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Archive for August, 2008

Coronary angiogram is a video graphic  snap shot of coronary arterial lumen which is filled with radio opaque dye. This is some times called as coronary luminogram . It is a paradox , when we say normal coronary angiogram we can only mean  normal coronary lumen. But  generally, this can provide sufficient  information regarding the status of  coronary blood flow.There are three structured layers in coronary artery wall . Coronary angiogram  can not give any information about the status of the intima, media or adventia .

Lesions A to F may be totally missed by conventional coronary angiogram

Lesions A to F may be totally missed by conventional coronary angiogram

A patient with normal coronay angiogram can have diffuse  atheroscelrosis or  localised atherosclerosis within the media of coronary artery .Many times these atherosclerotic plaques grow outward into the adventia and fail to encroach upon the lumen to be detected by coronary angiogram. These plaques , even though has an hemodynamic advantage, in that it doesn’t block blood flow , has a serious risk for sudden rupture and result in an acute coronary syndrome.

So what is the message?

A normal coronary angiogram can never convey a meaning of normal coronary arteries.


A person who has a normal coronary angiogram has no guarantee that he won’t develop a coronary event in the near future.(But the the chances are very low)

If coronary angiogram has serious limitations  what is the next alternative ?

Intra vascular ultra sound imaging(IVUS) can give us an idea of the coronary arterial wall anatomy. This investigation , though available for clinical application is too complex for regular use.So , you  can’t subject every patient with normal CAG  to an IVUS  (Intra vascualar ultra sound) to confirm the normality. The best option is what we follow every day in our practice  .Tell your patients   with normal coronary angiogram , that they are likely to  have  normal coronary arteries  ! don’t add up to their anxiety by saying,  in spite of normal CAG  still they  can carry  gross atherosclerosis in their  arteries. Anxiety can precipitate an coronary event. Too much technical information to the patients  can be counter productive. Instead  advice regular life style modification,  blood pressure ,diabetes, lipid  control  etc .

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The debate of rate control verses rhythm control in atrial fibrillation  goes on and on. The AFFIRM, RACE,PIAF, STAF the HOT CAFE all went against sinus rhythm in the last 10 years . This was one of the settled contoversies in cardiology . The conclusion was ventricular  rate control was no way inferior to rhythm control in patients with SHT, CAD population .This made the electrophyiologists wonder how can a natural rhythm fare bad ! . But the findings  were consistent .Rhythm control neither improved the quality of life nor  it reduced the incidence of stroke. The later finding was very surprising but the explanation was convincing as stroke in elderly was more related to SHT, CAD, DM etc than  AF itself. The source of emboli in ischemic stroke could come any where distal to LA .The big assumtion that all strokes in elderly  should come from LA appendage or the body  of LA was  premature and  wrong. What prevented stroke in AF was not restoration of SR but administration of oral anticoagulants with adequate INR.(2-3)

Having failed to document superiority in elderly  population   , the  logic machine  strongly suggested restoring SR  in patients with CHF,  will atleast provide hemodynamic and also survival  benefit .

And thus came the AF-CHF trial  published in NEJM 2008

Alas !  AF-CHF  also found there is no useful purpose of restoring sinus rhythm in patients  with atrial fibrillation and cardiac failure. In fact patients in SR fared little worse !

 Why . . .  why . . . why ?

Should we ask the seemingly absurd question !

Is sinus rhythm poorly tolerated by cardiac failure  patients ?

It is some times possible atrial fibrillation by itself could be a mechanism to amplify the  cardiac reserve by which it provides a  relatively high ventricular rate to improve the cardiac index  . Even though the optimal ventricular rate in AF is around 80-90 at times of need it has to increase to 120-130. Patients in class 3 CHF and AF often achieve this in times of demand .This is not possible in patients who are getting rhythm control drugs and further patients in SR can  not increase the HR suddenly from 80 -130  .

So is this a  wild imagination !   AF could be a safety valve mechanism in CHF to increase the HR . Where the atria come to the rescue of ventricle like a rate adaptive pacemaker .

