Archive for the ‘ICD and Pacemakers’ Category

A 5-minute session: Answers are my own. Please cross-check.

1. Is Brugada syndrome clinical or ECG diagnosis?

Always clinical. Never get confused on this.

2. Spontaneous type 1 vs Induced Type 1 (from type 2) which carries more risk?

Both are risky since they are close cousins. But, spontaneous type 1 is the dreaded devil. 

3. Is Brugada primarily a defect of myocardial depolarization or repolarisation?

Not clear. Often in both. In fact a mismatch between them. (Don’t ask how Na+ Channel defect affects repolarisation !)

4. Is Brugada VT is monomorphic, polymorphic?

Both. What determines morphology is not clear though. (All de-nova monomorphic VT will degenerate to polymorphic en route to cardiac arrest)

5. Should  Fever induced Brugada pattern be investigated further?

Better, it is not to be reported in ECG. May not be important in the majority if there is no adverse family history. (If the patient is well educated and afflicted  by Dr.Google and cardiologists can’t escape from ordering sophisticated tests)     

6. What is the overlap between ERS and Brugada?

It is all about the Idiosyncrasy of the K+ channel phenotypes ( Transmural dispersion heterogeneity )  

7. Is a benign Brugada better than a malignant ERS?

Yes, it would seem so. (Inferior or Infero -lateral ERS prone for primary VF in case they develop ischemic / ? also non-ischemic stress)

8. How important is the link between Brugada and Long QT 3 syndrome?

A rare entity, but It is double jeopardy for VT risk. The entire action potential width is vulnerable right from phase 0 to 3 or 4 A case report Sandhu A Clin Case Rep. 2017;5(8):1315-1319.

9. Is Amiodarone really contraindicated in VT?

Not really. Though Amiodarone unmasks Brugada, it can still be used during episodes of VT in patients with manifest or unmanifest Brugada. Maybe in Long QT 3 overlap, it may perpetuate the VT.

10. How important is the structural myocardial defect in Brugada?

Not important in the majority. Though localized RVOT abnormalities are noted in some..RV abaltion can be succesful in odd case.

11. What happens to the ST segment in Brugada during exercise stress?

ST-segment may normalize in some. A stress test can help to risk stratify.  Subramanian M, J Cardiovasc Electrophysiol. 2017 Jun;28(6):677-683.0

12. Which drug is probably best for Brugada as of now?

Quininde , A fairly specific blocker of Ito current. However, it needs to be used diligently. Management of Brugada Syndrome: Belhassen B, Rahkovich M, Michowitz Y, Glick A, Viskin S Circ Arrhythm Electrophysiol. 2015 Dec; 8(6):1393-402.

13. Is ICD definitive therapy?

Obviously not. But, definitely life-saving in high-risk survivors. I guess definitive therapy is possible for future generations through the science of genetic reprogramming of Na+ channels. (Of course, our planet shouldn’t succumb to man-made climatic arrhythmia, by then ) 

14. Does widespread genetic testing & screening of families help in the management and reduce anxiety?

Cracking the genomic code of cardiac ion channels is the ultimate sophistication (Blueprint of fate ?) However, there is no guarantee this information is going to ease out the family members who harbor a genocopy with or without a phenocopy. 

15. Is Brugada getting undue attention in cardiology literature compared to many other common arrhythmias?

      You can answer this …………………………………….


Further reading

Li KHC, Lee S, Yin C, et al. Brugada syndrome: A comprehensive review of pathophysiological mechanisms and risk stratification strategies [published correction appears in Int J Cardiol Heart Vasc. 2020 Dec 19;32:100699]. Int J Cardiol Heart Vasc. 2020;26:100468. Published 2020 Jan 21. doi:10.1016/j.ijcha.2020.100468


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ICDs are one of revolutionary devices , invented last century  that can defy “death & fate”  in high risk cardiac patients who are threatened with ventricular tachycardia or fibrillation .A decade long hard work by  Mirowski  and team from John Hopkins culminated in the dramatic  the first AICD implant in 198o. ( In my opinion, this medical invention can be compared to an event of such  significance as moon landing by Armstrong and team ! ) Ironically , in the last decade such a revolutionary device was sort of misused and thousands of devices were explanted for inappropriate indications.

Fortunately , better sense prevailed recently .The indications are getting  refined. I am sure ICD will go a long way in prevention of  both expected and unexpected sudden  electrical deaths .We are into  the 4th decade of its evolution.While the electrical circuitry has been mastered , power supply remains an issue as they require continuous power supply like a mobile phone. Current technology allows about 6-8 years of battery life.

EL-ICD boston scientific longest life icd smallest profiale dynagen inogen madit indication for icd

Now , Boston scientific  has come out with new technology which make its  battery life extend  by 100%  to 12 years.  It is a major break through , expected to evolve  further  until probably we have rechargeable  batteries or biological power sources .Stretching a wild thought , the days couldn’t be far off  when the smart phones which are omnipresent in every human-being  , could not only power the ICD  remotely and control it too !


Indications (ESC/AHA 2012)


  •  Post MI* /LV dysfunction  ≤ 35% /NYHA   class II or III  (*  > 40 days)
  •  Post MI* /LV dysfunction ≤ 30% /NYHA Class I (* > 40 days )
  •  With non-sustained VT due to prior MI, LVEF < 40%, and inducible VF or sustained VT at  EP study

Non ischemic structural disease ( Idiopathic DCM, ARVD etc)

  • With structural heart disease and spontaneous sustained VT, whether hemodynamically stable or unstable.

Primary electrical disease

  • With syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or VF induced at electrophysiological study



Link to Product manual form Boston scientific.

Boston scientific



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We live in curious times .As we  advance in our intellect and wisdom ,bullet firings (either cross or straight !) have become an important cause  for sudden cardiac death.Sometimes a life is saved by unexpected way in extraordinary circumstances. Here is a man  from Florida , whose life was saved by  an ICD not by shocking a VF . . . but by blocking a bullet

ICD acts like a bullet proof jacket


A case report from Heart Rhythm


Bullet proof ICD jacket saves life

Complete Heart  Bullet Block : The Aftermath


It seems ICD is strong enough to stop a bullet !

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