Cardiology Module
Comprehensive clinical resource for clinicians, residents & students — Calculators · Drug Dosing · Protocols · Indian Guidelines
🧮 Risk Stratification Calculators 10 tools
Validated stroke risk score for non-valvular AF. Score ≥2 (male) or ≥3 (female) = anticoagulation recommended. NOACs preferred over warfarin (except mechanical valves/MS).
65–74 = +1 · ≥75 = +2
Ref: Lip 2010 · ESC AF Guidelines 2020 · KD Tripathi 8th Ed
Use alongside CHA₂DS₂-VASc — NOT to withhold anticoagulation, but to identify and correct modifiable bleeding risk factors. Score ≥3 = high risk; address modifiable factors.
Ref: Pisters 2010 · ESC AF Guidelines 2020
Identifies low-risk chest pain patients safe for early discharge. Each component scored 0–2. Validated in multiple ED populations. MACE = MI, PCI, CABG, death at 6 weeks.
Ref: Backus 2010 · Six 2008 · ACC/AHA Chest Pain Guidelines 2021
Global Registry of Acute Coronary Events. Guides decision for in-hospital invasive strategy in NSTE-ACS. High risk (GRACE >140) → early invasive (<24h).
Ref: Fox 2006 · ESC NSTE-ACS Guidelines 2020 · Low ≤108 · Intermediate 109–140 · High >140
Thrombolysis In Myocardial Infarction risk score for UA/NSTEMI. Predicts all-cause mortality, new/recurrent MI, or severe recurrent ischaemia requiring urgent revascularisation at 14 days.
Ref: Antman 2000 · TIMI 11B trial · Low 0–2 · Intermediate 3–4 · High 5–7
Combines clinical features to estimate DVT probability. Guides use of D-dimer vs direct imaging. Score ≤0 + negative D-dimer = DVT excluded (99% NPV).
Ref: Wells 1997, 2003 · NICE NG158 · Low ≤0 · Moderate 1–2 · High ≥3
Clinically validated score to guide PE workup. Score ≤1 (unlikely) + negative D-dimer = PE excluded without CT. Score >1 or high clinical suspicion → CTPA.
Ref: Wells 2000 · ESC PE Guidelines 2019 · PE Unlikely ≤1 · Possible 2–6 · Likely >6
AHA/ACC Pooled Cohort Equations for primary prevention. Validated for ages 40–79 years without pre-existing CVD. Use alongside clinical judgement for South Asian/Indian patients (consider multiplying by 1.3–1.5 for Indian ethnicity).
Ref: Goff 2014 · ACC/AHA Cholesterol Guidelines 2019 · InSH 2023 for Indian adaptation
Rapid bedside tool. ≥2 points → consider sepsis, prompt full assessment, blood cultures, lactate, fluid resuscitation. Does not replace full SOFA in ICU.
Ref: Singer 2016 · Seymour 2016 · Surviving Sepsis Campaign 2021
Uses WHO Asian/Indian population cutoffs: Normal 18.5–22.9 · Overweight ≥23 · Obese ≥27.5 kg/m². Western cutoffs (overweight ≥25, obese ≥30) underestimate cardiometabolic risk in South Asians.
Ref: WHO Expert Consultation 2004 · Misra 2009 (Indian guidelines)
Race-free CKD-EPI 2021 equation. Critical for dose adjustment of: DOACs (rivaroxaban, apixaban, dabigatran), digoxin, metformin, ACE inhibitors, ARBs, spironolactone, low-molecular-weight heparin.
💊 Key thresholds: Metformin — avoid if eGFR <30 · Dabigatran — avoid if <30 · Rivaroxaban — reduce if <50 · Digoxin — caution if <60
Ref: Inker 2021 (CKD-EPI 2021) · KDIGO CKD 2022 · KD Tripathi 8th Ed
QTc >450ms (M) / >460ms (F) = prolonged. QTc >500ms = high Torsades de Pointes risk. Check for QTc-prolonging drugs (amiodarone, sotalol, macrolides, fluoroquinolones, antipsychotics, methadone, ondansetron) and electrolyte imbalances.
