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Archive for the ‘Infrequently asked questions in cardiology (iFAQs)’ Category

One of my fellows gave a discharge summary  for a 62 year old patient with stable diabetic  CAD  who had Triple vessel disease with a final advice reading as CABG / PCI/or OMT .

There was a near fury over his angiogram report in the cath meet. How can be  eligible for all the three Intervention at the same time ?.(PCI -Percutaneous coroanry Inervention ,CABG-Coroanry artery by-pass graft, OMT-Optimal medical therapy )

The lesion in question was , Triple vessel disease(Non critical LAD) and significant LCX and again a non critical RCA .Syntax was less than 22 for sure , however the patient  had class 2 angina (now reducing ) .When asked to explain  , the fellow  argued since the patient  is symptomatic , has DM with TVD  he is eligible for CABG , since  LCX lesion was discrete and PCI was distinctly possible , of course as all three  lesions would be  eligible for OMT on any given day  ! he inferred .

How can  a cardiologist be so casual and non-commital in an important medical decision where a life of a heart is at stake.There was a unanimous condemnation about the report. As a consultant he has to be specific , one can’t leave the decision to  your patient’s whims  . . . rather it’s our scientific whims  that should prevail  !

 

MEDICAL VS PCI VS CABG OMT COURAGE BARI 2D FREEDOM FAME STUDY MASS 2 CASS OPTOMAL MEDICAL MANAGEMENT SYNTAX ACC AHA ESC GUIDELINES PTCA STS EUROSCORE NEJM

The curiosity continued and looked amusing for many. I was the only one supporting  his argument ! After all , he is being frank and understood the futility of  applying  evolving knowledge base in critical decision making. But, I  asked him to grade the choices .In my opinion  OMT should be the first choice if it can be administered , but reality tells me  true OMT is rare as a modality  at-least in  this  part of world . However every one should insist for it.

Apart from poor  compliance for OMT , pressure  mounts for a procedure from peers and non peers . I am  sure  many  patients  will end up with an  invasive modality sooner or later  backed by a  second or  third opinion  driven by that elusive googled intellect !

Final message

When clinical decision making is debatable with available knowledge (Especially with futile and evolving knowledge base !) , please include your patient into the debate and you may even consider giving him the veto power.If Hippocrates is alive today , I am sure he will argue for medical  knowledge and ignorance should be equally shared with their  patients.

Counter thoughts

Don’t give the choice to your patient  . . . that would mean you lack  clarity, wisdom and confidence !

No, I don’t agree , I know there are  some  patients who are  well informed , rational , more focused than even a professional  !

 

 

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Junctional tachycardia(JT) is often a misunderstood arrhythmia. Technically,  any tachycardia arising from the AV junction could be termed as JT.Even AVNRT was considered as a form of Junctional tachycardia till recently.The crux of the issue is , true anatomical extent and borders of  so called AV junction is  yet to be clearly demarcated .The common perception that  AV node is a discrete  structure is  an anatomical illusion  , rather its collection of  condensed fibers with proximal  nodal approach and distal fanning .

Now , we have a  proper definition by the apex scientific bodies  ACC/AHA/HRS 2015)

definition of junctional tachycardia

Source :2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: Executive summary A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society April 2016Volume 13, Issue 4, Pages e92–e135

Please note :The key point is , JT by definition  should  be a focal  /automatic tachycardia either due to triggered activity or after depolarisation and the boundaries of  junctional tissue is liberally extended up to  His bundle.

Read  related post  :What does the term junctional tachycardia mean in current era?

Reference

http://www.heartrhythmjournal.com/article/S1547-5271%2815%2901188-1/pdf

 

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Inferior STEMI is as  common as Anterior  STEMI .Unlike the anterior  STMI  which  auto localises  to LAD , inferior STEMI has to be fixed either RCA or LCX.

Following ECG features help localize Inferior STEMI  .

  • ST elevation in lead 3 > lead 2  suggest RCA (Not always true )
  • ST depression in lead V1,V2,V3 strongly suggest LCX. (More objectively the sum of  ST depression in V1, 2 , 3 divided by sum ST elevation in 2,3, AVF ,  if less than 1 indicate LCX.   Or simply ST depression  V3 > Lead 3 indicate LCX.)
  • ST depression in lead 1 indicate RCA
  • ST elevation in lead V6 strongly suggest LCX

Finally , and most importantly RV infarction as documented  by  ST elevation in V4R almost always localises the lesion in proximal RCA.

