Flashcards in Cardio Deck (120)
PR - 0.12-0,2 secs
QRS - 0.1s
QT interval - 0.4 secs
QTc - <450ms
Causes of PR interval shortening and lengthening
• Shortening - WPW syndrome
Lengthening - beta blockers, type 1 heart block, fit pt
What is the timing of the ECG squares?
• Small square = 0.04 seconds
Large square = 0.2 seconds
State the arteries of the leads on ECG
I, aVL, V5, V6 - LCx or diagonal branch of LAD (lateral)
V1-V4 - LAD (anterior)
II, III, aVF - RCA or LCx (inferior)
Sequence of evolving MIs on ECG?
1. In minutes - ST elevation and T wave bigger
2. Hours - R wave begins to decrease and Q wave begins to deepen
3. 1-2 days - T wave inverts and Q wave deeper.
4. Days later - ST normalises
5. Weeks later - normal except for Q wave persistence
How would posterior MI present on ECG?
Reciprocal changes - ST depression
ECG changes for NSTEMI?
• ST segment depression
• T wave flattening or depression
NSTEMI is more persistant than UA
How can you clinically differentiate between unstable angina and NSTEMI?
NSTEMI - ELEVATED BIOMARKERS. UA NO ELEVATION
ECG changes for pericarditis?
Widespread ST elevation with saddle back shape
ECG changes for pace makers?
paceing spikes before QRS.
ECG changes for wandering pacemeker? Patho of wandering pacemaker? Pts who get it?
• Atrial arrhythmia where cardiac pacemaker switches between SAN, atria, and AVN
• Pts with resp failure eg exacerbation of COPD
Varying PP and PR intervals. 3 distinct P wave morphologies in the same lead
Causes of long QT
• Antiarrhythmics - amiodarone, sotalol
• Erythromycin and azithromycin
Electrolyte - hypocalcemia, hypokalaemia, hypomagnesaemia
Patho of WPW
• Congenital accessory conducting pathway leading to atrioventricular re-entry tachycardia (AVRT)
Can degenerate rapidly to VF
ECG changes for WPW
• Short PR
Wide QRS complex with delta wave - slurred upstroke
Tx of WPW?
• Ablation of accessory pathway - definitive
Medical management - sotalol (avoid if AF), amiodarone, flecainide
Hypokalaemia on ECG?
• U waves
• Small or absent T waves
• Prolonged PR interval
• ST depression
• Long QT
"In hypokalaemia, U have no Pot and no T, but a long PR and a long QT"
Hyperkalaemia on ECG?
• Flattened P waves
• Widened QRS
• Tall tented T waves
ECG changes for hypothermia?
• J wave - size of wave is proportional to hypothermia
ECG changes for digoxin?
• Downsloping ST depression
• Flattened, inverted or biphasic T waves
• Shortened QT
Acute tx for STEMI?
Acute Treatment (MONA):
• M - Morphine + metoclopramide
• O - Oxygen (if O2 <94%)
• N - Nitrates (if hemocompromised DO NOT USE)
• A - Antiplatelets (aspirin + prasugrel)
Is PCI available within 120 mins?
a. Yes - pci
No- Fibrinolysis (tPA) with rescue PCI if not successful
ECG indications for PCI for STEMI
• ST elevation of >2mm in V1-V6 OR
• ST elevation of >1mm in inferior leads OR
New left bundle branch block
Post MI tx?
• Lifelong therapy of:
○ Antiplatelet eg clopidogrel
○ Beta blocker
• Lifestyle advice:
○ Mediterranean diet
○ Exercise - until slight breathlessness
• Due to antiplatelets
• High risk of bleeding
• Uncontrolled HT
Acute tx of NSTEMI?
1. Morphine +anti emetic (metoclopromide) + GTN (don’t use if hemocompromised)
2. Antiplatelets - aspirin (300mg PO) + clopidogrel
3. Beta blockers to limit ischemia (metoprolol) or verapamil if contra
4. Fondaparindux to disrupt thrombus
5. IV nitrate if pain continues
6. Record ECG and stratify risk using GRACE + TIMI
a. High risk - infusion of GPIIb/IIIa antagonist + angiography referral
b. Low risk - Treat medically and arrange further investigation eg stress test
Pathology of STEMI/atheroma?
1. Initial endothelial damage caused by smoking, HT, or hyperglycemia etc
2. Results in inflammation and oxidative damage
3. LDL particles infiltrate subendothelial space
4. Macrophages infiltrate and phagocytose LDL and turn into foam cells. Macrophages die and propagate inflammation
Smooth muscle proliferation and migration into tunica intima results in formation of fibrous capsule covering fatty plaque
IHD RFs modifiable and non modifiable
H - HTN
O - Obesity
P - PVD
E - Elevated LDL
F - FHx
U - Up glucose (DM)
L - Low HDL
S - Smoking, Sex (male), Sedentary
S&S of ACS
• Typically central or left sided
• May Radiate to jaw or left arm
• Described as heavy or constricting
Certain pts eg elderly or diabetics may experience no CP
• Cold and Clammy
All life signs may be normal
Diagnostic criteria for ACS?
2 of 3 needed:
• Clinical history
• ECG changes
Ix for ACS?
Bloods - troponin