Posted in cardiac surgery, Cardiology - Clinical, cardiology-Anatomy, Uncategorized, tagged coroanry anatomy, left main, trifurcation and quadrification on January 30, 2011| Leave a Comment »
Left main divides into two. Some times into three . Very rarely into 4
Look at this angiogram , This looks like a quadrification, if not quadrification equivalent
Clinical implication
A 4 way division invariably means the OM and diagonal or going to be diminutive.These people are expected to have favorable coronary hemodynamics during ACS , and left main lesions are less likely to occur
Reference
This article is from Singapore medical Journal
Posted in bio ethics, Cardiology -Interventional -PCI, cardiology -Therapeutics, tagged pci, poba, ptca, stents on January 28, 2011| Leave a Comment »
Life cycle of PTCA : Let us hope it do not become extinct !
Does PTCA , a great Innovation for mankind, is facing a threat of extinction ?
It seems so . . . the stents are losing its shine in most situations. A simple evidence . . . for that . . . can be found in answering the following question
What drives the extensive research in biodegradable stents now ?
The simple answer is , we are fed up with the metals inside the coronary artery. We want to get rid of it !
Too much of knowledge , often blunts our senses . Our track record clearly reveals this fact. We needed a major study INTERHEART to tell the world that ,exercise is good and tobacco is bad for heart ! Now ,we forgot a simplest solution for getting rid of metal inside the coronary artery , which is “not to implant the stent” at all ! (Instead we do billion dollar research for making bio – absorbable stents , which in the first place may not be required in the majority !
Read the related article . Does POBA has a role now ? in my site
The only situation , where PCI may withstand the test of time could be in ACS (Both in STEMI and high risk NSTEMI !) PCI is cosmetic in most of the chronic coronary syndromes .
Final message
Our fight against human atherosclerosis will have to be , by medical means .PCI at best will provide a supportive role in selected patient group. It requires lots of common sense and scientific ignorance to achieve this. Risk reduction , prevention , optimal medical therapy will have to play a dominant role in the next few decades . This is something similar to the environmental issues we face in protecting our planet .No amount of green industry will protect the earth . It requires better social and behavioral ethics from mankind and their rulers !
Posted in Cardiology - Clinical, Cardiology -Interventional -PCI, cardiology-Anatomy, Uncategorized, tagged left main coronary artery, ramus intermedius, true trifurcation on January 28, 2011| Leave a Comment »
God creates life with infinite variation . The heart gets bulk of its blood supply from the left coronary artery , which divides into two after a short course. Bifurcation is the rule . Left main becomes left circumflex and LAD in about in 85-90 %.
Note the left main divides into 3 equal caliber vessels.very lucky to have such a branching pattern !Distal left main is unloaded by three large ostia . This makes stasis of blood in left main very unlikely . LAO caudal view
Note : The OMs are small in these people. RAO caudal view
Few men and women are blessed with three branches from LCA . The anatomical and physiological importance of this branching pattern is not well analysed in the literature .There could be few advantages of having a trifurcation instead of bifurcation .
Disadvantage of trifurcation !
* A related blog elsewhere in my site . The explanations offered above are based on personal observation .
Posted in echocardiography, tagged best web site for echocardiography, canadian society of echocardiography, cardiomath, echocardiography, mitral valve orifice, myocardial performance index, pisa mitral, stress tests on January 27, 2011| Leave a Comment »
Few web sites provide free cardiology service. This one from cardiomath beats all ! It makes the job easier for all those cardiologists who spend lots of time in echo lab . It provides simple online tool for all common calculations in clinical echocardiography
Here is the link to the website of cardiomath
With due Courtesy to
Author: Dr. Chi-Ming Chow Developer: Edward Brawer Illustrator: Ellen Ho
Sponsored by Canadian society of echocardiography
Posted in Cardiology - Clinical, cardiology -ECG, Cardiology -Interventional -PCI, cardiology -Therapeutics, Cardiology -unresolved questions, cardiology-ethics, tagged failed thrombolysis, successful thrombolysis on January 26, 2011| 1 Comment »
Nothing in this world is black and white. In fact, most events are in between . The irony is , our brain always wants to view things in two distinct entities !
So it is no surprise ! cardiologists also travel in the same boat !
They classified the events after thrombolysis into two dogmatic categories . Successful thrombolysis or failed thrombolysis . . . as if no other event can occur in between .
Traditionally 50% regression of ST segment is called successful . What about 30% and 40 % ST regression ?
