Cardiovascular

Chemotherapy-induced cardiotoxicity: surveillance and management

Clinical Overview and When to Suspect Chemotherapy-Induced Cardiotoxicity

— Anthracyclines (doxorubicin, daunorubicin, epirubicin): dose-dependent, often irreversible HFrEF; risk rises sharply >250 mg/m² doxorubicin equivalent.

— HER2-targeted therapy (trastuzumab, pertuzumab): typically reversible LV dysfunction, potentiated by prior anthracycline.

— VEGF/TKIs (bevacizumab, sunitinib, sorafenib, lenvatinib): hypertension, LV dysfunction, arterial thromboembolism.

— Fluoropyrimidines (5-FU, capecitabine): coronary vasospasm/ischemia.

— Immune checkpoint inhibitors (ipilimumab, nivolumab, pembrolizumab): fulminant myocarditis, often with myositis/myasthenic overlap.

— BTK inhibitors (ibrutinib): atrial fibrillation, hypertension.

— Proteasome inhibitors (carfilzomib): HF, hypertension.

— Mediastinal/left chest radiation: late constrictive pericarditis, valvular disease, premature CAD.

Board pearl: A drop in LVEF ≥10 absolute points to below the lower limit of normal (typically <50%) defines symptomatic or asymptomatic CTRCD per ASCO/ESC Cardio-Oncology guidelines and triggers cardioprotective therapy even without symptoms.

Definition: Cancer therapy–related cardiac dysfunction (CTRCD) spans a spectrum from asymptomatic LVEF decline or rising troponin/BNP to overt heart failure, myocarditis, arrhythmia, ischemia, hypertension, QT prolongation, and vascular toxicity.

High-risk agents to memorize:

When to suspect on Step 3: any cancer survivor or active patient on the agents above presenting with new dyspnea, orthopnea, edema, palpitations, chest pain, syncope, or asymptomatic LVEF drop on surveillance imaging.

Baseline risk factors that amplify toxicity: age >65, preexisting HFrEF/CAD/HTN/DM, prior anthracycline exposure, chest XRT, baseline LVEF <50%, elevated baseline troponin/NT-proBNP, female sex (anthracyclines), trisomy 21 (pediatric ALL).

Presentation Patterns and Key History

— 5-FU/capecitabine: substernal chest pain mimicking ACS during or hours after infusion → coronary vasospasm; ECG may show transient ST changes.

— Checkpoint inhibitor myocarditis: usually within 6 weeks of first 1–2 doses; fatigue, dyspnea, chest pain, arrhythmia, often with concurrent myositis (proximal weakness, ptosis, elevated CK).

— High-dose cyclophosphamide (pre-transplant conditioning): hemorrhagic myopericarditis, acute HF.

— Trastuzumab: gradual exertional dyspnea, fatigue; often asymptomatic LVEF decline picked up on routine q3-month echo.

— VEGF inhibitors: new or worsening hypertension within weeks; HF can follow.

— Ibrutinib: palpitations from new AF, often within first 3 months.

— Anthracycline cardiomyopathy: classic late presentation in childhood cancer survivors decades later; dilated cardiomyopathy phenotype.

— Mediastinal radiation: constrictive pericarditis, restrictive cardiomyopathy, aortic stenosis, accelerated CAD, conduction disease — typically 10–20 years post-treatment.

— Specific agent, cumulative dose (doxorubicin mg/m²), number of cycles, infusion schedule.

— Prior or concurrent chest radiation (and laterality — left chest = higher cardiac dose).

— Baseline cardiac risk factors and baseline LVEF.

— Symptom onset relative to last dose.

— Concurrent QT-prolonging drugs (ondansetron, azoles, methadone) when arrhythmia is the complaint.

Key distinction: Anthracycline cardiotoxicity is dose-cumulative and often irreversible, whereas trastuzumab-induced dysfunction is typically reversible with drug interruption and HF therapy — Step 3 stems hinge on this contrast when deciding whether to permanently discontinue versus rechallenge after recovery.

Acute (hours–days):

Subacute (weeks–months):

Chronic/late (months–decades):

Key history elements to extract on the stem:

Physical Exam Findings and Hemodynamic Assessment

— Resting tachycardia or new irregularly irregular pulse (ibrutinib-AF).

— New hypertension >140/90 on VEGF/TKI — recheck and chart trend; a 10–20 mmHg rise from baseline counts.

— Hypotension + tachycardia + cool extremities → cardiogenic shock pattern, especially in checkpoint myocarditis.

— S3 gallop → elevated LV filling pressures, sensitive marker of decompensated HFrEF.

— Displaced/diffuse PMI → LV dilation (anthracycline DCM).

— Pericardial friction rub → cyclophosphamide pericarditis or radiation pericarditis.

— Pericardial knock, Kussmaul sign, pulsus paradoxus → constrictive pericarditis after mediastinal XRT.

— Diastolic murmur of AR or systolic murmur of AS → late radiation valvulopathy.

— Elevated JVP, hepatojugular reflux, peripheral edema → biventricular failure.

— Cool, mottled extremities + narrow pulse pressure → low cardiac output state.

