Atrial fibrilation

http://cardiologysearch.blogspot.in/

Atrial fibrillationAtrial fibrillation (Classification, Mechanism & (Classification, Mechanism &

Management)Management)


Introduction…Introduction… AF is characterised by wavelets propagating in different AF is characterised by wavelets propagating in different

directions causing disorganized atrial depolarization directions causing disorganized atrial depolarization without effective atrial contractionwithout effective atrial contraction

Electrical activity of atrium can be detected in ECG as Electrical activity of atrium can be detected in ECG as small irregular baseline undulations of variable small irregular baseline undulations of variable amplitude & morphology (f waves) at rate of 350 to 600amplitude & morphology (f waves) at rate of 350 to 600

Ventricular response is irregularly irregular, & in Ventricular response is irregularly irregular, & in untreated patients with normal AV conduction, is untreated patients with normal AV conduction, is usually between 100 to 160usually between 100 to 160

WPWsyndrome ventricular rate may be rapid >300 due WPWsyndrome ventricular rate may be rapid >300 due to conduction over accessory pathway( short antegrade to conduction over accessory pathway( short antegrade refractory periods) refractory periods)


Introduction…Introduction…

ventricular rate during AF is altered ventricular rate during AF is altered due todue to

Autonomic toneAutonomic toneProperty of AV nodeProperty of AV nodeEffect of drugs on AV conductionEffect of drugs on AV conduction


Atrial fibrillation is the most common arrhythmia & Atrial fibrillation is the most common arrhythmia & the incidence & prevalence increases with the agethe incidence & prevalence increases with the age

The incidenceThe incidence <0.5% below 50Yrs<0.5% below 50Yrs 2% in age 60-692% in age 60-69 4.6% in age 70-794.6% in age 70-79 8.8% in age 80-898.8% in age 80-89

Men were 1.5 times more likely to develop AF than Men were 1.5 times more likely to develop AF than womenwomen

Whites were more likely to develop AF than blacksWhites were more likely to develop AF than blacks

IntroductionIntroduction


Framingham heart studyFramingham heart study ---cardiac ---cardiac factor predicting AFfactor predicting AF

• CHFCHF• RHDRHD• HTHT• StrokeStroke• Left atrial enlargementLeft atrial enlargement• Increased LV wall thicknessIncreased LV wall thickness• Decreased LV fractional shorteningDecreased LV fractional shortening


Relative risk of stroke - 6 fold in non Relative risk of stroke - 6 fold in non rheumatic AFrheumatic AF

Relative risk of stroke - 17 fold in Relative risk of stroke - 17 fold in rheumatic AFrheumatic AF

Annual risk of stroke in pt aged 50-Annual risk of stroke in pt aged 50-59:1.5%59:1.5%

Annual risk of stroke in aged 80-Annual risk of stroke in aged 80-89:23.5%89:23.5%


Underlying causes of AFUnderlying causes of AF

CVS CVS Rheumatic heart diseaseRheumatic heart disease ASDASD Cardiac surgeryCardiac surgery CardiomyopathyCardiomyopathy HypertrophicHypertrophic IdiopathicIdiopathic InfiltrativeInfiltrative HypertensionHypertension CAD (Acute & chronic)CAD (Acute & chronic) MVPSMVPS Non rheumatic mitral or Non rheumatic mitral or

tricuspid valve diseasetricuspid valve disease PericarditisPericarditis Tacycardia-bradycardia Tacycardia-bradycardia

syndromesyndrome

TumorsTumors WPW syndromeWPW syndrome SystemicSystemic Alcohol (holiday heart Alcohol (holiday heart

syndrome)syndrome) CVACVA COPDCOPD DefibrillationDefibrillation EffortEffort ElectrocutionElectrocution Electrolyte abnormalitiesElectrolyte abnormalities FeverFever HypothermiaHypothermia


PneumoniaPneumonia Pulmonary embolismPulmonary embolism Sudden emotionSudden emotion ThyrotoxicosisThyrotoxicosis TraumaTrauma RareRare Acute hypovolemiaAcute hypovolemia