OR enter HR below
Auto-calculates RR
⚠️ QTc-prolonging drugs in cardiology: Amiodarone · Sotalol · Quinidine · Disopyramide · Ibutilide. Check full list at CredibleMeds.org
Ref: Bazett 1920 · Fridericia 1920 · AHA/ACC/HRS 2017
💊 Drug Information & Dosing 6 categories
NOACs (DOACs) are preferred over warfarin for most indications. Warfarin remains first-line for mechanical heart valves, mitral stenosis, antiphospholipid syndrome (triple positive), and where NOACs are unavailable.
| Drug | Indication | Standard Dose | Renal Adjustment | Reversal |
|---|---|---|---|---|
| Warfarin | AF, MVR, DVT/PE | Individualised — INR target 2–3 (AF/DVT) or 2.5–3.5 (MVR) | Use with caution; INR monitoring essential | Vit K, FFP, PCC (4-factor) |
| Apixaban | AF, DVT/PE, VTE prophylaxis | AF: 5 mg BD (2.5 mg BD if ≥2 of: age ≥80, wt ≤60 kg, Cr ≥1.5 mg/dL) DVT/PE: 10 mg BD ×7d → 5 mg BD | Use with caution if CrCl <25; avoid <15 | Andexanet alfa (approved) |
| Rivaroxaban | AF, DVT/PE, ACS (low dose) | AF: 20 mg OD with dinner DVT/PE: 15 mg BD ×21d → 20 mg OD ACS: 2.5 mg BD (+ DAPT) | AF: reduce to 15 mg OD if CrCl 15–49 | Andexanet alfa |
| Dabigatran | AF, DVT/PE (not ACS) | 150 mg BD (AF) — or 110 mg BD if age ≥80 / + verapamil | Avoid if CrCl <30; dose reduce 30–50 | Idarucizumab (specific antidote) |
| Edoxaban | AF, DVT/PE | 60 mg OD (AF, after ≥5–10d parenteral) 30 mg OD if CrCl 15–50 or wt ≤60 kg | Reduce to 30 mg if CrCl 15–50 | Andexanet alfa |
| Enoxaparin | Bridging, ACS, VTE prophylaxis | Therapeutic: 1 mg/kg SC BD (or 1.5 mg/kg OD) Prophylactic: 40 mg SC OD | Reduce to 1 mg/kg OD if CrCl <30; monitor anti-Xa | Protamine sulfate (partial) |
⚠️ Bridging: DOACs do NOT require bridging pre-procedure in most cases. Hold based on CrCl and bleeding risk (1–2 days for low, 3–5 days for high-risk procedures). Restart 24–48h post-procedure when haemostasis achieved.
Ref: KD Tripathi 8th Ed · BNF 2024 · ESC AF 2020 · CDSCO Drug Approvals
| Drug | Dose | Duration | Key Notes |
|---|---|---|---|
| Aspirin | Loading: 300 mg stat Maintenance: 75–100 mg OD | Lifelong post-ACS/PCI | PPI co-prescription recommended. Avoid in active peptic ulcer. |
| Clopidogrel | Loading: 300–600 mg stat Maintenance: 75 mg OD | 12 months post-ACS/drug-eluting stent; 1 month post-BMS | Prodrug — CYP2C19 polymorphism reduces efficacy (~25% South Asians). Preferred in patients taking PPIs (less interaction vs ticagrelor). |
| Ticagrelor | Loading: 180 mg stat Maintenance: 90 mg BD | 12 months post-ACS (preferred over clopidogrel) | Direct-acting P2Y12 inhibitor. Caution: dyspnoea (common), bradycardia, avoid if prior intracranial bleed. Do NOT use with strong CYP3A4 inhibitors (ketoconazole). ESC-preferred P2Y12 in ACS. |
| Prasugrel | Loading: 60 mg stat Maintenance: 10 mg OD (5 mg if <60 kg or >75 yrs) | 12 months post-PCI (ACS) | More potent, faster onset. Contraindicated: prior stroke/TIA, age ≥75 (relative), weight <60 kg (use 5 mg). Higher bleeding risk vs clopidogrel. |
DAPT Duration Guidance (ESC/ACC 2023)
ACS (STEMI/NSTEMI) — No bleeding concern12 months DAPT → aspirin lifelong
ACS — High bleeding risk (HBR)6 months DAPT then aspirin monotherapy
Elective PCI (stable CAD) — DES6 months DAPT → aspirin lifelong
Elective PCI — BMS1 month DAPT → aspirin lifelong
AF + PCI (triple therapy)1–4 weeks triple → DAPT or OAC+single antiplatelet up to 12m
Ref: ESC ACS Guidelines 2020, 2023 · ACC/AHA 2021 · KD Tripathi · PLATO, TRITON trials
The "Fantastic Four" disease-modifying therapies for HFrEF (EF ≤40%): ACEi/ARB/ARNI + Beta-blocker + MRA + SGLT2i. Target maximum tolerated doses. Start low, go slow.
