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Ch.20 Anesthesia for patients with cardiovascular disease. R1 문은진. Introduction. Cardiovascular disease Most frequently encountered in anesthetic practice Major cause of perioperative morbidity & mortality Compromised cardiovascular system 에 부담을 주는 요인

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Ch.20 Anesthesia for patients with cardiovascular disease


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    1. Ch.20 Anesthesia for patients with cardiovascular disease R1 문은진

    2. Introduction • Cardiovascular disease • Most frequently encountered in anesthetic practice • Major cause of perioperative morbidity & mortality • Compromised cardiovascular system에 부담을 주는 요인 • The adrenergic response to surgical stimulation • The circulatory effects of anesthetic agents • Endotracheal intubation • Positive-pr ventilation • Blood loss • Fluid shifts • Alterations in body temp • Most anesthetic agents • Cardiac depression, vasodilation, or both 일으킴 • 직접적인 circulatory effect가 없는 마취제라 할지라도 심한 질환을 가지고 있는 환자에서는 만성적으로 항진된 교감신경활동으로 인하여 명백한 circulatory depression 을 일으킬 수 있다.

    3. Cardiac risk factor

    4. Preexisting cardiovascular disease를 가지고 있는 환자에서 흔히 나타나는 것 • Perioperative myocardial infarction • Pulmonary edema • Congestive heart failure • Arrhythmias • Thromboembolism • Noncardiac surgery후에 일어나는 cardiovascular complication이 25-50%에 이른다

    5. Clinical markers of increased cardiovascular risk • Major predictors -intensive management 필요로 함 • Intermediate predictors -careful preoperative assessment 필요 • Minor predictors -독립적으로 perioperative risk를 증가시킨다고 명백히 밝혀지지 않은 markers

    6. Management of pts with intermediate or minor predictors

    7. Two most important preoperative risk factors - Unstable coronary syndrome • Evidence of congestive heart failure • Cardiac complication이 생길 위험이 높은 환자에서 • Invasive monitoring • Aggressive hemodynamic interventions(eg. Vasodilators, adrenergic blockade) • > complication rate를 낮출 수 있다. • Elective noncardiac surgery 의 CIx • 수술 전 1개월 이내의 MI (Sx이나 noninvasive testing 을통해 persistent ischemic risk 의 증거가 있는 경우) • Uncompensated heart failure • Severe aortic or mitral stenosis

    8. Cardiac risk stratification for noncardiac surgical procedures • Emergency surgery의 경우 2-5배의 위험성 • Cardiac complication의 대부분은 • Major thoracic, abdominal, vascular op와 관련 • Poorly controlled HTN 은 수술 중 BP의 큰 변동과 관련 • Intraoperative HTN은 hypotension 보다 cardiac morbidity 와 더욱 연관됨. • 어떤 경우에서 spinal and epidural anesthesia 가 well-managed general anesthesia 보다 더 해로운hemodynamic effect를가져올 수 있다.

    9. Hypertension

    10. Preoperative considerations • Hypertension • Leading cause of death and disability in most Western societies • Most frequent preoperative abnormality in surgical pts • overall prevalence of 20-25% • Uncontrolled HTN->atherosclerosis, hypertensive organ damage 가속화 • Major risk factor for cardiac, cerebral, renal, vascular disease • Complication!!! • Myocardial infarction • Congestive heart failure • Stroke • Renal failure • Peripheral occlusive disease • Aortic dissection

    11. Definition • BP측정에 영향을 주는 요인 • equipment, technique, posture, time of day or night, emotional state, recent activity, drug intake • 한번의 측정으로 진단되지 않고 지속적으로 증가된 BP Hx있어야 한다 • Borderline HTN; DBP 85-89mmHg or SBP 130-139mmHg • Stage3 ; accelerated or severe HTN • Renal dysfunction 흔함 • Malignant hypertension ; - true medical emergency • >210/120mmHg • Papilledema, encephalopathy와 관련

    12. Pathophysiology • Idiopathic(essential) • Secondary to other medical conditions(renal dis, primary hyperaldosteronism, Cushing’s syndrome, acromegaly, pheochromocytoma, pregnancy, estrogen therapy) • Essential hypertension의 course of the disease • Cardiac output 증가, but, SVR appears in NL ->Cardiac output 회복, but, SVR becomes high 2. Chronic increase in cardiac afterload로 인해 concentric LVH, diastolic function의변화 3. Cb autoregulation 변화로 NL Cb blood flow는 유지(autoregulation limit: MBP 110-180mmHg)

