Dr.S.Venkatesan MD

This Innocuous looking ECG made me scratch the basics of EP without an answer !

August 11, 2018 by dr s venkatesan

This 70 year old man in routine check up showed up this ECG.

What is it ? a  quick debate ensued !

Is this

1. RVH
2. RBBB
3. Or Both ?
4. Neither RBBB nor RVH
5. Wrong lead placement
6. Is it a normal ECG after all ?

Incidentally the ECG shows a Wenkebach AV block in the bottom strip lead 2.

I thought it was RVH. (do considered RBBB) but since lead V 2 showed tall R , I was more than sure RVH was likely . Many voted for RBBB. .Some others said RBBB can never occur in monophasic form.I said it’s possible.

Some body challenged me without Echo Imaging a  monophasic RBBB can never be differentiated from RVH. After a mini argument I reluctantly agreed.Yes, it seemed there is no way to differentiate the two.

What do you think ?

Curious to know the Echo finding in the above patient  ? Yes , your guess was right /wrong. There was no RVH.He had normal Echocardiogram.

How to diagnose RVH in RBBB ?

1. Look at the r’ wave if its taller than initial r by more than 5mm suggest RVH (Not absolute evidence though)
2. Look for other evidence like Right axis , RV strain etc.

How to diagnose RBBB in RVH ?

Sorry.I don’t know the exact answer.It could be masked within Qrs complex of RVH.RVH could convert biphasic  RBBB into monophasic RBBB.

Some more about this RVH/RBBB duo

• The term incomplete RBBB is liberally used with minor rsr’ pattern.It is not advisable to do so.
• RBBB is classically multiphasic (To be precise RBBB can be complete to incomplete  rsr’ with various combinations of small r and big s big R or big S).
• But more than the morphology of Qrs in V1 the S wave in lead V 6 or Lead 1 could be Important.It should be delayed slurred.
• QRS width has no great use to diagnose RBBB as it can be narrow or wide.

Final message 

To diagnose monophasic RBBB( in V1 ) by itself requires some guts.However ,the entity do exist.

Finally , please recall there is a traditional list for  tall R in V1 other than RVH.

• Wrong lead placement
• RBBB
• Some cardiomyopathy(RV myopathy)
• Systemic Duchenne’s muscular dystrophy
• Pre-excitation
• Posterior MI
• Normal variant*

*Why should normal guys grow a tall R in V1 , it mystifies ! but true.

What is the rarest cause of tall R in V1 ?

Localised cardaic tumors over RVOT. Cagli K , Tok D, Basar FN   .An unusual cause of tall R wave in lead V1: cardiac lipoma.Heart Asia. 2013 Mar 7;5(1):33. 

 

Annexure : Further questions in RBBB

 

1.How does AV bundle penetrate to become bundle of HIS and branches ?

Note AV node is fully Intra atrial structure , while part of His bundle is atrial , after crossing the membranous septum second part lies within the ventricle at the crest of muscular septum .Then the bundle of His goes for the famous division. Left fans out  tow streams, while right descends on right side of IVS. Note : Applied anatomy 1.Its this small portion of HIS we are trying to physiologically pace the ventricle 2.In proximal LAD lesions both RBBB and LBBB is common still LBBB can’t be used to localise but RBBB can be.Guess why ? Read the next question and find the answer..

 

2.What is the blood supply of bundle branches ?

Image source Clinical Cardiovascular Physiology April, 1976 by Herbert J. Levine

 

3.What is the mechanism of RBBB in ASD ?

Is it true RBBB or Right bundle delay ? Students should know there need not be conduction system pathology to cause RBBB. Simple delayed conduction in RVOT can cause a RBBB. (The concept of central RBBB vs Peripheral RBBB) This is what happens in ASD.

In fact , true pathological damage due to right bundle branch due to necrosis, Ischemia, Infiltration is much rarer than pathological LBBB.

4. What are the  structural , histological  difference between right and left bundle branches that has electrophysiological Importance ?

Wait . . . I am trying to collect info for this .Meanwhile ,Why don’t one of the energetic young  fellows in cardiology find the answer and post here !

