Chapter 8 Flashcards
(19 cards)
Which patients presenting with syncope need cardiac monitoring?
Unexplained syncope, especially during exercise. Known structural heart disease, abnormal ECG especially long QT
Situational syncope, simple faints, orthostatic hypotension do not need monitoring/admission
How should ECG electrodes be attached?
Red - right arm
Yellow - left arm
Green - spleen
Make sure skin is dry, not greasy. On hair-free skin. On bone rather than muscle.
Conventional defib pad positions
Beneath right clavicle and in left mid-axillary line
What do P waves, PR interval, QRS and T waves represent?
P atrial depolarisation
PR interval delay through AV node
QRS ventricular depolarisation
T ventricular repolarisation
Normal PR interval and QRS duration
PR interval (from start of P to Q) - 0.12-0.2 seconds (3-5 small squaews)
QRS duration - <0.12 (<3 small sqaures)
What does asystole look like?
Usually some undulation of baseline
Usually atrial and ventricular asystole
If completely straight line usually disconnected lead
What to do if unsure if fine VF or asystole?
Don’t spend time deciding
Treat as one or other depending on which looks more likely
How to calculate ventricular rate?
Number of cardiac cycles in 6 seconds (30 big squares) x 10
When are ectopics consider tachyarrhythmia?
If 3 or more in immediate succession
Which rhythms can mimic VF?
Polymorphic VT - would have the same treatment in a cardiac arrest
AF with pre-excitation e.g. WPW causes irregular broad complex tachycardia. If causes cardiac arrest treatment would be immediate defibrillation
Why is recognition of torsade de pointes important?
Usually caused by long QT
May be inherited condition, effect of drugs (e.g. amiodarone) or due to hypokalaemia/hypomagnesaemia
Need to correct electrolytes/stop provoking drugs
Reversible causes of PEA
Severe fluid depletion
Blood loss
Cardiac tamponade
Massive PE
Tension pneumothorax
Heart block definitions
1st degree - prolonged PR >0.2 seconds (5 small squares)
2nd degree Mobitz type I - progressive prolongation of PR with dropped QRS
2nd degree Mobitz type 2 - constant often prolonged PR with random dropped QRS
3rd degree (complete) - no relationship between P and QRS
Consequences of heart block
1st degree usually harmless, no symptoms
2nd degree Mobitz I usually asymptomatic not requiring immediate treatment
Mobitz II increased risk of progression to complete AV block and asystole
Complete risk of aystole high
Are intrinsic ventricular rhythms slower or faster than atrial?
Slower
What is an agonal rhythm?
Seen in dying patients. Slow, irregular, wide QRS complexes with varying morphology.
What causes broad complex tachycardia?
Tachycardia originating below the bifurcation of the Bundle of His or supraventricular tachycardia aberrantly conducted (bundle branch block) to the ventricles
Normal QT interval
Man <0.43 seconds
Woman <0.45 seconds
Causes of short QT
Hypercalcaemia
Digoxin