Step 3 management: In an ambulatory cancer patient on anthracycline or trastuzumab presenting with new dyspnea, perform a focused volume assessment (JVP, lungs, edema) plus orthostatics, then order BNP/NT-proBNP, troponin, ECG, and transthoracic echo with GLS before next chemo cycle — do not simply attribute symptoms to anemia or deconditioning.

Board pearl: A >15% relative decline in global longitudinal strain (GLS) from baseline predicts subsequent LVEF drop and is the earliest reliable imaging marker of subclinical cardiotoxicity.

General: assess functional status (NYHA class), weight trend, volume status — often the deciding factor for outpatient vs inpatient management.

Vitals:

Cardiac exam:

Pulmonary: bibasilar crackles, dullness from effusion.

Peripheral:

Neuromuscular overlay (critical in checkpoint inhibitor myocarditis): ptosis, diplopia, neck flexor weakness, proximal myopathy — checkpoint myocarditis frequently co-occurs with myositis ± myasthenia gravis–like syndrome and portends very high mortality.

Diagnostic Workup — Initial Labs, ECG, Biomarkers, Baseline Imaging

— History, exam, BP, BMI.

— ECG: QTc, conduction, baseline ST/T abnormalities.

— TTE with LVEF + global longitudinal strain (GLS); cardiac MRI if echo windows poor.

— Baseline biomarkers: high-sensitivity troponin and NT-proBNP/BNP — establish reference values.

— Lipid panel, A1c, renal/hepatic function.

— Anthracyclines: echo at baseline, at cumulative dose milestones (e.g., 240 mg/m² doxorubicin), at completion, then 6–12 months post-therapy; longer in high-risk patients.

— Trastuzumab (adjuvant breast cancer): echo at baseline, every 3 months during therapy, and at completion.

— VEGF inhibitors: home BP monitoring; echo if symptoms or new HTN; baseline and periodic.

— Checkpoint inhibitors: baseline ECG + troponin; recheck troponin with each of the first few cycles in high-risk patients per emerging practice.

— Repeat ECG (look for low voltage, new conduction block, diffuse ST elevations of myocarditis, QT prolongation).

— Troponin — elevation in a patient on checkpoint inhibitor is myocarditis until proven otherwise.

— NT-proBNP for HF assessment.

— CBC (anemia worsens dyspnea), electrolytes (K, Mg for QT and arrhythmia), TSH (anthracycline survivors; checkpoint thyroiditis), creatinine.

— Chest X-ray for cardiomegaly, effusion, congestion.

CCS pearl: On a CCS case of a breast cancer patient on adjuvant trastuzumab with new dyspnea, advance the clock and order TTE with strain, NT-proBNP, troponin, ECG, BMP, CBC simultaneously rather than sequentially — and hold the next trastuzumab dose pending results.

Key distinction: Troponin elevation on checkpoint inhibitor = myocarditis workup; troponin elevation on 5-FU during infusion = vasospasm workup.

Baseline (before initiating cardiotoxic therapy):

Surveillance schedule (high-risk agents):

When symptoms or surveillance triggers concern:

Diagnostic Workup — Advanced and Confirmatory Studies

— Most accurate LVEF; characterizes tissue.

— Late gadolinium enhancement (LGE) + edema on T2 imaging supports myocarditis (especially checkpoint inhibitor).

— Detects radiation-induced fibrosis, constrictive physiology, infiltrative patterns.

— Indicated when echo is equivocal, GLS abnormal without LVEF drop, or myocarditis suspected.

— Stress testing or CT coronary angiography in radiation survivors with chest pain — accelerated CAD with often ostial lesions.

— Invasive coronary angiography for ACS-pattern presentations; in 5-FU/capecitabine chest pain, angiography often normal → diagnosis of vasospasm.

— Holter or 14-day patch for ibrutinib-associated AF or palpitations.

— Telemetry inpatient for QT-prolonging regimens (arsenic trioxide, nilotinib).

Board pearl: In suspected immune checkpoint inhibitor myocarditis, the combination of elevated troponin + new ECG abnormality + CMR LGE/edema establishes the diagnosis; do not wait for biopsy before starting high-dose IV methylprednisolone (500–1000 mg/day) — delay increases mortality, which can approach 50% in fulminant cases.

Transthoracic echocardiogram with 3D LVEF and GLS: gold-standard surveillance modality; 3D LVEF more reproducible than 2D Simpson's; GLS detects subclinical injury before LVEF falls.

Cardiac MRI (CMR):

Multigated acquisition (MUGA) scan: highly reproducible LVEF; historical use in anthracycline surveillance; now largely replaced by echo/CMR but still acceptable when serial precise LVEF measurement is needed.

Coronary evaluation:

Endomyocardial biopsy: confirms checkpoint inhibitor myocarditis (lymphocytic infiltrate) when imaging/biomarkers inconclusive and stakes are high; rarely needed if CMR + troponin + clinical picture clear.

Ambulatory rhythm monitoring:

Right heart catheterization: for refractory HF, suspected constriction vs restriction, or cardiogenic shock requiring tailored therapy.

Risk Stratification and First-Line Management Logic

— Low risk: no risk factors, normal LVEF, normal biomarkers → standard surveillance.

