Flashcards in Cardiology Deck (148)
ECG signs of firs degree block, second degree and third degree heart block
1 = PR interval > 0.2 seconds
2.1 = Increasing delays until dropped
2.2 = Intermittent drops, in a ratio
3 = Complete dissociation
ECG signs of RVH vs LVH?
RVH = Tall R wave in V1, deep S in V6
e.g. cor pulmonale
LVH is Deep S in V1, tall R in V6
e.g. HTN, aortic stenosis and co-arctation
Causes of long QT?
Toxins e.g. macrolides / amiodarone
Mitral valve prolapse
Electrolyte = Low K/Ca/Mg
Short QT causes?
Digoxin, BB, phenytoin
What is a trifasicular block and when do you see it?
1st degree heart block with LAD and RBBB
Commonly presents as falls in the elderly
What is p pulmonale and p mitrale?
Pulmonale = Peaked p wave in RAH e.g. Pulmonary HTN or tricuspid stenosis
P mitrale = Broad bifid p wave in LAH = mitral stenosis
ECG changes in VT?
No p waves or T waves. Regular broad QRS
ECG changes in Brugada syndrome?
RBBB and coved ST elevation in V1-V3
Digoxin ECG changes?
Reverse tick = down sloping ST segment and T-wave inversion
ECG changes in hyperkalaemia vs hypokalaemia?
Hyper = Tall tented t waves, wide QRS and absent/flat p-waves
Hypo = Small T waves, ST depression. Prolonged QT and prominent U waves
Causes of bradycardia?
Drugs e.g. CCB, BB, amiodarone
Vagal hypotonia e.g. athletes
Infection e.g. infective endocarditis
Sick sinus syndrome = damage to the SAN / AVN or conducting tissue
Infiltration e.g. sarcoidosis
O's = hypothyroid, hypokalaemia
N = neuro = raised ICP
Investigations of bradycardia?
ECG, bloods (cardiac enzymes), event monitor and exercise testing
Management of bradycardia?
Unstable = Atropine 0.5mg IV bolus, repeat 3mg max
If refractory can use pacing if:
-Complete heart block, systole, mobitz type 2 or ventricular pause > 3 seconds
- transvenous pacing = lead into RV, only for a few days. Mechanical tricuspid is CI
Mild = treat underlying cause + theophylline 200mg PO BD
Severe = Treat and temporary dual chamber pacing
Definition of narrow complex tachycardia?
Rate >100BPM, QRS <120ms
2 types of narrow complex tachycardias?
- Sinus tachy
- Atrial tachycardia = different focus takes over from SA node
- atrial fibrillation
- flutter = macro re-entry rhythm, atria rhythm of 300 (ventricles can't conduct 300 so P:QRS is usually 2:1)
AV node dependent:
- AVNRT = within node so activates atria and ventricles simultaneously
-AVRT = large accessory pathway e.g. WPW bundle of Kent :
+ Can be orthodromic = down AV node and back round up accessory pathway into atria. p follows each QRS, delayed RP interval
+ can be antidromic = conducted down accessory pathway, and re-enters atria via retrograde flow = broad QRS
Management of unstable narrow complex tachycardia?
DC cardio version x 3
Amiodarone 300mg IV over 10 minutes
Amiodarone 900mg over 24 hours
management of stable narrow complex tachycardia?
Irregular = treat as AF:
- Rate with BB/CCB + digoxin
- onset <48 hours = cardioversion
- Vagal manouvres
- Adenosine 6mg IV bolus, then 12 then 12. (Use verapamil in asthmatics) If it is AV dependent the adenosine will stop the arrhythmia as it cause AV block.
If it doesn't work means independent = Flutter, AF or ST
Management of atrial tachycardia and atrial flutter?
1st line = Diltiazem or Verapamil
2nd line = amiodarone
3rd line = Flecainide
Refractory = ablation
Unstable = DC cardiovert
Stable = BB e.g. metoprolol 5mg bolus, repeating up to 3 times
- Amiodarone if refractory
Then cardiovert if refractory (electrical or medical with ibutilide)
For ongoing can ablate the tricuspid isthmus if symptomatic, or asymptomatic give Metoprolol
What drugs should you avoid in WPW?
Verapamil and digoxin
Definition of brand complex tachycardia?
>100 BPM, QRS > 120ms
Classification of broad complex tachycardia?
Most are ventricular:
- monomorphic = single form QRS
- Fascicular = Arise from LV with re-entrant into Purkinje's = Sensitive to verapamil
- RV outflow tract tachy = Due to cAMP activity = uniquely sensitive to adenosine
- Torsades des pointes = type of polymorphic
Some are SVT's with aberrant conduction
Ventricular tachycardia causes?
Long QT: TIMME
Electrolytes low K/Mg/Ca
Management of unstable VT?
DC cardioversion x 3
Amiodarone 300mg IV over 10-20 minutes
Amiodarone 900mg over 24 hours
Management of torsades des pointes?
In line with ACLS guidelines for unstable VT.
+ usually due to low potassium / magnesium so aggressively replenish
magnesium sulphate 1-2g IV single dose
KCL max 60mM
Management of stable broad complex tachycardia?
Correct electrolyte balance
- Amiodarone 150mg bolus then 1mg/min for 6 hours then 0.5mg/min for 18 hours
- 2nd line = lidocaine
Implanatble cardioverter defibrillator if = Cardiomyopathy, previous VT/VF or congenital arrhythmia problem e.g. Long QT
Anti-arrhythmics e.g. Metoprolol 50mg PO BD
What is atrial fibrillation?
Supraventricular tachyarrhythmia, with an irregularly irregular rhythm.
Abnormal atria promoting electrical re-entry
How do we classify atrial fibrillation?
First diagnosed = new diagnosis regardless of duration
Paroxysmal = self terminating, usually within 2 days
Persistent = longer than 7 days, including episodes cardioverted post 7 days
Long standing = continuous > 1 year, have adopted rhythm control
Permanent = No rhythm control
Causes of atrial fibrillation?
Cardiac = HTN, LV failure, ischaemic heart disease
Non-cardiac = thyrotoxicosis, pulmonary e.g. PE, drugs and alcohol
Management of unstable AF?
Unstable = DC cardiovert, if >48 hours must do a TOE to exclude atrial thrombus