Role of Echo

If ECG  features  are not clear , a rapid bed side echo has a very good  localizing value. To fix RCA  look specifically for wall motion defect between “6 to  8”  O-clock position .It corresponds to  infero basal septum  that is invariably  supplied by RCA. For LCX involvement concentrate  on “3 to 6” o clock position.

stemi localisation by echo inferior rca lcx

Image source and courtesy http://www.aseuniversity.org

Which has better  outcome RCA or LCX STEMI ?

  • Though RV infarction  does not occur with  LCX , incidence  of MR is more with LCX and  can be truly troublesome. This probably negates the potential advantage of  “protected RV”  in  LCX  STEMI.
  • Since LV lateral free wall involvement  is extremely rare with RCA STEMI , it  has a lesser  impact on LV function while LCX STEMI can  give a double blow to LV   (MR and LV dysfunction)
  • On the down side ,coronary artery spasm and thrombus load are more with RCA .

Interventions in RCA is fairly straightforward ,while acute LCX PCI  has some  issues . Apart from technicalities of  intubating  the posteriorly  curving LCX ,realistically it involves fishing in troubled waters , as we need to cross the left main , likely physical contacts with LAD ostium , which is the sole supply chain for the injured and ischemic LV myocardium . Meanwhile ,  If RCA  is the culprit  , its a well cordoned crime scene where one can spend time liberally and fix the lesion.

Final message 

It is easier to localisethe culprit artery in inferior STEMI ,but its a tricky  to  predict outcome .Both can be troublesome .It depends on  dominance of the RCA/LCX ,proximal nature of lesion, the number and caliber of OMs, and PLVs and RV branch .However, it remains a fact  LCX STEMI has a  overall turbulent course.

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Mitral regurgitation is expected to occur only in systole during  left ventricular contraction. In rare pathological states , if   LV pressure exceeds the mean LA pressure at any point in diastole , small  puffs of regurgitation into LA can occur.The genesis of this MR and its  hemodynamic  significance has generated much interest .

Causes

  1. Aortic regurgitation -Severe . (Occurs mainly in acute AR or chronic AR with decompensated LV )
  2. AV blocks (especially complete AV block )
  3. Any cardiomyopathy with severely elevated LV diastolic pressures

Mechanism

No single mechanism is  responsible.

  • Common hemodynamic denominator  is transient cross over of LV pressure over and above LA pressure curve .
  • This tends to happen often soon after the atria contracts  specifically so , if the atrial contraction is not followed by a QRS complex as in heart block .
  • The fact that its reported even in the presence of atrial fibrillation (As in some cardiomyopathy ) atrial mechanism is not exclusive.
  • In Aortic regurgitation the mechanism is  different (More of  volume dependent ,  Read below )

diastolic mitral regurgitation animationTiming of  diastolic MR

It occurs in later part of diastole as it takes a time lapse for raising LV diastolic pressure  to cross the LAP and generate a reversed ventricular gradient.

Will there be a clinical evidence for this MR ?

Its silent in most cases .Some patients with complete heart block may  generate  mid diastolic murmur . (Rytand AHJ 1946) .Retrospectively this could be due to diastolic MR

Is there a link between Austin flint murmur and diastolic MR ?

Many researchers believe the generation of diastolic murmur in severe AR is attributable to premature closure of mitral valve and the poorly compliant LV  is not able to accommodate the leaking blood and it tends to regurgitate into  LA  through partially closed mitral valve in diastole (Ochaya  S,  Am Heart J. 74 1967:161-169)

Echo features

  • Doppler flow signal in mitral inflow is diagnostic
  • Color M-mode is ideal to map  diastolic MR.

Cath correlation

Wong has demonstrated this phenomenon by direct hemodynamic  recording in 4 patients

Further research

While the field of diastology is growing , still we are not clear how significant this MR in clinical diastolic dysfunction and acute LV failure that results in flash  edema.