| Drug | Starting Dose | Target Dose | Key Monitoring |
|---|---|---|---|
| Ramipril (ACEi) | 1.25–2.5 mg OD/BD | 5–10 mg OD | BP, K⁺, creatinine (check 1–2 wk after initiation). Avoid if K⁺ >5.5, eGFR <30, bilateral RAS. |
| Enalapril (ACEi) | 2.5 mg BD | 10–20 mg BD | As above. Switch to sacubitril/valsartan when haemodynamically stable. |
| Sacubitril/Valsartan (ARNI) | 24/26 mg BD (after 36h wash-out from ACEi) | 97/103 mg BD | Preferred over ACEi if tolerated. Contraindicated with ACEi (36h wash-out required to avoid angioedema). Monitor BP, K⁺, eGFR. |
| Carvedilol (Beta-blocker) | 3.125 mg BD | 25 mg BD (50 mg BD if >85 kg) | Initiate when euvolaemic. HR, BP. Avoid in reactive airways disease — use bisoprolol instead. |
| Bisoprolol (Beta-blocker) | 1.25 mg OD | 10 mg OD | More cardioselective. Safe in mild-moderate COPD/asthma. Titrate every 2 weeks. |
| Spironolactone (MRA) | 12.5–25 mg OD | 25–50 mg OD | Monitor K⁺ and creatinine (↑ risk hyperkalaemia with ACEi). Avoid if K⁺ >5.0 or eGFR <30. Gynaecomastia in males — switch to eplerenone. |
| Eplerenone (MRA) | 25 mg OD | 50 mg OD | No gynaecomastia. Post-MI HFrEF (EPHESUS trial). Same K⁺/renal monitoring. |
| Dapagliflozin (SGLT2i) | 10 mg OD | 10 mg OD (fixed) | HFrEF AND HFpEF benefit (DAPA-HF, DELIVER). Beneficial regardless of diabetes status. Caution: recurrent UTI, DKA risk. Hold peri-operatively (3 days prior). |
| Empagliflozin (SGLT2i) | 10 mg OD | 10 mg OD (fixed) | Also HFrEF + HFpEF (EMPEROR-Reduced/Preserved). As above. |
| Furosemide (loop diuretic) | 20–40 mg OD | Symptom-guided | NOT disease-modifying. Use for decongestion only. Monitor electrolytes (K⁺, Na⁺, Mg²⁺). Worsens renal function in dehydration. |
| Ivabradine | 5 mg BD | 7.5 mg BD | Add if HR ≥75 despite max beta-blocker + sinus rhythm. Do not use in AF. |
| Digoxin | 0.125–0.25 mg OD | Serum level 0.5–0.9 ng/mL | Reduce dose if eGFR <60. Drug interactions (amiodarone, verapamil ↑ levels). Narrow TI — check levels if toxicity suspected. |
📋 HFpEF (EF >50%): SGLT2i (dapagliflozin/empagliflozin) are now recommended. Evidence also supports spironolactone (modest benefit). ACEi/ARBs and beta-blockers — no mortality benefit proven in HFpEF but used for comorbidities.
Ref: ESC HF Guidelines 2021 · HFAI (Heart Failure Association of India) 2022 · DAPA-HF · EMPEROR · PARADIGM-HF · KD Tripathi
Indian Society of Hypertension 2023 recommends: single-pill combination (SPC) preferred from initiation for stage 2 HTN. Target <130/80 mmHg for most patients. CCBs are particularly effective in South Asians (lower renin activity).
