophy, family history, exertional syncope

— ARVC — RV fatty replacement, epsilon waves, T-wave inversion V1–V3, athletes

— Cardiac sarcoidosis — middle-aged, AV block + VT, patchy LGE, FDG-PET uptake

— Cardiac amyloid — low voltage, thick walls, restrictive physiology

— Myocarditis — viral, giant cell (rapid VT, refractory), eosinophilic

— Chagas — Latin American origin, apical aneurysm, RBBB + LAFB

— Long QT syndrome (types 1, 2, 3 — exercise, auditory/emotional, sleep triggers)

— Brugada syndrome — sleep, fever, sodium-channel blockers

— CPVT — exertional bidirectional VT

— Short QT, early repolarization syndrome

— RVOT VT — LBBB + inferior axis, V1 negative; adenosine-sensitive; verapamil or beta-blockers; ablation curative

— Fascicular VT — RBBB + LAD; verapamil-sensitive

— Electrolyte: hypoK, hypoMg, hypoCa

— Drugs: digoxin toxicity, QT prolongers, stimulants

— Hypoxia, acidosis, hypothermia

— Thyrotoxicosis, pheochromocytoma

Board pearl: First 48 hours post-MI VT is treated as ischemia/reperfusion phenomenon — does NOT trigger ICD placement on its own. Wait 40 days post-MI and reassess EF on GDMT to determine primary-prevention ICD candidacy.

Ischemic causes (most common adult substrate):

Nonischemic structural causes:

Inherited channelopathies (structurally normal heart):

Idiopathic VT (no structural disease):

Reversible/precipitating causes (must exclude):

Secondary Prevention and Discharge Plan

— Secondary-prevention ICD (or wearable defibrillator bridge in some scenarios)

— Ensure post-implant CXR confirms lead position, no pneumothorax

— Schedule device interrogation at 2–12 weeks post-implant, then every 3–12 months (remote monitoring)

— Beta-blocker (carvedilol, metoprolol succinate, bisoprolol) — every patient unless contraindicated; reduces SCD

— ARNI (sacubitril-valsartan) preferred over ACEi/ARB

— MRA (spironolactone, eplerenone)

— SGLT2 inhibitor (dapagliflozin, empagliflozin)

— Titrate to target doses over 3–6 months

— Amiodarone or sotalol if recurrent VT/ICD shocks despite GDMT

— Consider VT ablation referral early rather than long-term amiodarone in younger patients

— Dual antiplatelet therapy if stented; aspirin lifelong

— High-intensity statin

— ACEi/ARB, BP control to <130/80

— Smoking cessation, cardiac rehab referral

— Discontinue and document all QT-prolonging drugs

— Replete and maintain K >4.0, Mg >2.0

— Address sleep apnea (untreated OSA increases VT recurrence)

— Alcohol and stimulant abstinence

Step 3 management: Patients discharged after VT episode should leave with: beta-blocker, statin (if any CAD), GDMT for HFrEF, ICD if indicated, EP follow-up in 2–4 weeks, primary cardiology in 1–2 weeks, repeat echo in 3 months to reassess EF on optimized therapy.

Device disposition:

Guideline-directed medical therapy (GDMT) for HFrEF substrate:

Antiarrhythmic adjuncts:

Coronary disease management:

Trigger mitigation:

Family screening if channelopathy or genetic cardiomyopathy identified — first-degree relatives via ECG ± echo ± genetic testing

Follow-Up, Monitoring, and Counseling

— Within 1–2 weeks of discharge: primary care or cardiology for medication titration, symptom review, wound check if implanted

— 2–4 weeks: EP clinic for device check and lead maturation

— 3 months: repeat echocardiogram on optimized GDMT — if EF improves to >35%, primary prevention ICD might have been avoided (consider wearable defibrillator strategy for de novo patients)

— 6–12 months: routine device interrogation; remote monitoring detects lead issues and arrhythmia recurrence between visits

— BMP, Mg at each visit; tighter on diuretics

— On amiodarone: TSH and LFTs q6 months; PFTs and CXR baseline + annually or per symptoms; eye exam annually

— On sotalol/dofetilide: QTc and renal function periodically

— Secondary prevention ICD (post-arrest/sustained VT): no driving private vehicle x 6 months after event or last shock

— Primary prevention ICD: typically no driving x 1 week post-implant

— Commercial driving (DOT): generally disqualified after sustained VT or ICD

— Counsel and document the discussion

— Avoid strong electromagnetic fields (industrial welders, MRI without MR-conditional verification)

— Cell phones >6 inches from device

— Airport security disclosure

— Avoid heavy lifting/arm-over-head x 4–6 weeks post-implant

Board pearl: Driving restrictions are commonly tested. 6 months no private driving after secondary-prevention ICD or sustained VT; only 1 week after primary prevention ICD implant. Commercial driving is essentially permanently disqualified after sustained VT/ICD.