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Posted in cardiology -ECG, RBBB vs RVH | Tagged how to diagnose RBBB in RVH and vice versa, rbbb in rvh, rvh in rbbb, tall r in v1 differential diagnosis |

Friendly Infarcts in ACS : Ischemic mitral regurgitation and the Papillary muscle paradox !

July 18, 2018 by dr s venkatesan

Ischemic MR is a critical entity in determining the long-term survival in post MI patients as well as dilated cardiomyopathy. (Originally described  by J. H. Philips Ann Intern Med. 1963;59(4):508-520)

The mechanism of MR  can really be complex .We know mitral apparatus consists of  six components.The sub valvular apparatus plays a key role. LV  free wall especially the inferior and lateral segments which subtends the two papillary muscle has a critical role in maintaining the mitral valve competency .

There seems to me a complex mechano -anatomical behavior of subvalvular structures in progressive LV dysfunction especially so in ischemic cardiomyopathy. The LV size, shape eccentricity in attachment of leaflets to papillary muscle is (Simply called altered geometry ) .The intraventricular desynchrony ,disproportionate  LV dysfunction also make MR more likely .

Beware of a striking  physiological irony in ischemic MR.

While infero basal free wall dysfunction occurs commonly with  LCX/RCA Infarct and  is commonly associated with Ischemic of MR .There is something unique happens . . . when the infarct is larger and involves the head of the papillary muscle .Yes, it attenuates the severity of MR.(Friendly Infarct extension!) The mechanism is , papillary muscle dysfunction  tends to prevent apical tensor effect leading to   improved tethering of leaflets .This may appear a blessing in terms of  prevention of acute pulmonary edema. This also explains why some patients are as cool as cucumbers and lie flat comfortably with silent lungs in spite of severe LV dysfunction .The LV is too weak it doesn’t  have contractile energy to generate acute  severe MR.

Here is an illustration  from circulation .Note: The Infarct extends to pap muscle head, the MR is arrested.

Image courtesy : Emmanuel Messas J. Luis Guerrero, Mark D. Handschumacher, et all  Paradoxic Decrease in Ischemic Mitral Regurgitation With Papillary Muscle Dysfunction Insights From Three-Dimensional and Contrast Echocardiography With Strain Rate Measurement Circulation. 2001; 104: 1952-1957

Further debates 

Papillary muscle dysfunction may be protective against progressive MR.Still ,sudden papillary muscle rupture result in flash pulmonary edema and death is imminent . How ? Complete rupture  causes flail free-floating leaflet that prolapse into LA and result in free MR.While simple dysfunction without flail leaflet is less likely to cause MR . The key determinant seems to be the net force that keeps the alignment of mitral,leaflet at annular level.

In this context , we also realise the impact of primary PCI on the  regression of  Ischemic MR is not uniformly positive.Reasons not clear.

Final message

Ischemic MR  due to LV free wall infarct is a near knockout punch , that may determine the ultimate ACS  outcome. However , a simultaneous lesser punch ( by a friendly devil ! ) on the adjacent head of papillary muscle neutralises the effect of Initial Injury. While such non academic scripts are enjoyable , we are still a long way away to understand this anatomical ,hemodynamic conundrum.

Reference

1.

2.Leaflet remodelling in functional mitral valve regurgitation: characteristics, determinants, and relation to regurgitation severity Philippe Debonnaire , Ibtihal Al Amri , Darryl P./ehjci/jeu216 290-299 First published online: 3 November 2014

3.Fang Zhu, Yutaka Otsuji, Goichi Yotsumoto Mechanism of Persistent Ischemic Mitral Regurgitation After AnnuloplastyImportance of Augmented Posterior Mitral Leaflet Tethering , Circulation. 2005; 112: I-396-I-401

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Posted in Dilated cardiomyopathy, Mitral regurgitation | Tagged mechanism of ischemic mitral regurgitation, papillary muscle dysfunction | Leave a Comment »

What is the blood supply for the coronary artery ?

July 10, 2018 by dr s venkatesan

One may recall some stunningly simple facts from our high school biology classes that every living cell needs energy on a moment to moment basis.

