Flashcards in Cardiology Seminars Deck (25):
SEMINAR ONE - VALVULAR HEART DISEASE
DR BINNS (to do)
SEMINAR TWO - ECGs
DR BINNS (started)
How can the axis of an ECG be calculated?
Using vectors - look at the difference between upstrokes and downstrokes of the QRS complex in leads I and aVF. This will show which quadrant the axis is in and if there is deviation. Positive on the axis is left and down, negative is up and right.
What are the boundaries for the different axes of ECGs?
Normal: -30 to +90
Left axis deviation: -30 to -90
Right axis deviation: +90 to +180
Bizarre: +180 to -90
What are the causes of left axis deviation?
Left anterior fascicular block, left ventricular hypertrophy, or RBBB.
What are the causes of right axis deviation?
Right ventricular hypertrophy or strain, left posterior fascicular block, or RBBB.
What are the three types of P wave seen on ECG?
Normal, P-mitrale, P-pulmonale.
What is the appearance and cause of P-mitrale?
Mitre's hat (two mini peaks), due to increased left atrium.
What is the appearance and cause of P-pulmonale?
Tall tented P wave, due to increased right atrium.
What is the normal PR interval?
3-5 small squares = 0.12-0.2 seconds.
Where is the PR interval measured from and to?
Start of the P wave to the start of the QRS complex.
What causes lengthened PR intervals?
When is a long PR interval worrying?
When it's very long - 0.28 seconds, there are other conducting tissue disease signs (trivesicular block = long AVN + RBBB + left anterior fascicular block), aortic valve has infective endocarditis *SURGICAL EMERGENCY*.
What causes shortened PR intervals?
Accessory pathways where depolarisation starts earlier from pre-excitation.
What are the voltage criteria for left ventricular hypertrophy?
S wave in V1/2 + R wave in V5/6 > 35. Any S or R wave in chest lead > 30mm. R wave in lead I and aVL >14mm.
What are the criteria for a pathological Q wave?
The very first deflection, at least 1/4 of the height of the subsequent R wave, not in lead III unless also in II and/or aVF.
What are Q waves a sign of?
Full thickness MI that happened at some point.
What can ST elevation be due to?
Acute myocardial injury or pericarditis.
How does the shape of ST elevation in AMI and pericarditis differ?
AMI - tombstones. Pericarditis - saddle shaped.
Where is there ST elevation in AMI vs pericarditis?
AMI - regional, others have ST depression. Pericarditis - all leads.
What is the PR in AMI vs pericarditis?
No PR depression in AMI, PR depression in pericarditis.
What is the history of AMI and pericarditis with ST elevation?
AMI - bad pain on history. Pericarditis - worse pain on lying down.
What are the possible causes of ST depression on exercise ECGs?
Fine and of no consequence, coronary disease.
What are the possible morphologies of T waves?
Peaked, flat, inverted, biphasic, deep inversion, asymmetric.