— Moderate risk: 1–2 risk factors (age, HTN, DM) → consider baseline cardioprotection optimization, closer monitoring.

— High/very high risk: prior anthracycline, prior chest XRT, baseline LVEF 50–54%, elevated baseline troponin/NT-proBNP, established CVD → cardio-oncology referral before therapy, consider dexrazoxane (anthracyclines), liposomal formulations, or alternative regimen.

— GLS drop >15% relative with preserved LVEF: subclinical CTRCD → initiate ACEi/ARB + beta-blocker, continue chemo with closer follow-up.

— Asymptomatic LVEF drop ≥10 points to <50%: moderate CTRCD → start GDMT, temporarily hold cardiotoxic drug, repeat echo in 3 weeks; resume if recovery and oncology benefit outweighs risk.

— Symptomatic HF or LVEF <40%: severe CTRCD → discontinue cardiotoxic agent, full guideline-directed HF therapy, cardio-oncology multidisciplinary decision on rechallenge.

Step 3 management: Decision to continue, hold, or stop a cardiotoxic agent is multidisciplinary — oncology weighs tumor benefit, cardiology weighs reversibility; document shared decision-making. For trastuzumab-induced LVEF 40–49% asymptomatic, the typical move is hold trastuzumab, start ACEi + beta-blocker, repeat echo in 3 weeks, then rechallenge if LVEF recovers ≥50%.

Pre-treatment risk stratification (HFA-ICOS risk tool concepts):

During therapy — graded response to LVEF/strain changes:

General cardioprotective measures: aggressive BP control (<130/80), statin if indicated, smoking cessation, treat diabetes, correct anemia, optimize volume.

Dexrazoxane: iron-chelating cardioprotectant, indicated for patients receiving high cumulative doxorubicin (>300 mg/m²) in metastatic breast cancer; reduces HF risk without compromising tumor response in approved settings.

Pharmacotherapy — First-Line Cardioprotective and HF Regimens

— ACE inhibitor or ARB (enalapril, lisinopril, candesartan, valsartan) — first-line; reduces LV remodeling. Use ARNI (sacubitril/valsartan) in established symptomatic HFrEF once stable.

— Beta-blocker with mortality benefit in HFrEF: carvedilol, metoprolol succinate, or bisoprolol. Carvedilol has the most cardio-oncology data and antioxidant properties relevant to anthracyclines.

— Mineralocorticoid receptor antagonist (spironolactone, eplerenone) in NYHA II–IV with LVEF ≤35% and acceptable K+/creatinine.

— SGLT2 inhibitor (dapagliflozin, empagliflozin): now standard across HFrEF and HFpEF; emerging data support use in CTRCD.

— Loop diuretic (furosemide, torsemide) for congestion — symptom control, not mortality.

— ACEi/ARB + beta-blocker initiated at baseline or at first sign of GLS decline can attenuate LVEF drop (CECCY, SAFE-HEaRt, PRADA-style data).

— First-line: ACEi/ARB or dihydropyridine CCB (amlodipine).

— Avoid non-dihydropyridines (diltiazem, verapamil) with sorafenib/sunitinib — CYP3A4 interaction.

— Goal <140/90, ideally <130/80; do not stop the TKI for HTN alone unless severe/refractory.

Board pearl: Carvedilol + enalapril/candesartan is the most board-favored cardioprotective duo for anthracycline/trastuzumab CTRCD; add MRA and SGLT2 inhibitor as LVEF and symptoms warrant.

Foundational HF therapy in CTRCD with reduced EF (mirrors HFrEF GDMT):

Prophylactic/early use in high-risk patients:

Hypertension on VEGF/TKI:

5-FU/capecitabine vasospasm: stop infusion; nitrates + calcium channel blocker (amlodipine, diltiazem) for active ischemia; avoid rechallenge unless essential.

Checkpoint inhibitor myocarditis: permanently discontinue the agent; methylprednisolone 500–1000 mg IV daily × 3–5 days, taper over 4–6 weeks; if steroid-refractory, escalate to mycophenolate, infliximab (avoid in HF), ATG, abatacept, or tofacitinib.

Expanded Pharmacology — Agent-Specific Management and Drug Interactions

— Limit cumulative doxorubicin to <450–500 mg/m² (lower if risk factors).

— Continuous infusion lowers peak levels and cardiotoxicity vs bolus.

— Liposomal doxorubicin reduces cardiotoxicity at comparable efficacy in some tumors.

— Dexrazoxane for high-dose or high-risk regimens.

— Hold for asymptomatic LVEF drop ≥10 points to <50% or symptomatic HF.

— Recheck echo in 3 weeks; rechallenge if recovery; permanent discontinuation if no recovery after 2 holds or persistent symptomatic HF.

— Home BP log; weekly BP early in therapy.

— Add antihypertensive; avoid stopping the TKI for HTN.

— Watch for arterial thromboembolism (stroke, MI) — antiplatelet considered case-by-case.

— New AF in ~10–15%; assess CHA₂DS₂-VASc.

— Avoid warfarin (bleeding risk with ibrutinib); use apixaban preferentially; reduce ibrutinib dose if CYP3A4 inhibitor needed.

— Rate control with beta-blocker; avoid amiodarone, diltiazem, verapamil (CYP3A4 interaction) when possible.

