Dr.S.Venkatesan MD

A 55  year old man came with a BP of  1o0/70 with vague symptoms of back  pain to our ER.

Troponin T  was positive

Can we thrombolyse ?

There is a minimal ST elevation in inferior leads  but not amounting to  the required criteria 1 mm

Technically No , Academically yes , scientifically No , logically  yes

*I wont thromolyse but i will take him to cath lab maybe the modern answer

 What we did ?

We did neither !

Just observed in CCU with heparin infusion , Aspirin and clopidogrel .

Note: The ECG becomes almost normal .The initial suggestion of inferior MI is stands questionable

Serial ECGs  were taken .

And now . . . after 24 hours a new complete heart block appear with classical evolved pattern of inferior MI.The most interesting feature is patient has been comfortable all along even as his posterior aspect of heart is experiencing terrible electrical earth quakes.

Is troponin Guided thrombolyis  an accepted  concept  ?

Yes ,  only in few situations like , posterior MI ,   LBBB  , pacemaker rhythm, re infarction .(Note , true posterior MI do not elevate the ST segment but depress it ) .

One may be surprised why we shouldn’t lyse a patient  whenever  troponin is elevated in acute coronary syndrome  (After all it denotes myocardial necrosis and infarct !)  The point here  is ,  troponin can raise in all forms of MI (NSTEMI, even in some cases of chronic stable angina )  Read in this link Why thrombolysis is contrindicated in UA/NSTEMI

The benefits of thrombolysis  is not proven in small and micro infarcts.  ECG  ST  eelvation   remain the  sole criteria for thromolysis for STEMI because  of  high degree of  correlation with total coronary occlusion .

In this era of rapid interventions the treatment concepts has blurred as we tend to do PCI and stenting  most cases of ACS including UA/Unstable angina

OK , what happened to this patient ?

Temporary pacer  was kept stand by with a sheath and catheter in situ.

Next day  morning  AV block disappeared .Patient was comfortable .

To our surprise , in the same  evening his ECG showed a complete heart block with AV dissociation . Still the heart rate was good . The demand temporary pacemaker didn’t take over .

On the third day , every conduction disturbance disappeared and  patient was sent to the wards. He is being discharged in a  stable condition with std drugs .there was  a minimal wall motion defect in infero-posterior segments with an ejection fraction of 50 % . He is  scheduled for coronary angiogram  2 weeks later.

What is the pathology ?

Pathologicallyit could be a small focal area of Infarct  incidenataly invloving the AV node .(This is alss refered to as vital area Infarct”  )It is hard to differentiate whether AV block is due to revrible ischemia or necrosis  , simple tissue edema ,  high vagal tone . or combination of above .If the block recovers it can be concluded necrosis is not the dominant theme.

Final message

STEMI presenting  primarily as heart block is less common .  When such a presentation occurs extra caution is required.

Many  of these patients  may not show a classical ST elevation  and hence do not permit us to thrombolyse   as per criteria.

It is  the  individual physician’s discretion to do so ( or not to do  ! ) . No body is going to fault. After  all  5 % of thrombolyis world over is for  benign early  repolarisation syndromes.

The above description is  an example of complicated inferior MI  . . .  still managed effectively by conventional methods.

Further reading

Why inferior MI is considered Inferior ?