1. INTERESTING ECG OF THE
WEEK
FROM PROF.DR.NOORUL AMEEN’S UNIT

2.  58 year old male Mr.Kannan, who came to
hypertension OP for routine checkup
 No H/o chest pain, palpitation or syncope
 Known smoker for past 20 years – 10
cigarettes per day
 Not an acoholic
 Not a K/C/o
DM, CAD, COPD, BA, PTB, Epilepsy, Thyr
oid disease

3. Examination
 Conscious
 Oriented
 Afebrile
 CVS - S1S2 +, No murmur
 RS – NVBS + No added sounds
 P/A – soft
 CNS – NFND
 PR – 84 / min, regularly irregular
 BP – 140 / 90 mmHg

5.  ECG shows alternate complexes with 2
population of P waves P-P interval : 0.6 sec and 1
sec
 Alternating PR interval : 0.04 sec and 0.05 sec
 Normal axis
 QRS duration - 0.8 sec
 QT interval 0.4 sec
 No ST – T changes
 Incomplete compensatory pause
 Fixed coupling interval

6. ATRIAL BIGEMINY
 DISCUSSION
 Due to an ectopic from a single irritable focus in
either of the atria
 CAUSES
 Stress
 Exercise • Drugs
 Sympathetic over activity •Caffeine
 Smoking •Theophylline
 Alcoholism
•Cocaine
•Digoxin
 Hyperthyroidism
•Amphetamine
 COPD •Isoproterenol
 RHD

7. INCOMPLETE COMPENSATORY
PAUSE
 It is a feature of atrial ectopic
 Sum of the pre and post ectopic interval is less
than the sum of two consequetive intervals
 MECHANISM
 Transit time required to enter sinus node and reset
it followed by the time required for ensuring sinus
discharge to traverse sino-atrial juntion and
depolarise atria
 But In VPD
 No influence on SA node
 No re-setting of SA node
 Complete compensatory pause

8. FIXED COUPLING INTERVAL
 Interval between the extra-systole and the
preceding beat tends to be the same for all
unifocal extra-systoles

9. LOCALISATION
 RIGHT ATRIAL
 Negative / biphasic in V1
 Positive followed by negative
 LEFT ATRIAL
 Positive or biphasic in V1
 Negative followed by positive

10. A P-wave algorithm constructed on the basis of findings from 130 atrial tachycardias
correctly localized the focus in 93%

11. In Our ECG, Atrial ectopic localises to High Crista (Left
Atrium)

13. MECHANISM OF ATRIAL BIGEMINAL
RHYTHM
 Sinus rhythm with alternate atrial extrasystole
 Sinus rhythm with alternate sinus extra systole
 Sins rhytym with alternate AV nodal extra systole
conducted retrograde to atria
 Sinus rhythm with alternate ventricular
extrasystole conducted to the atria
 Sinus rhythm with 3 : 2 SA block
 AV nodal rhythm with 3: 2 retrograde AV block

14. DIFFERENTIAL DIAGNOSIS
 Sinus arrhythmia
 3 : 2 atrial block
 2 : 1 atrial flutter

15. SIGNIFICANCE
 Usually benign
 Can be a forerunner of atrial tachycardias and
atrial fibrillations

16. THANK YOU