— Baseline and serial ECGs; keep K+ >4, Mg²⁺ >2; avoid concomitant QT-prolonging drugs (ondansetron, azoles, fluoroquinolones, methadone).

— Hold drug if QTc >500 ms or increase >60 ms from baseline.

CCS pearl: For ibrutinib-induced AF with CHA₂DS₂-VASc ≥2, order apixaban 5 mg BID, metoprolol succinate for rate control, and consult cardio-oncology and hematology to discuss dose reduction or switch to a second-generation BTK inhibitor (acalabrutinib, zanubrutinib — lower AF risk).

Anthracyclines:

Trastuzumab:

VEGF inhibitors (bevacizumab, sunitinib, sorafenib, lenvatinib, axitinib):

Ibrutinib:

QT-prolonging agents (arsenic trioxide, nilotinib, vandetanib, ribociclib):

Carfilzomib: aggressive volume management, treat HTN, monitor LVEF; hold for grade 3+ events.

Fluoropyrimidines: avoid rechallenge after vasospasm; alternative agents (raltitrexed) or DPD-genotype-guided dosing.

Special Populations — Elderly and Renal/Hepatic Impairment

— Higher baseline prevalence of HTN, CAD, CKD, and reduced cardiac reserve → markedly elevated CTRCD risk, particularly with anthracyclines and HER2 therapy.

— Consider geriatric assessment (CGA) before high-risk regimens; functional status predicts toxicity better than chronologic age.

— Favor liposomal anthracyclines, dose reduction, or anthracycline-sparing regimens (e.g., TCH for HER2+ breast cancer in select patients).

— Polypharmacy review for QT-prolonging and AV-nodal drugs.

— Start ACEi/beta-blocker at low doses; titrate slowly; watch for orthostasis and falls.

— ACEi/ARB still indicated for CTRCD-HFrEF; tolerate creatinine rise up to ~30% and K+ ≤5.5.

— SGLT2 inhibitors usable down to eGFR 20–25 (dapagliflozin, empagliflozin); cardiorenal benefit.

— Avoid NSAIDs.

— Dose-adjust hydrophilic beta-blockers (atenolol, bisoprolol); carvedilol and metoprolol are hepatically cleared and preferred.

— Cisplatin and carfilzomib have direct renal toxicity that worsens HF management — hydrate, monitor Mg²⁺/K⁺.

— Doxorubicin dose-reduce for elevated bilirubin (e.g., 50% reduction if bilirubin 1.2–3, 75% if >3).

— Avoid hepatically cleared TKIs without dose adjustment.

— Carvedilol, metoprolol require caution in severe hepatic dysfunction.

Step 3 management: In a 78-year-old with HER2+ breast cancer, baseline LVEF 55%, CKD stage 3, and HTN: optimize BP to <130/80, start low-dose carvedilol + losartan, choose non-anthracycline TCH regimen, and schedule echo every 3 months during trastuzumab.

Board pearl: Age >65 plus baseline LVEF 50–54% places a patient in high HFA-ICOS risk — independent of any single comorbidity.

Elderly (≥65):

Chronic kidney disease:

Hepatic impairment:

Frailty: even when oncology indication is strong, a frail patient with baseline LVEF 45% rarely tolerates anthracycline — escalate to multidisciplinary discussion.

Special Populations — Pregnancy, Pediatrics, and Survivors

— Breast cancer and hematologic malignancies are the most common cancers in pregnancy.

— Anthracyclines (doxorubicin, epirubicin) acceptable in 2nd/3rd trimester; avoid trastuzumab (oligohydramnios, fetal renal failure) and tamoxifen throughout pregnancy.

— ACEi/ARB/ARNI/MRA contraindicated in pregnancy → for CTRCD-HF use hydralazine + nitrates + beta-blocker (metoprolol or labetalol); loop diuretics cautiously.

— Postpartum echo and HF reassessment; distinguish CTRCD from peripartum cardiomyopathy by timing and exposure history.

— Childhood cancer survivors (ALL, lymphoma, sarcoma, Wilms) exposed to anthracyclines and/or chest XRT have lifetime HF risk 5–15× general population.

— Children's Oncology Group (COG) long-term follow-up guidelines: echo every 2–5 years lifelong based on cumulative anthracycline dose and radiation exposure.

— Pre-conception counseling: pregnancy doubles cardiac workload and can unmask subclinical cardiomyopathy in survivors — obtain echo before and during pregnancy.

— Avoid second-hit insults: HTN control, no smoking, no recreational stimulants.

— Stress testing or coronary CT starting 5–10 years post-radiation, then periodically.

— Heightened screening for valvular disease and constriction.

Key distinction: A pregnant patient with new HFrEF in the third trimester or first month postpartum without prior chemo = peripartum cardiomyopathy; same picture during anthracycline therapy in pregnancy = CTRCD. Management overlaps but ACEi/ARB are deferred until after delivery and lactation.

Board pearl: Childhood ALL survivors who received >250 mg/m² doxorubicin require lifelong echo surveillance and pre-pregnancy cardiac evaluation.

