Posted in cardiac surgery, cardiology journals, tagged cardiology journals, great cardiology journals, ijtcvs, indian heart journal, indian journal of thoracic and cardiovascualr surgery, medical journals from India on April 19, 2010| 1 Comment »
The one and only journal for cardiovascular surgery from the subcontinent. Great to know full text articles are available from year 2003 , free of cost .Every cardiologists from India must read this journal regularly to update about what our surgical colleagues are doing in our country.
Thanks to the National Informatic centre for hosting this journal in their server .
Posted in cardiac surgery, Cardiology -Interventional -PCI, Hemodynamics, Uncategorized, tagged 100% oxygen, asd, bi directional shunt, bosentan, cyantoic heart disease, eisenmenger syndrome, heath edwards, irreversible pulmonary hypertension, left to right shunt, mean pulmonary arterial pressure, mean pulmonary artery pressure, oximetry, pah, papp, pda, pht, prostocyclin, pulmonary artery diastolic pressure, pulmonary artery pulse pressure, pulmonary hypertension, pvr vs svr, reversible pulmonary, right to left shunt, sildanefil, tolazoline, vsd on December 20, 2009| Leave a Comment »
PAH is the major determinant of surgical outcome of left to right shunts. In this modern era of cardiac care allowing a child with left to right shunt to progress to a stage of Eisenmenger syndrome is considered as a huge medical failure . But , this is still rampant in many of the developing countries .
Cardiologists are divided over the issue of operability of Eisenmenger syndrome .The confusion is largely due to the conflicting data of outcome in these patients. While there is strong data when PVR exceeds SVR , the death is imminent in the post operative period .
What has complicated the issue is there are many case reports where severe PAH patients have been successfully operated. Most would think it is a statistical exception and one can not alter the traditional criteria based on few case reports.
But ,it remains an irony as on 2009 , we do not have a proper methodology to assess reversibility of PAH in Eisenmenger syndrome . Further , there is a significant number of patients with high PVR , who continue to experience an unabated left to right shunting . We do not have an answer for either the mechanism of such shunts and how to manage these patients.
Click over the slide to view full PPT presentation in PDF format .
This short paper was presented in the Annual scientific sessions of cardiological society of India 2009 regarding the usefulness of a new parameter to assess reversibility of PAH. This may not be called as a study rather a report of our experience in five patients with eisenmenger syndrome
Download the full PPT presentation in PDF format.
Posted in cardiac surgery, Cardiology - Clinical, Uncategorized, tagged diastolic dysfunction on December 14, 2009| Leave a Comment »
Diastolic dysfunction is a common clinical cardiac problem which has no specific therapy.It can occur either in isolation or in combination with systolic dysfunction.The later may be more common.
Isolated diastolic dysfunction
In association with systolic dysfunction
General principles of management
Even though there is no specific drugs to tackle diastolic dysfunction the following measures may have significant impact.
What are the treatments in the horizon ?
Antifibrotic drugs ,Antiproliferative drugs
Collagen breakers ,
Posted in cardiac surgery, tagged bmj, clinicaltrials, doubleblinded, lancet, medicalresearch, nejm, observationalstudiesbetterthanrct, observationalstudyvsrct, plos, pubmed, Randomisedcontrolledtrial, rct, what is rct? on December 7, 2009| Leave a Comment »
What are the fundamental difference between randomised studies and observational studies ?
New discoveries come from shrewed observations made in bedside or labside while , randomised studies evaluate these discoveries for it’s effectiveness or futileness .
Let us realise , RCTs primarily never contribute to generation of original concepts or discoveries ! .It is a statistical tool to assess an observation .
Click below to reach the excellent knowledge source on above the issue .
PLoS Medicine: Observational Research, Randomised Trials, and Two Views of Medical Science
The fact that observational studies are done with open eyes & mind , it is obvious it demands intense conceptualization and thinking .
Blinded studies are mechanical studies . It is pure statistical research . It requires no thinking , medical mind , in fact one can do it with eyes closed as it is a strict protocol driven , even a non medical men can do a medical research , while it needs a alert mind to do a observational study .
Observational studies , especialy when done retrospectively has zero bias as the case selection and the potential intervention are completed even before the research question is raised. In fact many of the greatest medical breakthrough comes from retrospective analysis. Of course this has to be proved prospectively preferably in a randomised fashion.
So , we the medical professionals , shall do great observational research with open eyes and mind and let the the statisiticins do the outcome analysis blind folded .