    13. Mechanisms remain elusive but : • Vascular hypertrophy • Hyperinsulinemia • intracellular Ca 증가 • vascular smooth muscle과 renal tubular cell 내의 Na 농도 증가 • Sympathetic nervous system overactivity • Overactivity of renin-angiotensin-aldosterone system : important role in accelerated HTN

    14. Long term treatment • Drug therapy • progression of HTN 감소 • Stroke, CHF, CAD, renal damage의발생감소 • LVH, altered Cb autoregulation등의 회복 가능 • 대부분 single-drug therapy로 치료 가능 • Low doses of a thiazide diuretic for most patients • ACE inhibitor : Lt ventricular dysfunction or heart failure 시 : 1st-line choice • ACEI or ARB : hyperlipidemia, chr. renal dis., DM(특히 nephropathy)시 optimal initial single agent • β-adrenergic blocker, calcium channel blocker :1st-line agent for CAD • Elderly Pt. : diuretic with or without β-adrenergic blocker, or calcium channel blocker alone

    15. Preopertaive management hypertention

    16. Untreated or poorly controlled hypertensive pt. -myocardial ischemia, arrhythmias, both hypertension and hypotension 등의 intraoperative episodes가 나타나기 쉽다. • altered cerebral autoregulation-> 과도한 혈압강하는 cerebral perfusion을 감소시킬 수 있다. • Antihypertensive drug은 수술 직전까지 지속 • 일부에서는 intraop hypotension 우려 때문에 수술 아침에 ACE inhibitor 투여를 중단하기도 함 -> 이러한 경우 perioperative HTN 위험이 높아지며 parenteral antihypertensive agent 필요성이 증가함 • 110 ㎜Hg 이상의 sustained preoperative diastolic BP 시에는 (특히 end-organ damage 있을 경우) 수일에 걸쳐 BP control이 잘 될 때까지 수술 연기

    17. History • Severity and duration of the HTN, drug therapy, hypertensive complication 유무 • Pt’s record of compliance with the drug regimen • Sx of MI, ventricular failure, impaired Cb perfusion, peripheral vascular dis. • Questions should concern : • Chest pains, exercise tolerance • Shortness of breath(특히 밤에) • Dependent edema, postural lightheadedness, • Syncope, amaurosis, claudication • Adverse effects of current antihypertensive drug

    18. Physical examination & laboratory evaluation • Ophthalmoscopy • Visible changes in the retinal vasculature ; Arteriosclerosis 및 다른 장기의 hypertensive damage 정도와 진행에 비례 • Physical findings • S4 gallop : LVH • Pulmonary rale & S3 gallop : CHF • Orthostatic BP change : volume depletion, excessive vasodilation, sympatholytic drug therapy 등의 원인-> preoperative fluid administration으로 induction시의 severe hypotension을 예방할 수 있다. • Asymptomatic carotid bruits • Coronary circulation에 영향을 미치는 atherosclerotic vascular dis.를 반영

    19. ECG : 대개 정상 • Evidence of ischemia, conduction abnormalities, old infarction, LVH, strain • NL ECG로 CAD or LVH 가능성을 배제할 수 없음 • Echocardiography : • more sensitive of LVH • Heart failure Sx이 있는 환자에서 ventricular systolic, diastolic Fn을 평가할 수 있다. • CXR • Boot-shaped heart : LVH 시사 • Frank cardiomegaly • Pulmonary vascular congestion

    20. Renal function • Serum Cr, BUN level로 평가 가능 • serum-electrolyte : diuretics, digoxin 복용중이거나 renal impairment있는 환자에게 필요 • Mild to moderate hypokalemia(3-3.5mEq) - diuretics복용 중인 환자에서 나타남 • K replacement는 증상 있거나 digoxin 복용 중에만 시행 • Hypomagnesemia : perioperative arrhythmia중요 원인 • Hyperkalemia : taking K-sparing diuretics or ACE inhibitors(특히 impaired renal function시)

