1. Síndrome Coronario Agudo Flashcards
What is acute coronary syndrome (ACS)?
The clinical manifestation of myocardial infarct and commonly the default working diagnosis in patients with new-onset chest pain suspected to be of cardiac ischemic origin.
What is an infarction?
Tissue necrosis that results from insufficient blood and oxygen supply to the affected region. Etiologies include thromboembolic occlusion, rupture, vasoconstriction, and vessel compression.
What are the mainstays of the diagnosis of ACS?
- Clinical findings (onset and characteristics of pain, patient history)
- ECG
- Troponin
How are the patients classified based on ECG findings?
- With ST-elevation (STE-ACS)
- Non-ST-elevation ACS (NSTE-ACS).
What is a “ST elevation”?
An elevation of the ST segment above the isoelectric line.
Considered significant if it is ≥ 0.1 mV in a limb lead or ≥ 0.2 mV in a precordial lead.
What can be some of the causes of a ST elevation?
- Myocardial ischemia
- Pericarditis (diffuse ST elevations).
What is Troponin?
A group of muscle proteins found in skeletal and cardiac muscle that are involved in muscle contraction.
¿Para qué nos sirve la troponina en el contexto de un SCA?
In acute myocardial injury, troponins and other cardiac biomarkers are released into the blood.
Used as a highly sensitive and specific biomarker for cardiac muscle cell death (e.g., from myocardial ischemia in acute myocardial infarction).
What is Non-ST-elevation acute coronary syndrome (NSTE-ACS)?
An umbrella term for the entities NSTEMI and unstable angina (UA).
How are NSTE-ACS categorized?
Depending on serum levels of cardiac troponin (cTn):
- NSTEMI: positive myocardial injury biomarkers
- Unstable angina (UA): absence of detectable myocardial injury biomarkers
What do STE-ACS patients require immediately?
Revascularization therapy with percutaneous coronary intervention (PCI) or Fibrinolytic therapy.
What is revascularization therapy?
The restoration or augmentation of blood flow in a previously ischemic organ or body part (e.g., due to embolism or thrombotic occlusion).
Can be performed surgically (bypass surgery, endarterectomy, or surgical embolectomy) or through other interventions (percutaneous transluminal angioplasty or stenting, pharmacologic or mechanical thrombectomy/embolectomy).
What are some of the indications of thrombolytic therapy?
- STEMI
- Stroke
- Massive pulmonary embolism
- Severe deep vein thrombosis
- Acute limb ischemia
What are the two things all ACS patients receive?
- Dual antiplatelet therapy
- Anitially anticoagulation.
What is dual antiplatelet therapy?
Combination treatment with aspirin and a platelet P2Y12 receptor blocker (e.g., clopidogrel) used to reduce the risk of thrombosis after arterial stenting (e.g., PCI) and for secondary prevention of stroke.
What are the benefits of adjunctive therapy for ACS?
Beta blockers and oxygen can help reduce symptoms and have a positive impact on mortality.
What is acute coronary syndrome (ACS)?
The suspicion or confirmed presence of acute myocardial ischemia
Can subtypes of ACS be differentiated based on clinical presentation alone?
No
What is unstable angina?
Acute myocardial ischemia that is not severe enough to cause detectable quantities of myocardial injury biomarkers or ST-segment elevations on ECG
What is non-ST-segment elevation myocardial infarction (NSTEMI)?
Acute myocardial ischemia that is severe enough to cause detectable quantities of myocardial injury biomarkers but without ST-segment elevations on ECG
What is ST-segment elevation myocardial infarction (STEMI)?
Acute myocardial ischemia that is severe enough to cause ST-segment elevations on ECG
What are some of the symptoms of an acute myocardial infarction?
- Chest pain (Nonfocal retrosternal discomfort or pressure)
- Nausea
- Diaphoresis
- Lightheadedness
- Palpitations
- Dyspnea
What is the of athophysiology of unstable angina?
Partial occlusion of coronary vessel → decreased blood supply → ischemic symptoms without infarction
What is the of athophysiology of NSTEMI?
Classically due to partial occlusion of a coronary artery.
Affects the inner layer of the heart (subendocardial infarction)
What is the of athophysiology of STEMI?
Classically due to complete occlusion of a coronary artery.
Affects the full thickness of the myocardium (transmural infarction)
How will we find the cardiac troponin in cases of unstable angina?
Not elevated
How will we find the cardiac troponin in cases of NSTEMI?
Elevated (within 1–6 hours)
How will we find the cardiac troponin in cases of STEMI?
Elevated (within 1–6 hours)
What are the ECG findings we`lll encounter in cases of unstable angina?
- No ST elevations.
- Normal or nonspecific (e.g., ST depression, loss of R wave, T-wave inversion)
What are the ECG findings we`lll encounter in cases of NSTEMI?
- No ST elevations.
- Normal or nonspecific (e.g., ST depression, loss of R wave, T-wave inversion)
What are the ECG findings we`lll encounter in cases of STEMI?
ST elevations (in two contiguous leads) or new left bundle branch block with strong clinical suspicion of myocardial ischemia
What does ST depression suggest?
Myocardial ischemia without progression to full thickness infarction.
Seen in unstable angina and non-ST elevation myocardial infarction (NSTEMI).