Blood vessels which take care of the vital organ’s energy supply also need the same blood (Nutrients /Oxygen) for its own survival.

Coronary arteries carry about 250 ml of blood every minute , 24/7 supplying ATP enriched fuel to the heart.

Who is feeding these delicate vessels which carry on this life-sustaining work ?

It is easier to assume the three layers of the blood vessels which are bathed with blood would never suffer from Ischemia. Reality is different .Blood vessels do suffer from Ischemia.We do have evidence medial necrosis, plaque instablity , fibrous cap disruptions may be due to a vascular insult or vessel wall energy deficit.

The much debated entities like endothelial erosion and dysfunction are often atributed to mechanical stress , sympathetic spike , or smoke . This may be a virtual guess as no one knows what causes these. It could well be a patchy Ischemia due to endothelial perfusion defect from within or a vasavasoral dysfunction from outside. Coronary ulcers some times mimic gastric ones and guess the cause ! yes it is mucosal ischemia !) *Ischemic ulcers in GI tracts can be common (Schweiz Rundsch Med Prax. 1993 Jun 15;82(24):709-13)

Image source http://www.wikidoc.com

How does coronary artery gets it blood supply ?

Busy cardiologists have no time to worry about nourishment of the coronary arteries . . . even as they play inside with unlimited arms and ammunition.We leave it to our basic scientists.

So , how does coronary artery gets its blood supply ?

The easiest answer is, blood supply to coronary artery is taken care by a vast network of micro vessels called vasa vasorum(VV) . Of course, the inner layers of Intima and media do get some nourishment by the flowing blood as mentioned earlier.No one really knows the quantum of blood flow that perfuse within the planes of coronary artery.

*By the way , does the vasa -vasorum comes from extra-coronary source or from the same parent vessel ? (I think the answer is both ! will try to find out!)

It should be noted Vasa vasorum is well developed only in large arteries. VV has one more important function ie to drain the metabolic excreta from the walls of blood vessels. This function could never be taken lightly as failure to do so will result in vascular wall edema in acute setting or thickening In chronic setting.

Does coronary arterial tree goes for necrosis in STEMI ?

There is some evidence , when acute total occlusion happens in an epicardial vessel , not only the myocardium is ischemic , the entire distal coronary vascular tree becomes vulnerable. The ischemic time and resistance of coronary macro vs micro vasculature is currently not known. It is expected to show significant variation . We know ,one of the important mechanism of no re-flow following PCI is due to microvascular damage(Non thrombotic)

Many times we fail to realise myocardial viablity and micro-vasculature integirty are two different things. ! This questions the concept of reperfusion based on the status of viable myocardium alone.This we have experienced in many patients as myocardial viability doesn’t guarantee you full recovery from LV dysfunction as microvasculature may recovery may lag behind or never restored (Permanent vasa-vasoral damage ?)

What is our knowledge base about exclusive pathology of coronary vasa vasorum ?

Do you know, ectasia, arteritis, aneurysms and external band like compression of coronary artery all are related to some sort of vasa vasoral dysfunction ? We are not yet clear whether atherosclerosis really involves the vasa vasorum.(Takayasu does it for sure ! )

What is the relationship between vasa vasorum and coronary collaterals ?

It seems to me , many of bridging collaterals are nothing but extension of vasa vasorum and ultimately arise from epicardial coronary collaterals. (Some youngster’s take up this topics for research)

Why is high pressure post dilatation a double-edged sword ?

It’s often thought , larger the lumen its better. Need not be. These are all some questions which we don’t have an answer.

What is the radial pressure exerted by coronary stents on coronary trans -arterial perfusion ?

Does coronary artery go for Ischemic necrosis with high pressure Inflations ? As such there is no published evidence . By the time we wait for published evidence enough number of coronary arteries might get damaged. So try to use common sense .

Relationship between delayed Mal-apposition & vasa vasoral damage

It is very likely ,the so-called endo-leak which is quiet prevalent in aortic interventions is could be seen in coronary arteries. We are not recognising it. It could be same as Intramural hematoma in certain subsets.