    21. Premedication • Reduce preoperative anxiety • Highly desirable in hypertensive pt. • Mild to moderate preop. HTN • Anxiolytic agent (midazolam) • Antihypertensive agents should be continued • With a small sip of water • Central α2-adrenergic agonist (clonidine 0.2mg) • Sedation 증대 • Intraop. anesthetic 필요량 감소 • Periop. HTN 감소 • But, profound intraop. hypotension and bradycardia 관련

    22. Intraoperative management Hypertention

    23. Objectives • Maintain an appropriate stable BP range • Long-standing or poorly controlled HTN • Cb blood flow의 autoregulation 변화 • 적정 뇌혈류량 유지 위해 높은 BP 필요 • HTN, with tachycardia • MI, ventricular dysfunction 악화 가능 • Marked HTN(>180/120 ㎜Hg) in preop. • High-NL range(150-140/90-80 ㎜Hg) 유지

    24. Monitoring • Direct intraarterial pr. Monitoring • wide swings in BP 이 나타나는 환자에서 monitoring • Cardiac preload or afterload의 큰 변화가 예상되는 major surgical procedures • ECG monitoring • Detecting signs of ischemia • Urinary output • Renal impairment있는 환자에서 2시간 이상의 procedure를하는 경우 indwelling urinary catheter 거치하여 monitoring • Invasive hemodynamic monitoring • LVEDV,CO유지 위해 PCWP12-18mmHg로 높게 유지

    25. Induction • Induction, endotracheal intubation : period of hemodynamic instability • Preoperative BP control level에 상관없이 대부분의 HTN환자에서 induction시 hypotension, intubation시 심한 hypertensive response 보임 • Induction시 나타나는 hypotensive response의 원인 • anesthetic agents와 antihypertensive agents의 additive circulatory depressant effects에 의함(vasodilator & cardiac depressants 역할) • 대개의 HTN 환자는 이미 volume depleted state • Sympatholytic agents 또한 정상적인 protective circulatory reflex 감소시키기 때문

    26. 25%가량에서 endotracheal intubation후 severe hypertension 보임 • 가능한 한 duration of laryngoscopy 줄여야 함 • Intubation은 deep anesthesia 상태에서 시행 • Intubation 전 hypertensive response 줄이는 방법 • Potent volatile agent를 이용하여 5-10분에 걸쳐 마취심도 깊게 • Bolus opioid (fentanyl 2.5-5㎍/㎏; alfentanil 15-25 ㎍/㎏; sufentanil 0.25-0.5 ㎍/㎏; remifentanil 0.5-1 ㎍/㎏) • Lidocaine 1.5㎎/㎏ iv or intratracheally • β-adrenergic blockade č esmolol 0.3-1.5㎎/㎏; propranolol 1-3㎎; labetalol 5-20㎎ • Topical airway anesthesia

    27. Choice of anesthetic agents • Induction agents • Propofol, barbiturates, benzodiazepines, etomidate ; 대부분의 고혈압 환자에서 전신마취 유도에 안전하다 • Ketamin ; elective procedures에서 단독으로 사용 금기 sympathetic stimulation으로 인해 hypertension악화 다른 agent, 특히 benzodiazepine이나 propofol등의 small dose 병용으로 이러한 sympathetic stimulating properties를 줄일 수 있다.

    28. Choice of anesthetic agentsB. Maintenance agent • Volatile agents(±nitrous oxide) • A balanced technique (opioid+nitrous oxide + m. relaxant) • Totally intravenous technique • Addition of volatile agent or IV vasodilator ->more satisfactory intraoperative BP control 가능 • Volatile agent • Vasodilation and relatively rapid & reversible myocardial depression => BP 변화에 따라 titration 가능 • 일부에서는 sufentanil이 the greatest autonomic suppression 과 BP control 를 가능하게 한다고 믿음.

    29. Choice of anesthetic agentsC. Muscle relaxants • Can be used routinely (exception of large boluses of pancuronium) • Pancuronium • vagal blockade, neural release of catecholamines -> exacerbate HTN in poorly controlled Pts • opioid 또는 surgical manipulation에 의한 excessive vagal tone을 보완하는데 유용 • Large doses of tubocurarine, metocurine, atracurium, mivacurium에 의한 hypotension은 hypertensive pts 에서 두드러질 수 있다.