CongenitalCongenital Multiple sclerosisMultiple sclerosis Muscular dystrophyMuscular dystrophy PheochromocytomaPheochromocytoma Right atrial cold Right atrial cold

injectionsinjections SwallowingSwallowing Tyramine foodsTyramine foods

Underlying causes of AF…Underlying causes of AF…


Classification of Atrial fibrillationClassification of Atrial fibrillation


Classification of Atrial Classification of Atrial fibrillationfibrillation

First detected AFFirst detected AF -usually <48hr -usually <48hr in AF during diagnosisin AF during diagnosis

Paraoxysmal AFParaoxysmal AF - last < 7days - last < 7days (most<24hrs) self-terminating (most<24hrs) self-terminating episodesepisodes

Persistent AFPersistent AF - last >7days - last >7days requires electrical or pharmacologic requires electrical or pharmacologic cardioversioncardioversion

Permanent AFPermanent AF - sustained >1yr & - sustained >1yr & failed cardioversion failed cardioversion


It was first thought that irregular contractions of the atria It was first thought that irregular contractions of the atria are caused by either single or multiple fociare caused by either single or multiple foci

In 1924, In 1924, GarryGarry had suggested reentry to be the mechanism had suggested reentry to be the mechanism behind the AFbehind the AF

In 1960, In 1960, MoeMoe suggested the suggested the ““multiple wavelet multiple wavelet hypothesishypothesis” ”

AF is characterized by fragmentation of a wavefront into AF is characterized by fragmentation of a wavefront into multiple, independent daughter wavelets that move multiple, independent daughter wavelets that move randomly throughout the atrium, giving rise to new wavelets randomly throughout the atrium, giving rise to new wavelets that collide with each other & mutually annihilate, or that that collide with each other & mutually annihilate, or that give rise to new wavelets in a perpetual activity that give rise to new wavelets in a perpetual activity that resembles Brownian motionresembles Brownian motion

MechanismsMechanisms


Stability of AF is a function of several Stability of AF is a function of several factorsfactors

Non-uniform distribution of refractory periodsNon-uniform distribution of refractory periods

Specially large tissue areaSpecially large tissue area

Either a relatively brief refractory period or a Either a relatively brief refractory period or a relatively slow conduction velocity of the relatively slow conduction velocity of the impulse, or bothimpulse, or both

Average no. of the waveletsAverage no. of the wavelets

Allessie et al,Allessie et al, estimated the critical no. of estimated the critical no. of wavelets to sustain AF was approximately 4 - 6 wavelets to sustain AF was approximately 4 - 6






Trigger factor - self-terminating AFTrigger factor - self-terminating AFPerpetuating factor - AF does not Perpetuating factor - AF does not

terminate spontaneouslyterminate spontaneouslyParaoxysmal AF - 95% of Triggering Paraoxysmal AF - 95% of Triggering

foci are mapped in pulmonary veinfoci are mapped in pulmonary veinOther foci - within SVC ,coronary Other foci - within SVC ,coronary

sinussinus

http://cardiologysearch.blogspot.in/Anatomic distribution of Anatomic distribution of

focal trigger in focal trigger in Paraoxysmal AFParaoxysmal AF


Waldo et alWaldo et al divided AF into 4 types according divided AF into 4 types according atrial electrogramatrial electrogram

• Type – IType – I --- ECG showed discrete complexes of --- ECG showed discrete complexes of variable morphology separated by a clear variable morphology separated by a clear isoelectric baselineisoelectric baseline

• Type – IIType – II --- ECG characterized by discrete atrial --- ECG characterized by discrete atrial complexes with variable cycle lengths and complexes with variable cycle lengths and morphology, the baseline is not isoelectric morphology, the baseline is not isoelectric

• Type – IIIType – III --- ECGs were highly fragmented, --- ECGs were highly fragmented, showing no discrete complexes or isoelectric showing no discrete complexes or isoelectric intervalsintervals

• Type – IVType – IV --- Fibrillation was characterized by --- Fibrillation was characterized by alterations between type III & other typesalterations between type III & other types



““f” wavesf” waves They do not represent total atrial activity but depict They do not represent total atrial activity but depict

only the larger vectors generated by the multiple only the larger vectors generated by the multiple wavelets of depolarization that occur at any given timewavelets of depolarization that occur at any given time

