Heart rythms Flashcards
What are the two types of bradycardia?
-Absolute- <50 bpm
Relative- this is when the BP sytolic is <90 bpm but the HR is not compensating- therefore HR is <50 bpm-
(also can be sinus or av node bradycardia)
Types of rythms associated with SAN?
-Sinus bradycardia- can be due to meds - hypothyroidism and hypothermia, sleep apnoea, rheumatic fever,pericarditis, haemochromatosis
-Sick sinus syndrome (tachy-brady)
What is sinus bradycardia?
slow HR- but each QRS has a P wave before
What is a 1st degree heart block and what are the causes?
-PR interval >0.2s - usually caused by digoxin
What is second degree heart block?
TYPE I- progressive lengthening of PR- then loss of QRS - no need for management unless patients are dizzy and lose consciousness
TYPEII- prolonged PR- then sudden loss of QRS- permanent pacing is required
Describe a Third degree heart block?
-no relationship between P wave and QRS - can have narrow complex escape rhythm is escape rhythm is above AV node- or broad complex if block is above.
can also have LBBB and RBBB and prolonging PR intervals- trifasicular heart block
What are the causes of 3rd degree heart block?
-Digoxin toxicity- can occure after inferior stemi- this would usually resolve itself in a couple of hours- however, if it has occurred after an anterior MI- much more serious
-severe hyperkalemia- treat with IV calcium chloride or atropine in hemodynamically unstable patient
Treatment for third degree heart block?
-permenant pacing- unless recent MI then recovery is likely
What is the criteria for diagnosis AF risk?
CHADVASC
Investigations for AF?
-Manual pulse
-symptomatic- breathlessness and palpitations syncope, ECG
-can give intermittent cardiac monitoring- for intermittent arrhythmias
-ECHO- is suspected structural heart disease, or is cardioversion is being considered,
Treatment for AF?
-Anticoag if CHAD score is greater than 2 give anticoag, if score 1in men is intermediate risk- consider antocoag but also bleeding risk, if score 0 don’t offer. in women score1 /0 no anticoag. DOACS - does not require regular testing of INR unlike Warfarin- and no dietary restriction.
-Rate control- depends on if patient is hemodynamically stable- if not Electrical cardioversion, if they are consider pharmacological cardioversion-.
Severe HFREF, aortic stenosis- amiodarone
Coronary artery disease- Amiodarone-IV
No structural problem-Flecainide.
Rhythm control- if LVEF<40%- digoxin and B- blocker - or early low dose combination therapy
-if LVEF >40% diltiazem, B-blocker, digoxin
What is a CHADVASC score?
-considers diabetes, hypertension previosu strokes, gender, age and LVEF.
What scoring is used to determine bleeding score?
HASBLED - this considers uncontrolled hypertension, poor INR, any other meds like aspirin and NSAIDs and Harmful alcohol consumption (>14 units)
What is a supraventricular tachycardia?
- most of them originate from the AVN- this is where the tachycardia originates- Av node reentrant tachycardia
What are treatment options for SVT?
- you can terminate the re-entrant circuit through vagal manoeuvres:
-breath holding
-blowing hard in a syringe
-carotid massage - massage carotid sinus on non-dominant cerebral side- usually on young patients - only on hemodynamically stable patients - short term management- iv adenosine- rapid IV bolus followed by saline flush - warn patients about chest discomfort.
or calcium channel blockers
-if tachycardia continues usually AVnRT
what is the difference between AVRT and AVNRT?
-AVNRT has P waves buried in QRS, AVRT has P waves following QRS.
What are medications that should be considered for SVT?
- in hypotensive patients- or patients with pulmonary oedema- synchronised Cardioversion- after sedation.
-verapamil- 5-10mg IV slowly - contraindicated in patients on B- blockers- if verapamil and adenosine contraindicated- cardioversion
-IV flecainide- should be avoided in patients with past MI
Second line drugs- sotalol, flecainide and amiodarone
When should you suspect VT?
if patient has had a recent STEMI and has broad complex tachycardia.
Treatment for VT?
-cardioversion
-B-blockers - be careful if hypotensive
-Amiodarone 300mg iv over a few minutes, then 900mg over 24 hours
-Lidocaine- no more than 300mg in one hour.