    30. Choice of anesthetic agentsD. vasopressors • HTN Pts는 endogenous catecholamine이나 exogenous sympathetic agonist에 강한 반응 보임 • Excessive hypotension을 치료 하기 위해 vasopressor가 필요하다면 • Small dose of a direct-acting agent (phenylephrine 25-50㎍) • High vagal tone : small dose ephedrine (5-10㎎) • 술전에 Sympatholytics 투여받았을 경우 vasopressor, 특히 ephedrine에 대한 반응 감소할 수 있어, 드물게 epinephrine 2-5 ㎍필요할 수도 있음 • Improper dosing of epinephrine은 significant cardiovascular morbidity 초래 가능

    31. Intraoperative HTN • Anesthetic depth증가에 반응이 없는 intraoperative HTN의 경우 여러 parenteral agent로 치료 가능 • Antihypertensive therapy 시작 전 inadequate anesthetic depth, hypoxemia, hypercapnia 등 교정 가능한 원인부터 제거해야 함 • Selection of a hypotensive agent - severity, acuteness, cause of HTN, the baseline ventricular fn, HR, the presence of bronchospastic pulmonary dz를 고려함 • β-adrenergic blockade • Good ventricular function and elevated heart rate 의 경우 good choice • C/I in bronchospastic disease • Nicardipine - preferable for pts with bronchospastic disease • Sublingual nifedipine - 사용후 나타나는 reflex tachycardia은 myocardial ischemia와 연관 - antihypertensive effect는 delayed onset 지님

    32. Nitroprusside • Most rapid and effective agent for the intraoperative treatment of moderate to severe HTN • Nitroglycerin • Less effective but useful in treating or preventing MI • Fenoldopam • Improve or maintain renal function • Hydralazine • Sustained BP control 가능 • Delayed onset, can cause reflex tachycardia • Reflex tachycardia는 labetalol 병용시 combined α- & β-adrenergic blockade 작용으로 없앨 수 있음

    33. Postoperative management • Postop HTNis common • poorly controlled HTN Pts에서 주로 나타남 • ClosedBP monitoring in recovery room & early postop period • Marked sustained elevations in BP로 인해 • MI and CHF • Formation of wound hematomas • Disruption of vascular suture lines • HTN in recovery period의 다양한 원인 • Respiratory abNL, pain, volume overload, bladder distention • Labetalol useful in HTN and tachycardia • Nicardipine useful in HTN with slow heart rate • 특히 MI가 예상되거나 bronchospasm 있을 경우 • Oral intake 가능해지면 preoperative medication 재개

    34. ISCHEMIC HEART DISEASE

    35. Preoperative considerations Myocardial ischemia - marked increase in myocardial metabolic demand - reduction in myocardial O2 delivery Common causes • Severe HTN or tachycardia(특히 ventricular hypertrophy가 존재하는 경우) • Coronary arterial vasospasm or anatomic obx. • Severe hypotension, hypoxemia, anemia • Severe aortic stenosis or regurgitation

    36. Preoperative considerations(2)Artherosclerosis of the coronary arteries m/c cause of myocardial ischemia Major cause of perioperative morbidity & mortality Major risk factors • Hyperlipidemia, HTN, diabetes, cigarette smoking • Increasing age, male sex, positive family history • Obesity, menopause • History of cerebrovascular or pph vascular disease • High estrogen oral contraceptives (with smoking) • Sedentary lifestyle, coronary-prone behavior pattern Clinical manifestation bySx • myocardial necrosis (infarction) • ischemia (usually angina) • Arrhythmias (including sudden death) • Ventricular dysfunction (CHF)

    37. Unstable angina Defined as • An abrupt increase inseverity, frequency (1일 3회 이상), or duration of anginal attacks (crescendo angina) • Angina at rest • New onset of angina(2달 이내) with severe or frequent episodes(1일 3회 이상) 휴식시에 significant ST-segment changes와연관 대개 severe underlying coronary dis를 반영하며 MI에 선행 Pathological correlates • plaque disruption with platelet aggregates or thrombi • Vasospasm 진단 및 치료 위해 coronary care unit 입원 필요 • Anticoagulation with heparin • Together with aspirin, iv nitroglycerin, β-blockers, calcium channel blockers • 24-48h내에 회복 없으면 angioplasty or emergency surgical revascularization를 위해 coronaryangiography 시행