Why ventricular response is irregularly irregular?Why ventricular response is irregularly irregular? Large no. of atrial impulses that penetrate the AV node, Large no. of atrial impulses that penetrate the AV node,

makes it partially refractory to subsequent impulsesmakes it partially refractory to subsequent impulses

These effect of non conducted atrial impulses to These effect of non conducted atrial impulses to influence the response of subsequent atrial impulse is influence the response of subsequent atrial impulse is called as called as “concealed conduction”“concealed conduction”



Electrical remodellingElectrical remodelling It means long term changes in refractory periods It means long term changes in refractory periods

resulting from prolonged changes in atrial rateresulting from prolonged changes in atrial rate EPS EPS --- --- ↓ERP,↓↓ERP,↓Action potential, Action potential, ↓↓ amplitude of AP amplitude of AP

plateauplateau MechanismsMechanisms --- Structural , cellular or ion channels It --- Structural , cellular or ion channels It

encompasses diverse structural changes in the encompasses diverse structural changes in the myocardium -interstitial fibrosismyocardium -interstitial fibrosis

Alteration in quantity or properties of ion channel Alteration in quantity or properties of ion channel proteins in sarcolemmaproteins in sarcolemma

Microscopic changes in cell size , content & extra Microscopic changes in cell size , content & extra cellular matrix leads to irreversible macroscopic changescellular matrix leads to irreversible macroscopic changes



Maladoptations of atrial refractionaries – cause of Maladoptations of atrial refractionaries – cause of chronic AFchronic AF

Atrial remodellingAtrial remodelling Caused by atrial ischemia & stretch leads to AF due Caused by atrial ischemia & stretch leads to AF due

to to ↑ ↑ automaticity & reentry automaticity & reentry

After AF has continued for a long time, atria are not After AF has continued for a long time, atria are not only electrically remodelled, but atrial contractile only electrically remodelled, but atrial contractile function is also disturbedfunction is also disturbed

Recovery of atrial transport function may depend upon Recovery of atrial transport function may depend upon duration of AFduration of AF

After sinus rhythm is restored, it may take several After sinus rhythm is restored, it may take several weeks before atrial contractility fully returnsweeks before atrial contractility fully returns



Modulating factorsModulating factors The onset & persistence of AF may be modulated by The onset & persistence of AF may be modulated by

autonomic nervous systemautonomic nervous system

Coumel etCoumel et al distinguished vagal & adrenergic AF al distinguished vagal & adrenergic AF (distinction is not clear)(distinction is not clear)

Vagally mediated AFVagally mediated AF Occurs more frequently in men than in womenOccurs more frequently in men than in women

Usually younger age group (30 – 50 years)Usually younger age group (30 – 50 years)



Predominantly occurs in the absence of structural heart Predominantly occurs in the absence of structural heart diseasedisease

Rarely progresses to permanent AFRarely progresses to permanent AF

Attacks occur at night, end of the morningAttacks occur at night, end of the morning

Neither emotional stress nor exertion trigger the arrhythmia Neither emotional stress nor exertion trigger the arrhythmia

Rest, postprandial state, & alcohol are other precipitating Rest, postprandial state, & alcohol are other precipitating factorsfactors

Mechanism may relate to vagally induced shortening of the Mechanism may relate to vagally induced shortening of the atrial refractory periodatrial refractory period



Adrenergic AFAdrenergic AF More frequently associated with structural heart More frequently associated with structural heart

disease (IHD)disease (IHD)

Occurs during the day time, & it is precipitated by Occurs during the day time, & it is precipitated by stress, exercise, tea, coffee or alcoholstress, exercise, tea, coffee or alcohol

