Posted in Brugada syndrome, Cardiology - Electrophysiology -Pacemaker, early repolarisation syndrome, tagged brugada syndrome, consensus conference brugada syndrome, how to follow up brugada pattern ecg, suspected brugada syndrome on April 26, 2015| Leave a Comment »
Have you felt like this query any time in your office ?
If “Yes” is your answer, then you are not alone .There was a unique conference that took place in 2010 to answer the same query in Rome , Italy on behalf of Italian cardiology society , where this entity is researched more than any other place.Its worth going through this.
Reference
Posted in Cardiology - Electrophysiology -Pacemaker, Pace maker Tips and tricks, tagged atrial lead issues in ddd pacing, best pacemaker tips and tricks, capture failure pacemaker, dc shock in pacing rhythm, ddd vs vvi pacing, intermittent pacemaker spikes, pacemaker syndrome, pacemaker trouble shooting best algorhythm, random pacemaker spikes, sensing and oversensing, sensing vs pacing failure on March 22, 2015| Leave a Comment »
We have been taught right from first year cardiology residency how to trouble shoot a pacemaker .It has been a real complex thing for us. Now looking back ,all the troubles we took to understand seems to be redundant.Here is a summary of my thought process on the issue. It can be approached with reference to time, symptoms and ECG features. With due respects to all those brainy hardworking EP experts , I have taken few academic liberties!
Timing
Symptoms
* Syncope can be unrelated to pacemaker but always consider them electrical unless proved otherwise . Few patients may continue to have significant symptoms in-spite of normal pacemaker parameters. This would mean , the original symptom for which pacemaker was put is not related to the Brady-arrhythmia .It could suggest alternative hemodynamic explanation like vaso-depressive component of vagal syncope ,autonomic dysfunction , orthostatic intolerance or a coexisting neurological /systemic condition.
**Never forget syncope is not an exclusive symptom of bradycardia .A new onset tachycardia , which is either a part of brady- tachy syndrome or separate arrhythmia can continue to provoke the symptom.
Gross ECG findings
Bradycardia /Often implies back to original rhythm – Indicates real trouble . Since ,in a paced patient HR cannot be less than programmed rate of 70.
Tachycardia -No spike.( Not to worry ?) A common situation if the original indication was sinus node dysfunction . Many of them are in own sinus rhythm or AF . Just ensure spikes reappear when the rate falls below 70 . If the rate never goes down , what to do ? Try a carotid massage or observe a nocturnal ECG or call analyst and increase the rate to document pacing . (In DDD mode we have a rare PM mediated re-entrant tachycardia , which is mainly used to grill cardiology fellows in their board exams with all those PVARP stuff !)
Simple pauses – Any pause more than the pacing interval is a definite concern .
Spikes more than QRS – Indicate capture failure.
No spikes (Can be so benign to ultimate danger )
* Anatomical issues like lead dislodgement , fracture , compression , perforation are to be ruled out in every pateitn with intermittent capture or failure .This is done by combinations of imaging as well physiological assessment.Dislodgement must be visualized .The term micro dislodgement may not exist.
Other Investigations
Pacemaker analysis
Management
The principle of management are simple. Few logical questions ,
Technical jargon like under sensing , over sensing or no sensing , fusion beats , micro dis-lodgement etc are important for academic reasons . We may talk any thing , realistically , what the ventricle want is a non stop heart beat every second or so !
Emergency
Bradycardia – Insert a temporary pacemaker /Call the analyst /Inform the electrophysiologist /Senior cardiologists /(Please realise , some fellows can be better than the personnel mentioned above in tackling emergencies !)
Tachycardia : Native or machine induced ?
Native – Mostly safe , Ignore or treat with drugs.
Machine induced :(very rare) Switch of the pacemaker . No off switch available as in a mobile phone ? *What to do ? if unclear about the whereabouts tachycardia origin . If hemodynamically unstable no harm in shocking .Nothing will happen .Call the EP guys on hot line and decide.
Elective symptom guided.
** While the above principles apply for both single and dual chamber pacemakers , the later doubles our thinking burden . While atrial tracking is a great technological advancement , what to do with those sensed event can be really tricky .The response of ventricles and the AV intervals can be tentative at times. Cross talks from unexpected atrial and ventricular arrhythmia can occur. Further , mechanical atrial lead issues are far more common . When confronted with recurrent atrial lead related problems , one simple solution is silently convert the mode to single chamber VVI mode.