Pregnancy:

Pediatric and AYA survivors:

Breast cancer survivors with mediastinal/left chest radiation:

Complications and Adverse Outcomes

— Anthracycline DCM: progressive LV dilation, often irreversible; advanced HF, transplant or LVAD candidacy in young survivors.

— Trastuzumab dysfunction: usually recovers within 3–6 months of cessation + GDMT in 70–80%.

— Atrial fibrillation (ibrutinib, anthracyclines, melphalan, post-XRT atrial fibrosis) → stroke risk.

— Ventricular arrhythmias and torsades with QT prolongation (arsenic, nilotinib, vandetanib) — especially with electrolyte derangement from vomiting/diarrhea.

— Bradyarrhythmias and AV block in radiation-induced conduction system disease.

— 5-FU vasospasm → MI, sudden death.

— VEGF inhibitors → arterial thrombosis, MI, stroke.

— Radiation → premature CAD, often ostial LM/LAD; restenosis after PCI is more common in irradiated vessels.

— Acute pericarditis (cyclophosphamide, anthracyclines, immunotherapy).

— Late constrictive pericarditis (mediastinal XRT) — Kussmaul sign, pericardial knock, septal bounce on echo.

— VTE (cisplatin, lenalidomide/thalidomide + dexamethasone).

— Arterial events (VEGF, BCR-ABL TKIs nilotinib/ponatinib → PAD, MI, stroke).

Board pearl: Ponatinib carries a black-box warning for arterial occlusive events — MI, stroke, peripheral arterial disease — and demands aggressive cardiovascular risk factor optimization and the lowest effective dose.

Key distinction: Trastuzumab cardiotoxicity is largely reversible; anthracycline cardiotoxicity is largely irreversible — this drives long-term prognosis.

Heart failure progression:

Arrhythmias:

Acute coronary syndromes and ischemia:

Pericardial disease:

Valvular disease: late radiation-induced AS, AR, MR; thickening and calcification of leaflets and aortomitral curtain.

Vascular and thromboembolic:

Hypertensive emergency: VEGF inhibitors, carfilzomib.

Sudden cardiac death: fulminant checkpoint myocarditis, torsades, post-XRT conduction disease.

When to Escalate Care — ICU, Consult, and Inpatient Triage

— Suspected immune checkpoint inhibitor myocarditis (elevated troponin + new ECG changes or arrhythmia, even mild symptoms) → admit, telemetry/ICU, IV methylprednisolone 1 g daily, urgent cardiology + oncology consult.

— Cardiogenic shock (SBP <90, lactate ↑, end-organ hypoperfusion) → ICU, inotropes (dobutamine, milrinone), consider mechanical circulatory support (IABP, Impella, VA-ECMO).

— Sustained VT, torsades, complete heart block, QTc >500 ms with arrhythmia → telemetry/ICU, correct K⁺/Mg²⁺, IV magnesium, isoproterenol or pacing for bradyarrhythmia.

— Hypertensive emergency on VEGF/TKI with target organ damage → ICU, IV agents.

— Acute MI / 5-FU vasospasm with refractory chest pain or hemodynamic instability.

— New symptomatic HF with congestion requiring IV diuresis.

— New AF with rapid ventricular response in cancer patient on ibrutinib needing rate/rhythm control and anticoagulation initiation.

— Pericardial effusion with tamponade physiology → pericardiocentesis.

— Asymptomatic LVEF drop ≥10 points to <50%.

— GLS decline >15% relative.

— Persistent HTN >160/100 on VEGF inhibitor despite two agents.

— Survivors with new exertional symptoms.

— Baseline high HFA-ICOS risk before initiating anthracycline/trastuzumab/VEGF therapy.

— Pre-conception planning in survivors.

CCS pearl: Checkpoint inhibitor myocarditis on a CCS case: admit to CCU, order continuous telemetry, troponin q6h, CMR, cardiology + oncology consults, start methylprednisolone 1 g IV daily, hold all immunotherapy, and prepare for escalation if hemodynamics deteriorate — do not delay steroids waiting for biopsy.

Immediate ED/ICU triage:

Hospital admission (floor):

Urgent outpatient cardio-oncology referral (within days):

Routine cardio-oncology referral:

Key Differentials — Cardiac/Same-Category Causes of HF or Chest Pain in Cancer Patients

— Pre-existing CAD destabilized by anemia, hypoxia, tachycardia, or vasospastic agents.

— Distinguish with troponin trajectory, ECG, coronary imaging.

— Common in older oncology patients; preserved EF with diastolic dysfunction.

— VEGF inhibitor HTN can unmask or worsen HFpEF.

— Apical ballooning, often after emotional/physical stressor, sometimes precipitated by 5-FU or capecitabine, or after surgery.

— Coronary angiography shows non-obstructive vessels; recovery typically in weeks.

— Persistent SVT or AF (ibrutinib) → LV dysfunction reversible with rate control.

— Malignant pericardial effusion vs chemo/radiation pericarditis vs uremic.

— Echo with tamponade physiology (RA/RV collapse, IVC plethora, respirophasic flow variation).

— Carcinoid heart disease (right-sided lesions with metastatic carcinoid).

— Radiation valvulopathy (left-sided AS/AR/MR years later).

— Marantic (NBTE) endocarditis with adenocarcinomas → embolic stroke, MI.