If the core medical professionals are bothered more about randomised blinded studies ,which is meant only for evaluation purposes , the future of intellectual medical research is going to be in jeopardy!
Posted in cardiac surgery, Cardiology - Clinical, Cardiology -Interventional -PCI, cardiology journal club, tagged beating heart surgery, Beware of beating heart CABG : It is minimally invasive and minimally effective !, cabg, cardiac surgery, cardio pulmonary bypass, cardiology journal club, jacc, LAD, lima graft, midcab, minimally invasive cardia surgery, nejm, obcab, off pump cabg, on pump cabg, RCA, rooby, rooby cabg study, svg graft on November 6, 2009| Leave a Comment »
The NEJM’s breaks the hidden truths about cardiopulmonary bypass in a beating heart. The irony in medical science is , trend setting land mark articles usually arrive very late . . . to disappoint all those patients who got the wrong treatment ! Off pump by pass is definitely one among them . . .
The major reason for off pump CABG’s s poor showing is
Click on the link to NEJM abstract ROOBY study
Posted in cardiac drugs, cardiac surgery, cardiology -ECG, Cardiology -Interventional -PCI, cardiology- coronary care, tagged aminophylline, atropine, av block, av nodal ischemia, av nodal necrosis, complete heart block, coroanry care, inferior myocardial infarction, inferior wall mi, ivabradine, junctional rhythm, lcx, nstemi, pacemaker, ppm, RCA, reperfusion arrhythmias, sa block, sinus pause, stemi, temporary pacemaker, thrombolysis, weaning of pacemaker on August 13, 2009| 1 Comment »
Conduction disturbance is a fairly common occurrence following MI. Inferior STEMI is especially prone for AV blocks. This is because the blood supply to AV nodal tissues and the inferoposterior surface of the heart share the same arterial territory . AV node gets it supply 90% of time by right coronary artery(RCA ) and 10% by LCX. Very rarely from both .
The common bradyarrhytmias that we encounter in inferior MI are
Sinus bradycardia
Sinus pauses ,SA blocks
AV blocks
Functional
Vagotonic
Organic
Ischemic
Necrotic
ECG types
1 degree AV block
2 degree AV block – Type 1 Wenke bach
Complete heart blcok
Mechanisms
The inferior aspect of the heart has rich innervation of vagal nerve terminals (While the sympathetic adrenergic system is concentrated in the anterior surface) . The moment infero posterior MI occur it stimualtes the vagus and a prompt bradycardic response occur .Many times the classical hypotension /bradycardia reaction is simply a reflection of heightened vagal tone.
Consequence of vagal tone on SA nodal and AV nodal conduction
As expected, vagal stimulation can result in a spectrum of arrhythmias from the simple bradycardia to complete SA block to AV block. Extreme bradycardia , may release the junctional pace maker and result in junctional rhythm with a rate of around 40-50. There can be a functional AV dissociation between SA node and AV node. Careful ECG analysis is required here , as it can mimic organic AV block.The simple way to differentiate between organic AV block from simple AV dissociation is to look at the p waves.In AV dissociation both atrial rate and ventricular rate are nearly equal or VR is slightly more than AR .In CHB atrial rate exceeds ventricular rate.
SA and AV block occur due to various mechanisms in inferior MI
Ischemic AV nodal arrhythmias are some times very difficult to differentiate from vagotonia especially if occur within 24h.
Irreversible AV nodal block due to necrosis is rare.But if occur , usually associated with extensive inferior mI/RVMI/ .AV block that persist beyond 48-72hours should raise the suspicion of damage to AV node.( As vagal tone is very unlikely;y to last beyond 48h)
* Some time a an episode of sudden severe bradycardia can be manifestation of RCA reperfusion.Flushing of SA nodal or AV nodal branch of RCA might trigger this. This has a potential to bring the heart to asystole.The resultant extreme bradycardia often triggers VT/VF .The reported high incidence of primary VF in infero posterior MI is attributed to this sudden RCA perfusion.
Medical management for CHB
Brady arrhythmia’s due to high vagal tone are generally benign .No specific intervention is required.Atropine will be suffice in most situations.Some times isoprenaline may be required. Aminophyline , now Ivabradine may have a role. Atropine not only corrects the HR it raises the BP also as it counters both cardioinhibitory and vasodepressive limbs of vagal stimulus mediated by acetyl choline .
Pacing for Bradycardias in inferior MI.
Weaning of temporary pacing in inferior MI.