Final message
Pacemaker trouble shooting appears complex at the first look .It’s all common sense.Thinking with simple state of mind and being clear about the intended goal is vital. Electrical intricacies are tough to understand but most situations do not require them. However ,If the initial indication was for complete heart block one has to be very alert.
Principles of medicine argue us to make an exact diagnosis before treating . But,realise this is rarely possible or even desirable in emergency .Curiously , most pacemaker troubles can be solved successfully without making a proper trouble shoot !
If we can summarize in one line , a prompt emergency back up temporary pacemaker insertion is key to management most of the serious pacemaker related problems.It ,not only tackles the emergency , buys time till we decode the real problem . . . if we wish to !
Related article.
Role of magnet application in pacemaker trouble shoot
Posted in Cardiology - Electrophysiology -Pacemaker, WPW syndrome, tagged wide qrs irregualr tachycardia, wide qrs regular vs irregular tachycardia on March 15, 2015| Leave a Comment »
We know , any wide QRS tachycardia would argue us to make a default diagnosis of VT.But, one has to be extremely cautious to apply this rule if wide QRS tachycardia shows significant irregularity in RR interval .
All classical VTs are fairly regular tachycardia (Note the key words , fair and regular) . Small cycle length variations are observed in VT, but they are usually not discernible in surface ECG.
There are no practical rules .A well appreciable irregularity in RR interval will seriously question the diagnosis of classical VT. To make an another statement, most of the irregular wide QRS tachycardias infact turns out to be atrial fibrillation with some form distal widening mechanism .(Preexisting blocks, or rate dependent or antidromic conduction through accessory pathways)
However , irregularity is still possible during VT .(May be less than 10% of times)
When can VT can be irregular ?
Final message
Statistically , as well as realistically , the commonest cause for any highly irregular tachycardia turns out to be AF , whether QRS is wide or narrow !
Posted in Cardiology - Electrophysiology -Pacemaker, ICD, tagged dual vs single chamber ICD, Indication for ICD, Which ICD to choose on March 7, 2015| Leave a Comment »
ICDs are primarily life saving devices.Whether single or dual chamber it does this function effectively.They will also take care of bradycardia by default back up pacing .For most indications single chamber ICDs are good enough.
My professor used to tell us , dual lead means , dual expertise , dual cost , dual caution and dual set of complication . One should avoid it whenever possible. Make things as simple as it could be , without compromising the main goal (Here prevention of SCD) . The incidence of inappropriate shocks being lesser with dual chamber ICD has not been truly realised in real world scenario.
Recent studies tend to give credence to this perception .(Peterson JAMA 2013)
Dual Chamber ICDs may have an edge only in few situations .
Reference.
Posted in Cardiology - Electrophysiology -Pacemaker, RBBB/LBBB, tagged bundle branch reentry, eelctrophysiology, electrophysiology, ers pattern, moes theory, rentry mechanism, sloe conduction and reentry, theories on genesis of cardiac arrhythmias on February 12, 2015| Leave a Comment »
In the last few decades we have understood a major concept in the genesis of cardiac arrhythmia.Slowing in the propagation of cardiac impulse is a key trigger to precipitate a reentry circuit and initiate a tachy- arrhythmia.Still , many conditions like first degree AV block, chronic RBBB or even LBBB are benign entities as along as the heart is structurally normal .They seem never increase the incidence or life time risk of cardiac arrhythmia . Longevity is unaffected.( Or do we assume many things ?)
How is this possible ? or is the theory of slow conduction triggering reentry is flawed ?
Think again . . . if these patients who later on develop a structural heart disease , with an episode of ACS , myocardial or valvular disease, the original slow conduction substrates these people were harboring , will it become important ?
Surprisingly , we have no answers in literature.When Haissaguerre et al found preexisting ERS pattern could be a trigger for primary VF in case they develop ACS , he opened up a huge debate as it involved converting a vast number of normal population electrically anxious.
Now ,is it possible the so called benign blocks of heart like first degree AV blocks , RBBB , LAHBa , would be important at times of ACS and possibly make them prone for for primary ischemic arrhythmia .