The underlying mechanism is unknownThe underlying mechanism is unknown



Hemodynamic effectHemodynamic effect

Loss of atrial contractionLoss of atrial contractionRapid ventricular rate - Rapid ventricular rate - ↓duration of ↓duration of

diastole & ventricular fillingdiastole & ventricular filling irregular ventricular rhythm - irregular ventricular rhythm - ↓ CO & ↓ CO &

coronary blood flowcoronary blood flowLoss of AV synchrony - Loss of AV synchrony - ↓LVEDP - ↓SV↓LVEDP - ↓SVAF causes hypotension or pulmonary AF causes hypotension or pulmonary

oedema in the setting of restrictive oedema in the setting of restrictive physiologyphysiology

http://cardiologysearch.blogspot.in/Antiarrhythmic therapy of atrial Antiarrhythmic therapy of atrial

fibrillationfibrillation Three antiarrhythmic strategiesThree antiarrhythmic strategies Acute pharmacologic terminationAcute pharmacologic termination Prevention of recurrence after cardioversionPrevention of recurrence after cardioversion Control of ventricular rate Control of ventricular rate Acute conversion of paroxysmal AFAcute conversion of paroxysmal AF Pharmacologic cardioversionPharmacologic cardioversion Most effective if initiated within 7 days after onset of AFMost effective if initiated within 7 days after onset of AF Restoration of sinus rhythm can be achieved in 70% of Restoration of sinus rhythm can be achieved in 70% of

the patientsthe patients First choiceFirst choice: Propafenone & flecainide (po & iv), : Propafenone & flecainide (po & iv),

ibutilide, dofetilideibutilide, dofetilide Second choiceSecond choice: Amaiodarone (high dose, iv +oral) & : Amaiodarone (high dose, iv +oral) &

Qunidine (po)Qunidine (po)

http://cardiologysearch.blogspot.in/Antiarrhythmic to maintain sinus rhythm Antiarrhythmic to maintain sinus rhythm in AFin AF


Class IC drugsClass IC drugs – Restore sinus rhythm with in a – Restore sinus rhythm with in a short period of time ( 1 hour) – conversion rate up to short period of time ( 1 hour) – conversion rate up to 90% (PAFIT-3)90% (PAFIT-3)

IbutilideIbutilide It acts twice more effectively for conversion of atrial It acts twice more effectively for conversion of atrial

flutter than atrial fibrillation (63% v 31%)flutter than atrial fibrillation (63% v 31%)

Efficacy decreased significantly with AF of >7 daysEfficacy decreased significantly with AF of >7 days

Studies, enrolled patients with mild to moderate Studies, enrolled patients with mild to moderate underlying disease, so these results may not be underlying disease, so these results may not be generalizable to patients with markedly depressed LVFgeneralizable to patients with markedly depressed LVF

Antiarrhythmic therapy of atrial Antiarrhythmic therapy of atrial fibrillationfibrillation


Dofetilide Dofetilide DIAMOND-CHFDIAMOND-CHF Study of 1518 patients with symptomatic heart failure Study of 1518 patients with symptomatic heart failure

(EF <35%)(EF <35%)

Therapy with 1000mic.g was associated with a greater Therapy with 1000mic.g was associated with a greater rate of conversion to sinus rhythm (44% v14%)rate of conversion to sinus rhythm (44% v14%)

SAFIRE-DSAFIRE-D Study of 325 patients with persistent AF &/or atrial flutterStudy of 325 patients with persistent AF &/or atrial flutter

Cardioversion rates were 6.1%,9.8% & 29.9% for 125, Cardioversion rates were 6.1%,9.8% & 29.9% for 125, 250 & 500mic.g bid compared with 1.2% of conversion 250 & 500mic.g bid compared with 1.2% of conversion with placebowith placebo



AmiodaroneAmiodarone Produce sinus rhythm in 80% within 24hours (late Produce sinus rhythm in 80% within 24hours (late

conversion)conversion) AdvantagesAdvantages It lowers ventricular rate before conversion (IC drugs It lowers ventricular rate before conversion (IC drugs

increase the rate)increase the rate) Recommended in hemodynamically compromised Recommended in hemodynamically compromised

patients since it is less negatively inotropicpatients since it is less negatively inotropic Prefered in pts with LVF, LVH, IHDPrefered in pts with LVF, LVH, IHD IV amiodarone is moderately effective in converting AF IV amiodarone is moderately effective in converting AF

compared with placebo (63% v 44%), with maximum compared with placebo (63% v 44%), with maximum effect at 24hours (74% v 55%) --- 12 meta-analysiseffect at 24hours (74% v 55%) --- 12 meta-analysis

Higher than usual dose & combination of IV & oral Higher than usual dose & combination of IV & oral administration may enhance the cardioversion rate administration may enhance the cardioversion rate



