Ischaemic Heart Disease Flashcards
Define Cardiovascular disease
Any condition that affects the structure and function of the heart and blood vessels
What are some examples of cardiovascular disease?
Coronary Artery Disease (CAD) - Angina, myocardial infarction
Cerebrovascular disease (CVD)
Peripheral vascular disease (PVD)
Heart Failure (HF)
Hypertension
Rheumatic Heart Disease
Congenital Heart Disease
What is Rheumatic Fever?
Autoimmune disease that results from a Group A Streptococcus (GAS) infection in the throat
Is linked to poor housing conditions, overcrowding, socioeconomic deprivation, barriers to primary health care access and a lack of treatment for strep throat
Is largely unseen in the developed world but NZ has one of the highest rates in the world - mainly in the North Island
If untreated, it may develop into rheumatic heart disease and go on to damage the heart - valve/s may need to be replaced
92% of all cases of rheumatic fever affect Māori and pacific island children and young people (aged 4-19)
Define Ischaemic Heart Disease
The term is given to heart problems caused by narrowed heart arteries. When arteries are narrowed, less blood and oxygen reach the heart muscle. Ischemia occurs when there is insufficient blood flow and blood volume to supply the O2 needs of the myocardium
What is the underlying pathophysiology of Ischaemic Heart Disease?
Usually atherosclerosis
What is Angina?
Symptom of reversible myocardial ischaemia
Usually predictable and manageable
Occurs due to a stable lesion/plaque in the coronary artery
A type of chest pain caused by reduced blood flow to the heart (often described as squeezing, pressure, heaviness, tightness or pain in the chest)
What is the key pathophysiology of IHD?
Ineffective myocardial oxygen perfusion
-Myocardial oxygen demand is greater than oxygen supply
-At risk of heart muscle damage/necrosis
-Damaged muscle behaves ineffectively
-At risk of arrhythmia (damaged muscle does not convey impulses well)
-May lead to cardiac arrest
What is a Myocardial Infarction and its characteristics?
-Results from sustained ischaemia or sudden complete blockage of the coronary artery from plaques (atherosclerosis). -If the plaques rupture, you can have a heart attack (myocardial infarction)
-Myocardial tissue distal to the obstruction dies
-Can be partial thickness (NSTEMI) or full thickness (transmural) (STEMI)
-Life-threatening
-Complications include:
Cardiogenic shock, heart failure, ventricular fibrillation (VF) which can lead to death
Definition of an MI
-Non-ST-Elevation Myocardial Infarction (NSTEMI) involves partial thickness myocardial wall damage
-ST-Elevation Myocardial Infarction (STEMI) involves full thickness myocardial wall damage (with/without necrosis)
Compare STEMI and NSTEMI together
Stemi:
-Full thickness damage to the myocardium (transmural)
-Sudden complete blockage of a coronary artery
-ST segment evaluation on an
-ECG
-No need to wait for bloods
-ECG finding is definitive
NSTEMI:
-Partial thickness damage to the myocardium
-Partial blockage of a coronary artery
-Not visible on an ECG
-Need bloods for cardiac biomarkers to diagnose
What is Acute Coronary Syndrome (ACS)?
-Group of clinical symptoms that are consistent with acute myocardial ischaemia. Unless interventions are applied promptly ACS can result in myocardial death
-ACS is the term for an imbalance of 02 supply and demand. The underlying pathophysiology is atherosclerosis which can lead to plaque rupture and thrombus formation
What conditions fall under Acute Coronary Syndrome?
Unstable angina (UA),
Non—ST-segment elevation myocardial infarction (NSTEMI),
ST-segment elevation myocardial infarction (STEMI)
What are some Signs and symptoms of IHD & ACS?
Pale, grey, confused, tachycardic, hypotensive, hypertensive, chest pain, dyspnoea, weak thready pulse, feeling of impending doom, think it’s indigestion, feel like an elephant on their chest, tachypnoeic, fatigue, anxiety, ECG abnormalities, pain radiating across the chest, down the left arm, into the jaw, into the back, palpitations, restlessness, tightness in chest, hypoxaemia, diaphoresis, cyanosis, dizzy, light-headed, nausea
How does the body minimise the effects of an MI?
In absence of O2, cell function will deteriorate:
-Ischaemia: Lack of O2
-Injury: Potentially reversible damage
-Infarction: Necrosis - permanent damage
How is ACS/MI diagnosed?
History (chest pain and related symptoms)
12 Lead ECG (ST elevation height and area of the heart)
Blood tests
Other Diagnostic Investigations that may be Untaken Include::
Coronary angiogram +/- Angioplasty
Echocardiography (ECHO)
Transoesophageal Echocardiography
Exercise tolerance test (ETT)
Electrophysiological studies (EPS)
Chest X-Ray
What are some blood tests that might be used for the diagnosis of ACS?MI?
Troponin T and I - Cardiac specific enzymes
Cardiac enzymes: Creatinine kinase (CK-MB) - mainly in cardiac muscle, myoglobin -
cardiac and skeletal muscle
Electrolytes - K+, NA+, important for electrical conduction and kidney function
Complete blood count (CBC)
Lipid Profile - fasting
Brain Naturide Peptide (BNP)
What is the underlying pathophysiology for ACS?
Group of clinical symptoms that are consistent with acute myocardial ischaemia. Unless interventions are applied promptly ACS can result in myocardial death
ACS is the term for an imbalance of O2 supply & demand. The underlying pathophysiology is atherosclerosis which can lead to plaque rupture and thrombus formation
Unstable Angina Pectoris
STEMI
Non-STEMI
What are precipitants of angina/ACS?
Exercise/ Exertion
↑ HR, ↑ CO, ↑ myocardial O2 demand
Extremes of temperature
Vasoconstriction ↑resistance
vasodilation ↓venous return
Eating a heavy meal
↑ parasympathetic stimulation – blood diverted to the GI system
Emotions/stress
↑ HR, ↑ CO, ↑ myocardial O2 demand
Effects of drugs
Can ↑ or ↓ HR, BP
What are some intervention of ACS?
Follow the Heart Foundation Angina Action Plan (copy on Moodle)
Percutaneous Coronary Intervention (PCI) – the gold standard (watch the YouTube clip on Moodle)
Thrombolysis - fibrinolytic therapy (dissolves clots)
- Alteplase / Metalyse
- Streptokinase
- Tissue plasminogen activator (TPA)
What is the difference between Heart attack and Cardiac Arrest?
Heart attack is a MI
Results from a blocked coronary artery
This prevents oxygen-rich blood from reaching the myocardium
Without oxygen the myocardial cells begin to die
A circulation problem
Cardiac arrest a sudden, cessation of the heart’s functioning
Triggered by electrical malfunction in the heart that causes an arrhythmia (irregular heart beat)
Disrupts the pumping action
An electrical problem
What are the priority goals in management?
OPEN THE ARTERY AND KEEP IT OPEN
Increase oxygen supply to the myocardium → give nitrates and consider O2 if SaO2 < 93%
Relieve pain, reduce O2 demand & signs of ischaemia
Preserve viable myocytes
Relieve obstruction:
- Manage thrombus to reperfuse the artery & minimise permanent damage
What are the common cardiac medications?
Aspirin
Metoprolol
Atorvastatin
Cilazapril
GTN spray