Is bundle branch re-entry possible in structurally normal heart ?
We need answers. Some one , (Any EP fellow) somewhere could take up the issue and enlighten us !
Posted in Cardiology - Electrophysiology -Pacemaker, ICD -Tips and Tricks, ICD and Pacemakers, tagged aicd mirowski, boston scientific icd extedended life, el icd dynogen inogen, icd indication, life of icd, madit study icd on February 10, 2015| Leave a Comment »
ICDs are one of revolutionary devices , invented last century that can defy “death & fate” in high risk cardiac patients who are threatened with ventricular tachycardia or fibrillation .A decade long hard work by Mirowski and team from John Hopkins culminated in the dramatic the first AICD implant in 198o. ( In my opinion, this medical invention can be compared to an event of such significance as moon landing by Armstrong and team ! ) Ironically , in the last decade such a revolutionary device was sort of misused and thousands of devices were explanted for inappropriate indications.
Fortunately , better sense prevailed recently .The indications are getting refined. I am sure ICD will go a long way in prevention of both expected and unexpected sudden electrical deaths .We are into the 4th decade of its evolution.While the electrical circuitry has been mastered , power supply remains an issue as they require continuous power supply like a mobile phone. Current technology allows about 6-8 years of battery life.
Now , Boston scientific has come out with new technology which make its battery life extend by 100% to 12 years. It is a major break through , expected to evolve further until probably we have rechargeable batteries or biological power sources .Stretching a wild thought , the days couldn’t be far off when the smart phones which are omnipresent in every human-being , could not only power the ICD remotely and control it too !
Indications (ESC/AHA 2012)
CAD
Non ischemic structural disease ( Idiopathic DCM, ARVD etc)
Primary electrical disease
Reference
Link to Product manual form Boston scientific.
Posted in Brugada syndrome, Cardiology - Electrophysiology -Pacemaker, cardiology -ECG, Cardiology -Therapeutic dilemma, Cardiology -unresolved questions, tagged av blocks in brugada sysndrome, mechanism of syncope in brugada syndrome, non vt mechansims in brugada, vaso vagal syncope in brugada syndrome on November 29, 2014| 1 Comment »
Brugada syndrome is due to a genetically impaired sodium channel activity ( SCN5A) in phase o, of action potential .This results in phase 1 (Ito channel) failing to inscribe the transition between phase 0 and 1 that result in loss of dome .This loss of dome is dominant in epicardial cells compared to endocardial cells.This result in electrical heterogeneity and a hence a voltage gradient in repolarisation phase that can trigger a Phase 2 reentry mediated VT /VF.The above said defects are either dormant, manifest, self extinguishing , dynamic subjected to autonomic tone , ambient myocardial temperature (Febrile VTs) making this a complex entity.
There are three distinct types according to surface ECG.It can be either spontaneous or induced. The arrhythmic events and prognosis and hence management differs according to the types.
All types carry a minimal risk of SCD , variable though . Of course syncope has to be much more common. Curiously every episode of syncope is seen as naturally aborted SCD by physicians ! (No one to be blamed for this .The definition of syncope is like that !If the patient doesn’t wake from syncope it becomes death !).
When a patient with Brugada has a syncope , it doesn’t imply he experienced a dreaded VT or VF.While SCD is invariably due to ventricular fibrillation , a spontaneously terminating VF as a cause for syncope is rare in Brugada . (Ref 2 : ILRs have documented though in few)
So what exactly is the cause for syncope in Brugada ? The issue is real and critical in clinical decision-making. We are beginning to document variety of mechanisms. Following are the possible causes
Final message
It is to be strongly emphasised a significant subset of Brugada patients especially in Type 1 Brugada (spontaneous or drug induced ) the mechanism of syncope is often not related to the dreaded VT/VF. It can simply represent high vagal tone and unexplained dynamism of autonomic activity .ICD is not a default indication for all those with syncope in Brugada syndrome.Think , pause and decide when you deal with such patients. ICDs are true revolutionary devices . . . no two thoughts about it,but it can make a hell out of heaven if used in an inappropriate situation !