QuinidineQuinidine Usually administered in conjunction with B-BlockerUsually administered in conjunction with B-Blocker

Cumulative dose of up to 1350mg has shown to Cumulative dose of up to 1350mg has shown to cardiovert 50-77% of patients with cardiovert 50-77% of patients with recent onset AFrecent onset AF

SotalolSotalol It is ineffective in acute conversionIt is ineffective in acute conversion

It is effective for the prevention of AFIt is effective for the prevention of AF

This discrepancy relates to its property to prolong the This discrepancy relates to its property to prolong the refractory period predominantly at lower atrial rates, refractory period predominantly at lower atrial rates, but not during rapid AF but not during rapid AF



Availability of studies on the efficacy of procainamide & Availability of studies on the efficacy of procainamide & disopyramide is limited, precluding definite conclusions disopyramide is limited, precluding definite conclusions

Digitalis, B-Blockers, & CCBs are ineffective for acute Digitalis, B-Blockers, & CCBs are ineffective for acute conversion of AFconversion of AF

DAAF study (Digoxin in acute AF)DAAF study (Digoxin in acute AF) There was no difference in cardioversion rates at 16 There was no difference in cardioversion rates at 16

hours between IV digoxin & placebo (51% v 46%) hours between IV digoxin & placebo (51% v 46%)

Digoxin can Digoxin can facilitate AFfacilitate AF due to its cholinergic effects due to its cholinergic effects which may cause a non-uniform reduction in conduction which may cause a non-uniform reduction in conduction velocity & effective refractory periods of the atria, and to velocity & effective refractory periods of the atria, and to delay the reversal of remodellingdelay the reversal of remodelling after restoration of after restoration of sinus rhythmsinus rhythm



Conversion of paroxysmal AF(<3days)Conversion of paroxysmal AF(<3days)


Prevention of paroxysmal AFPrevention of paroxysmal AF No need for prophylactic AADNo need for prophylactic AAD After first episode of AF which may self terminate or After first episode of AF which may self terminate or

require electrical or pharmacologic cardioversionrequire electrical or pharmacologic cardioversion

Patients with infrequent, self limiting & well tolerated Patients with infrequent, self limiting & well tolerated paroxysms of AFparoxysms of AF

Prophylactic AAD are recommended ifProphylactic AAD are recommended if Occurs frequently (1 episode per 3 months)Occurs frequently (1 episode per 3 months)

Associated with significant symptomsAssociated with significant symptoms



Prophylactic AAD are recommended if…Prophylactic AAD are recommended if… Worsening of LV functionWorsening of LV function

In the presence of left atrial enlargement, LVD, In the presence of left atrial enlargement, LVD, underlying CVS pathology, long duration of AF, underlying CVS pathology, long duration of AF, advanced ageadvanced age

B-blockersB-blockers Effective in adrenergic dependent AF (class IA & IC are Effective in adrenergic dependent AF (class IA & IC are

ineffective) ineffective)

It prevents the recurrence of persistent AF after It prevents the recurrence of persistent AF after cardioversion cardioversion



Control of ventricular rate during paroxysmal AFControl of ventricular rate during paroxysmal AF Digitalis, B-blockers, CCBs are useful Digitalis, B-blockers, CCBs are useful

Addition of rate controlling drugs is necessary with class IA Addition of rate controlling drugs is necessary with class IA & IC drugs (not needed with amiodarone or sotalol)& IC drugs (not needed with amiodarone or sotalol)

Control of ventricular rate Control of ventricular rate in the setting of SSSin the setting of SSS may be may be impossible without implanting pacemakerimpossible without implanting pacemaker

In WPW syndromeIn WPW syndrome complicated by AF – acute rate control complicated by AF – acute rate control & conversion to SR may be achieved by & conversion to SR may be achieved by procainamide or procainamide or flecainideflecainide




Antithrombotic therapyAntithrombotic therapy Whether AF is persistent or intermittent --- Whether AF is persistent or intermittent ---