What is a T-wave inversion?
A deflection of the T wave in the opposite direction of the QRS complex that precedes it.
When is a T-wave inversion normal or abnormal?
NORMAL: TWI in lead III
ABNORMAL: new T-wave inversion compared to prior ECGs. Pathological TWIs are usually symmetric and > 3 mm in amplitude.
What could be the cause of downsloping ST depression?
Myocardial ischemia
What could be the cause of upsloping ST depression?
IT could be due to physical activity, or associated with ischemia if prominent t-waves.
What could be the cause of horizontal ST depression?
Myocardial ischemia
What could be the cause of sagging ST depression?
Digoxin toxicity
What is a left bundle branch block?
Cardiac conduction alteration in which there is delay or obstruction of impulses sent through the left bundle branch pathway, leading to delayed left ventricle contraction.
What are some of the ECG signs of left bundle branch block?
- QRS duration ≥ 120 ms
- rS or QS complex in lead V1
- Notched (M-shaped) R wave in V6.
What is the treatment for Unstable angina and NSTEMI?
- Invasive management depends on risk stratification (TIMI score).
- Anticoagulants, antiplatelet therapy (aspirin, ADP receptor inhibitors)
- Statins
- Beta blockers
- ACEIs
- Pain management (opioids, nitrates)
What is the treatment for STEMI?
- Immediate revascularization
- Adjunctive medical therapy similar to NSTE-ACS
What is TIMI score?
A risk score for patients with unstable angina or NSTEMI that functions as a prognostic tool to calculate a patient’s risk of death and ischemic events. Can also be used to guide the therapeutic regimen.
How to intepret the results of the TIMI score?
Patients with a TIMI score ≥ 3 benefited from an early invasive strategy.
Patients with a TIMI score ≥ 4 benefited from enoxaparin (as opposed to unfractionated heparin) and the addition of a IIb:IIIa inhibitor (Tirofiban) to heparin.
What are some ADP receptor inhibitors?
Ticagrelor or Clopidogrel
What is the GRACE score?
A risk score that is used to estimate mortality in patients with ACS. Can help to guide management (e.g., timing of reperfusion therapy in NSTEMI).
Mention the 7 steps of the acute management checklist for NSTE-ACS
- Evaluate for very-high risk factors requiring urgent coronary angiography: If present, follow STEMI checklist.
- Start antiplatelet therapy and anticoagulation.
- Aspirin
- ADP receptor inhibitor: ticagrelor or clopidogrel
- Anticoagulation with UFH, enoxaparin, bivalirudin, or fondaparinux - Calculate TIMI score and GRACE score.
- Cardiology consult for discussion of strategy (“Risk-dependent timing of revascularization in NSTE-ACS”)
- Adjunctive medical therapy for ACS
- Supplemental oxygen as needed: target SpO2 > 90%
- Nitroglycerin for patients with ongoing chest pain or hypertension
- Analgesia with morphine only for patients with very strong pain
- High-intensity statin
- Consider beta blocker if no contraindications.
- Consider ACE inhibitor if no contraindications. - Order continuous telemetry, serial ECG, and serum troponins every 3–6 hours.
- Transfer to cardiac telemetry floor or (cardiac) ICU.
¿Qué es el SCA?
Afección aguda de la circulación coronaria
¿Por qué es importante saber de SCA?
Principal causa de mortalidad a nivel mundial
¿Cuál es el origen de las arterias coronarias izquierda y derecha?
Son ramas de la aorta ascendente
¿En qué ramas se divide la coronaria izquierda?
Rama circunfleja y rama descendente anterior.
¿Qué porciones del corazón irriga la rama descendente anterior?
Septum y cara anterior del ventrículo izquierdo
¿Qué porciones del corazón irriga la rama circunfleja?
Cara lateral y el 30% de la cara inferior del ventrículo izquierdo
¿Qué porciones del corazón irriga la coronaria derecha?
Todo el ventrículo derecho
¿En qué ramas se divide la coronaria derecha?
Rama marginal y rama descendente posterior
¿Qué porciones del corazón irriga la rama descendente posterior?
70% de la cara inferior del ventrículo izquierdo
Complete la frase: “El 50% de los infartos se deben a lesiones en la ______·”
Descendente anterior
¿Cómo se forman las placas ateromatosas?
- Lesión endotelial
- Acumulación de lipoproteínas en la túnica íntima y de la túnica media.
- Oxidación de LDL y VLDL
- Diapedesis y respuesta inflamatoria
- Migración de músculo liso y formación de capa fibrótica
- Rotura de placa
- SCA
¿Qué elementos pueden desencadenar lesión endotelial?
Hipertensión, diabetes, gabaquismo
¿Qué es diapedesis?
Activación de macrófagos y formación de células espumosas
¿Qué es un infarto?
Lesión miocárdica aguda secundaria a isquemia.
¿Cómo se define una lesión miocárdica?
Caída o elevación de troponinas, con por lo menos un valor superior al percentil 99
¿Qué es el delta de troponinas?
Para diagnosticar una lesión miocárdica, yo necesito 2 mediciones de troponinas. Y el cambio entre estos valores (sea caída o elevación) se denomina como delta de troponinas.
Se necesita un delta de 20%
Mencione 9 causas de elevación de troponinas