| Drug Class | First-line Agents | Usual Dose | Preferred In | Avoid In |
|---|---|---|---|---|
| ACE Inhibitors | Ramipril, Enalapril, Perindopril | Ramipril: 2.5–10 mg OD Perindopril: 4–8 mg OD | CKD, DM with proteinuria, HFrEF, post-MI | Pregnancy, bilateral RAS, K⁺>5.5, Angioedema hx |
| ARBs | Losartan, Telmisartan, Olmesartan, Candesartan | Telmisartan: 40–80 mg OD Losartan: 50–100 mg OD | As ACEi — use if ACEi-intolerant (cough) | Pregnancy. Never combine with ACEi. |
| CCB (dihydropyridine) | Amlodipine, Cilnidipine | Amlodipine: 2.5–10 mg OD Cilnidipine: 5–10 mg OD (N+L channel — less oedema) | Elderly, isolated systolic HTN, Angina, South Asian patients | Severe aortic stenosis |
| CCB (non-DHP) | Diltiazem, Verapamil | Diltiazem SR: 120–360 mg OD | Angina + HTN, Supraventricular arrhythmia | HFrEF, AV block, WPW |
| Thiazide / Thiazide-like | Chlorthalidone, Indapamide (preferred over HCTZ) | Chlorthalidone: 12.5–25 mg OD Indapamide: 1.5 mg SR OD | Elderly, isolated systolic HTN, Salt-sensitive HTN (common in Indians) | Gout (caution), Hyponatraemia |
| Beta-blockers | Metoprolol, Bisoprolol, Nebivolol | Bisoprolol: 2.5–10 mg OD Metoprolol XL: 25–200 mg OD | Post-MI, HFrEF, AF rate control, Young HTN with tachycardia, Pregnancy (labetalol/methyldopa preferred) | Asthma, High-degree AV block. NOT first-line monotherapy for uncomplicated HTN |
| MRA / Potassium-sparing | Spironolactone, Eplerenone | Spironolactone: 25–50 mg OD | Resistant HTN (4th agent), HF, Primary hyperaldosteronism | K⁺>5.0, eGFR <30 |
| Alpha-1 blocker | Prazosin, Doxazosin | Doxazosin: 1–8 mg OD | BPH + HTN, Resistant HTN (add-on) | Orthostatic hypotension risk — 1st dose at night |
| Central acting | Methyldopa, Clonidine | Methyldopa: 250–500 mg BD–TDS | Methyldopa: Pregnancy (drug of choice) | Clonidine — rebound hypertension on withdrawal |
InSH 2023 — Preferred Single-Pill Combinations (SPCs)
Step 1 (low–moderate risk)ACEi/ARB + CCB or ACEi/ARB + Thiazide
Step 2ACEi/ARB + CCB + Thiazide (triple SPC)
Step 3 (resistant)+ Spironolactone 25–50 mg OD
BP Target (general)<130/80 mmHg; <140/90 if elderly/frail
Ref: InSH Guidelines 2023 · ESC HTN 2018/2023 update · JNC 8 · KD Tripathi 8th Ed
| Intensity | Agent + Dose | LDL ↓ | Indication |
|---|---|---|---|
| High intensity | Atorvastatin 40–80 mg OD Rosuvastatin 20–40 mg OD | >50% | ASCVD ≥20%, known CVD (post-MI, stroke, PAD), very high-risk primary prevention |
| Moderate intensity | Atorvastatin 10–20 mg OD Rosuvastatin 5–10 mg OD Simvastatin 20–40 mg OD | 30–50% | ASCVD 7.5–20%, DM age 40–75, LDL ≥4.9 mmol/L |
| Low intensity | Simvastatin 10 mg OD Pravastatin 10–20 mg OD | <30% | Statin intolerance, elderly (>75 years) — use lower doses |
| Ezetimibe (add-on) | 10 mg OD | +18–25% on top of statin | Add if LDL target not met on maximally tolerated statin. IMPROVE-IT trial. |
LDL-C Targets (ACC/AHA 2019 · ESC 2019)
Very high risk (known ASCVD, DM + organ damage)<1.4 mmol/L (<55 mg/dL)
High risk (ASCVD 10yr 10–20%, DM no complications)<1.8 mmol/L (<70 mg/dL)
Moderate risk (ASCVD 5–10%)<2.6 mmol/L (<100 mg/dL)
⚠️ Myopathy risk: Simvastatin 80 mg — avoid. Simvastatin + amlodipine — max 20 mg. Rosuvastatin 40 mg — monitor in Asian patients (lower doses effective). CK if myalgia >10× ULN — stop statin. Statin + fibrate: avoid gemfibrozil (prefer fenofibrate if needed).
Ref: ACC/AHA Cholesterol 2019 · ESC/EAS 2019 · IMPROVE-IT · KD Tripathi · CDSCO
| Drug | Class | QTc Risk | Management |
|---|---|---|---|
| Amiodarone | Class III antiarrhythmic | HIGH — QTc prolongation common but TdP paradoxically low | Baseline ECG, monitor QTc. Thyroid, LFTs, pulmonary function annually. |
| Sotalol | Class III antiarrhythmic | HIGH — dose-dependent TdP risk. Avoid if QTc >500ms | Initiate in hospital with cardiac monitoring. Dose reduce in renal impairment. Correct K⁺/Mg²⁺. |
| Quinidine | Class IA | HIGH — TdP risk | Largely replaced by safer agents. Monitor QTc closely. |
| Azithromycin | Macrolide antibiotic | MODERATE — especially with other QTc-prolonging drugs | Avoid with amiodarone/sotalol. Use with caution in HF, bradycardia. Clarithromycin: higher risk. |
| Moxifloxacin | Fluoroquinolone | HIGH — among fluoroquinolones | Avoid in prolonged QTc, with antiarrhythmics. Ciprofloxacin: lower risk. |
| Haloperidol/Antipsychotics | Dopamine antagonist | MODERATE–HIGH | IV haloperidol: HIGH risk — use oral route. Monitor ECG in ICU patients. |
| Ondansetron | 5-HT3 antagonist | MODERATE — 32 mg IV dose highest risk (now restricted) | Max IV dose 16 mg in adults. Avoid with other QTc-prolonging agents. |
| Methadone | Opioid analgesic | HIGH — dose-dependent, unpredictable | Baseline ECG, monitor QTc. Avoid with CYP3A4 inhibitors (antifungals, macrolides). |
🚨 High-risk combinations: Amiodarone + Azithromycin · Sotalol + Moxifloxacin · Any two QTc-prolonging drugs + hypokalaemia + bradycardia. Always correct K⁺ >4.0 mmol/L and Mg²⁺ >0.8 mmol/L in at-risk patients.