This could be a tricky issue. It can be weaned off in less than a week.A practical way is to use temporary pacing only in back up mode at a heart rate of few beats less than the patients rhythm.Pacing for long hours at high rates may delay the resumption of patients own rhythm and may result in false diagnosis of irreversible CHB and a subsequent PPM
How many will require permanent pacing following infero posterior MI ?
Only a fraction of patients with CHB require long term pacing . There are some centres tend to overuse PPM in this situation. Wait and watch policy may be the best.A unnecessary lead within a infarcted ventricle has a potential to create problems .There have been occasions a stable RV MI has been destabilised due to RV pacing lead triggered recurrent VF.
Tachycardias in inferior MI
It is relatively uncommon.Atrial involvement is more common with infero posterior MI and hence a greater incidence of atrial fibrillation .
RV MI can induce ventricular tachycardia arising from the RV myocardium
Posted in cardiac surgery, Cardiology - Clinical, tagged chiary network, eustashian valve, ivc, paradoxical embolism, right atrail mass, right atrial thrombus, right atrium, tricuspid valve endocarditis, tricuspid valve vegetation on July 5, 2009| Leave a Comment »
It is the embryological remnant within right atrium often observed as , mobile strands within RA extending fromIVC orifice to IAS. Some times it is difficult to differentiate from eustachian valve of IVC.The network is formed by collagenous material and mimic valvular tissue
Incidence
2% of general population . ( Means 10 crore persons in our world ! )
What is considered a benign echocardiographic observation for long , may not be innocuous . It can predispose to certain clinical events , although rare.
Reference
http://content.onlinejacc.org/cgi/content/abstract/26/1/203
http://ats.ctsnetjournals.org/cgi/content/abstract/76/4/1303
http://content.karger.com/ProdukteDB/produkte.asp?doi=10.1159/000096780
Posted in cardiac surgery, tagged amplatzer asd device, asd, asd surgery, asdos, device closure, ostium primum, ostium secundum, pfo, starflex on May 11, 2009| 8 Comments »
Atrial septal defect is one among the commonest congenital heart disease .After years of controversy, there is consensus now , all significant ASDs need to be closed , at whatever age it is detected.
This rule does not apply to small ASDs without chamber right atrial and right ventricular dilatation. These defects and PFOs need not be closed .
Over the years , the controversy has shifted from Should we close ? to How to close ?
There are two options available : Device closure , Surgical closure
The following table compares the both treatment modalities
( Personal perspective )
Final message
Device closure is a complex, costly, often difficult and error prone cardiac procedure .It needs long term follow up and may carry a life long risk of major cardiac complication.It is useful only in selected subset of ASD patients. Surgical closure prevails over device closure in most situations.
Is this article has biased view against this emerging pediatric interventional procedure of ASD closure ?
It may appear so . But that is the reality as on 2009 !.May we hope technology evolves further and take our surgeons head on .
2012 update on ASD device closure .
The hard-ware as well as the expertise has improved a lot and it is on right track to become a real challenge to surgery.
The only issue again is the availability of rims to mount the device . Another realistic and sensitive issue which have I come across is , many interventionist cardiologist do feel awkward when they experience unexpected rim shortage on table. They should realise it is not their fault.
Always be ready to abandon the procedure and refer to the surgeon , according to your true conscience
After all , improperly delivered device is a life long pain for the patient .He has come to you with a great belief isn’t !
2014 update
Device closure for most ASDs in both children and adult is now possible with high degree of success. We have crossed about 50 patient experience. And I am truly amazed , how within a short period the device closure is about to conquer the crown from the surgeons ! (Exciting new data are coming from my colleague Dr Gnanavelu from the new Super specialty hospital of Government of Tamil Nadu Chennai. )
Reference
Aortic erosion following ASD closure
Posted in cardiac drugs, cardiac surgery, Cardiology - Clinical, Cardiology -unresolved questions, Uncategorized, tagged lv dysfcuntion on April 20, 2009| 12 Comments »
LV dysfunction , perhaps is the most common medical term used by physicians world over.But surprisingly , It is not easy to infer what they mean by it ! The term literally means left ventricle is not functioning all right .
LV dysfunction can be classified by many ways.
If you analyse the above classification LV dysfunction can mean different things to different people , at different times.Though systolic dysfunction , as reflected by low EF % ( Less than 50% ) is the major cause of LV dysfunction the issue is not simple.
Is coronary artery disease ( CAD ) a must for LV to become dysfunctional ?