Follow-up schedule:

Lab monitoring:

Driving restrictions (AHA/HRS consensus):

Lifestyle counseling:

Cardiac rehabilitation: indicated post-MI and HF; safe with ICD; reduces mortality

Mental health: screen for depression/anxiety/PTSD especially after shocks; refer to ICD-patient support groups

Ethical, Legal, and Patient Safety Considerations

— Before primary prevention ICD, formal SDM encounter using an evidence-based decision aid is required for Medicare reimbursement

— Discuss: 5-year SCD risk reduction (~5–7 absolute %), shock burden, infection risk, end-of-life issues

— Document in chart; this is a known Step 3 systems-of-care item

— Ethically and legally permissible to deactivate ICD shocks in terminally ill patients to prevent unwanted shocks during dying process

— Distinct from euthanasia or PAS — withdrawing a previously consented therapy

— Hospice patients with ICDs frequently retain active defibrillation by default — proactively discuss

— Magnet can suspend shock therapy temporarily; formal reprogramming preferred

— Pacemaker dependence does not change the ethics — pacing can continue if desired

— Patient refusing ICD with class I indication — explore reasons (depression, misinformation, religious beliefs); respect autonomy in capacitated patient; document

— Surrogate decision-making for incapacitated post-arrest patient — use prior wishes if known, otherwise substituted judgment

— Physicians have an ethical duty to counsel restrictions; reporting requirements vary by state (some mandatory, e.g., California — know local laws)

— Failure to counsel is a malpractice exposure

— Discharge with new antiarrhythmic + beta-blocker = bradycardia and QT-prolongation risk → medication reconciliation, primary care notification, early follow-up

— Communicate device type and programming to all future providers; alert MRI staff (MR-conditional vs not)

— Confirm allergy and medication reconciliation prior to amiodarone (digoxin, warfarin interactions)

— Standardize handoff with explicit mention of ICD presence to avoid CPR/defibrillation pitfalls

Step 3 management: A hospice patient with active ICD who is actively dying: deactivate shock therapy after discussion with patient/surrogate to prevent distressing terminal shocks. This is appropriate, ethical, and frequently tested.

Shared decision-making (SDM) for ICD — CMS mandate:

ICD deactivation at end of life:

Informed consent edge cases:

Driving and public safety:

Transitions of care:

Patient safety:

High-Yield Associations and Rapid-Fire Facts

Board pearl: The single highest-yield differentiator: prior MI + wide-complex tachycardia = VT. The single highest-yield management triad: assess pulse → assess stability → defibrillate, cardiovert, or treat medically accordingly.

AV dissociation, capture beats, fusion beats → diagnostic for VT

Brugada criteria wide-complex tachycardia algorithm → favors VT

Concordance in precordial leads → VT

QRS >140 ms (RBBB-like) or >160 ms (LBBB-like) → VT

First 48 h post-MI VT → NOT an ICD indication; reassess at 40 days

Primary prevention ICD: LVEF ≤35%, NYHA II–III, ≥40 d post-MI, ≥90 d post-revasc, on GDMT, life expectancy >1 yr

Secondary prevention ICD: survived cardiac arrest from VT/VF, or sustained VT with structural heart disease

Torsades → IV magnesium first, regardless of level

Polymorphic VT with normal QT → ischemia until proven otherwise

WPW + AF ("FBI" — fast, broad, irregular) → procainamide or cardioversion; avoid AV nodal blockers

CAST trial legacy: class Ic (flecainide, propafenone) increases mortality in structural heart disease — contraindicated post-MI/HFrEF

PROCAMIO trial: procainamide superior to amiodarone for stable monomorphic VT termination

MADIT-II: primary prevention ICD reduces mortality in ischemic CM with EF ≤30%

SCD-HeFT: ICD reduces mortality in NYHA II–III HF with EF ≤35%, both ischemic and nonischemic

DANISH: ICD did not reduce all-cause mortality in nonischemic CM (still guideline-indicated)

MADIT-RIT: programming with longer detection delays and higher rate cutoffs reduces inappropriate shocks and mortality

VANISH/PAUSE-SCD: VT ablation reduces recurrence vs escalating antiarrhythmics

Epsilon wave in V1 → ARVC

Bidirectional VT → digoxin toxicity or CPVT

AV block + VT in middle-aged adult → cardiac sarcoidosis

Driving: 6 months after sustained VT or secondary ICD; 1 week after primary ICD

Amiodarone monitoring: TSH, LFTs q6 mo; CXR/PFTs annually

Sotalol/dofetilide: renal dosing, QTc monitoring during loading

Adenosine in stable wide-complex tachycardia: can help diagnose but don't give if irregular (AF+WPW)

Hypothermia (32–36°C) x 24 h for comatose post-VT/VF arrest survivors

Board Question Stem Patterns

Key distinction: Step 3 stems hinge on timing relative to MI, hemodynamic stability, and EF on optimized GDMT. Anchor every answer to these three variables.