Meanwhile, self expanding stents with good radial strength has made a come back .While it may prevent a mal-apposition ,has a potential to stress the vessel wall (Radially) and in the process interfering with perfusion.

 

Does Vasa vasorum promotes Atherosclerosis or negates it ?

hehttps://www.hindawi.com/journals/bmri/2014/701571

 

The irony is, while de-novo vasa vasorum is the life line for coronary arterial nutrition, neo-vascularisation is problematic .Then how to selectively promote good vasa vasoral growth and avoid the pathological network that promotes adventitial nodular degeneration ? This is were the curious basic scientists and casual cath lab guys need to interact.What is positive remodelling ? (Often referred to the famous concept of Glagov ) How can we promote it to maintain good luminal diameter inspite of large burden of atherosclerosis by manipulating the vasavasorum.

 

Final message

Cardiologists are ahead of others in many cutting edge technology. There is no two opinions about it. Who can repair a live beating heart without stoping it for a moment ? Still, there is a whole lot of coronary Ignorance waiting to be explored. Blood supply to coronary artery is one such area to be decoded.This will have larger implications as Vascular healing , plaque survival and growth depends upon vasa vasoral integrity as well as neo vascularisation.

While , metallic management of CAD seems to be the order of the day as it tends to give an instant fix .My guess would be medical sense would ultimately prevail one day with controlled vascular aging and natural ,pharmacological ,biological repair of cells will prevail over temporary patch work in cath labs.

Reference

What is the role of newer Imaging and OCT in visualising Vasa vasorum ?

It is going to open up new avenues in our coronary vision.

Vasavasorum review article

(Kensuke Nishimiya European Cardiology Review 2017;12(2):121–3)

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Side branch sacrifice : Smart cardiologists shall do it scientifically !

June 2, 2018 by dr s venkatesan

This seems to be good side branch sir, … a resident was mumbling as he was reviewing the RAO caudal test shot .Forget that diagonal man , focus your mind on main vessel , If you keep pitying these small twigs , you can never become a glorified Interventionist .I heard one of the senior consultant  was telling (rather yelling) at his assistant !

I used to wonder ,why should the fate of side branches be decided by the mercy of semi cardiac Intellectuals ?

What determines the hemodynamics after side branch jailing ?

• Size
• Territory
• Myocardial viability
• Alternate source
• Collaterals

How do you classify side branch jailing ?

Okamura et all (Ref 3)offered a new OCT based classification based on the shape of the jail grills.

JACC Cardiovascualr Interventions 2010 : Okamura  types V, T , and H jails. Implications are many both during short term as you cross , recross /rewire etc.Long term implications are largely unknown.

Does Jailing Implies flow is Interrupted  ?

This is the most critical question, We got the answer from University of Southampton in 2007 a rare and vital contribution to the knowledge base of coronary physiology. It said the struts won’t block the flow, it simply bumps on the path of blood.

You know , if the side branch ostial diameter is 2.5 mm the luminal area will be around 6sqmm. At least 1 or two struts is likely  occupy and criss cross the ostium. The issue is more than  simple compromise of side branch flow .The major concern is  the ostial jail should not be a nidus for future thrombosis that can spill over to main branch.Unfortunately there is no single meaningful study that addresses this issue of long-term patency of main vessel  in which  small side branches were jailed.(We in our department  have just started to analyse this aspect of coronary Intelligence )

Markers of significant side branch compromise.

For most of us it is not a big deal .I think there is none .There are little discussion  on new onset angina or troponin elevation after side branch jailing.

Can we Jail LCX ostium (or even LAD ostium ) during Left main PCI ?

• Jailing a side branch can be casual or even a fashionable act , but can you do the same for left main bifurcation ?
• It’s all about what you mean by side branch ? and the reaction time , and the useful muscle mass the branch would supply etc.
• In emergency situations , there has been occasions one even put a stent across left main to LCX.Tackle the jailed LAD later if required.

FFR analysis of side branch jailing

Image courtesy from Bellenger 2007 Heart

Doing a FFR to assess the significance of side branch is simply a obsessive academic exercise .It is not warranted in most clinical situations. This study has taught us most side branches retain good FFR give us more confidence to sacrifice the sibling branches of main stem arteries.