    38. Chronic stable angina Chest pain • Substernal, exertional, radiating to the neck or arm, relieved by rest or nitroglycerin • Epigastric, back, or neck pain, or transient shortness of breath from ventricular dysfunction(anginal equivalent) • Nonexertional ischemia & silent (asymptomatic) ischemia도 흔함 • DM 환자에서 상대적으로 silent ischemia 발생율 높음 대개 artherosclerotic lesion이 50-75% occlusion 일으킬 때까지 증상 없음 • Stenotic segment가 70%에 이르러도 maximum compensatory dilatation으로 휴식시 blood flow는 유지되지만, metabolic demand증가 시에는 부족 • 일부의 경우 extensive collateral blood supply로 인해 severe disease에도 불구하고 상대적으로 asyptomatic 할 수 있다. Coronary vasospasm cause of transient transmural ischemia Emotional upset & hyperventilation에 의해 악화(Prinzmetal’s angina) Varying levels of activity or emotional stress를 가진 angina 환자에서 나타나는 경우(variable-threshold) Least common with classic exertional (fixed-threshold) angina

    39. Treatment of ischemic heart dis The general approach-5 fold • Progression을 늦추기 위해 coronary risk factor 교정 • Exercise tolerance 증대, stress제거를 위해 lifestyle 교정 • Complicating medical condition 교정 (HTN, anemia, hypoxemia, thyrotoxicosis, fever, infection, adverse drug effects 등) • Myocardial oxygen supply-demand relationship의 pharmachological manipulation • Coronary lesion 교정 • Percutaneous coronary intervention • PCI (angioplasty with or without stenting, or atherectomy) • Coronary artery bypass surgery Pharmacological agents • Calcium channel blockers : vasospastic angina • β-blockers :exertional angina & adequate ventricular function • Nitrates : both types of angina

    40. Treatment of ischemic heart disa. nitrates Relax all vascular smooth muscle (vein》artery) • venous tone & return (cardiac preload)을 감소 →wall tension과 afterload를 줄여주어 myocardial O2 demand를 감소시킴 • Prominent venodilation의효과로 CHF를 동반한 환자에서excellent agent Dilate coronary arteries • Flow는 radius의 4제곱에 비례하므로 stenotic site가 조금만 확장되어도 blood flow를 늘리기에 충분 • 허혈부위의 subendocardial blood flow가 증가 (favorable redistribution of coronary blood flow to ischemic areas) →이러한 효과는 collateral의 유무에 따름 Acute ischemia 치료 및 frequent anginal episode에 예방적으로 사용 No negative inotropic effect(unlike β-blocker, CCB)-ventricular dysfunction이 있는 경우desirable

    41. Treatment of ischemic heart disb. calcium channel blockers Cardiac afterload를 줄여 myocardial O2 demand를 감소시키고 coronary vasodilation 시켜 blood flow를 늘려 O2공급을 증가시킴 Nifedipine– hypotension, reflex tachycardia • Sublingual 등 fast-onset preparation은 일부에서 MI를 일으키기도 함 • Slow-release form : reflex tachycardia를줄일 수 있고, ventricular dysfunction 시에 다른 agents보다 효과적 • Amlodipine : similar to nifedipine but no effect on heart rate ventricular dysfunction 환자에 사용가능

    42. Treatment of ischemic heart disb. calcium channel blockers(2) Verapamil & diltiazem : greater effects on cardiac contractility & AV conduction • Ventricular dysfunction, conduction abNL, bradyarrhythmia 있을 시 더욱 주의하여야 함 • ventricular dysfunction있을 시 diltiazem이 보다 적합 Nicardipine & nimodipine : same effects as nifedipine • Nimodipine : SAH 후의 cerebral vasospasm 방지 • Nicardipine : iv arterial vasodilator • CCB- significant interactions with anesthetic agents • Potentiate both depolarizing and nondepolarizing neuromuscular blocking agents • Potentiate the circulatory effects of volatile agents