Stem 1 — Post-MI VT timing: 62 yo man with anterior STEMI 6 months ago, EF 28% on GDMT, presents with palpitations and a 60-second monomorphic VT captured. Next step? → Primary-prevention ICD candidate evaluation; refer to EP. (He also meets secondary-prevention criteria from the sustained VT.)

Stem 2 — Stable monomorphic VT: 58 yo with HFrEF, hemodynamically stable wide-complex tachycardia at 170, BP 110/70. Best management? → IV amiodarone or procainamide; defibrillator at bedside; if deteriorates, synchronized cardioversion.

Stem 3 — Unstable VT: 70 yo with chest pain, BP 78/40, wide regular tachycardia at 200. → Synchronized cardioversion 100 J biphasic. Not adenosine, not amiodarone first.

Stem 4 — Torsades: Patient on azithromycin and ondansetron with polymorphic VT, QTc 580. → IV magnesium 2 g, stop offending drugs, replete K to >4.5, overdrive pacing or isoproterenol if recurrent.

Stem 5 — WPW + AF: Young patient with rapid irregular wide-complex tachycardia at 240, delta wave on prior ECG. → Procainamide or cardioversion; avoid adenosine, beta-blockers, calcium channel blockers, digoxin.

Stem 6 — Early post-MI VT: VT 12 hours after STEMI, otherwise revascularized. → Treat acutely; does NOT qualify for ICD based on this episode; reassess EF at ≥40 days.

Stem 7 — Electrical storm: 5 ICD shocks in 24 hours. → IV beta-blocker, amiodarone, sedate/intubate, urgent EP for ablation, consider MCS.

Stem 8 — Hospice patient with ICD: terminal cancer, family wants to prevent shocks. → Deactivate ICD shock therapy after SDM; magnet temporarily, formal reprogramming preferred.

Stem 9 — Driving question: ICD placed for sustained VT. When can he drive? → 6 months for private; commercial driving disqualified.

Stem 10 — Bidirectional VT in elderly with AKI and nausea, on digoxin. → Digoxin toxicity; check level, give digoxin immune Fab.

Stem 11 — Young athlete with exertional syncope and bidirectional VT on exercise test, normal resting ECG. → CPVT; nadolol; avoid competitive sports; consider ICD if syncope persists on therapy.

Stem 12 — Middle-aged patient with AV block and VT, LGE patchy on MRI. → Cardiac sarcoidosis; FDG-PET, immunosuppression, ICD.

One-Line Recap

Sustained ventricular tachycardia management hinges on three sequential questions — pulse, stability, and substrate — followed by ICD candidacy determined by event etiology and LVEF on optimized GDMT.

— Secondary prevention: survivor of VT/VF arrest or sustained VT with structural heart disease (regardless of EF), after reversible causes excluded

— Primary prevention: LVEF ≤35%, NYHA II–III, ≥40 days post-MI, ≥90 days post-revascularization, on GDMT ≥3 months, expected survival >1 year

— Special: HCM with high SCD risk score, LQTS/Brugada/CPVT with syncope on therapy, ARVC, sarcoidosis

— No class Ic in structural heart disease (CAST)

— No AV nodal blockers in AF + WPW

— No sotalol in CrCl <40

— Sodium bicarb for TCA/sodium-channel toxicity wide QRS

Board pearl: When a stem gives you a patient with prior MI and a wide-complex tachycardia, the answer is almost always (1) treat as VT, (2) cardiovert/defibrillate based on stability, (3) evaluate for ICD based on substrate and EF on GDMT. Master this triad and the vast majority of Step 3 VT questions answer themselves.

Acute algorithm: Pulseless → unsynchronized defibrillation + ACLS. Unstable with pulse → synchronized cardioversion. Stable monomorphic → IV amiodarone or procainamide. Torsades → IV magnesium. Polymorphic with normal QT → treat as ischemia.

ICD indications — memorize cold:

Drug avoidances that win points:

Discharge essentials: beta-blocker + GDMT for HFrEF; ICD if indicated; EP follow-up in 2–4 weeks; repeat echo at 3 months; driving restriction 6 months after sustained VT/secondary ICD; shared decision-making documented for all primary-prevention ICDs; deactivation discussion at end of life.