— Constriction: radiation; respirophasic septal bounce, preserved tissue Doppler e′.

— Restriction: cardiac amyloid (especially AL with myeloma) — low voltage on ECG, increased wall thickness on echo, apical sparing on strain.

Key distinction: A myeloma patient with HFpEF physiology, low ECG voltage, and increased LV wall thickness has AL cardiac amyloidosis until proven otherwise — not isolated chemotherapy cardiotoxicity. Confirm with serum/urine immunofixation, free light chains, and CMR or PYP scan (PYP positive for ATTR, not AL).

Underlying ischemic heart disease:

Hypertensive heart disease / HFpEF:

Stress (Takotsubo) cardiomyopathy:

Tachycardia-mediated cardiomyopathy:

Pericardial disease:

Valvular dysfunction:

Constrictive vs restrictive cardiomyopathy:

Key Differentials — Non-Cardiac and Other-Category Causes

— Chemo-induced pneumonitis: bleomycin, methotrexate, checkpoint inhibitors → dyspnea, cough, hypoxia; CT shows ground-glass opacities; echo and BNP normal.

— Pulmonary embolism: cancer is a hypercoagulable state; sudden dyspnea, tachycardia, pleuritic chest pain → CT-PA; treat with apixaban or rivaroxaban or LMWH (per current ASCO/ITAC: DOACs first-line for most, LMWH preferred in GI/GU cancers with mucosal lesions).

— Radiation pneumonitis: weeks–months after chest XRT; fibrosis on imaging in radiation port.

— Hypokalemia/hypomagnesemia from vomiting/diarrhea → arrhythmia.

— Tumor lysis syndrome → hyperkalemia → arrhythmia.

— Hypothyroidism (post-checkpoint, post-neck XRT, anthracycline-associated) → bradycardia, effusion, low-output state.

Step 3 management: In a lymphoma patient on a checkpoint inhibitor with dyspnea, normal troponin, and ground-glass opacities on CT, the answer is immune-related pneumonitis — hold the drug and start prednisone 1 mg/kg/day, not HF therapy.

Board pearl: Always check TSH in a cancer patient with fatigue and bradycardia — both anthracyclines and checkpoint inhibitors can induce hypothyroidism that mimics or worsens cardiotoxicity.

Pulmonary causes:

Anemia: dyspnea, tachycardia, exertional fatigue mimicking HF; check CBC, iron studies.

Sepsis in neutropenic patient: hypotension and tachycardia mistaken for cardiogenic shock; obtain lactate, cultures, broad-spectrum antibiotics within 1 hour.

Electrolyte and metabolic:

Adrenal insufficiency: checkpoint inhibitor hypophysitis → hypotension, hyponatremia, fatigue, mistaken for cardiogenic.

Volume overload from IV hydration: especially with cisplatin pre-hydration in patients with limited cardiac reserve.

Drug-drug interactions: QT prolongation from ondansetron + methadone + fluoroquinolone stack; CYP3A4 interactions with TKIs and azole antifungals.

Secondary Prevention, Survivorship Medications, and Long-Term Plan

— ACEi/ARB or ARNI + beta-blocker + MRA + SGLT2 inhibitor (the "four pillars").

— Trial of withdrawal in fully recovered, asymptomatic patients is generally discouraged based on TRED-HF–style data showing relapse — for boards, do not stop HF meds after LVEF normalizes.

— BP <130/80; aggressive in survivors with prior anthracycline or chest XRT.

— Statin therapy per ASCVD risk (and standard of care after radiation-induced CAD).

— A1c <7% (individualized).

— Smoking cessation, weight management, Mediterranean-style diet, regular aerobic + resistance exercise (cardiac rehab eligible after HF hospitalization).

— Annual influenza and updated COVID/pneumococcal/RSV vaccines.

— Anthracycline + radiation: echo at 6–12 months post-therapy, then every 2–5 years lifelong based on risk.

— Mediastinal radiation: screen for CAD (stress test or CTCA) starting 5–10 years post-radiation, then every 5 years; periodic echo for valves and pericardium.

— Continue DOAC for cancer-associated VTE for as long as cancer is active.

— Atrial fibrillation: CHA₂DS₂-VASc–guided; apixaban preferred in cancer.

Step 3 management: A 52-year-old breast cancer survivor with trastuzumab-induced LVEF recovery from 38% → 55% on carvedilol + lisinopril asks to stop her HF meds — counsel her to continue indefinitely given risk of relapse, and reinforce annual echo + cardio-oncology follow-up.

Continue lifelong GDMT in patients who developed CTRCD-HFrEF, even after LVEF recovery:

Cardiovascular risk factor optimization:

Surveillance imaging in survivors:

Anticoagulation considerations:

Avoid cardiotoxic re-exposures when possible: anthracycline rechallenge in a patient with documented CTRCD is generally contraindicated unless no alternative exists and multidisciplinary discussion supports it.

Follow-Up, Monitoring Parameters, and Counseling

— Trastuzumab: echo every 3 months during therapy and at completion; symptom check each cycle.

— Anthracycline: echo at baseline, mid-treatment, completion, and 6–12 months later.

— VEGF/TKI: home BP log; review at every visit; weekly BP early.

