W12 57 cardiology for dentists Flashcards
What do heart diseases affect?
Heart blood supply, muscles, valves
What are some common signs and symptoms of heart diseases?
Chest pain - SOCRATES, common in ischaemic heart disease but can be unspecific
Dyspnoea - exertional, orthopnoea, paraoxysmal nocturnal dyspnoea
Palpitation - arrhythmia eg atrial flutter, AF
Oedema - eg heart failure
Clubbing - eg infective endocarditis
Syncope - eg heart block, AF
What is orthopnoea?
Shortness of breath upon lying flat
What is paroxysmal nocturnal dyspnoea?
Short breath while sleeping
What is dyspnoea?
Shortness of breath
What is clubbing?
Ask pt to put fingers together, if you see a diamond then no clubbing. Big nail beds = clubbing. Clubbing is also seen in lung diseases, lung cancers or liver diseases.
What is syncope?
When the heart does not supply enough blood to the brain
What is a P wave in an ECG? (PG402)
P wave represents depolarisation of the atria. Atrial depolarisation spreads from the SA node towards the AV node, and from the right atrium to the left atrium.
What is the PR interval in an ECG? (PG402)
PR interval is measured from the beginning of the P wave to the beginning of the QRS complex. This interval reflects the time the electrical impulse takes to travel from the SA node through the AVN.
What is the QRS complex in an ECG? (PG402)
The QRS complex represents the rapid depolarisation of the right and left ventricles. The ventricles have a large muscle mass compared to the atria, so the QRS complex usually has a much larger amplitude than the P wave.
What is the ST segment in an ECG? (PG402)
The ST segment connects the QRS complex and the T wave; it represents the period when the ventricles are depolarised.
What is a T wave in an ECG? (PG402)
The T wave represents the repolarisation of the ventricles.
Briefly how does an electrical impulse move through the heart?
Activity starts from the SAN and spreads to the atrium to form the P wave
From the atrium down to whole ventricles through Bundle of His forms the QRS complex
When ventricular depolarisation happens that forms the T wave
What is the 12 lead ECG? (PG403)
10 electrodes, 4 on limbs and 6 on chest wall
Forms 12 different circuits
What other heart investigations can be done?
Chest x-ray
Echocardiography
24hr ambulatory taped ECG
CT/CT angiogram - to assess vessels in heart
Cardiovascular magnetic resonance - to assess vessels in heart
Exercise ECG - when or has chest pain on exertion
What will chest x-ray show in heart failure and what can it rule out?
Patients with heart failure you’ll see a big heart in chest x-ray, normally more than 50% the length of the diaphragm.
Can help rule out pneumonia - will see white patches (consoligations) in lung fields
What is an echocardiograph and what is it good for?
Ultrasound scan of blood flow in the heart
Useful for patients with vulval disease such as aortic or mitral regurgitations
When might you use a 24hr ambulatory taped ECG?
Useful when you think pt has atrial fibrillation or any irregular heartbeats but unable to capture this in 1 time 12 lead ECG. Measure over 24hrs and forms a report.
What can you see on a 12 lead ECG that you can’t see on a single ECG?
Single lead ECG can tell you if you are in atrial fibrillation but not if you are in MI
What is ischaemic heart disease?
An imbalance between the supply of oxygen to cardiac muscle and myocardial demand
What are some causes of ischaemic heart disease?
Ischaemia - coronary artery atheroma leading to a fixed obstruction of blood flow or coronary artery thrombosis/spasm/arteritis
Increase oxygen demand - thyrotoxicosis, myocardial hypertrophy (eg from aortic stenosis or hypertension)
What is thyrotoxicosis?
Thyroid gland releases too much thyroid hormone increasing metabolic rate of the heart
What are the risk factors for ischaemic heart disease?
Hyperlipidaemia
Smoking
Hypertension
Metabolic factors - eg uncontrolled diabetes
Lifestyle: diet, exercise, alcohol
What would pain history be if angina was occurring?
Central chest, sudden onset, sharp pain, radiates to left arm and jaw, associations are sweat syncope and shortness of breath, worse with stress and exercise but GTN spray helped, pain score 10/10
Angina is a medical emergency! What would you do?
A-E approach - airway breathing circulation disability exposure
15L oxygen through a non-rebreathable mask if shortness of breath
GTN spray 1-2 activations, sublingually (will help relieve pain and improve blood supply to heart)
Dispersible Aspirin 300mg to chew
What happens if the pt does not respond to your angina treatment?
They are in MI, call 999
What investigations are done after angina turns into MI in secondary care?
ECG
Blood test - cardiac markers: troponin I or T - these elevate when there are ischaemic heart events that cause cardiac muscle damage
Coronary angiography - identify the presence and location of coronary artery vascular blockage
What is unstable angina?
Myocardial ischaemic at rest or in minimal exertion in the absence of acute cardiomyocyte injury/necrosis.
Prolonged (>20mins) angina at rest
New onset of severe angina
Angina that is increasing in frequency, longer in duration, or lower in threshold
Angina that occurs after a recent episode of myocardial infarction
What is myocardial infarction?
Necrosis of myocardial tissue following occlusion of a coronary artery and subsequent ischaemia
What are the 2 types of MI (depending on the ECG changes)?
ST-segment elevation myocardial infarction (STEMI) - complete and persisting blockage of the artery
Non-ST-segment elevation myocardial infarction (NSTEMI) - partial or intermittent blockage of the artery
How is the diagnosis of NSTEMI made?
A combination of: clinical history, abnormal troponins, the absence of ST-elevation on ECG
In patients with STEMI you see an ST elevation. What might be seen in NSTEMI? (PG406 WAVES!)
In NSTEMI you might see depressant of T wave inversion.
The ST wave is differential between STEMI a and NSTEMI, but what things definitely indicate an MI?
Positive history and abnormal troponins
What is the management of MI?
Percutaneous coronary intervention
Coronary artery bypass grafting
Medical treatment
Statins (meds to prevent future heart attacks)
What medical treatment is given to manage MI?
Antiplatelets - eg aspirin, clopidogrel
Anticoagulation - heparin/low-molecular weight heparin in hospital eg DOACs like apixaban, rivaroxaban. Warfarin.
Antianginals - nitrate, beta blocker, calcium channel blockers
What are complications of MI?
Acute heart failure
Chronic heart failure
Post-infarction angina
Stroke
Depression
Dressler’s syndrome (post MI periocarditis, inflammation response in heart)
Sudden death
What should be checked in dental practice about a patient with history of MI?
If they’re on their usual treatment, e.g. GTN spray
Risk of bleeding (from anticoagulation/antiplatelets)
Managing potential triggers eg dental anxiety, pain
If prolonged chest pain or unwell, consider MI and call 999
What is heart failure?
Unable to function as a pump and maintain cardiac output to meet the demands of the body
What are the main causes of heart failure?
Ischaemic heart disease
Cardiomyopathy (dilated) - heart chamber esp ventricles are bigger than before so does not pump properly
Hypertension - resistance too high so does not function properly.