What is the latest management approach for a patient experiencing a heart attack, including immediate actions, hospital treatment, and long-term secondary prevention?

Management of Evolving Heart Attack (STEMI)

For patients presenting with ST-elevation myocardial infarction (STEMI), primary percutaneous coronary intervention (PCI) performed within 120 minutes of diagnosis is the preferred reperfusion strategy, and if this cannot be achieved, fibrinolytic therapy should be initiated immediately within 12 hours of symptom onset. 1

Immediate Actions (First 10 Minutes)

Initial Assessment and Stabilization

• Obtain a 12-lead ECG within 10 minutes of arrival to identify ST-segment elevation ≥1 mV in contiguous leads or new left bundle branch block, which mandates immediate reperfusion therapy 2, 3
• Administer aspirin 160-325 mg immediately (chewable or water-soluble for faster absorption) upon arrival, which reduces 35-day mortality by 21% when combined with reperfusion therapy 2, 3
• Provide oxygen only if oxygen saturation <90% via nasal prongs; routine oxygen in non-hypoxemic patients may increase myocardial injury through hyperoxia 2
• Give sublingual nitroglycerin unless systolic BP <90 mmHg, heart rate <50 or >100 bpm, or right ventricular infarction is suspected (avoid completely in RV infarction due to profound hypotension risk) 2, 3
• Administer intravenous morphine 4-8 mg (or meperidine) with concurrent antiemetics for adequate analgesia and to reduce sympathetic activation 2, 3

Reperfusion Strategy Decision (Within 120 Minutes)

Primary PCI (Preferred Strategy)

• Primary PCI is the preferred reperfusion strategy when it can be performed within 120 minutes of STEMI diagnosis by experienced operators with prompt access to emergency CABG surgery 1, 2
• Patients should bypass the emergency department and CCU/ICCU and transfer directly to the catheterization laboratory to minimize door-to-balloon time 1
• Radial access is preferred over femoral access to reduce bleeding complications 4
• Drug-eluting stents are recommended over bare-metal stents to reduce restenosis rates 4

Fibrinolytic Therapy (When PCI Cannot Be Achieved Timely)

• If primary PCI cannot be performed within 120 minutes, initiate fibrinolytic therapy immediately if presenting within 12 hours of symptom onset and no contraindications exist 1, 2
• Fibrin-specific agents (tenecteplase, alteplase, or reteplase) are recommended, with tenecteplase dose reduced by 50% in patients ≥75 years to minimize stroke risk 1, 2
• Fibrinolysis should preferably be initiated in the pre-hospital setting to maximize time-dependent benefit; treatment within the first hour saves 35 lives per 1000 patients treated versus 16 lives per 1000 when given 7-12 hours after onset 1, 3
• All patients receiving fibrinolysis must be transferred immediately to a PCI-capable centre for angiography between 2-24 hours after successful fibrinolysis 1
• Rescue PCI is indicated immediately when fibrinolysis has failed (<50% ST-segment resolution at 60-90 minutes) or at any time with hemodynamic/electrical instability or worsening ischemia 1

Antithrombotic Therapy

Antiplatelet Therapy for Primary PCI

• A potent P2Y12 inhibitor (prasugrel or ticagrelor) is recommended before or at the time of PCI and maintained for 12 months unless excessive bleeding risk exists 1
• Prasugrel: 60 mg loading dose, then 10 mg daily (reduce to 5 mg if age ≥75 years or weight <60 kg); use only after coronary angiography and prior to PCI 1, 4
• Ticagrelor: 180 mg loading dose, then 90 mg twice daily is preferred over clopidogrel for all moderate-to-high risk patients regardless of management strategy 4
• Clopidogrel: 300 mg loading dose, then 75 mg daily if prasugrel or ticagrelor are unavailable or contraindicated 1

Antiplatelet Therapy for Fibrinolysis

• Oral or intravenous aspirin is indicated as soon as possible 1
• Clopidogrel is indicated in addition to aspirin for patients receiving fibrinolytic therapy 1

Anticoagulation

• For primary PCI: Unfractionated heparin (UFH) or bivalirudin is recommended during the procedure 1
• Fondaparinux is not recommended for primary PCI 1
• For fibrinolysis: Enoxaparin intravenous followed by subcutaneous (preferred over UFH) or UFH given as weight-adjusted intravenous bolus followed by infusion, continued until revascularization or for duration of hospital stay up to 8 days 1

Hospital Treatment (First 24 Hours)

