Type Name What is it? ECG – Rhythm Strip
An atrial contraction rate of over 250-300 bpm.
Rapid and regular form of atrial tachycardia.
Atria depolarize in an organised circular
movement caused by a re-entrant circuit of
excitation i.e.it goes straight back into the atria
instead of the impulsesjust travellingto the
Patients presenting with paroxysms of atrial flutter
often have normal hearts, whereas patients with
chronic atrial flutter usually haveunderlyingheart
disease. Chronic atrial flutter eventually converts to
chronic atrial fibrillation.
“sawtoothpattern”of ECG esp.inLead II
Signsof heart failure (raisedJVP,peripheral oedemaetc)
Do U&Es, TFTs and Echocardiography.
Ischaemic heart disease, hyperthyroidism, cardiomyopathy and
rheumatic heart disease can all cause it but sometimes, no cause is found
Arial Fibrillation This is an atrial rhythm which is ineffective,
chaotic and irregular, usually of around 300-
Paroxysmal - Lastinglessthan48 hour - Often
Persistent- Anepisode of AFlastinggreaterthan
48 hours,whichcan still be cardiovertedtoNSR.
Permanent- Inabilityof pharmacologicornon-
Lone (idiopathic) AF: Absence of anyheart
disease andnoevidence of ventricular
dysfunction.A diagnosisof exclusion.Couldbe
stroke rate if > 75 years of age.
FBC, U&Es, TFTs, CXR,Echocardigraphy.
IrregularQRS complexes(some maybe normal)
Asymptomatic. Palpitations, Chest pain, Pre-syncope (dizziness),
Dyspnea, Syncope, Sweatiness, Fatigue. Symptomsoftenworse atthe
onsetof AF. Suddencardiacdeath.Worseningpre-existingcondition:
An arrhythmia caused by a second connection
between atria and ventricles,in addition to the
normal conduction system. There are two
AVRNT (Atrio-Ventricular Node Re-entry
Tachycardia) - the second connection is closely
related to the AV
Rate of 130-250. Narrow QRS complex (except in bundle branch block), P
waves are: inverted, masked by QRS complex (AVNRT) or occur halfway
between complexes (AVRT), one P wave per QRS complex.
AVRT (Atrio-Ventricular Re-entry Tachycardia) - the second connection is
not related to the AV node.
WPW is caused by the presence of an
abnormal accessory electrical conduction
pathway between the atria and
the ventricles. Electrical signals travelling
down this abnormal pathway (known as
the bundle of Kent) may stimulate the
ventricles to contract prematurely (pre-
excitation syndrome), resulting in
supraventricular tachycardia -
atrioventricular reciprocating tachycardia.
Sinusrhythmandveryshort PR interval
DominantR wave inV1 – “Type A” WPW and isassociatedwithaleftsided
Notshown – DominantSwave in V1 – “Type B” WPW and indicatesaright
It can alsobe causedby sinus tachycardia i.e.the normal physiological
response tocertainstimuli whichcause the heartrate torise.
Chaoticdepolarisationof the ventricles.
VFcan onlybe treatedby
Bloods– cardiac enzymes(TroponinTandI, CK-
Usuallyoccurs duringan MI. symptomschestpain,tiredness,palpitations
QRS >120ms/3 small squares whichoriginatesin
disease orhaemodynamiccompromise. Chest
pain, palpitations, dyspnoea,dizziness,syncope
and possibly symptomsof heartfailure.
The QRS complexesare rapid,wide,anddistorted.
The T wavesare large withdeflectionsopposite the QRScomplexes.
P wavesare usuallynotvisible. The PRinterval isnotmeasurable.
A-V dissociationmaybe present.
V-A conductionmayor may notbe present
Bradyarrythmias: Heart Block 1st degree – slowdownof conduction. Notreally
“block”.JustP-R interval longerthan normal (>
2nd degree – some conductionbutnotothers.
Intermittentblockatthe AVN (droppedbeats)
Progressive lengtheningof the PRinterval,
Must see PR prolongationtomake diagnosisof
Usually2:1, or 3:1, but may be variable
3rd degree –complete blockbetweenatriaand
P wavesare independentof the wide QRScomplex
not usingnormal conductingsystemsoitisan escaped
Figure 1. Mobitz I
Figure 2. Mobitz II
Figure 3. 3rd degree/complete heart block
Cessationof appropriate electrical conduction
downeitherthe R or L bundle branch.
In bothcasesthere is a wide QRScomplex.
RBBB- M shapein V1 and an N shape in V6 (the N can
also stand for "normal"). The "M" wave here has a
small rise(r),a big drop (S) and an even bigger rise(R)
givingan rSR wave. Finally,theN is your normal QRS
complex but justwider.
LBBB - V shape in V1 and an M shapein V6. The "V"
wave is also called an rS wave because ithas a very
slightrise(r) and a big drop (S) in amplitude.The "M"
Figure 4. RBBB
wave, also called R,is justa largerise(R) with a tiny
dip and tiny rise.
Can justbe left unless severe and a cardiac pacemaker
Figure 5. LBBB