Medical Archive

Introduction

Pathophysiology: role of acute plaque rupture

Clinical presentation

?? 30? ?? ???? pain, ??? NTG? ?? x
Abnormal Q? ?? MI? ??? ??? ?? ?. (R? 1/4 ??)
STEMI? NSTEMI?? ?? PCI, fibrinolysis ? ??? ?? ??.

Biomarker	Myolglobin: few hours ~24hr CK-MB: 4-8hr ~ 48-72hr Troponin: ?? ~ 7-10days
EKG	V1,2: septal / V3,4: anterior / V5,6: lateral
Echo	???? MI?? wall motion ?? ?? Sensitivity ?? ???. Old MI ?????.
Nuclear medicine	Small infarction ?? ??. Old infarc ??? ?? Hybernating: ?? ??, ? ?? ?? Stunned: ?? ??, ? ?? ?? FDG PET / Stress redistribution TI-201 SPECT
MRI	Gadolinium ?? ? “White is dead!”

Atypical MI

• Painless STEMI, dyspnea? cc? ?? ?? 
• HTN, DM, ??, old age, post.op.
• DM: ?? ?? multivessel ??

Laboratory findings

ECG

ST elevation

Serum cardiac biomarker

Troponin: AMI??? 2~3??? ??? ????. 

Cardiac imaging

Initial management

Management in the emergency department

Control of discomfort

Management strategies

Limitation of infarct size

Primary PCI

?? ??? 30?, ? ? 90? ??? ??? (6hr ??? ??O)

• Primary PCI ???
  • ?? <12hr
  • Fibrinolysis CIx
  • Severe HF or cardiac shock
  • Ongoing ischemia, 12~24hr
• Fibrinolysis ?? ? ???? ??
  • ??? ????? ??
  • Cardiogenic shock? ??? ??
  • ?? ???? ?? ??
  • ??? ??? 2-3?? ?? ???? ?????? ?? ?? ?? ?? ??.
• ?? ? long term dual antiplatelet
  • Aspirin + P2Y12R blocker (eg, clopidogrel, prasugrel, ticagrelor)
  • Mitigate the increased thrombotic risk by BMS or DES
• Complication following PCI
  • Restenosis
    • By elastic recoil, thrombosis, intima hyperplasia(m/c)
    • Prevented by clopidogrel

Fibrinolysis

• 1~3?? ??? ?? ?? ??
• ??: tPA, streptokinase, tenecteplase (TNK), reteplase (rPA)
• Absolute contraindication
  • ????? ???? ??? history
  • 1? ? ???? ????? ?? ?????? ??
  • Active internal bleeding (?? ??)
  • Marked hypertension > 180/110 
  • Aortic dissection? ??? ?
  • ??? ????? STE ?? ?

Reperfusion of irreversibly-damaged cells results in calcium influx, leading to hypercontraction of myofibrils (contraction band necrosis).

Return of oxygen and inflammatory cells may lead to free radical generation, further damaging myocytes (reperfusion injury).

Integrated reperfusion strategy

Evidence of reperfusion

• Pain relief
• ST normalization >50%
• Reperfusion arrhythmia (AIVR)
• (Acelerated idioventricular rhythm)
• Early peak of cardiac markers (10-15hrs)

Hospital phase management

1. ?? ??? ?? EKG ??? NSTE, STE ??
   • STE ??: 2?? ?? precordial?? 2mm, 2?? limb lead?? 1mm STE
   • NSTE? ?? ???? ???? UA/NSTEMI ??
2. STE?? ???? ??? ???? ? primary PCI? thrombolysis ? ??.

Pharmacotherapy

For detail: Tintinalli S4 Resuscitative Procedures

??? – MONA(B)
AMI??? ?? Aspirin, hypoxia? O2 (2-4L/min)\
??? ??: NTG (5??? 3?) ? morphine IV

• ??? ?? ??: aspirin+/-clopidogrel, BB, ACEi, warfarin
• HR>60, SBP>100, PR<0.24? ??
  • BB 2-5? ?? 3?
  • Non-selective BB (N to Z): can trigger bronchospasm 
  • ?1-selective BB (A to M): safe in COPD/asthma

ACEi

preload, afterload ?? ??, remodeling ?
24hr ? ???? ??? ???? ??
??? – ABA
Aspirin, BB, ACEi, ??? +statin

NTG

• Contraindication
  • ??? (<90 or 30?), ?? ??(50)/??(100), RV infarc, 24hr ? PDEi ??
    ??? ?? or ??? or ??? ??? IV?.

# Cocaine-induced MI

Treated the same way as atherosclerotic MI
Except that BB are not used, and BZD are used.