Further , there is an important caveat in the timing, as we traditionally assess , 90 minutes of thrombolysis .
Consider the following situation :
So, without finding answers to some critical questions , we have defined the success of thrombolysis with half baked data .
This is exactly , is the reason we are unable to do a valid study on failed thrombolysis, rescue PCI etc . We know the results of rescue PCI , always been contradictory to the general logic !
It is estimated a substantial number of STEMI patients following thrombolysis fall into a category of partially successful thrombolysis implying partial restoration of blood flow and salvage. The correct definition for successful thrombolysis and reperfusion should be at the myocardial mass level , and not at the level of coronary artery.The ECG is the best available indicator.
Implication for having a poor definition of failed thrombolysis
It is not a rare sight to wheel in , a patient to a cath lab with label of failed thrombolysis dangling in his neck who is clinically stable (Has a less than required 50% ST regression , but a definite, favorable trend with a 30 % ST regression at 90 minutes )
How many cardiologists will be willing to abort a CAG/PCI , as a repeat ECG just before puncturing in the cath lab reveals successful thrombolysis ? (little delayed though !)
If only we have better methods to risk stratify patients following thrombolysis , we can avoid
Final message
Classifying thrombolyis into success or failure is a skewed way of looking at this important issue .
It is an irony , cardiologists often triage LV dysfunction , valve disease , cardiac failure etc into 4 grades ( minimal , mild , moderate or severe ) . It is still a mystery , why thrombolysis is never graded like that , and it is always considered as all or none phenomenon !
There is a substantial number of patients with partially successful ( or shall we call partially failed !) thrombolyis .This group must be given adequate attention or inattention . There is a urgent need for a through review of how we look at the post thrombolysis status . It is better to use the newer imaging modalities like PET/MRI more liberally to identify exact sub group of failed thrombolysis who will benefit form revascularisation .
Posted in Uncategorized, tagged abnormal coronary artery origin, absent leftmain, anomalous coronary artery, coronary angiogram, lad and lcx, lcx from right sinus, left anterior descending artery, left circumflex artery, left main artery, rare coronary angiograms, split left main on January 26, 2011| Leave a Comment »
Is it not , boring to see normal coronary arteries every day ! There need to be surprises in cath lab to make our time lively and keep our brain alert . Have a look at this angiogram in RAO caudal view.One of our junior cardiology fellows thought it was a split left main artery .
How can an artery split . . .of course the image indeed looks like that !
It was indeed an absent left main. Also called as separate origin of LAD and RCA.
Note : There can be three types of absent left main.
* Some books mention about a left main of 0 -5mm .
** Very difficult to delineate and is rare
Zero mm left main is nothing but single ostial origin of both LAD and LCX. A very short left main , say 1 0r 2 mm will practically mimic an absent left main.
Here is the the dynamic angio image. It is surprising how a catheter in left sinus is able to visualise the LCX from right sinus so well !
Note the separate origin of LAD and LCX.The LCX was originating near the right sinus.It is intriguing to note even though they originate in different sinuses , the main stem of LAD and LCX wants to maintain a close parallel relation.
Advantages of having absent left main .
Implications for interventional cardiologists
Guiding catheter selection and positioning could be difficult.
Posted in Best books in cardiology, Cardiology - Clinical, tagged BARI 2D, courage study, heart repair manual, MASS 2 study, medcial vs pci, pci stent, zerbini foundation mass 2 study on January 20, 2011| 1 Comment »
Manuals are not only for doctors . There are few heart maintenance manuals for patients as well.
This one from Philadelphia , is worth reading and of-course following thereafter !
Posted in Cardiology - Electrophysiology -Pacemaker, cardiology -ECG, great illustrations in cardiology, history of cardiology, Uncategorized, tagged atrial pacing through esophagus, emergency temporary pacing, medtronic transesophageal lead, oesophageal pacing, over drive pacing through esophagus, pacing electrode within ryles tube, pacing the esophagus, pacing threshold in esophageal pacing, pacing via nasopharnynx, sinus braducardia, temporary pacing through esophagus on January 20, 2011| Leave a Comment »
God has created and arranged every organ in an order with a purpose . The unique relationship of the food tube and the heart which run silently , posterior to the heart has evoked much interest for the cardiologists.
Whenever LA is enlarged it pushes the Esophagus back .We also know the vintage clinical entities of cardiac dysphagia that occurred with rheumatic mitral stenosis.