No , not at all .CAD is the leading cause of LV dysfunction .Primary muscle disorders -cardiomyopathy is an equally common entity. Valve disorders especially aortic valve stenosis is another common cause for LV dysfunction. Further , systemic hypertension, diabetes mellites, renal failure, can result in serious impairment of LV function .Some drugs ( Adriamycin ) can either precipitate or aggravate LV dysfunction.
If physicians themselves are confronted with such complexity , how are , our other medical colleagues (Forget about the patients ! ) will understand the concept of LV dysfunction.
But , the crux of the matter is every doctor believes LV dysfunction is synonymous with low ejection fraction. A surgeon or an anesthetist is quiet happy to operate if the ejection fraction is above 60% .
Can a patient have significant LV dysfunction with normal Ejection fraction ? (EF )
Yes , this can occur in advanced degrees of diastolic dysfunction, where cardiac contractility is normal but
fails to relax adequately .
Is diastolic dysfunction less dangerous than systolic dysfunction?
May be , that is the dominant opinion , but there are sufficient evidence emerging that opinion is wrong.The main reason for diastolic dysfunction to send a ” not so sinister signal ” is over diagnosis of grade 1 diastolic dysfunction in the general population . The echocardiologists considered it fashionable for a quiet a longtime (Many have changed since then !) to report all patients with reversed E :A ratio in the mitral inflow doppler profile as diastolic dysfunction. This has resulted in thousands of asymptomatic , healthy people getting labelled as grade 1 diastolic dysfunction undermining the importance of this entity.
The fact of the matter is true diastolic dysfunction is indeed dangerous , if not more dangerous than systolic dysfunction for the simple reason , there is no specific treatment for this condition
To improve the specificity to diagnose genuine LV diastolic dysfunction it is suggested to remove grade 1 diastolic dysfunction from the literature .
Other causes of LV dysfunction with normal EF
What is the difference between LV dysfunction and LV failure ?
Many times both these terms are perceived to convey the same meaning .But it can never be used synonymously .Cardiac failure is a clinical entity while LV dysfunction is a derived technical parameter by and large an echocardiographic enity. Cardiac failure is defined classically as a clinical syndrome .(elevated jvp, edema * S 3 rales etc) Neuroueohormonal activation can occur with both.
A patient with LV dysfunction when destabilsed develops LV failure and after stabilisation of LV failure he is brought back to the baseline LV dysfunction
*What is the link between LV dysfunction and RV dysfunction ?
RV can not be silent companion when the LV fails . There always have been link between the two.
LV dysfucntion begets RV dysfunction and LV failure can trigger a total heart failure
Apart from the classical concept of ventricular interdependence , where inter ventricular septum plays a pivotal role , now there is strong evidence to prove both LV and RV myocardial muscle bundles are interwoven . In fact failing LV drags the muscle bundles over RV also (Friendly pull , let us die together !) and this is classically seen in idiopathic dilated cardiomyopathy where all four chambers of the heart dilate. There is also biochemical evidence the RV myocytes deplete thier norepinephrine stores in LV failure.
Is there an entity called transient or temporary LV dysfunction ?
The classical chronic reversible LV dysfunction also called hibernating myocardium is a different topic shall be discussed later.
Can acute ischemia cause LV dysfunction ?
Yes .This can occur during ischemic stunning of myocardium during NSTEMI .This can result in acute pulmonary edema* at times.This can be termed as ischemic LV dysfunction as there is no myocardial necrosis .
* The pulmoanry edema mentioned here is the flash pulmonary edema carries very dis prognosis.
What is the cause of LV dysfunction in critical aortic stenosis ?
Is it fibrotic ?
Is it necrotic ?
Is it ischemic ? (Associated CAD )
Or is it simply a mechanical inability* to contract as the outflow is closed ?
There is no specific answer . All the above factors may contribute .*But the fact that most patients recover full normal LV function following aortic valve replacement would make the last explanation more likely.
What does the term LV dysfunction mean to a cardiac surgeon when he plans for a CABG ?
LV dysfunction becomes an important determinant of overall outcome in patients who are going to receive a CABG .The surgeon will have contingent strategies during peroperative and post operative phase while operating in hearts with severe LV dysfunction.
How much of LV function is going to recover after CABG ?
This can not be predicted accurately but CABG may not resucitate all dying myocytes and bring life in them .The buttressing effect of blood within the dysfunctional segement can improve contractility and reduce the wall motion defect(This is an indirect mechanism of improving EF )
Dr.S.Venkatesan MD 