Predisposes to strokePredisposes to stroke Non valvular AFNon valvular AF Most common cardiac disease associated with Most common cardiac disease associated with

cerebral embolism cerebral embolism The risk of stroke is 5-7 times greater when The risk of stroke is 5-7 times greater when

compared to control groupcompared to control group Risk factors that predicts strokeRisk factors that predicts stroke Previous stroke or TIAPrevious stroke or TIA Diabetes mellitus Diabetes mellitus Systemic hypertensionSystemic hypertension Increasing ageIncreasing age CADCAD CHFCHF


LV dysfunction & left atrial size > 2.5cm/sq.m --- LV dysfunction & left atrial size > 2.5cm/sq.m --- associated with thromboembolismassociated with thromboembolism

Age - 60-65, normal echo, no risk factors --- Age - 60-65, normal echo, no risk factors --- Extremely low risk for stroke (1% per year)Extremely low risk for stroke (1% per year)

Results from 5 large anticoagulation Results from 5 large anticoagulation trails trails

Annual rate of stroke in control group --- 4.5%Annual rate of stroke in control group --- 4.5%

Annual rate of stroke in warfarin-treated group --- Annual rate of stroke in warfarin-treated group --- 1.4% (68% risk reduction)1.4% (68% risk reduction)

Aspirin 325mg/d produced a risk reduction of 44%Aspirin 325mg/d produced a risk reduction of 44%

Antithrombotic therapyAntithrombotic therapy


Annual rate of major hemorrhageAnnual rate of major hemorrhage Control group --- 1%Control group --- 1%

Aspirin group --- 1%Aspirin group --- 1%

Warfarin group --- 1.3%Warfarin group --- 1.3%

No difference was noted in stroke risk, when patients No difference was noted in stroke risk, when patients with paroxysmal (intermittent) AF were compared with paroxysmal (intermittent) AF were compared with chronic AFwith chronic AF

Anticoagulation was 50% more effective than aspirin Anticoagulation was 50% more effective than aspirin in preventing ischemic strokein preventing ischemic stroke



Risk factors for strokeRisk factors for stroke Prior stroke or TIAPrior stroke or TIA Significant valvular heart diseaseSignificant valvular heart disease HypertensionHypertension Diabetes mellitusDiabetes mellitus Age >65 yearsAge >65 years Left atrial enlargementLeft atrial enlargement CADCAD Congestive heart failureCongestive heart failure



Lone AFLone AF Age <60years, no risk factorsAge <60years, no risk factors ---No antithrombotic ---No antithrombotic

therapytherapy

Age - 60-75 years (risk-2%per year)Age - 60-75 years (risk-2%per year) ---Aspirin ---Aspirin

Age > 75 yearsAge > 75 years --- Anticoagulation (INR – 2.0) --- Anticoagulation (INR – 2.0)

Any patients with AF + Risk factors for strokeAny patients with AF + Risk factors for stroke --- --- Treated with warfarin anticoagulation (INR – 2 to 3)Treated with warfarin anticoagulation (INR – 2 to 3)

Patients with contraindication to anticoagulation (or) Patients with contraindication to anticoagulation (or) unreliable individualunreliable individual (or) (or) no risk factorsno risk factors --- Aspirin --- Aspirin



Risk of embolism after cardioversionRisk of embolism after cardioversion Risk --- 0 -7%Risk --- 0 -7%

Risk is independent of mode of cardioversionRisk is independent of mode of cardioversion High risk patients areHigh risk patients are Prior embolism, Mechanical valve prosthesis, Mitral Prior embolism, Mechanical valve prosthesis, Mitral

stenosisstenosis

In AF (>2d)In AF (>2d) --- Warfarin for 3 weeks before cardioversion --- Warfarin for 3 weeks before cardioversion + 3-4 weeks after reversion to sinus rhythm+ 3-4 weeks after reversion to sinus rhythm

Alternate strategyAlternate strategy --- TEE (to exclude LA thrombus) + --- TEE (to exclude LA thrombus) + heparin before cardioversion + followed by warfarin for heparin before cardioversion + followed by warfarin for 4weeks4weeks



Risk of embolism after cardioversion…Risk of embolism after cardioversion… For emergency cardioversion (TEE cannot be For emergency cardioversion (TEE cannot be

obtained)obtained) --- heparin before cardioversion + followed --- heparin before cardioversion + followed by warfarin for 4weeksby warfarin for 4weeks