Complications and their management

Ventricular dysfunction

By remodeling.
Can occur secondary to LV infarction, VSD, free wall rupture, papillary muscle rupture

Hemodynamic assessment

Hypovolemia

Treatment

Cardiogenic shock

??: PCWP >18mmHg, cardiac index <2.2, hypotension <90mmHg
Anterior wall infarction ????? ???.

Treatment

• ???? ??
  • Hypoxemia? acidosis? ??
  • Hyperglycemia -> insulin?? ??
  • Bradyarrhythmia -> transvenous pacing. ???? VT? AF? ?? ??.
• Vasopressors
• IABP
  • Early diastole ? inflated -> coronary flow? peripheral perfusion ??
  • Early systole ? collapse -> afterload ??, CO ??.
  • ??: AR, aortic dissection, large AV shunt

Right ventricular infarction

Inferoposterior infarction ???? ??.
PCWP <15mmHg, clear lung

Treatment

• HR <50
  • RCA? AV, SA node ? ?????. 
  • Enhanced vagal tone ? Atropin ??
  • Temporary AV sequential pacing (?? ???)
• BP <90
  • Volume expansion (N/S)
    • Pulmonary edema? ?? ? ??
  • Dopamine, dobutamin
• Reduce RV afterload
  • IABP, arterial vasodilators (sodium nitroprusside, hydralazine), ACEi
• Normal
  • ?? Inf.wall infarc??? STEMI? ?? MONABR ??.

Arrhythmias 

??: Ant. Wall < Inf. Wall
Inf. Wall: ??? vagal tone ?? – 1? AV block ? IV atropine

• Phase 1a ventricular arrhythmias
  • “Immediate”: occur within 10 minutes of coronary occlusion
  • Predisposes to reentrant arrhythmias
• Phase 1b ventricular arrhythmias
  • “Delayed”: occur about 10-60 minutes after acute infarction
  • Result from abnormal automaticity
• VT
  • https://hsnow.net/2020/07/01/c248-premature-ventricular-beats-non-sustained-ventricular-tachycardia-and-idioventricular-rhythm/

Other complications

Recurrent chest discomfort

Pericarditis

• 2-4 days following a transmural MI. “peri-infarction pericarditis (PIP)”
• PIP results from localized inflammation triggered by transmural myocardial necrosis following STEMI
• Prevention: early coronary reperfusion therapy.
• Management: the condition is generally short-lived and resolves with 1-3 days of aspirin therapy.

Thromboembolism

LV aneurysm

• False LV anneurysm? ?? ??? ??? ??? ??
• True LV anneurysm? ?? ??????

Mechanical complications

Complication	Time course	Involved coronary artery	Clinical findings	Auscultation	ECG findings	Management
RV failure	Acute	RCA	Hypotension Clear lungs		Hypokinetic RV
LV pseudoaneurysm	Acute or within 3-5 days		Risk of embolus from mural thrombi			Immediate surgery d/t high risk of rupture
Papillary muscle rupture	Acute or within 3-5 days	RCA (PDA)	Severe pulmonary edema	Silent in ~50% New mid-to-late systolic murmur (50%)	Severe MR with flail leaflet	IV Nitroglycerin or nitroprusside to lower afterload MR: Valve surgery ± CABG
Interventricular septum rupture	Acute or within 3-5 days	LAD (apical septal) or RCA (basal septal)	Chest pain Biventricular failure Shock	New holosystolic murmur at the LLSB (90%)	L-to-R ventricular shunt ↑O2 level from RA to RV	IV Nitroglycerin or nitroprusside to lower afterload
Free wall rupture	within 5 days to 2 weeks	LAD	Chest pain, shock 10% of MI-related death Related to steroid, NSAID use	Distant heart sound	Large Q wave Pericardial effusion with tampoonade
LV aneurysm	up to several months	LAD	Refractory heart failure Continuous ST-elevation Stable angina Stasis → LV thrombus		Thin & dyskinetic myocardial wall	Anticoagulant if there is any thrombus
Peri-infarction pericarditis (Local inflammation)	Within 4 days				Widespread ST elevation & PR depression	NSAIDs +/- corticosteroid
Immune-mediated pericarditis (Dressler syndrome)	2 weeks ~ up to 14 weeks	–	1-3%. 발열이나 흉통과 함께 심장막염, 흉막염, 폐장염 병발.			NSAIDs + colchicine +/- corticosteroid. NO ANTICOAGULANT (tamponade 형성)

Postinfarction risk stratification and management

Secondary prevention

• Antiplatelet (Aspirin or Clop.)
• Beta blocker
• ACEi / ARB / andosterone antagonist
• Warfarin
  • ?? Severe LV dysfunction, ?? ????.
  • Late mortality? reinfarction ?? ??
  • Embolism? ??? ???? ?? ???? aspirin? ???? ?? ??.