    43. Treatment of ischemic heart disc. β-adrenergic blocking agents HR와 contractility를 줄여 myocardial oxygen demand를 감소시킴 Optimal blockade • Resting HR를 50-60beats/min으로 줄임 • Exercise동안에 HR 증가를 20beats/min이내로 Membrane stabilization • Quinidine-like effect • Antiarrhythmic activity Intrinsic sympathomimetic properties • Mild to moderate ventricular dysfunction 환자에 더 적합 Low dose BB • beneficial for compensated CHF Nonselective β-receptor blockade • C/I in significant ventricular dysfunction, conduction abNL, bronchospastic dis, vasospastic angina • β2-adrenergic receptors blockade • Can mask hypoglycemic Sx in awake DM Pt. • Delay metabolic recovery from hypoglycemia • Impair the handling of large potassium loads

    44. Treatment of ischemic heart disd. other agents ACE inhibitors • Prolong survival in CHF or LV dysfunction Digoxin • Rapid ventricular response 가능한 atrial fibrillation • Cardiomegaly Pt (특히 heart failureSx 있을 경우) Chronic aspirin therapy : coronary events감소 Inducible sustained ventricular tachycardia or ventricular fibrillation • Automatic internal cardioverter-defibrillator (ICD) 적용 가능

    45. Treatment of ischemic heart dise. combination therapy • Pt with ventricular dysfunction • Not tolerate the combined negative inotropic effect of a ß-blocker & CCB together • ACE inhibitor is better tolerated • BB와 CCB의 AV node에 대한 additive effect는 감수성 있는 환자에서 heart block을 조장할 수 있다. • Combination of amlodipine & long acting nitirate • Significant ventricular dysfunction 환자에 적합 • 어떤 환자에서는 excessive vasodilation 일으킬수

    46. Preoperative managementIschemic heart dis PREOPERATIVE MANAGEMENT

    47. Perioperative outcome은 disease severity와 ventricular function과 관련 • Extensive(3-vessel or Lt main) CAD, recent Hx of MI, or ventricular dysfunction => greatest risk for cardiac complications Perioperative MI 의 대다수가 non-Q wave infarction이지만 perioperative infarct의 mortality rates는 50%에 이름 Preop. PCI • high-risk Pt에서 cardiovascular Cx 를 감소시키는지에 대한 자료가 부족 • 또한 surgical procedure는 postsurgical bleeding을 막기 위해 PCI 최소 2주 후에 행해야 함 Chronic stable angina 는 perioperative risk를 증가시키지 않음 CABG 또는 coronary angioplasty Hx가 있는 경우에도 perioperative risk 증가하지 않음 Preop. β-blocker • Periop. mortality 및 postop. cardiovascular Cx 감소 시킴

    48. History Questions : Sx, Tx, Cx, 예전의 evaluation 등 포함 -> ds severity, ventricular function을 예측할 수 있다 Sx • Include chest pains, dyspnea, poor exercise tolerance, syncope or near syncope • Ability to do light work at home or climb one flight of stairs slowly -> 4 metabolic equivalents(METs)와 상응 • severe dis.의경우 sedentary lifestyle로 인해 비교적 asymptomatic 할 수 있음 • Easy fatigability or shortness of breath는 compromised ventricular function 시사

    49. Physical examination &Routine laboratory evaluation Serum cardiac enzymes • Cardiac-specific troponins (T or I), creatine kinase (MB isoenzyme), lactate dehydrogenase (LDH, type 1 isoenzyme):excluding MI • Serum digoxin levels : excluding drug toxicity ECG • Baseline ECG : CAD 있는 환자의 25~50%에서 NL • Very straight ST : underlying CAD와 관련 • m/c baseline abNL : nonspecific ST- & T-wave changes • Prior infarction : infarct 부근의 lead에서 Q waves or loss of R waves • First-degree AV block, bundle-branch block, hemiblock 등도 나타날 수 있음 • MI후의 Persistent ST-segment elevation : indicative of LV aneurysm • Long QT interval : underlying ischemia, drug toxicity, electrolyte abNL, autonomic dysfunction, mitral valve prolapse, 드물게 congenital abNL 반영, ventricular arrhythmia (특히, polymorphic ventricular tachycardia)발생 가능 Chest film • Screening test in excluding cardiomegaly or pulm. congestion secondary to ventricular dysfunction