Ref: CredibleMeds.org · AHA/ACC/HRS 2017 · KD Tripathi · Arizona CERT QTDrugs Database
📋 Guideline-Based Protocols 4 protocols
1
Confirm Diagnosis: ≥2 readings on ≥2 occasions. BP ≥140/90 = HTN. Use HBPM or ABPM to exclude white coat HTN. Classify: Stage 1 (140–159/90–99) vs Stage 2 (≥160/100).
2
CVD Risk Assessment: Estimate 10-year ASCVD risk. Assess for target organ damage (LVH, CKD, retinopathy, stroke), DM, dyslipidaemia. Fasting lipids, fasting glucose/HbA1c, urine ACR, eGFR, ECG baseline.
3
Lifestyle Modification (all patients): DASH diet (reduce Na⁺ <5g/day), weight reduction (BMI <23 kg/m²), physical activity (150 min/week moderate), smoking cessation, alcohol reduction (<1 unit/day women, <2 men), stress management.
4
Pharmacotherapy Initiation (InSH 2023):
• Stage 1 + low risk: Lifestyle 3–6 months, then drug if target not achieved
• Stage 1 + high risk / Stage 2: Start drug therapy immediately alongside lifestyle
• Preferred first-line SPC: ACEi/ARB + CCB (Amlodipine) — most evidence in Indians
• Step 2: Add Chlorthalidone/Indapamide (thiazide-like)
• Step 3 (resistant): Add Spironolactone 25–50 mg OD after ruling out secondary causes
• Stage 1 + low risk: Lifestyle 3–6 months, then drug if target not achieved
• Stage 1 + high risk / Stage 2: Start drug therapy immediately alongside lifestyle
• Preferred first-line SPC: ACEi/ARB + CCB (Amlodipine) — most evidence in Indians
• Step 2: Add Chlorthalidone/Indapamide (thiazide-like)
• Step 3 (resistant): Add Spironolactone 25–50 mg OD after ruling out secondary causes
5
Special Populations:
• Pregnancy: Methyldopa, Labetalol, Nifedipine (avoid ACEi/ARB, diuretics in 1st trimester)
• CKD: ACEi/ARB first-line (reduce proteinuria); target <130/80
• DM: ACEi/ARB preferred; target <130/80
• Elderly (≥65): Start low; target <140/80 (SBP); beware orthostasis
• Pregnancy: Methyldopa, Labetalol, Nifedipine (avoid ACEi/ARB, diuretics in 1st trimester)
• CKD: ACEi/ARB first-line (reduce proteinuria); target <130/80
• DM: ACEi/ARB preferred; target <130/80
• Elderly (≥65): Start low; target <140/80 (SBP); beware orthostasis
6
Follow-up: Review in 4 weeks initially (or 1 week if stage 2/high risk). Once at target: every 3–6 months. Annual bloods: K⁺, creatinine, fasting glucose, urine ACR.
🚨 Hypertensive Emergency (BP >180/120 + end-organ damage): IV labetalol 20 mg bolus then infusion, or IV nicardipine, or IV sodium nitroprusside. Target: reduce MAP by ≤25% in first hour, then gradual. Admit HDU/ICU.
Ref: InSH Guidelines 2023 · ESC/ESH HTN 2018 · JNC 8 · WHO HEARTS Technical Package
1
Diagnosis: Symptoms (dyspnoea, orthopnoea, oedema) + Signs + Evidence of structural/functional cardiac abnormality. Echo (EF ≤40%) is key. BNP >35 pg/mL or NT-proBNP >125 pg/mL supports diagnosis.
2
Identify & Treat Precipitants: ACS, AF (rate control), hypertensive emergency, infection, anaemia, non-adherence to diet/drugs, NSAID/steroid use, thyroid disease, alcohol.