Since the lower end of esophagus just hugs the left atrium , this anatomical concept was successfully exploited for imaging heart in TEE.Now cardiac anesthetists routinely use the esophagus as an imaging port during complex mitral valve surgeries.
How esophagus can be utilized to resuscitate the heart at times of emergency ?
Note , the esophagus does a friendly hug as it crosses the heart posteriorly .It is a perfect anatomical sense , to Image and pace the heart from within the esophagus !
In a cardiac arrest situation , when we need to rapidly access to heart , we have multiple options .Each has some advantage and few draw backs.
It was in 1980 , a dramatic concept was conceived . Why not use the esophagus as an access for pacing the heart
after all , it reaches as close as possible to the heart !
How to convert a Ryles tube into a a trans – esophageal pacing lead ?
There was a certain article on this topic , which I read , when I was cardiology resident. It answers the following. Distance form mouth , Discomfort of the lead , Pacing threshold , Esophageal burns .
I am unable locate that article. Will post it once I get it.
Limitations of trans-esophageal pacing*
* Primarily useful in acute SA nodal defects, sinus arrest or any other atrial electrical failure. Infra- nodal complete heart block trans esophageal pacing may not be effective .
Other potential uses of trans-esophageal leads
Over drive pacing
Overdrive entrainment of tachycardias , including resistant ventricular tachycardia is possible.
Trans esophageal ECG recording .
This can magnify p waves during supra ventricular tachycardias and aid in decoding narrow qrs tachycardias
Safety Issues and Caution
Good earthing is necessary .Burns can occur.
Final message
Every cardiac physician is expected to possess the expertise to rapidly pace a heart by trans jugular /subclavian access at times of emergency .
Further , any modern CCU will have a defibrillator equipped with trans-cutaneous pacer as well. (The disposable pads are too costly and is a deterrent in many hospitals !).
This article explores other possible way to pace the heart in dire emergency situations.
It has one more purpose ! It rekindles the acumen , motivation and hard work of our cardiac ancestors (Which many of us are pathetically lacking !)
http://circ.ahajournals.org/cgi/reprint/65/2/336
Role of trans-esophageal lead during EP study atrial fibrillation
http://cardiovascres.oxfordjournals.org/content/38/1/69.full
Posted in Cardiology - Clinical, Cardiology - Electrophysiology -Pacemaker, tagged aai mode, can single cahmber pacemaker be physiological, david study, dual chamber pacing, floating atrial sensing lead, medtronic, mode switching, non physiologcal pacing, pacing modes in sick sinus syndrome, pathologicalpacing, physiological pacing, rate adaptive pacemakers, single vs dual chamber pacing, sinus node dysfunction, st judes, triple cahmber pacing, vdd mode, vvi mode, wahat is a physiological pacemaker on January 18, 2011| Leave a Comment »
In pacemaker science , any pacemaker that maintains AV synchrony is often referred to as physiological pacemaker. This is of course , a wrong reasoning .None of the pacemakers available today can be claimed to be completely physiological .All pacemakers which paces the right ventricle induces IVS dysynchrony (Including the modern DDD)
Single chamber physiological pacing
AAI
Paradoxically , the most primitive of pacemakers AAI can be the near perfect physiological pacemaker . The simple explanation is , In AAI mode , expect for the origin of pacemaker impulse the entire depolarisation and repolarisation is through the normally existing physiological conducting system .(AV node, HIS, Purkinje etc)
(It not only has atrio ventricular synchrony but also has ventriculo ventricular and intra ventricular synchrony )
So, technically AAIR is most physiological pacemaker possible .But the practical utility of such a pacemaker is limited.It can be used only in isolated sinus node dysfunction with intact AV conduction . (The problem is the AV nodal conduction can develop later ) To over come this DDDR pacemaker can be programmed to AAIR as a default mode.
VVIR
This rate adaptive pacemaker , to a certain extent can be termed physiological as the heart rate can improve with exercise . (Still it is unphysiological as it paces the RV )
VVD
This is based on the concept , for pacing to be physiological , it requires atria to be at least sensed not necessarily paced.This mode which has a floating sensor attached to the lead as it crosses the atria.This facilitates atrial sensed ventricular pacing .But many believe the atrial sensing is not consistent in VDD mode.Currently this mode is not popular.There is scope for improving the atrial sensor technology .
Dual chamber physiological pacing
DDD, DDRR
Both these are the prototype dual chamber physiological pacing modes.
Bi-Ventricular or triple chamber pacing ( one atria two ventricle) are our elusive answers for attaining perfect physiological pacing . it need to be realized, we simply , can not mimic the natural cardiac conduction system.It is estimated to be more than 10 miles long specialized fibers .