Final message

Practicing cardiology in a truly professional way in cath lab can be tricky.We need to disrespect most of the side branches .Believe in your gut feeling (or your consultant’s.) If you are a sensitive scientific cardiologist do FFR pre / post procedure to the side branch .If compromised physiologically try probing the jailed struts and dilate one of them in absolute blindness , of course with a strong conviction of doing good for the science’s  sake.

A Research concept  

Long term sequelae of side branch jailing on the main branch ostia  (Please acknowledge  if some one take up this study )

References

1.

2. Bon-KwonKooMD, Hyun-JaiKang,Tae-JinYoun Physiologic Assessment of Jailed Side Branch Lesions Using Fractional Flow Reserve Journal of the American College of Cardiology Volume 46, Issue 4, 16 August 2005, Pages 633-637

3. Okamura T¹, Onuma Y, García-García HM, Regar E3-Dimensional optical coherence tomography assessment of jailed side branches by bioresorbable vascular scaffolds: a proposal for classification. JACC Cardiovasc Interv. 2010 Aug;3(8):836-44

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Posted in Cardiology-Coronary artery disese, cath lab tips and tricks, side branch jailing | Tagged ffr in side branch jailing, side branch jailing, what is the significance of side branch compromise, what is the significant side branch |

As CABANA waves a final good bye to catheters in AF . . . let the pulmonary veins rejoice !

May 31, 2018 by dr s venkatesan

There is a tough ongoing rivalry between drugs and catheters to conquer the commonest electrical chaos in human heart, namely Atrial fibrillation (AF). Mind you,the confusion about the importance of this arrhythmia is huge and real.Bulk of these episodes are transient , paroxysmal and do not require rigorous management.While stroke prevention seems to be the major aim and target , the real world scenario seems to tell a different story.

The nomenclature conundrum

AF may be classified as many ways a learned cardiologists can think . Often it’s done with reference to etiology, duration , rate, neural (sympathetic or parasympathetic) humoral , cardiac or non cardiac , reversible or irreversible ( Endocrine, Electrolytic, hypoxia etc).

Unlike VT , bifurcating AF with reference to the presence or absence of structural heart disease is rarely meaningful.Subclinical atrial interstitial fibrosis in elderly is so common especially so in hypertensive individuals making all lone atrial fibrillation as true structural disease.

Classifying AF with reference to atrial enlargement again is problematic as any sustained AF can dilate these thin atrial chambers in few weeks time making it a sequel to AF rather than a cause to it.

Adding further fuel to the confusion is the recent man-made (read cardiac scientists!) problem .Linking the etiology of AF with the presence or absence of valves pathology is definitely not helping us. In the process , we forget a casual fact that valvular AF needs aggressive valvular Intervention and not arrhythmia Intervention !*A patient with dilated cardiomyopathy with mitral regurgitation and LA enlargement with AF is considered non valvular AF in spite of clear pathology in mitral valve apparatus.(Is there myocardial AF by the way ?)

What is the current role for catheter ablation in AF ?

The question of advanced catheter based management boils down to a minority of refractory, fast , troublesome AF which has failed by most available drugs. More Importantly the long-term success of ablation is lowly 20% ( PV reconnection, geographical miss, atrial focus etc) and follow-up medication is absolute must even after successful ablation. Its well-known , severe the underlying heart disease more likely is the recurrence .Ironically these are same ones that attract the catheters.

The previous debate of rate control vs rhythm control gave sufficient lessons that complex modalities to restore sinus rhythm is unwarranted . As scientific cardiologists we continue to be adamant and don’t learn from our mistakes and blindly adore and adopt technological excessess.

Now, thanks to CABANA* the ablation for AF has proven to be a fruitless process considering the time ,effort and potential (& real )complications.

*The Catheter Ablation Versus Anti-arrhythmic Drug Therapy for Atrial Fibrillation . Just presented in HRS annual meet at Boston MAy 2018.

