Diseases Of The Cardiovascular System Flashcards
What is stable angina pectoris?
It is due to an atherosclerotic lesions that narrow (>70% stenosis) the major coronary arteries causing ischemia due to an imbalance between blood supply and oxygen demand.
What are the major risk factors for stable angina pectoris?
- DM is the WORST RF
- Hyperlipidemia, especially high LDL
- HTN is the most COMMON RF
- Cigarette Smoking
- Age (>45 in males and >55 in females)
- Family history of premature CAD or MI in first degree relatives
- Low HDL
What are the 3 features of typical angina heat pain?
- Substernal
- Worse with exertion
- Relieved with rest or nitroglycerin
What are the different clinical presentation of CAD?
- Asymptomatic
- Stable angina
- Unstable angina
- MI (STEMI or NSTEMI)
- Sudden cardiac death
How is CAD diagnosed?
- History
- Physical examination (Most likely to be normal)
- Resting ECG (usually normal in stable angina) + Cardiac enzymes
- Stress test (Stress ECG, Stress Echo, Stress myocardial perfusion imaging)
- Pharmacological stress test if patient can’t exercise (IV adenosine, dipyridamole, dobutamine)
- Cardiac catheterization with coronary angiography (especially if stress test is positive)
When is a stress test considered positive?
If the patient develops any of the following during exercise: ST-segment depression, hypotension, chest pain, significant arrhythmias.
How is stable angina pectoris managed?
- Risk factors modification
- Aspirin
- Lipid lowering agents
- Beta-blockers
- Nitrates
- CCB if b-blockers and nitrates are not fully effective
- Revascularization is indicated for stable angina refractory to medical therapy for symptom control
What are the side effects of beta-blockers and nitrates?
Beta-blockers: Erectile dysfunction, inability to increase HR in response to exercise, hypotension, bronchospasm
Nitrates: headache, orthostatic hypotension, tolerance, syncope
What is unstable angina pectoris?
Reduced resting coronary flow due to significant stenosis that is exaggerated by thrombosis or hemorrhage
What are the main indications for CABG?
Three-vessel disease with >70% stenosis in each vessel.
Left main coronary disease with >50% stenosis, left ventricular dysfunction.
When can we say that a patient has unstable angina?
- If a patient with chronic angina has increased frequency, duration, or intensity of chest pain
- Patient with new onset angina that is severe and worsening
- Patient with angina at rest
How can we differentiate NSTEMI from unstable angina?
The only difference is that NSTEMI has elevation of troponin or CK-MB
What is acute coronary syndrome (ACS)?
The clinical manifestations of atherosclerotic plaque rupture and coronary occlusion. It generally refers to unstable angina, NSTEMI, or STEMI.
How is unstable angina managed initially?
- Hospital admission with cardiac monitoring. Establish IV access, give supplemental oxygen and pain control with nitrates and opioids.
- Dual antiplatelet therapy with aspirin and clopidogrel
- Beta-blockers
- LMWH (continued for at least 48 hours) Enoxaparin is the DOC
- Nitrates
- Glycoprotein IIb/IIIa inhibitors (helpful adjunct if patient is undergoing PCI)
- High-intensity statin
- Oxygen
- Cardiac catheterization/revascularization
- Considered if patient responds to medical therapy and a stress test is done to assess the need for catheterization/revascularization
-Considered if patient fails to respond to medical therapy
- Considered if patient responds to medical therapy and a stress test is done to assess the need for catheterization/revascularization
What is the treatment plan after initial management?
- Continue aspirin life-long, clopidogrel for 1 year, beta-blockers, nitrates, and statin therapy (patients with any form of CAD should be started on statins regardless of LDL level)
- Reduce risk factors
What is myocardial infarction?
Necrosis of myocardium as a results of an interruption of blood supply after a thrombotic occlusion of a coronary artery previously narrowed by atherosclerosis
How does MI present?
- Sudden onset of chest pain that is an intense substernal pressure sensation. May radiate to back, jaw, neck or arms, commonly to the left side.
- Asymptomatic
- Others include: diaphoresis, dyspnea, weakness, fatigue, nausea and vomiting, sense of impending doom, syncope.
- Sudden cardiac death.
How can a stable angina pectoris chest pain be differentiated from MI chest pain?