Low risk patientsLow risk patients Age <65 years without risk factor for stroke in Age <65 years without risk factor for stroke in

nonvalvular AFnonvalvular AF

Anticoagulation may not be necessary before Anticoagulation may not be necessary before cardioversion but aspirin is indicatedcardioversion but aspirin is indicated

It is important to emphasize that suggestions must be It is important to emphasize that suggestions must be individualized for a given patientindividualized for a given patient

Absolute contraindication for anticoagulation - Absolute contraindication for anticoagulation - ICH,SDH,GI bleedICH,SDH,GI bleed



Non – pharmacologic therapiesNon – pharmacologic therapies

Rhythm control strategiesRhythm control strategies Device therapyDevice therapy Single site pacingSingle site pacing --- High right atrial & septal --- High right atrial & septal In many patients with SSS, atrial pacmaker allows In many patients with SSS, atrial pacmaker allows

higher dose of AAD since sinus node dysfunction is higher dose of AAD since sinus node dysfunction is treatedtreated

In patients with paroxysmal AF, there is evidence for In patients with paroxysmal AF, there is evidence for intraatrial conduction delayintraatrial conduction delay

Atrial pacing may decrease the frequency of recurrent Atrial pacing may decrease the frequency of recurrent AF in patients who have SSSAF in patients who have SSS


Incidence of AF is lower in patients treated by Incidence of AF is lower in patients treated by atrial pacing than ventricular pacing atrial pacing than ventricular pacing (prospective studies)(prospective studies)

Multisite pacingMultisite pacing --- Biatrial synchronous & Dual --- Biatrial synchronous & Dual site atrial pacingsite atrial pacing

In addition to the high RA lead, another atrial In addition to the high RA lead, another atrial lead is placed just outside the CS ostium for lead is placed just outside the CS ostium for stability & LA synchronization stability & LA synchronization

These pacing cause resynchronization of atrial These pacing cause resynchronization of atrial depolarisation & helpful in patients with intra depolarisation & helpful in patients with intra atrial conduction delayatrial conduction delay



Usually performed in patients with recurrent, Usually performed in patients with recurrent, symptomatic & drug refractory AFsymptomatic & drug refractory AF

ECG showed biphasic ‘p’ wave in inferior leads ECG showed biphasic ‘p’ wave in inferior leads with abbreviation of ‘P’ wave durationwith abbreviation of ‘P’ wave duration

Implantable atrial defibrillatorImplantable atrial defibrillator

Automatic atrial defibrillatorAutomatic atrial defibrillator• It detect AF by means of implanted RA, CS & RV It detect AF by means of implanted RA, CS & RV

leadsleads



• It delivers ‘R’ wave synchronization shock of 6J It delivers ‘R’ wave synchronization shock of 6J after a minimal preceding R-R interval of 500 msafter a minimal preceding R-R interval of 500 ms

• Unfortunately this device in its current form is not Unfortunately this device in its current form is not in usein use

Atrial-ventricular defibrillator/pacemaker Atrial-ventricular defibrillator/pacemaker • It has dual chamber algorithm-based arrhythmia It has dual chamber algorithm-based arrhythmia

detectiondetection

• Pacing & defibrillation therapies for treatment of Pacing & defibrillation therapies for treatment of AF & atrial tachycardiasAF & atrial tachycardias

• Therapy for VT/VFTherapy for VT/VF



Ablation therapy --- surgicalAblation therapy --- surgical His bundle ablationHis bundle ablation (surgical ligation, mechanical, (surgical ligation, mechanical,

cryothermia) + Pace maker implantationcryothermia) + Pace maker implantation

Corridor surgeryCorridor surgery Creating an isolated strip of muscle to isolate the SA & Creating an isolated strip of muscle to isolate the SA &

AV nodes, thus driving ventricular rate via AV node-His AV nodes, thus driving ventricular rate via AV node-His bundle complexbundle complex

But, atrial areas outside of narrow RA corridor continued But, atrial areas outside of narrow RA corridor continued to fibrillate with persistent loss of atrial transport to fibrillate with persistent loss of atrial transport function & persistent risk of thromboembolismfunction & persistent risk of thromboembolism