Final message
In our quest for physiological pacemaker we often forget the fact , AAI is the most physiological pacemaker mode available .(It even has VV synchrony ! )
We should use it liberally whenever possible .Of course ,we cannot use it in complete heart block .Still 50 % the permanent pacemaker we implant is for sinus node dysfunction. Many of them could be candidates for AAI mode .If current generation cardiac physicians feel out dated to insert a AAI pacemaker, at the least they should program the DDDR into AAI mode with a mode switching to ventricular pacing modes whenever required.
In spite of all advantages , why atrial based pacemakers are not gaining popularity ?
Posted in cardiac surgery, Cardiology - Clinical, cardiology -Therapeutics, tagged ball valve, cardiommc, departemnt of cardiology, dr sadasivam madras medcial college, dr sadasivan, dr vasudevan, mitral starr edwards, portland hospital, prosthetic heart valve, solomon victor india chennai madras medical college, starr edwards valve, www.cardiommc.com, www.cardiommc.org on January 15, 2011| 5 Comments »
Prosthetic valve implantation has revolutionized the management of valvular heart disease . The original concept valve was a ball in a cage valve , still considered as a fascinating discovery. It was conceived by the young Dr Starr and made by Engineer Edwards .This was followed by long hours of arguments, debates and experiments that ran into many months . The silent corridors of Oregon hospital Portland USA remain the only witness to their hard work and motivation. At last, it happened , the first human valve was implanted in the year 1960. Since then . . . for nearly 50 years these valves have done a seminal job for the mankind.
With the advent of disc valve and bi-leaflet valve in the later decades of 20th century , we had to say a reluctant good-bye to this valve.
There is a lingering question among many of the current generation cardiologists and surgeons why this valve became extinct ?
Starr and Edwards with their child !
We in India , are witnessing these old warrior inside the heart functioning for more than 30 years.From my institute of Madras medical college which probably has inserted more Starr Edwards valve than any other during the 1970s and 80s by Prof . Sadasivan , Solomon victor , and Vasudevan and others .
It is still a mystery why this valve lost its popularity and ultimately died a premature death.The modern hemodynamic men working from a theoretical labs thought this valve was hemodynamically inferior. These Inferior valves worked like a power horse inside the hearts the poor Indian laborers for over 30 years.
A Starr Edwards valve rocking inside the heart in mitral position
The cage which gives a radial support* mimic sub valvular apparatus, which none of the other valves can provide.
* Mitral apparatus has 5 major components. Annulus, leaflets, chordae, pap muscle, LV free wall.None of the artificial valves has all these components. Though , we would love to have all of them technically it is simply not possible. The metal cage of Starr Edwards valve partially satisfies this , as it acts as a virtual sub valvular apparatus.Even though the cage has no contact with LV free wall, the mechano hydrolic transduction of LV forces to the annulus is possible .
Further , the good hemodyanmics of this valve indicate , the cage ensures co axial blood flow across the mitral inflow throughout diastole. .Unlike the bi-leaflet valve , where the direction of blood flow is determined by the quantum of leaflet excursion in every beat . In bileaflet valves each leaflet has independent determinants of valve motion . In Starr Edwards valve the ball is the leaflet . In contrast to bi-leaflet valve , the contact area of the ball and the blood in Starr Edwards is a smooth affair and ball makes sure the LV forces are equally transmitted to it’s surface .
The superiority of bi-leaflet valves and disc valves (Over ball and cage ) were never proven convincingly in a randomized fashion . The other factor which pulled down this valve’s popularity was the supposedly high profile nature of this valve. LVOT tend to get narrowed in few undersized hearts. This can not be an excuse , as no consistent efforts were made to miniaturize this valve which is distinctly possible.
Sudden deaths from Starr Edwards valve .
Final message
Science is considered as sacred as our religion . Patients believe in us. We believe in science. A good durable valve was dumped from this world for no good reason. If commerce is the the main issue ( as many still believe it to be ! ) history will never forgive those people who were behind the murder of this innocent device.
Cardiologists and Cardio thoracic surgeons are equally culpable for the pre- mature exit of this valve from human domain. Why didn’t they protest ? We can get some solace , if only we can impress upon the current valve manufacturers to give a fresh lease of life to this valve .
http://www.heartlungcirc.org/article/S1443-9506%2810%2900076-4/abstract
Dr.S.Venkatesan MD 