The other logical* ! argument is that  there  is nothing wrong with restoring  SR , but the  methods to achieve and  maintain SR  is too cumbersome and results in adverse outcome .The currently available  drugs are too toxic for the purpose  .

If we have a simple and safe way to restore SR in these patients it should always be superior to AF .

But it is a well  known fact  that , whatever be the rhythm or rate the ultimate outcome will be dictated by the LV function, mitral valve function etc.

 Read abstract of AF-CHF

Rhythm Control versus Rate Control for Atrial Fibrillation and Heart Failure

Denis Roy, M.D., Mario Talajic, M.D., Stanley Nattel, M.D., ., for the Atrial Fibrillation and Congestive Heart Failure Investigators

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Rhythm Control versus Rate Control for Atrial Fibrillation and Heart Failure

Denis Roy, M.D., Mario Talajic, M.D., Stanley Nattel, M.D.,  the Atrial Fibrillation and Congestive Heart Failure Investigators* –>ABSTRACT

Background It is common practice to restore and maintain sinus rhythm in patients with atrial fibrillation and heart failure. This approach is based in part on data indicating that atrial fibrillation is a predictor of death in patients with heart failure and suggesting that the suppression of atrial fibrillation may favorably affect the outcome. However, the benefits and risks of this approach have not been adequately studied. Methods We conducted a multicenter, randomized trial comparing the maintenance of sinus rhythm (rhythm control) with control of the ventricular rate (rate control) in patients with a left ventricular ejection fraction of 35% or less, symptoms of congestive heart failure, and a history of atrial fibrillation. The primary outcome was the time to death from cardiovascular causes.
Results A total of 1376 patients were enrolled (682 in the rhythm-control group and 694 in the rate-control group) and were followed for a mean of 37 months. Of these patients, 182 (27%) in the rhythm-control group died from cardiovascular causes, as compared with 175 (25%) in the rate-control group (hazard ratio in the rhythm-control group, 1.06; 95% confidence interval, 0.86 to 1.30; P=0.59 by the log-rank test). Secondary outcomes were similar in the two groups, including death from any cause (32% in the rhythm-control group and 33% in the rate-control group), stroke (3% and 4%, respectively), worsening heart failure (28% and 31%), and the composite of death from cardiovascular causes, stroke, or worsening heart failure (43% and 46%). There were also no significant differences favoring either strategy in any predefined subgroup.
Conclusions In patients with atrial fibrillation and congestive heart failure, a routine strategy of rhythm control does not reduce the rate of death from cardiovascular causes, as compared with a rate-control strategy.
 
 

 

 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 

 

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                                                          Left main coronary  lesions are  fairly common  during routine coronary angiogram.These may be a critical or a innocuous lesion.The  word “left main” triggers a sort of alarm reaction to many cath lab staff as well as the cardiologists and surgeon.Many times, these left main lesions are detected in patients   with chronic stable angina who have stable symptoms. Left main disese has not been graded  clearly in literature . Often it is perceived , any lesion in LM is serious.

There is an unwritten rule,  rather a medical compulsion  to take a patient  with left main disease  for emergency CABG ( Now some centres ,emergency PCI) .Some institutions make it  a rule these patients  are posted  in the  next available slot in the theatre.

 The basic question we raise here is   “Should we consider all  left main  disease  as  an  emergency”?

Not really , especially when it occurs in a stable angina .One can wait , buy some time to fully evaluate and prepare  the patient  and may be the patient can be posted  as an elective case. It is a well recognised fact that, CABG carries adverse outcome when done as an emergency procedure. This is primarily due to inadequate pre op work up and resultant complications. It is also well known ,  surgical  back up team may not be available in full strength in odd hours .

This post is  to convey the message , that left main is  a serious disease but that doesn’t  mean it should elicit  a panic reaction and be taken as an ultra emergency . There has been many morbid and fatal outcomes in many hospitals due to this apparent  pseudo emergency !

 

Note* 1.Left main  disease during acute coronary syndrome is to be seen in different perspective.2.Some of the proximal LAD lesions are so tight and  could be more significant than left main lesions.