3
Initiate "Fantastic Four" (ESC 2021 — Class I, Level A):
① ACEi/ARB → switch to ARNI (sacubitril/valsartan) when stable
② Beta-blocker (bisoprolol/carvedilol/metoprolol XL) — start only when euvolaemic
③ MRA (spironolactone/eplerenone) — start after ACEi + beta-blocker
④ SGLT2i (dapagliflozin 10 mg OD or empagliflozin 10 mg OD) — add regardless of DM status
Start all four at low doses; up-titrate every 2 weeks targeting maximum tolerated doses.
① ACEi/ARB → switch to ARNI (sacubitril/valsartan) when stable
② Beta-blocker (bisoprolol/carvedilol/metoprolol XL) — start only when euvolaemic
③ MRA (spironolactone/eplerenone) — start after ACEi + beta-blocker
④ SGLT2i (dapagliflozin 10 mg OD or empagliflozin 10 mg OD) — add regardless of DM status
Start all four at low doses; up-titrate every 2 weeks targeting maximum tolerated doses.
4
Diuretics for Congestion: Furosemide — use minimum effective dose to maintain euvolaemia. Combination with thiazide (metolazone) in diuretic resistance. Daily weight monitoring (alert if +2 kg in 2 days).
5
Device Therapy (when appropriate):
• ICD: EF ≤35% + NYHA II–III despite ≥3 months GDMT + life expectancy >1 year
• CRT: EF ≤35% + LBBB + QRS ≥150 ms + sinus rhythm (NYHA II–IV)
• Ivabradine: Add if HR ≥75 in sinus rhythm despite max beta-blocker
• ICD: EF ≤35% + NYHA II–III despite ≥3 months GDMT + life expectancy >1 year
• CRT: EF ≤35% + LBBB + QRS ≥150 ms + sinus rhythm (NYHA II–IV)
• Ivabradine: Add if HR ≥75 in sinus rhythm despite max beta-blocker
6
Monitoring: BP, HR, weight daily at home. Renal function, K⁺, eGFR: at initiation of each drug, 1–2 weeks after each dose change, then 3–6 monthly. NT-proBNP trend for treatment response.
ℹ️ HFAI (India) note: Access to ARNI and SGLT2i is improving in India. If unavailable, ACEi + beta-blocker + MRA remain Class I and should be maximally up-titrated. Generic sacubitril/valsartan now available in India (2023).
Ref: ESC HF Guidelines 2021 · HFAI Consensus 2022 · PARADIGM-HF · DAPA-HF · EMPEROR · EMPHASIS-HF
1
Immediate Assessment (0–10 min): 12-lead ECG within 10 minutes. IV access × 2. O₂ only if SpO₂ <90%. Continuous cardiac monitoring. Troponin (high-sensitivity), CBC, RFT, LFT, coagulation, lipid profile. CXR.
2
STEMI — Reperfusion (Door-to-Balloon <90 min / Door-to-Needle <30 min):
• Primary PCI preferred if available within 120 min
• Fibrinolysis if PCI not possible within 120 min: Tenecteplase (weight-based IV bolus), Streptokinase 1.5 MU over 60 min (if tenecteplase unavailable)
• Anticoagulation during PCI: Heparin (UFH) 70–100 U/kg IV bolus
• Primary PCI preferred if available within 120 min
• Fibrinolysis if PCI not possible within 120 min: Tenecteplase (weight-based IV bolus), Streptokinase 1.5 MU over 60 min (if tenecteplase unavailable)
• Anticoagulation during PCI: Heparin (UFH) 70–100 U/kg IV bolus
3
NSTEMI/UA — Anti-ischaemic & Antiplatelet:
• Aspirin 300 mg loading immediately
• P2Y12 inhibitor: Ticagrelor 180 mg (preferred) OR Clopidogrel 300–600 mg
• Anticoagulation: Fondaparinux 2.5 mg SC OD (preferred for NSTEMI/UA) OR Enoxaparin 1 mg/kg BD
• Beta-blocker (oral) within 24h if no contraindication
• High-intensity statin immediately (Atorvastatin 40–80 mg)
• Aspirin 300 mg loading immediately
• P2Y12 inhibitor: Ticagrelor 180 mg (preferred) OR Clopidogrel 300–600 mg
• Anticoagulation: Fondaparinux 2.5 mg SC OD (preferred for NSTEMI/UA) OR Enoxaparin 1 mg/kg BD
• Beta-blocker (oral) within 24h if no contraindication
• High-intensity statin immediately (Atorvastatin 40–80 mg)
4