Image source : http://www.auntminnie.com

The bright spot is even in these commercial medical world the study like CABANA is a silver lining. Mind you it’s partly sponsored by Industry , still went against them. Three cheers to the genuine medical research team of CABANA for bringing out a truth. Now, I am optimistic more such trials in cardiology will be proposed

A companion to CABANA from UK

A 2018 landmark paper from published in BMJ reveals a dramatic truth that the risk of stroke continues to persist even after resolved Atrial fibrillation, largely concurring with CABANA.(Nicola J Adderley, Risk of stroke and transient ischaemic attack in patients with a diagnosis of resolved atrial fibrillation: retrospective cohort studies BMJ 2018;361:k1717)

So, how to get out of these AF conundrum ?

Practically , an extreme simplification of AF classification is warranted . It should answer these couple of questions !

1. Will the AF in a given patient require long-term oral anticoagulants or not ? (or ok with antiplatelet drug !)

2. Should I make any meaningful attempt to convert the AF to sinus rhythm at all* ?

* You can also redefine the second question , does this AF deserve a EP consult or not ?

Final message

AF is largely a benign arrhythmia in global perspective . However, In those patients were its troublesome , safe and effective drugs are available to tackle it.We shouldn’t Insist to make it complicated.
Meanwhile . . .the anxious pulmonary veins seems to enjoy the moment as they escape from the fire .No wonder they will thank and celebrate the CABANA.

Reference

http://www.acc.org/latest-in-cardiology/clinical-trials/2018/05/10/15/57/cabana

Post-amble and counter point

The RF ablation is a high risk procedure , as we develop less injurious cryo balloons the results of Invasive ablation procedures may score over drugs.Let us wait and don’t prematurely ditch the catheters.

https://1drv.ms/v/s!Ahm_xjThT-nXgY5EtHnqjxFkb_PWtQ

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Posted in Uncategorized | Tagged ACC AHA ESC guidelines for AF, affirm race cabana, amiodarone for atrial fibrillation, atrial fibrillation, CABANA trial, carto pulmonary vein ablations, cryo balloon for af ablation, heart rhythm society atrial fibrillation guidelines, pulmonary vein ablation, rate vs rhythm control |

Madras medical college and Yale medical school : The 17th century siblings !

April 22, 2018 by dr s venkatesan

Indian subcontinent has a grand old history with a great civilization that began even before the ancient Greek and possibly Egyptian pharaohs .Post renaissance Europe made the British monarchy enter the country in early 1600s .This could be perceived as a new journey of modern India.In the early days of British colonization through East India company , the province in southern Indian Coramandal coast called Madras (Currently named Chennai) was a key economic and power center. Since the hospitals were the prime requirement to take care the Incoming officers ,Govt general hospital is the first major health care center to appear in India more than 300 years ago (In which the author of this blog is currently associated for over two decades) !

Though we currently call it as GGH , the original name was MGH* Madras General Hospital .

Originally built for the sick soldiers of east India company which functioned in the present St George fort premises.Then president of Madras fort Elihu Yale allotted the adjoining land and was instrumental in building the Govt general hospital in the year 1664 .The academic limb of the hospital the Madras medical college came more than a century later in 1835 .

Few decades later in 1718 a Governor of New heaven Connecticut , Cotton Mather from far way North America wanted to start a small hospital who was short of money.He requested through his American contacts of British east India company for a donation from a successful British businessman Yale from Wales who making a fortune in the Indian county of Madras . Since, Yale had an American connection by birth in Boston, was willing to donate the money through Indian gifts worth of 560 pounds which was good enough to build the legendary hospital in New Haven which was named later after his name.

*It should mentioned the first seed of this hospital was planted by another British Sir Edward winter (1622-1686) , the Madras agent for the East India Company .

Yale university / hospital , New Heavan Connecticut

An article which appeared in Yale journal recently recalled the link between these two institutes.

Yale, of course carried a tag of being a controversial leader of British empire for misusing his power, still has his name permanently etched in the history of two great medical institution located far across the globe.

His life ended in 1721 , was laid to rest inside the quiet compound of church of Wales .The dark black concrete letters telling to the occasional visitors about the extraordinary life he lived over 300 years ago.