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All is not well,  that ends well !

                                       Treatment guidelines in cardiology  practice  are periodically published by ACC/AHA/ESC.These guidelines  represent the current scientific practice. They are called some times as recommendations. Medical professionals tend to adhere to this guidelines whenever possible.They are not legally binding in most of the countries.In USA some states believe it, to be legally binding.

 

The problem with these guidelines  are , they are classified as class 1 ,class 2 , class 3 recommendations.

 

Class 1, A  drug , device  or a procedure  Is definitely useful and must be prescribed.

Class 3,   A  drug , device  or a procedure  Is not useful and should not be used .

Class 2*, A  drug , device  or a procedure  may be useful  or may be harmful , and hence may be used or may not be used . (Vaguest possible guideline!)

 *Altered to convey the meaning

What are the  guideline violations that can be sued in court of law  ?

A person with established  CAD who is not been prescribed a  statin (Cholesterol lowering drug)  can be sued straight away,  even if the patient has no adverse outcome due to the nonprescription of that drug. The issue here is , the doctor  has not prescribed  a drug which has  proven benefit .The law is clear on that .Most will  agree that,  the  doctor is at fault ,  and he  is never protected  even by their  colleagues .He  can’t defend his action.

What are the medical errors that can never* be sued in court of law !

But the same doctor who opens up a totally occluding coronary artery in an asymptomatic patient(CTO -chronic total occlusion) and lands up  in a complication and the  patient dies. This could be  major guideline violation as opening a CTO in an incidentally detected , asymptomatic patient is a class 3 recommendation. Neither the physician, patient , institution  nor  the regulatory authorities bother about this even though there is strong case for censure , in reality it never happens. Number  of  experts from leading hospitals do this procedure in live work shop all over the world with full media glare, It is an irony the same  experts are only  writing  in their  guidelines  that  these procedures should not be done inappropriately.

And this medical  error ( Should we call it a  crime if it is knowingly done ! )   keeps growing as the physician never feels guilty about it .

The message here is

 A physician of a state of the art hospital,  in a scientifically advanced  country  goes scott free and guilt free  even if he openly violate the scientific guidelines and do a inappropriate procedure that result in a patient death. Mean while a small time physician in a remote place in the same country can be taken to task  for not prescribing a officially  recommended drug (By standard guidelines) .He will be labelled unscientific and unethical even if his non prescription , had not caused any untoward health outcome .

In short , in today’s modern medical practice 

 Even a  ” Minor error of  ommision”   attracts guilt and perceived fear among the physicians. Meanwhile  many  of the ” Major errors of commission”  done by professionals are rarely frowned upon and thus these  mistakes continue to perpetuate !

*There should be a strong provision in medical law to address the issue of inappropriate procedures even if the procedure has not resulted any untoward effect to the patient.

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Interventional cardiology as a speciality is in cross roads.

The number of coronary interventions (PCI) has increased exponentially world over. With increasing  Cath labs and growing  expertise ,  access to PCI has enormously increased  even in underdeveloped countries.  Meanwhile ,  public lack  specific technical information about the appropriateness  of these costly procedures. It is our duty to do self audit on this issue.  .

                           In this context,  the evaluation  following a PCI  should look beyond  lumen oriented  endpoints.  Many  land mark trials on DES report 3 months are 6 months angiographic outcome and better luminal appearance . Many   tend to worry  more about the status of the stent rather than the patient !  This is primarily because the device companies have repeatedly stressed the technical end points rather than clinical end points .

It is a  well recognised fact  that ,stented coronary artery never guarantees against future  coronary events (ACS) either within the stent or away from it .It is an explict fact that , a patient  after getting a coronary stent , especially a drug eluting stent carries a life long risk of acute stent obstruction and possibly SCD .This information is rarely passed on to the patient in  and hence they are not able to take “learned consent”

It is true ,  one gets  a gratifying feeling  when  opening up a obstructed artery , but we also need  to answer this simple question   What is it’s impact on  patient’s  life  ?