Invasive Strategy (NSTE-ACS):
• Immediate (<2h): Haemodynamic instability, refractory ischaemia, life-threatening arrhythmia
• Early (<24h): GRACE >140, significant troponin rise, new ST changes
• Selective invasive (<72h): GRACE 109–140, recurrent symptoms, LVEF <40%
• Conservative: GRACE <109, no recurrence, LVEF >40%
• Immediate (<2h): Haemodynamic instability, refractory ischaemia, life-threatening arrhythmia
• Early (<24h): GRACE >140, significant troponin rise, new ST changes
• Selective invasive (<72h): GRACE 109–140, recurrent symptoms, LVEF <40%
• Conservative: GRACE <109, no recurrence, LVEF >40%
5
Secondary Prevention (post-ACS — initiate before discharge):
• DAPT: Aspirin 75 mg + Ticagrelor 90 mg BD (or Clopidogrel 75 mg) × 12 months
• ACEi/ARB: Ramipril (start low, titrate up)
• Beta-blocker: Continue for ≥1 year; lifelong if EF reduced
• High-intensity statin: Atorvastatin 40–80 mg
• Aldosterone antagonist if EF <40% + DM or HF symptoms
• DAPT: Aspirin 75 mg + Ticagrelor 90 mg BD (or Clopidogrel 75 mg) × 12 months
• ACEi/ARB: Ramipril (start low, titrate up)
• Beta-blocker: Continue for ≥1 year; lifelong if EF reduced
• High-intensity statin: Atorvastatin 40–80 mg
• Aldosterone antagonist if EF <40% + DM or HF symptoms
🚨 Morphine use in ACS: Evidence suggests potential harm (CRUSADE registry). Use with caution — may delay oral antiplatelet absorption. Prefer IV nitrates for pain relief if BP permits.
Ref: ESC STEMI 2017 · ESC NSTE-ACS 2020 · ACC/AHA 2022 · KD Tripathi · Cardiological Society of India
| Population | Preferred Agent | Dose Adjustment | Avoid |
|---|---|---|---|
| CKD Stage 3a (eGFR 45–59) | Apixaban or Rivaroxaban | Standard dose; monitor closely | Dabigatran (renally cleared 80%) |
| CKD Stage 3b–4 (eGFR 15–44) | Apixaban 2.5 mg BD (if criteria met) or Warfarin | Reduce dose; anti-Xa monitoring for LMWH | Dabigatran (avoid <30); Rivaroxaban (reduce to 15 mg in AF if 15–49) |
| ESRD / Dialysis (eGFR <15) | Warfarin (INR 2–3) or Apixaban 5 mg BD (limited data) | Frequent INR monitoring if warfarin | All DOACs — limited evidence; avoid if possible |
| Pregnancy (AF/VTE) | LMWH (Enoxaparin) throughout pregnancy | 1 mg/kg BD; anti-Xa monitoring target 0.6–1.0 U/mL (peak, 4h post-dose); increase dose in 3rd trimester as weight increases | Warfarin (1st trimester — embryopathy; 3rd trimester — neonatal haemorrhage); All DOACs (teratogenic, contraindicated) |
| Postpartum | LMWH or warfarin (warfarin safe in breastfeeding) | Resume 4–6h post-SVD, 6–12h post-CS if haemostasis achieved | DOACs — limited data in breastfeeding; avoid |
| Elderly (>75 years) | Apixaban (best safety profile in elderly — ARISTOTLE) | Check 2-of-3 criteria for dose reduction: age ≥80, wt ≤60 kg, Cr ≥1.5 mg/dL → 2.5 mg BD | Dabigatran 150 mg BD — high GI bleed risk in elderly; use 110 mg BD |
| Obesity (BMI >40 or >120 kg) | Warfarin or LMWH (weight-based) | Peak anti-Xa monitoring for LMWH; max capped dose or twice-daily regimen. DOACs: limited pharmacokinetic data in extreme obesity | Fixed low-dose LMWH (prophylaxis underdosing common in obesity) |
| Mechanical Heart Valve | Warfarin ONLY | INR 2.5–3.5 (mitral position or tilting disc); INR 2–3 (bileaflet aortic with no risk factors) | All DOACs (RE-ALIGN trial — excess valve thrombosis and bleeding with dabigatran) |
⚠️ Anticoagulation in active cancer: LMWH traditionally preferred. Apixaban and rivaroxaban now recommended by ESC/ISTH in most cancers except high GI/GU bleed risk cancers (gastric, GI tumours) where LMWH remains preferred.
