FROM PROF.DR.NOORUL AMEEN’S UNIT
INTERESTING ECG OF THE WEEK
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 acoholicNot a K/C/o DM, CAD, COPD, BA, PTB,
Epilepsy, Thyroid disease
Examination ConsciousOrientedAfebrileCVS - S1S2 +, No murmurRS – NVBS + No added soundsP/A – soft CNS – NFNDPR – 84 / min, regularly irregularBP – 140 / 90 mmHg
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 axisQRS duration - 0.8 secQT interval 0.4 secNo ST – T changesIncomplete compensatory pauseFixed coupling interval
ATRIAL BIGEMINYDISCUSSION
Due to an ectopic from a single irritable focus in either of the atria
CAUSESStressExerciseSympathetic over activitySmokingAlcoholismHyperthyroidismCOPDRHD
• Drugs•Caffeine•Theophylline•Cocaine•Digoxin•Amphetamine•Isoproterenol
INCOMPLETE COMPENSATORY PAUSEIt is a feature of atrial ectopicSum of the pre and post ectopic interval is less
than the sum of two consequetive intervals MECHANISMTransit 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 nodeNo re-setting of SA nodeComplete compensatory pause
FIXED COUPLING INTERVALInterval between the extra-systole and the
preceding beat tends to be the same for all unifocal extra-systoles
LOCALISATIONRIGHT ATRIAL
Negative / biphasic in V1Positive followed by negative
LEFT ATRIALPositive or biphasic in V1Negative followed by positive
A P-wave algorithm constructed on the basis of findings from 130 atrial tachycardias correctly localized the focus in 93%
In Our ECG, Atrial ectopic localises to High Crista (Left Atrium)
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 blockAV nodal rhythm with 3: 2 retrograde AV
block
DIFFERENTIAL DIAGNOSISSinus arrhythmia3 : 2 atrial block2 : 1 atrial flutter
SIGNIFICANCE Usually benignCan be a forerunner of atrial tachycardias
and atrial fibrillations
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