SCA Flashcards
The Canadian Cardiovascular Society (CCS) classification for angina is defined as follows:
Classe 1 à 4
Class I—no angina with ordinary physical activity
Class II—minimal limitation of normal activity as angina occurs with exertion or emotional stress
Class III—severe limitation of ordinary physical activity as angina occurs with exertion under normal physical conditions
Class IV—inability to perform any physical activity without discomfort as anginal symptoms occur at rest or with minimal physical exertion
Définir angine de repos
Rest angina is defined as angina occurring at rest, lasting longer than 20 minutes, and occurring within 1 week of presentation.
Définir new onset angina
New-onset angina is angina of at least CCS classification class II severity, with onset within the previous 2 months.
Définir angine crescendo
Increasing or progressive angina is diagnosed when a previously known angina becomes more frequent, longer in duration, or increased by one class within the previous 2 months of at least class III severity.
Décrire la pathophysiologie de Angine instable et les caractéristique à l’ECG
1) Plaque rupture accompanied by 2) thrombus formation and 3) vasospasm illustrate the intracoronary events angine instable.
Anomalies à l’ECG:
including T wave and ST segment changes.
Décrire la physiopatho, les modes de soulagement et les changements à l’ECG de l’angine de prinzmetal
Caused by coronary artery vasospasm at rest with minimal fixed coronary artery lesions
Soulagée par exercise or NTG.
The ECG reveals ST segment elevation that is impossible to discern from STEMI clinically and electrocardiographically.
Considering the myriad clinical situations in which AMI is encountered, the five primary types of infarction are described by the following classification:
Type 1—spontaneous MI related to ischemia resulting from a primary coronary event, such as plaque erosion rupture, erosion, fissuring, or dissection with accompanying thrombus formation and vasospasm. Type 1 infarctions represent the true ACS event.
Type 2—MI secondary to ischemia caused by increased oxygen demand or decreased supply, as seen in coronary artery spasm, coronary embolism, severe anemia, compromising arrhythmias, or significant systemic hypotension related to a range of causes.
Type 3—sudden unexpected cardiac death, including cardiac arrest, often with symptoms suggestive of myocardial ischemia, accompanied by presumably new ST segment elevation or new left bundle branch block (LBBB) pattern. Fresh coronary thrombus is noted via angiography or autopsy; death occurs before appropriate sampling of the blood to detect the abnormal cardiac biomarker.
Type 4—MI associated with coronary instrumentation, such as occurring after percutaneous coronary intervention (PCI). For PCIs in patients with normal baseline troponin values, elevations of cardiac biomarkers above the 99th percentile URL are indicative of periprocedural myocardial necrosis. By convention, increases of biomarkers greater than three times the 99th percentile URL are designated as defining PCI-related MI. A subtype related to a documented stent thrombosis is similarly recognized.
Type 5—MI associated with coronary artery bypass grafting (CABG). For CABG in patients with normal baseline troponin values, elevations of cardiac biomarkers above the 99th percentile URL are indicative of periprocedural myocardial necrosis. By convention, increases of biomarkers greater than five times the 99th percentile URL, plus any of the following, are designated as defining CABG-related MI:
- New pathologic Q waves or new LLLB
- Angiographically documented new graft or native coronary artery occlusion
- Imaging evidence of new loss of viable myocardium
The actual definition, referred to as the universal definition of myocardial infarction, includes the following; either one of these criteria satisfies the diagnosis for an acute, evolving, or recent MI:
1.Typical rise and gradual fall or more rapid rise and fall of biochemical markers of myocardial necrosis, avec au moins 1 valeur > 99e percentile et au moins une des présentations cliniques suivantes:
- Ischemic symptoms
- Electrocardiographic changes indicative of ischemia (T wave changes or ST segment deviation)
- Development of pathologic Q waves on the ECG and/or
- Imaging evidence of presumably new findings, such as a loss of viable myocardium or a regional wall motion abnormality
2.Pathologic findings of an AMI
Nommer 4 déterminants de la consommation en O2 du myocarde:
Myocardial oxygen consumption is determined:
Fréquence cardiaque
Post-charge
Contractilité
Étirement des fibres musculaire (wall tension)
À quel pourcentage une sténose coronarienne devient symptômatique:
Au repos
À l’effort
the reduction of coronary blood flow does not cause ischemic symptoms:
at rest until the vessel stenosis exceeds 95% obstruction to flow.
with exercise and increased myocardial oxygen consumption with as little as 60% vessel stenosis.
Nommer 3 most important factors in the infarction
Angiographic studies have demonstrated that the preceding coronary plaque lesion is often less than 50% stenotic, indicating that the most important factors in the infarction are the acute events of plaque rupture, platelet activation, and thrombus formation rather than the severity of the underlying coronary artery stenosis.
After significant coronary vessel occlusion, local mediators and vasoactive substances are released, inducing ….?
Vasospasme
Another important aspect of ACS is vasospasm. After significant coronary vessel occlusion, local mediators and vasoactive substances are released, inducing vasospasm, which further compromises blood flow. Central and sympathetic nervous system input increases within minutes of the occlusion, resulting in vasomotor hyperreactivity and coronary vasospasm. Sympathetic stimulation by endogenous hormones, such as epinephrine and serotonin, may also result in increased platelet aggregation and neutrophil-mediated vasoconstriction.
A prehospital 12-lead ECG offers high specificity ??? and positive predictive value ??? for STEMI in patients with atraumatic chest pain
Specificity (99%)
positive predictive value (93%)
for STEMI in patients with atraumatic chest pain while increasing the paramedic scene time by an average of only 3 minutes.
Nommer 4 avantages de faire ECG en pré-hosp pour dépister les STEMI
(1) earlier detection of STEMI;
(2) ability to base the destination on the availability of PCI;
(3) hospital-based preparation for patient arrival;
(4) more rapid initiation of hospital-based reperfusion therapy, either fibrinolysis or PCI.
ACS is significantly more likely if four of the five major risk factors. Nommer les 5 FR
ACS is significantly more likely if four of the five major risk factors—diabetes mellitus, smoking, hypertension, hyperlipidemia, and family history of AMI at an early age (usually <50 years)
