WRISKE Flashcards
How is bradycardia treated?
The following factors indicate haemodynamic compromise and hence the need for treatment:
shock: hypotension (systolic blood pressure < 90 mmHg), pallor, sweating, cold, clammy extremities, confusion or impaired consciousness
syncope
myocardial ischaemia
heart failure
Atropine (500mcg IV) is the first line treatment in this situation.
If there is an unsatisfactory response the following interventions may be used:
atropine, up to maximum of 3mg
transcutaneous pacing
isoprenaline/adrenaline infusion titrated to response
Specialist help should be sought for consideration of transvenous pacing if there is no response to the above measures.
What arteries are affected in different MI’s
Location of infarct Leads involved Coronary territory involved
Inferior II, III, aVF Right coronary artery
Anterior V1-V4 Left anterior descending artery
Posterior infarct ST depression in V1-V2 Left circumflex (or right coronary artery)
Lateral I, aVL, V5 and V6 Left circumflex
Anterolateral I, aVL, V1-V6 Left anterior descending or left circumflex
How to managed regular narrow complex tachycardia?
In regular narrow complex tachycardias if there is no evidence of adverse features then the following steps should be followed:
Vagal maneuvres. If no effect: 6mg Adenosine, IV. If no effect: 12 mg adenosine, IV. If no effect: 12 mg adenosine, IV. If no effect: Seek expert help (Trial of beta-blockers
What can cause complete heart block and how is it managed?
Complete heart block.
In complete heart block, there is a complete absence of AV conduction - none of the atrial contractions are conducted to the ventricles. This means ventricular contraction is generated from a focus underneath the AV node - this is what leads to the abnormally shaped QRS complexes.
In complete heart block, there is usually bradycardia because of the automaticity of the conduction system below the AV node has a slower intrinsic rate of contraction than the SA node and AV node (this is usually a rate of 40bpm)
Causes
Complete heart block can be the result progression of Mobitz type I or type II (although the latter is far more likely to progress to complete heart block)
Inferior myocardial infarction
AV nodal blocking drugs (calcium channel blockers, beta-blockers, amiodarone and digoxin)
Clinical significance
Patients with third-degree heart block are at high risk of ventricular pause and sudden cardiac death
Management
Patients with third-degree require urgent admission. They should be initially stabilised (with external pacing). The definitive management is via the insertion of a permanent pacemaker.
When should de fibril torts be given?
Implantable cardioverter defibrillators (ICDs): according to NICE are recommended for patients with:
sustained VT causing syncope.
sustained VT with ejection fraction <35%
Previous cardiac arrest due to VT or VF
What are the complications of MI?
Complication management
Pericarditis NSAIDs
Systemic embolism (may be caused by LV mural thrombus) Anti-coagulate with warfarin
Cardiac tamponade Pericardial aspiration
Ventricular septal defect Surgery
Dressler’s syndrome* NSAIDs or steroids if severe
Left ventricular anuerysm** Anticoagulation
Dressler’s syndrome:
This is characterised by recurrent pericarditis, pleural effusions, anaemia, fever and raised ESR 1-3wks post-MI.
Left ventricular aneurysm
This occurs 4-6 post-MI, it presents with left ventricular failure, angina, recurrent VT, Systemic embolisation. Presents with persistent ST elevation on ECG.
What are the complications of Inferior MI?
This ECG shows ST-segment elevation in leads II, III and aVF. This is an inferior infarct, which can lead to leftaxis deviation and NOT right axis deviation.
Severe hypotension in response to nitrates
14%
This is a rare complication of inferior myocardial infarction and occurs when there’s concurrent right ventricular wall infarct, this tends to happen when there’s occlusion in the proximal region of the RCA.
If there’s a right ventricular wall infarct, severe hypotension occurs in response to nitrates because nitrates cause peripheral vasodilation, which reduces venous return to the heart, and as right ventricular contraction is compromised - cardiac output is significantly reduced.
Heart block
8%
The right coronary artery supplies the AV node and the SA node - therefore in an inferior infarct - several types of heart block can occur. Those types of heart block tend to be reversible on revascularisation
Pericarditis
15%
Although this is not an immediate complication, pericarditis as part of Dressler’s syndrome can occur as part of post-MI complications. Usually, those symptoms occur 1-3 weeks post-MI, and those patients have characteristically raised ESR.