Reference

5.Diastolic atrioventricular valve closure and regurgitation following atrial contraction: their relation to timing of atrial contraction.Okamoto M1, Tsubokura T, Kajiyama GClin Cardiol. 1989 Mar;12(3):149-53.
7. An auricular diastolic murmur with heart block in elderly patients.Rytand  DA; Am Heart J. 32 1946:578-598.
8. Late diastolic mitral regurgitation secondary to aortic regurgitation its relationship to the Austin-Flint murmur.ochaya  S, Igarashi  M, Schaffer  AB; Am Heart J. 74 1967:161-169

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Atrial fibrillation is the most  common arrhythmia we encounter in clinical cardiology .Ironically it is  uncommon during ACS and extremely rare in association with UA/NSTEMI. Surprisingly , an entity ” Ischemic AF” is not to be found in cardiology literature.

The incidence of AF in STEMI is less than 5%. Occurs more often due to factors other than primary ischemia of atrial musculature. Of-course , AF in association with Infero posterio MI and RVMI is an important trigger for AF.LCX disease is more often associated with AF as it gives up a consistent branch to left atrium.

Though it is tempting to implicate ischemia as a trigger for AF ,most often it occurs , in elderly ,associated COPD ,hypoxia preexisting atrial disease .Acute elevation of LVEDP and stretch of left atrium could be a more logical mechanism.

Hemodynamic impact

  • AF can bring down the blood pressure.
  • Worsen ischemia by increasing the MVO2
  • Could be very destabilising in RV infarction
  • Surprisingly it is well tolerated in many STEMI patients.

AF in STEMI- Is it an emergency  ?

It would appear so. But , if hemodyanmicaly stable one need not panic.Many times they are transient .Correcting  hypoxia, optimizing beta blocker would help.

Role of DC Shock  , Precautions before shocking  & Post shock events

  • DC shock is done only if there is hemodynamic instability  or ongoing ischemia .(Very difficult to rule out the later )
  • Mural LV clots can form even within 24 hours and DC shock embolic strokes may ensue .
  • Hence it is mandatory to do an echocardiogram prior to shocking.

Drug of choice

  • Betablocker
  • Class 1c -Flecanide.
  • Class 3 -Amiodarone./Ibutilide/

Role of Digoxin

There used to be a concern about usage of Digoxin in the setting of ACS as it pro-arrhythmic , but it remains useful in the management of AF .There is no other  anti-arrhymic drug available to control, the heart rate without depression of  the LV  function

Rate control vs rhythm control

Always aim for rhythm control in the setting  of ACS.Rate control is may not be a  logical concept in acute settings though Amiodarone does both.

Wide QRS Atrial fibrillation

As we know , AF in STEMI can conduct with aberrancy , and we have a traditional teaching all wide qrs tachycardia are VT in the setting of MI making our patients statistically vulnerable.

After all , both entities lack discernible p waves. At high rates it may be difficult  to identify irregularity  RR interval. However , one would shock such patients  and both AF and VT would respond .All is well that ends well.

Summary

AF during STEMI is a risky arrhythmia and needs urgent intervention , but one need  not be alarmed .There is a set of protocol . Only hemodynamically unstable AF require DC shock .Many times it is just transient.There has been instances of  physician panicky that has resulted in more adverse events .

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In this era of synthesized evidence base,  one of my  intellectually aberrant  student asked  How can we indulge in  a popular coronary procedure   with  class 1 indication backed by level C evidence  ?   (As defined by  the seemingly invincible  guideline committee  of various  International cardiology organizations .)

medical ethics silence guidelines

I told him ,

  • Institutional protocols are to be followed
  • Guidelines are to be respected
  • Recommendations are to be considered
  • Please be reminded  all of the  above can be rejected  outright !

Finally , realise  Individual  decisions based on sound scientific understanding with zero non academic intrusions  will be revered forever !

*Caution : If you  think  you haven’t  yet reached that the level of  individuality , come what may ,  you are  expected follow these  advisories  which are primarily aimed at  providing quality care and  you will be pardoned of any adversaries as well  !

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The gradient across coarctation  is not  simply (& solely ) determined by degree of obstruction , as one would believe.Understanding the hemodynamics and various factors that can influence the gradient is essential Relieving the  obstruction /gradient by stent or surgery  may not be synonymous with successful treatment as we understand now the entire aorta right from the root to abdomen can influence the gradient ,along with systemic factors.We also know , some of these patients harbor histological abnormalities in the entire stretch of  Aorta , what is  being  referred to as pan aortopathy  , that may influence the long-term outcome.

coarctation gradient collaterals002

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