Monitoring and Assessment

• Continuous electrocardiographic monitoring for arrhythmias should be started immediately and continued for at least 24 hours 1
• Routine echocardiography during hospital stay is recommended to assess LV and RV function, detect early post-MI mechanical complications, and exclude LV thrombus 1
• Monitor for ST-segment recovery during the first hours following admission, as this provides important prognostic information and may guide rescue PCI decisions 1
• Arterial pressure monitoring should be undertaken in patients with cardiogenic shock, and balloon flotation catheters are indicated for cardiogenic shock, progressive heart failure, or suspected ventricular septal defect/papillary muscle dysfunction 1

Additional Pharmacotherapy

• Intravenous nitroglycerin should be used for 24-48 hours in patients with heart failure, large anterior MI, persistent ischemia, or hypertension, but avoided in right ventricular infarction 2
• Oral beta-blockers are indicated in patients with heart failure and/or LVEF <40% unless contraindicated; intravenous beta-blockers must be avoided in patients with hypotension, acute heart failure, AV block, or severe bradycardia 1
• ACE inhibitors should be initiated within the first 24 hours in patients with heart failure, LVEF <40%, diabetes, or anterior infarction 1, 2
• High-intensity statin therapy should be started as early as possible and maintained long-term, regardless of baseline cholesterol 1, 2

Special Consideration: Right Ventricular Infarction

• Up to 50% of inferior MIs involve right ventricular infarction, requiring specific management modifications including obtaining a V4R lead early 2
• Maintain right ventricular preload with intravenous saline boluses and avoid nitroglycerin completely due to profound hypotension risk 2

Long-Term Secondary Prevention

Dual Antiplatelet Therapy (DAPT)

• DAPT in the form of aspirin plus ticagrelor or prasugrel (or clopidogrel if unavailable/contraindicated) is recommended for 12 months after PCI unless excessive bleeding risk exists 1
• After 12 months, transition to aspirin monotherapy (75-100 mg daily) indefinitely 1
• A proton pump inhibitor (PPI) in combination with DAPT is recommended in patients at high risk of gastrointestinal bleeding 1

Lipid Management

• An LDL-C goal of <1.8 mmol/L (70 mg/dL) or a reduction of at least 50% if baseline LDL-C is between 1.8-3.5 mmol/L (70-135 mg/dL) is recommended 1
• Continue high-intensity statin therapy long-term based on evidence from 4S, CARE, and LIPID trials showing 24-35% reduction in LDL-C and 20-33% reduction in cardiovascular mortality 1

ACE Inhibitors/ARBs

• ACE inhibitors should be continued for at least 4-5 years even in the absence of ventricular dysfunction, based on post-infarction studies and HOPE trial data 1
• ACE inhibitors or ARBs are indicated for LVEF ≤40%, heart failure, hypertension, or diabetes to reduce adverse remodeling and improve survival 4

Lifestyle Modifications

• Identify smokers and provide repeated advice on stopping with offers of follow-up support, nicotine replacement therapies, varenicline, and bupropion individually or in combination 1
• Participation in a cardiac rehabilitation programme is recommended 1

Critical Time Targets and Common Pitfalls

Time Targets

• "Call to needle time" for fibrinolysis should be ≤90 minutes, ideally ≤60 minutes 1, 3
• "Door to balloon time" for primary PCI should be ≤30 minutes from emergency department arrival 1
• Greatest benefit occurs when reperfusion is initiated within the first hour (35 lives saved per 1000 patients) compared to 7-12 hours (16 lives saved per 1000 patients) 1, 3

Common Pitfalls to Avoid

• Do not routinely combine fibrinolysis with planned immediate PCI, as this increases mortality and adverse outcomes 2
• Do not give thrombolytics to patients with non-ST-elevation MI, as there is no benefit and increased bleeding risk 2
• Do not delay aspirin administration while waiting for ECG confirmation 2
• Do not use routine oxygen in non-hypoxemic patients (only if SpO2 <90%) 2
• Do not administer nitroglycerin in right ventricular infarction due to profound hypotension risk 2, 3
• Do not use prophylactic antiarrhythmic agents in the first 24 hours of hospitalization 1

Special Populations

• Elderly patients (≥75 years) have increased risk of intracranial hemorrhage with thrombolytic therapy, particularly with tissue plasminogen activator; reduce tenecteplase dose by 50% 1, 2
• Patients with atrial fibrillation requiring anticoagulation should transition from triple therapy (aspirin + clopidogrel + OAC) to dual therapy (OAC + clopidogrel) after the acute phase (up to 1 week) to reduce bleeding risk 4
• Adjust anticoagulant and antiplatelet doses according to renal function and use low- or iso-osmolar contrast if angiography is performed in patients with renal impairment 4