Reference
Posted in bio ethics, Cardiology - Electrophysiology -Pacemaker, Cardiology -Technology, tagged dick cheny and ICD, homeland seral pacemaker hacking icd, Pacemaker and ICD hacking, remote cardiovrsion, remote monitoring of pacemakers icd, wirless connectivity of icd on November 16, 2014| Leave a Comment »
In this wireless networked world nothing is personal, not even your heart beat.Modern pacemakers and ICDs have wireless connectivity with the manufacturers.This is value added service for regular monitoring and solving any technical issues.
Hacking a device like pacemaker and ICD and instant deactivation or triggering a new event is a distinct possibility .It was shown in a fictional TV series “Home land” that prompted the ex American wise president Dick Cheny to switch off all wireless function in his ICD. Now ,the US homeland security cyber emergency response team has decided to probe the issue .
Perils of technology is taking us to new uncharted territories , while your SA AV node are at risk of being remote controlled !
Meanwhile Medtronic has clarified they have increased the security features and pacemaker /ICD hacking is not an issue to be worried . But the threat is genuine !
Reference
1. Frenger P Hacking medical devices a review – Biomed Sci Instrum. biomed 2013.2013;49:40-7
3.Fox news
Posted in Cardiology - Electrophysiology -Pacemaker, Cardiology -Funny events, ICD and Pacemakers, tagged cardaic electrophysiology, crazy cardiology, ICD, icd blocks bulllet, icd complication, unusual beenfits of icd on October 31, 2014| Leave a Comment »
We live in curious times .As we advance in our intellect and wisdom ,bullet firings (either cross or straight !) have become an important cause for sudden cardiac death.Sometimes a life is saved by unexpected way in extraordinary circumstances. Here is a man from Florida , whose life was saved by an ICD not by shocking a VF . . . but by blocking a bullet
A case report from Heart Rhythm
Complete Heart Bullet Block : The Aftermath
It seems ICD is strong enough to stop a bullet !
Posted in cardiac resynchronisation, Cardiology - Electrophysiology -Pacemaker, Cardiology -unresolved questions, Dilated cardiomyopathy, Electro physiology, ICD -Tips and Tricks, Infrequently asked questions in cardiology (iFAQs), Land mark articles in cardiology, Pace maker Tips and tricks, Permanent pacemaker, tagged appropriate and inappropriate shocks post icd, dilated cardiomyopathy, icd in dcm, ICD tips and tricks, ischemic vs non ischemic dcm, myocardial damage following icd shocks, outcome after appropriate shocks on October 5, 2014| Leave a Comment »
Inserting an ICD for DCM may a be great therapeutic success for the physician as well as the patient . But there is one big truth hidden behind the statistical screen.
Following study provides dramatic data from Maanhiem in Germany in about 561 patients who had ICD .The long term patient outcome after appropriate shocks were much worse than those without shocks .This was more pronounced in Ischemic DCM .
Source : Streitner et al ,University Medical Centre Mannheim, Mannheim, Germany PLoS One. 2013 May 10;8(5):e6391
The fact that these patients continue to throw VT , some thing is wrong in the cellular milieu or a fresh scar / fibrosis / ischemia is progressing .Further , the VTs and the subsequent shocks set in temporary hemodynamic instability .We have evidence , EF can be depressed for days worsening the long-term out come.
While it is easy to blame it on natural course of DCM , there are solid reasons to believe , shock induced myocardial damage is definitely contributing to this excess mortality.
One important clinical tip is to screen all these so called Idiopathic DCM patients who had appropriate shocks. They should be monitored for fresh signs of any systemic illness , like a connective tissue disorder , chronic granulomatous lesions like sarcoid etc .To our surprise some specific myocardial disease may unmask themselves in the natural history. Identifying them may offer a dramatic cure .
Final message
Some where along our EP mind-set we are conditioned to think , as along as there is an ICD in situ and it appropriately shocks, every thing is bliss ! Blame it on semantics . The word “appropriate” inappropriately soothes our nerves.
The fact of the mater is , every appropriate shock is a grim reminder that the heart in question is restless electrically and VT continue to emanate from diseased myocardium . It could mean either the LV is destabilising , or the original disease is progressing or a new disease is evolving .
Mean while, paradoxically , inappropriate shocks give us a quixotic comfort , since the heart is not really throwing any dangerous arrhythmia, after all it is the device related false alarm that could be easily reprogrammed!
Reference
Dr.S.Venkatesan MD 