COURAGE & OAT trials have put a break on the  prevailing precondtioned behaviour in the labs, namely any obstruction must be relieved if  technically feasible .

One should recall  the Gruentzig’s legacy  . Whaterver,  we do inside  a  patient’s coronary artery must have some useful purpose . We should not use patient’s  coronary artery to show our expertise and skills !

Dr.S.Venkatesan, Madras Medical College, Chennai, India

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Recurrent myocardial infarction following an ACS is a fairly common clinical problem. Many times this is not recognised because it is difficult to establish the diagnosis.

The issues relevant here is

When does the first infarct (Index infact) process end ? and when the second infarct process start ?

Can the first infarct be a STEMI and the reinfarct be NSTEMI ? ( Dual acute coronary syndrome )

The only way to confirm a diagnosis of reinfarction is to document raising titres of cardiac enzymes and second peaking of CPK MB . New fresh ST elevation after a succesful thrombolysis is also a useful sign. But ST elevation in a q lead simply reflects a wall motion defect . So it requires enzymes to confirm it.

When there is tachycardia the ST segments tend to elevate following MI.

Other confounders are Infarct expansion and infarct extension .

These are macropathological entities almost impossible to dignose with surface ECG. What we diagnose as re-infarction could be an infact a infarct expansion.The modern terminology for infarct expansion is ventricle remodeling .The extreme remodeling results in ventricular aneurysm .Adverse acute ventricular remodeling can closely mimic a reinfarction .

What is clinical relevance of diagnosing reinfarction ?

Nothing great !

In modern day cardiology it is not a bother whether the infarct is expanding, extending or reinfarcting !All one has to do in a patient with chest pain ,showing a fresh ST elevation following STEMI is to take him/her to cath lab .

The only issue here one has to remember there are mechanical cause also for ST elevation following STEMI .

Dr.S.Venkatesan,Madras medical college, Chennai.

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Pulse deficit is a clinical sign wherein , one is able to find a difference in count between heart beat (Apical beat or Heart sounds ) and  peripheral pulse .This occurs even as the heart is  contracting , the pulse is not reaching the periphery.This can occur in few clinical situations .

1 . Atrial fibrillation.

2. Very early diastolic  ventricular  ectopic beats

3. Some patients with Pacemaker.

The mechanism is  , the ventricular contractions are  too weak and unable to open the aortic valve  , but at the same time they are good enough to close the mitral valve. To open the aortic valve it has to generate atleast 60-80 mmhg pressure , while mitral valve closes even  as LV generates  8-14mmhg  .(LV/LA pressure cross over). So intermitently the  second heart sound  is missed while S1 is retained,  producing more heart sounds and less pulse count in the periphery. The S1 is either felt or heard at the apex but the corresponding pulse is missing . Further , this intermittent absence of  S2  results in totally irregular S1 /S 2 relation.

Why some of the contractions of LV is too weak to open the aortic valve ?

Because the RR interval varies , the ventricular filling also varies , diastole duration is constantly changing some of the diastole are too short  and LV hardly gets filled , as the LV force of contraction is directly decided by the LVEDV and LV  fibre length these contractions are too weak. 

Other published studies

There has been some doppler observations ,where there is a midventricular LV blood flow reversal in atrial fibrillation that could  explain the pulse deficit . Mechanism of production of pulse deficit in atrial fibrillation: assessment by blood flow dynamics

Second Department of Internal Medicine, Kagoshima University School of Medicine.

 http://www.ncbi.nlm.nih.gov/pubmed/3221309

What is the clinical significance of pulse deficit ?

                                  Currently there is no great clinical significance of this phenomenon. But an astute clinician will pick up this sign and it may indicate underlying LV dysfunction. In patients with PPM,  pulse deficit  suggests  pacemaker malfunction .Some patients with cardiac tamponade &  pulsus paradoxus  systolic  blood pressure falls too low to make the pulse feeble or not palpable in the periphery .This situation may mimic a pulse deficit if not recognised.

 Dr.S.Venkatesan ,Madras Medical College , Chennai, India

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