chapter 8, Flashcards
patients with persistent arrythmia need what ?
establish ECG monitoring
as soon as possible record a good quality 12 lead ECG
what kind of syncope do not need continuous monitoring ?
situational syncope - during cougar micturition
or orthostatic hypotension
in which syncope is continuous ECG monitoring required ?
unexplained syncope
esp during exercise
syncope with evidence of structural heart disease
syncope with abnormal ecg - esp prolonged qt
where to place the electrodes of 12 lead ecg ?
dry , shaven area of skin
over bone not muscle
in which ecg lead do we most of the time begin monitoring ?
lead 2 - best p , qrs waves
try to minimise muscle movement = relaxed
in an emergency what is used to detect rhythm?
assess cardiac rhythm by applying defib pads
in an emergency what is used to detect rhythm?
assess cardiac rhythm by applying defib pads
WHEN TO PLACE PADS IN AP position
ICD or perm pacemaker jin right side , or chest wall trauma
When should ECG monitor changes be documented
When patient known to have tacy arrythmia being treated (eg carotid sinus massage and adenosine) - effects of such intervention on a CONTINIOUS ECG SHOULD BE MONITORED
What should be documented on continuous ECG monitoring ?
When intervention is in place and changes in ECG seen - such as carotid sinus massage , adenosine etc
What is the potential difference in the myocardium ?
90mV - sudden shift of ions causes depolarisation
What is sinus rhyth
P WAVE FOLLOWED BY QRS wave
what des the t wave represent ?
the cells going back to their resting potential
duration of normal qrs ?
less than 0.12
a completely straight line indicates ?
lead has been disconnected
during ASYSTOLE THERE IS SLIGHT UNDULATION OF THE BASELINE - may sure interference due to resp movement or chest compression
what is the normal heart rate ?
60-100
bradycardia <60
tachycardia >100
what does one large square represent in ecg strip ?
0.25sec
5 large sqaures =1sec
best way to calculate HR ?
count the number of r waves in 6 seconds =
30 large squares
and multiply by 10
=====
shower ecg strip
divide all by 2 )
(or find one r wave to r wave count how many big boxes and divide it by 300)
if the RR intervals are totally irregular and qrs complex has constant morphology what is it likely to be ?
afib
how can you know where ectopic beats come from - whether ventricle or atria ?
ventricle is less <0.12 - it is narrow
broad ectopic beats - maybe ventricle or supra ventricular with bundle branch block
what is escape rhythm ?
a beat that happens after a long pause - coming from av node or ventricular myocardium
ectopic beats can occur as ?
single
couplets
triplets
how many amount of ectopic bets are needed for it to be classified as tacyarrythmia ?
more than 3 in rapid succession
what is called an arrythmia that occurs intermittently , interspersed , with periods of normal sinus rhythm ?
paroxysmal
what is called when ectopic beats or arrythmia occurs alternately with sinus beats for a sustained amount of time ?
bigeminy
if qrs duration more than 0.12 where is it coming from ?
origin is from the ventricular myocardium or supra ventricular rhythm transmitted with bad conduction - such as bundle ranch block
why are p wave veryhrd to fid and should not waste time with it
and in which lead can p waves be more definingly found
can be present as positive , negative or biphasic deflections
u waves mistaken for p waves
p wave coincide within qrs or t wave or st segments
=====
lead v1 or lead 2
in which leads is atrial flutter best seen ?
inferior leads = 2,3 and avf
how to recognise retrograde activity of p waves
usual p waves positive n lead 2 and aVF
negative deflection if retrograde
if af accompanied by regular qrs complies why ?
due to complete av block with AF
in atrial flutter there ca be relationship with atria and ventricles ?
YES
most time
som instane atrial flutter with variable AV conduction
atrial fib - irregularly irregular
how d we know when the ecg strip is VF or artefact ?
if patient conscious and has pulse
rhythm abnormality can mimic vf which are they
polymorphic v tach
pre-excited af - WPW (LEFT UNTREATED CAN LEAD TO VF AND VT )
why is it safe to consider all SVT as VT unless proves otherwise
because in presence of bundle branch block - SVT will cause broad complex tacy
after MI out broad complex tacy cardia are ventricular in origin
when dp torso de pointes happen ?
prolonged qt interval- ca be inherited
or due to drugs less common myocardial ischemia , sme anti - arrhythmic drugs = AMIODARONE (SHOULD BE AVOIDED IN TDP)
many patients with TDP - hypo kalemic, magnesia
PEA is defines as what ?
no clinical cardiac output despite normal ectrical activity
causes of pea
HYPOTENSION
CARDIAC TAMPONADE
4H AND T’S
which drugs causes bradycardia ?
bb
timing of normal P-R interval
0.12-0.2
what is first degree block ?
prolonged PR interval of more than 0.2sec
= usually in trained athletes and can be physiological !
can be due to ischemia and drugs
Rarely causesanqy symptoms
Rarely requires treatmnet
second degree av block types
mobits type 1
prolonging of pr - until a p wave without qrs complex
= can be physiological - in athletes with high vagal tone
= most pf the time pathological due tp myocardial infraction
= treatment dependant on effect of bradyarrythmia
mobitz type 2
constant prolonged PR
some p waves not followed by qrs waves
= high risk asystole and complete av block
what is third degree av block ?
complete dissociation between atria and ventricles - site of pace maker will decide rate
rate of each side of pacemaker ?
AV node and proximal bundle of his = 40-50
= naeeower qrs complex
HISS and purkinje = 3-40 or less
what is idioventricular rhythm ?
rhythm arising from myocardium
= including escape rhythm
du to complete av block
accelerated idioventricular rhythm - just above normal HR
= observed after successful thrmbolysis or PCIA
WHEN IS AGONAL RHTHM SEEN?
charachterised by slow irregular broad qrs complexes
doe snot have pulse
seen in later stages of unsuccful resus attempts
common cause of af ?
alcohol
structural heart disease
hypertension
obesity
====
usually arising from right atrium LIKE MOST OF THE TIME FOR ATRIAL FLUTTER
disease like : copd
major pulmonary embolism
congenital heart disease
congestiv heart failure
what inreases risk of vtach going to vfib
ischemia
hypokalmeia and hypomagneisa
prolonged QT !!!
QT interval shortens as ?
hr increases
what is the corrected qt interval in men and women
men = 0.43
women = 0.45
a QTc of more than 0.5 is a high risk for what ?
cardiac arrest
causes for short qt interval ?
digoxin
hypercalcemia
causes for qt prolong
ischemia
amiodarone
hypo kal/ mag/ cal/ thermia
GENETICS
class 1 and 3 anti arrhythmic
what is qt period physiological ?
reploraisation