— Ibrutinib: pulse check, ECG at baseline, and any time symptoms.

— Checkpoint inhibitors: troponin and ECG at baseline; surveillance troponin in high-risk patients during first cycles.

— First post-treatment visit: 1–3 months — echo, biomarkers, symptom assessment.

— Year 1: every 3–6 months.

— Year 2–5: every 6–12 months.

— Lifelong: at least annual cardiovascular risk assessment; periodic echo per risk tier.

— Daily weights; call for >2 lb in a day or >5 lb in a week.

— Watch for dyspnea, orthopnea, leg swelling, palpitations, syncope, chest pain.

— Home BP twice daily on VEGF inhibitors; thresholds for clinic call (>160/100 or sustained >140/90).

— Medication adherence — particularly beta-blocker and ACEi/ARB, which patients often discontinue.

— Eligible after HF hospitalization, MI, or revascularization; oncology-tailored cardiac rehab (CORE) improves functional capacity in survivors.

— Aerobic exercise ≥150 min/week moderate intensity unless contraindicated; resistance training reduces sarcopenia of cancer treatment.

— Avoid stimulants (cocaine, high-dose caffeine, decongestants) in survivors.

— Alcohol limit per AHA guidance.

CCS pearl: On a CCS post-discharge sequence for trastuzumab-induced HF, schedule echo and BMP at 1 month, cardio-oncology and oncology follow-up at 2–4 weeks, and cardiac rehab referral — these orders earn management points.

Active therapy phase:

Survivorship clinic schedule:

Self-monitoring counseling:

Cardiac rehabilitation:

Lifestyle:

Ethical, Legal, and Patient Safety Considerations

— Document explicit discussion of HF risk, LVEF monitoring plan, and the possibility of drug interruption or discontinuation.

— In high-risk patients (baseline LVEF 50–54%, prior anthracycline, chest XRT), shared decision-making with cardio-oncology should be documented before first dose.

— In metastatic disease, the trade-off between tumor control and cardiac risk shifts; revisit advance directives if CTRCD progresses to advanced HF.

— A patient with metastatic HER2+ breast cancer and recovered LVEF may reasonably choose trastuzumab rechallenge after counseling on relapse risk — respect autonomy and document.

— Steroid-induced delirium or hypoxic encephalopathy from fulminant myocarditis may impair capacity; identify surrogate per state hierarchy.

— Highest-risk window is hospital discharge after CTRCD diagnosis: medication reconciliation, clear written plan, cardio-oncology appointment within 2 weeks, primary oncology follow-up within 1–2 weeks, scheduled labs (BMP at 1–2 weeks after ACEi/MRA initiation), and a single point-of-contact phone number.

— Ensure discharge summary explicitly states which chemotherapy is held, who decides on resumption, and what the LVEF threshold is for rechallenge.

— Serious checkpoint inhibitor myocarditis should be reported to FDA MedWatch; institutional adverse event tracking supports safety signals.

— Survivorship surveillance often falls through cracks for uninsured/underinsured patients — proactively connect to patient navigators and survivorship clinics.

Board pearl: The single highest-yield Step 3 safety move in CTRCD is a structured discharge plan with explicit medication, follow-up dates, monitoring labs, and parameters for re-contact — this prevents 30-day readmission.

Informed consent for cardiotoxic therapy:

Goals-of-care alignment:

Capacity and surrogate decision-making:

Transitions of care — major Step 3 safety theme:

Mandatory reporting and pharmacovigilance:

Health equity and access:

Driving and work: counsel on driving restrictions after syncope, ICD placement, or symptomatic arrhythmia per state law.

High-Yield Associations and Rapid-Fire Clinical Facts

Board pearl: When a stem mentions "global longitudinal strain decline" in a patient on chemotherapy with still-normal LVEF, the answer is initiate ACEi + beta-blocker rather than stop chemotherapy.

Doxorubicin cumulative dose threshold: HF risk rises sharply >250–300 mg/m² and is substantial >450 mg/m².

Carvedilol: preferred beta-blocker in anthracycline CTRCD (antioxidant α/β blockade).

Dexrazoxane: iron chelator, cardioprotective for high cumulative anthracycline exposure.

Trastuzumab + anthracycline concurrent: avoid — synergistic cardiotoxicity; give sequentially.

5-FU/capecitabine: coronary vasospasm; treat with nitrates and CCB; avoid rechallenge.

Bevacizumab/sunitinib/sorafenib: hypertension and arterial thromboembolism.

Ibrutinib: atrial fibrillation and hypertension; prefer apixaban, avoid warfarin and CYP3A4 interactions.

Nilotinib/ponatinib: arterial occlusive disease (MI, stroke, PAD); ponatinib carries black-box.

Arsenic trioxide, vandetanib: QT prolongation, torsades risk.

Carfilzomib: HF, hypertension, pulmonary HTN.

Cyclophosphamide high-dose: hemorrhagic myopericarditis.

Checkpoint inhibitor myocarditis: rare (<1%) but high mortality; troponin + ECG + CMR; high-dose steroids first-line; concurrent myositis/MG-like syndrome.

Mediastinal radiation: late constriction, valvulopathy (AS/AR), ostial CAD, conduction disease — typically >10 years out.

