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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