Ref: ESC AF 2020 · ESC VTE Guidelines 2019 · BTS/RCOG Pregnancy VTE · ISTH Guidance Cancer-associated VTE · KD Tripathi
🔬 Drug Interactions & Therapeutic Drug Monitoring
| Drug 1 | Drug 2 | Interaction | Management |
|---|---|---|---|
| Warfarin | Amiodarone | Amiodarone inhibits CYP2C9 → ↑ warfarin levels → ↑ bleeding risk (may persist 6+ months after amiodarone stopped) | Reduce warfarin dose by 30–50% proactively. Increase INR monitoring frequency to weekly initially. |
| Warfarin | Fluconazole / Antifungals | Strong CYP2C9 inhibition → marked ↑ INR | Avoid if possible; if essential, reduce warfarin dose 25–50% and monitor INR every 2–3 days. |
| Statin (Simvastatin/Lovastatin) | Amlodipine, Diltiazem, Verapamil | CYP3A4 inhibition → ↑ statin levels → myopathy/rhabdomyolysis risk | Simvastatin max 20 mg with amlodipine. Switch to rosuvastatin or pravastatin (not CYP3A4 metabolised). |
| Digoxin | Amiodarone, Verapamil, Spironolactone, Clarithromycin | ↑ Digoxin levels (P-glycoprotein inhibition and/or reduced renal clearance) → toxicity | Halve digoxin dose when starting amiodarone/verapamil. Monitor digoxin levels and ECG (AV block, arrhythmias). |
| ACEi / ARB | Spironolactone / MRA | ↑ Hyperkalaemia risk — especially in CKD, DM, high K⁺ diet | Avoid if K⁺ >5.0 or eGFR <30. Monitor K⁺ and creatinine at 1–2 weeks and 1 month after initiation. |
| Ticagrelor | Strong CYP3A4 inhibitors (Ketoconazole, Ritonavir, Clarithromycin) | ↑ Ticagrelor plasma levels → ↑ bleeding risk | Contraindicated. Use clopidogrel instead if these drugs are essential. |
| Beta-blocker | Verapamil / Diltiazem (IV) | Synergistic AV nodal blockade → severe bradycardia, complete heart block, asystole | Never give IV verapamil/diltiazem to patient on beta-blocker without careful monitoring. Oral combination is relatively safer but requires ECG monitoring. |
| Metformin | IV Contrast (iodinated) | ↑ Risk of contrast-induced nephropathy + lactic acidosis | Hold metformin 48h before IV contrast if eGFR <60. Resume only after renal function confirmed stable 48h post-procedure. |
Ref: KD Tripathi 8th Ed · BNF 2024 · Stockley's Drug Interactions · CDSCO · CredibleMeds.org
| Drug | Target Level / INR | Sampling Time | Notes on Interpretation |
|---|---|---|---|
| Digoxin | 0.5–0.9 ng/mL (HF/AF rate control) <1.2 ng/mL to avoid toxicity | Trough: ≥6h post-dose (≥12h preferred) | Levels >2 ng/mL = toxicity likely. Hypokalaemia, hypomagnesaemia, hypothyroidism potentiate toxicity even at "normal" levels. Adjust dose in renal impairment. |
| Warfarin (INR) | 2.0–3.0 (most AF/VTE) 2.5–3.5 (mechanical MV, some tilting disc valves) | Any time after stable dosing; trough preferred | INR <2 = subtherapeutic (thrombosis risk). INR >5 = high bleed risk (hold dose, consider Vit K). Labile INR: check adherence, dietary Vit K, drug interactions. |
| Amiodarone (thyroid/LFT monitoring) | Not routinely measured; Metabolite DEA therapeutic range approximately 0.5–2.0 mg/L if assay available | Not routine — assess for toxicity | Monitor TFTs, LFTs, PFTs, CXR annually (pulmonary toxicity). Corneal microdeposits, photosensitivity — counsel patients. Half-life 40–55 days. |
| Enoxaparin (anti-Xa) | Therapeutic: peak 0.6–1.0 U/mL (BD dosing) Prophylactic: peak 0.2–0.4 U/mL | 4h post SC dose (peak) | Indicated in: renal impairment (eGFR <30), obesity, pregnancy, extremes of weight. Anti-Xa not needed for standard dosing in normal renal function. |
| Unfractionated Heparin (UFH) | APTT ratio 1.5–2.5× control (60–100 seconds typically) | 6h after initiation; 6h after each dose change | Highly variable response. Use weight-based nomogram. Platelet count every 2–3 days — monitor for HIT (fall >50% from baseline). |
Ref: KD Tripathi 8th Ed · BNF 2024 · BCSH Guidelines · WHO Essential Medicines TDM guidance