Childhood ALL anthracycline survivors: lifetime HF risk; lifelong echo surveillance.

GLS >15% relative decline: earliest reliable imaging marker of subclinical cardiotoxicity.

HFA-ICOS risk score: standardized pre-treatment risk stratification.

Pregnancy + CTRCD: avoid ACEi/ARB/ARNI/MRA; use hydralazine/nitrates + metoprolol.

Acalabrutinib/zanubrutinib: lower AF rates than ibrutinib.

TCH (docetaxel/carboplatin/trastuzumab): anthracycline-sparing HER2+ regimen for cardiac-risk patients.

AL cardiac amyloidosis in myeloma: low ECG voltage + thick walls + apical sparing strain pattern.

Board Question Stem Patterns

Step 3 management: Whenever a stem pairs a cancer therapy with a new cardiac symptom, the answer almost always involves biomarkers + echo + multidisciplinary cardio-oncology decision, not jumping straight to discontinuation or rechallenge.

Stem 1 — Trastuzumab surveillance: 58F with HER2+ breast cancer 3 months into adjuvant trastuzumab; routine echo shows LVEF 45% (was 60%); asymptomatic. Answer: hold trastuzumab, start ACEi + carvedilol, repeat echo in 3 weeks.

Stem 2 — Checkpoint myocarditis: 65M on pembrolizumab for melanoma × 2 doses; fatigue, mild dyspnea; troponin elevated, new low-grade AV block. Answer: admit, high-dose IV methylprednisolone, permanently discontinue pembrolizumab, CMR for confirmation; do not delay steroids.

Stem 3 — 5-FU vasospasm: 60M on infusional 5-FU for colon cancer develops substernal chest pain during infusion; ECG with transient ST depressions; troponin mildly up. Answer: stop infusion, nitrates + CCB; avoid rechallenge.

Stem 4 — Ibrutinib AF: 72M with CLL on ibrutinib presents with palpitations, irregularly irregular pulse, AF on ECG; CHA₂DS₂-VASc 4. Answer: apixaban (not warfarin), beta-blocker for rate control, consider switching to acalabrutinib.

Stem 5 — Anthracycline late HF: 28F treated for childhood ALL with doxorubicin presents with dyspnea and orthopnea; LVEF 30%, dilated LV. Answer: GDMT (ACEi/ARNI, carvedilol, MRA, SGLT2i); pre-pregnancy cardiology counseling.

Stem 6 — Radiation late CAD: 45F treated for Hodgkin lymphoma 20 years ago with mantle XRT now with exertional angina. Answer: evaluate for premature CAD (stress imaging or CTCA), expect ostial lesions.

Stem 7 — VEGF HTN: 64M on bevacizumab develops BP 168/96. Answer: start amlodipine or ACEi, continue bevacizumab.

Stem 8 — Pregnant patient with CTRCD: 32F, 30 weeks, on doxorubicin for breast cancer, develops HFrEF. Answer: hydralazine + nitrates + metoprolol; avoid ACEi/ARB; deliver per OB; reinstitute full GDMT postpartum.

One-Line Recap

Chemotherapy-induced cardiotoxicity is a predictable, agent-specific spectrum of cardiac injury that demands risk-stratified baseline assessment, structured surveillance with echo/strain and biomarkers, prompt cardioprotective GDMT (ACEi/ARB + carvedilol ± MRA ± SGLT2i), agent-specific interventions (steroids for checkpoint myocarditis, dexrazoxane for high-dose anthracyclines, apixaban for ibrutinib AF), and lifelong survivorship cardiovascular care coordinated through cardio-oncology.

Board pearl: The default board answer when chemotherapy meets a new cardiac sign is biomarkers + echo with strain + multidisciplinary cardio-oncology decision, layered onto guideline-directed HF therapy — never reflex discontinuation alone.

Surveillance backbone: baseline + serial echo with GLS, troponin, NT-proBNP; trastuzumab every 3 months, anthracycline at dose milestones and 6–12 months post-therapy, lifelong follow-up for survivors with anthracycline or chest XRT exposure.

First-move pharmacology: carvedilol + ACEi/ARB as the cardio-oncology starter pair for any LVEF or GLS decline; add MRA and SGLT2 inhibitor as HFrEF criteria are met; continue indefinitely even after LVEF recovery.

Don't-miss diagnoses: checkpoint inhibitor myocarditis (troponin + ECG → high-dose steroids, permanent discontinuation), 5-FU vasospasm (stop infusion, nitrates/CCB, avoid rechallenge), ibrutinib AF (apixaban preferred), late radiation disease (ostial CAD, constriction, valvulopathy after 10+ years), AL cardiac amyloidosis in myeloma (low voltage + thick walls + apical-sparing strain).

Step 3 wrap-around: shared decision-making and documented informed consent before cardiotoxic regimens, structured transition-of-care plans at discharge with 2-week cardio-oncology follow-up, lifelong CV risk factor control (BP <130/80, statin, A1c, exercise, vaccines), and pre-pregnancy cardiac evaluation in any anthracycline-exposed survivor — the recurring exam theme is continue treating the cancer while protecting the heart, not choosing one over the other.