Acute Coronary Syndromes

Michelle Welsford, MD, FRCPCMichelle Welsford, MD, FRCPC

Fall Recertification 2004Fall Recertification 2004

ACS Overview

DefinitionPathophysiologyRisk FactorsClinical FeaturesAssessmentManagement

ACS Definition

Myocardial ischemia: insufficient blood supply to the heart muscle that results from coronary artery disease

ACS: Any group of symptoms compatible with myocardial ischemia.

Represent a continuum of the same disease process:– Angina– Unstable angina– Non-ST elevation MI– STEAMI

ACS Pathophysiology

All ACS - sudden ischemia that cannot be differentiated initially

Three common events:– Plaque rupture– Thrombus formation– Vasoconstriction

Lipid Core

Fibrous Cap

Lumen

ACS Pathophysiology

Plaque rupture

Thrombus formation - Fibrin cross-linking

Thrombus formation - Platelet aggregation

Risk Factors

HypertensionHyperlipidemiaDiabetes mellitusSmokingFamily historyMales and post-menopausal

womenAdvancing age

Clinical Features

Typical

Atypical – 25% of all AMIs – Pleuritic or sharp/stabbing CP– Palpable CP (10-33% AMI)– Arm pain only– Indigestion – SOB only (40% in elderly)– “Dizziness” (5% AMI)– Nausea – Syncope

Assessment – Examination

Exam usually normal (85%) May have:

– Diaphoresis – Extra heart sounds

(S3, S4 or rubs)– Dysrhythmias– Evidence of new or

worsening heart failure– Hypotension

Assessment – EKG

12-lead EKG– May be normal in ACS– May be nonspecific: ST or T wave ischemic changes– May be suspicious for injury: ST elevation

STEAMI– Fibrinolytic checklist

EKG - AMI Diagnosis

AMI Diagnosis:– At least 2 of 3 criteria

Clinical history suggestive of AMI EKG criteria Laboratory diagnosis

EKG criteria– ST elevation 1 mm or more in 2 anatomically

contiguous leads– OR BBB

EKG - Contiguous Leads

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Limb Leads Chest Leads

EKG - AMI Imitators

Causes of ST elevation– AMI– LVH– BBB– Ventricular beats – PVCs – Pericarditis– Early repolarization– Others

EKG Practice 1

EKG Practice 2

EKG Practice 3

EKG Practice 4

Management – Prehospital

Prehospital– Oxygen– ASA– Nitro– Morphine– Dysrhythmia treatment

Medication Defibrillation

– 12-lead EKG with notification of receiving hospital

– Prehospital thrombolysis– Triage to PCI facility

Management – Hospital

Hospital– Oxygen, ASA, Nitro,

Morphine– Dysrhythmia management– Anticoagulation - heparin – Reperfusion

Fibrinolysis PCI - percutaneous

coronary intervention

History/Assessment Risk factorsEKG Medical Management

ACS Management Summary

Questions ?