Elihu Yales 1641 -1721.Born in Boston , Lived in Madras died in London. This memorial is found just outside St.Giles Church Wrexham , Wales .UK

St.Giles Church Wrexham , Wales .UK

Click here : How to reach Wrexham ?

Another MGH . . .

The MGH as we know today is Massachusetts General hospital which was stated 150 years later than MGH senior in 1811 in Boston. It some times pains me to compare the growth of two . In terms of science , technology and research they are poles apart But in terms of equitable service , care , and social impact I think the senior MGH would still prevail over. !

Postamble

It is fascinating to know origins of college that taught us medicine.I wonder how many of the current students and the alumni know the grand old history of their Alma mater.I wish they pay a visit to St Giles church Wrexham , Wales once in life time. As we stand in-front of the Yale’s memorial one will definitely get that unique feel of travelling to the vintage past when Chennai GH was born with a baby cry !

Reference

1.http://en.wikipedia.org/wiki/Elihu_Yale

2.http://en.wikipedia.org/wiki/Yale_University

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Posted in history of cardiology, Histroy of medicine | Tagged elihu yale madras medical college, history of madras medical college, madras medical college and yale university | Leave a Comment »

New generation X-ray chest : Adding an “echo vision” to a blind PA view !

March 25, 2018 by dr s venkatesan

Reading X -ray chest can be as blind as a bat flying in the dark . It needs lots of Imagination . (Many times the blindness continues to cath lab as well during structural interventions is a different story !)

Yes ,its true any one can recognise a cardiomegaly in X-ray . . . but Which chamber is responsible for cardiomegaly ? and quantifying each ones contribution to the increased CTR is the critical question.

We know the 4 chambers in the heart are arranged in a complex pre-specified (Antero -superior and right to left orientation ) still , the CT ratio in X-RAY chest is based on the diameter formed by two chambers only ie right atrium and left ventricle.

However, any of the 4 chamber enlargement can increase CT ratio in pathological conditions.

• LV enlargement is the most common cause for cardiomegaly as it is the normally border forming.(DCM, Aortic valve, HT diseases)
• RV can do it when it enlarger grossly forming the left heart border(COPD, Severe pulmonary hypertension of any cause)
• RA can enlarge to both pressure and volume overload.(CHF, with RVF)
• LA is least likely to be border forming as it is midline structure .Since It tends to enlarge posteriorly and superiorly it rarely enlarges sideways. Occasionally In severe mitral stenosis it can enlarge to the right and cross the right heart border causing the classical shadow in shadow.

Since I have struggled with X ray orientation of heart chambers in my early days (Still i do sometimes!) Just thought , why we are not fusing a X-ray with a given patients echocardiogram that will help understand the chamber anatomy .

Fusion Image of X ray chest PA view with apical 4 chamber in ECHO. (Rotated to specified angle to match heart border)

Note : The Left atrium is not only left of RA , its also posterior and superior to RA.This makes the IAS not actually pure right left to relationship but also a slight infero to superior and antero posterior orientation.(This can be realised when we puncture the IAS from RA side the needle goes more of superior)

X ray chest left lateral view is fused with para- sternal long axis view. Please note this is not true anatomical correlates. The RV shown in echo is actually RVOT but in X-ray its more of RV body .

* A note of caution : The fused Images are rough attempt to co-register x-ray with echo. There is sophisticated software in some new generation cath labs to mix fluro images with live TEE data that aid in Interventions.

Postamble
A bedside Instant point of care echo is becoming a norm in clinical cardiology practice. Why bother about X-ray then ? Agreed to that point to a certain extent. But, I used to tell my (amused ) students that technology based lazy learning doesn’t help build a strong scientific foundation which would ultimately threaten the patient care one day !

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Posted in cardiac X ray, Cardiology - Animations, Cardiology - Clinical | Tagged basics of chest x ray, ct ratio how to measure, ct ratio in ra lv rv la enlargment, xray chest pa view, xray chest pa vs ap view, xray echo fusion Images | Leave a Comment »

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