Both have the same description of being substernal pressure sensation and radiating, but differ in duration in which stable angina lasts for 10-15 minutes and MI lasts for >30 minutes. Stable angina is related to exertion and relieved by rest or nitroglycerin and this doesn’t apply to MI.
How is MI diagnosed?
ECG
Cardiac enzymes (diagnostic gold standard)
What are the markers for ischemia/infarct on ECG?
- Peaked T wave: occurs very early
- ST-segment elevation: indicates transmural injury, diagnostic of acute infarct
- Q waves: Evidence of necrosis
- T waves
- ST-segment depression: indicates subendocardial injury
Which leads represent the anterior wall and what artery supplies it?
V1, V2, V3, V4
Supplied by left anterior descending
Which leads represent the lateral wall and what artery supplies it?
Lead I, aVL, V5, V6
Supplied by left circumflex artery
Which leads represent the inferior wall and what artery supplies it?
Lead II, Lead III, aVF
Supplied by right coronary artery
How does a posterior wall infarct appear on an ECG?
ST depression of V1, V2, V3, V4 (mirror image)
Troponin vs CK-MB
Troponin:
- increases within 3-5 hours, peaks within 24-48 hours
- returns back to normal in 5-14 days
- greater sensitivity and specificity that CK-MB
- obtain serum levels on admission and every 6 hours until 3 samples are obtained
CK-MB:
- increases within 4-8 hours, peaks within 24 hours
- returns to normal 48-72 hours
- obtain serum levels on admission and every 8 hours until 3 samples are obtained
- HELPFUL IN DETECTING RECURRENT INFARCTION
How is MI treated?
- Admit to CCU, establish IV access
- Medical therapy: Morphine, Oxygen, Nitrate, Aspirin, Beta-blockers, ACE inhibitors, Statins, LMWH (enoxaparin), Clopidogrel
- Revascularization:
- PCI: preferred for STEMI, should be done door to balloon time less than 90 minutes
- Thrombolytic therapy: best outcome if given within the first 6 hours
- Dual antiplatelet therapy should be continued if patient undergoes PCI - Cardiac rehabilitation
What are the absolute contraindications to thrombolytic therapy?
Recent head trauma or traumatic CPR
Previous stroke within past 3 months
Recent invasive procedure or surgery
Dissecting aortic aneurysm
Active bleeding or bleeding diathesis
Severe uncontrolled HTN
Known structural cerebral lesions or neoplasm
What is the most common cause of death in the first few days after MI?
Ventricular arrhythmias
What are the complications of acute MI?
- Congestive heart failure
- Arrhythmias
- Recurrent infarction
- Mechanical complications such as free wall rupture, rupture of interventricular septum and papillary muscle rupture
- Acute pericarditis
- Dressler syndrome
What is heart failure with reduced ejection fraction?
AKA systolic dysfunction, owing to impaired contractility
What is heart failure with preserved ejection fraction?
AKA diastolic dysfunction, owing to impaired ventricular filling during diastole (either impaired relaxation or increased stiffness of ventricle or both.
How is CHF diagnosed?
- CXR
- Echocardiogram (initial test of choice)
- ECG
- B-type natriuretic peptide (released from ventricles in response to ventricular volume expansion and pressure overload)
- Nuclear ventriculography
- Cardiac catheterization
- Stress testing
How is mild CHF (NYHA class I and II) managed?
- Mild restriction of sodium intake
- Loop diuretic if volume overload or pulmonary congestion is present
- ACE inhibitor
How is mild to moderate CHF (NYHA Class II and III) managed?
- Start loop diuretic and ACE inhibitor
- Add beta-blocker if moderate disease is present and the response to standard treatment is suboptimal
How is moderate to severe CHF (NYHA Class III and IV) managed?
- Add digoxin to loop diuretics and ACE inhibitors for relief of symptoms in patients with systolic dysfunction
- Add spironolactone if EF <35%
What are the findings of premature atrial complexes on an ECG?
An early P wave that is different from the sinus P wave and QRS complex is normal.
What are the findings of premature ventricular complexes on an ECG?
Wide bizarre QRS complexes followed by a compensatory pause
What is the characteristic feature of AFib on ECG?
Irregularly irregular rhythm with a wavy baseline and no identifiable P waves