Maze procedureMaze procedure The principle is compartmentalize both atria so The principle is compartmentalize both atria so

that AF cannot be maintainedthat AF cannot be maintained

Right & left atrial appendages were resected, Right & left atrial appendages were resected, pulmonary vein ostia are isolated, linear RA & pulmonary vein ostia are isolated, linear RA & LA lesions are connected to anatomic structures LA lesions are connected to anatomic structures to form an to form an “electrical maze” --- “Maze 3”“electrical maze” --- “Maze 3”

Appropriately placed atrial incisions not only Appropriately placed atrial incisions not only interrupt the conduction routes of reentrant interrupt the conduction routes of reentrant circuits, but they also direct the sinus impulse circuits, but they also direct the sinus impulse from SA to AV along a specified routefrom SA to AV along a specified route



Indication for maze procedureIndication for maze procedure

Symptomatic AFSymptomatic AFRefractory to AAD Refractory to AAD Recurrent systemic embolism despite Recurrent systemic embolism despite

anticoagulationanticoagulation


Maze procedureMaze procedure 90% pt cured of AF with operative mortality <190% pt cured of AF with operative mortality <1

<10% requires PPI due to sinus node <10% requires PPI due to sinus node dysfunctiondysfunction

Transient fluid retention due to Transient fluid retention due to ↓atrial ↓atrial natriuretic peptide must be treated with natriuretic peptide must be treated with diureticsdiuretics

The entire atrial myocardium was electrically The entire atrial myocardium was electrically activated & atrial transport function is activated & atrial transport function is preservedpreserved




Tans catheter ablation therapyTans catheter ablation therapy Linear atrial ablationLinear atrial ablation (Radiofrequency) (Radiofrequency) It is employed in LA & RA for substrate It is employed in LA & RA for substrate

compartmentalizationcompartmentalization

Trigger ablationTrigger ablation (Radiofrequency) (Radiofrequency) Focal pulmonary veinFocal pulmonary vein Pulmonary vein isolation - transseptal puncture Pulmonary vein isolation - transseptal puncture

followed by pulmonary venography to define anatomyfollowed by pulmonary venography to define anatomy

Adverse effect Adverse effect StrokeStroke Phrenic nerve injuryPhrenic nerve injury Pericardial effusion & tamponadePericardial effusion & tamponade Pulmonary vein stenosisPulmonary vein stenosis



Indication for ablationIndication for ablation

Symptomatic AF Symptomatic AF Refractory to AAD Refractory to AAD Without structural heart diseaseWithout structural heart disease


Rate control strategyRate control strategy Catheter AV junctional modificationCatheter AV junctional modification (radiofrequency) (radiofrequency) PrinciplePrinciple --- Posterior inputs of AV node have shorter ERP, --- Posterior inputs of AV node have shorter ERP,

their ablation slows the ventricular response during AFtheir ablation slows the ventricular response during AF

Patient who becomes symptomatic due rapid ventricular Patient who becomes symptomatic due rapid ventricular response will benefitresponse will benefit

Currently, AV node modification is usually reserved for Currently, AV node modification is usually reserved for patients who require non-pharmacologic control but are patients who require non-pharmacologic control but are opposed to pacemaker implantationopposed to pacemaker implantation



Catheter ablation (DC shock or radiofrequency) + Catheter ablation (DC shock or radiofrequency) + PacemakerPacemaker

It is performed in patients with unmanageable symptoms It is performed in patients with unmanageable symptoms related to rapid ventricular response related to rapid ventricular response

DC current ablation is highly dangerous --- produce electrical DC current ablation is highly dangerous --- produce electrical arcing & barotrauma ( cardiac perforation, tamponade, arcing & barotrauma ( cardiac perforation, tamponade, acute depression of LV, proarrhythmia & sudden deathacute depression of LV, proarrhythmia & sudden death

Radiofrequency ablation ---avoid complicationsRadiofrequency ablation ---avoid complications DisadvantagesDisadvantages Dependence on pacemakerDependence on pacemaker

Atria will continue to fibrillate --- need long term Atria will continue to fibrillate --- need long term anticoagulationanticoagulation



Choice of pace maker typeChoice of pace maker type --- determined by the current --- determined by the current phase of AFphase of AF

Chronic AF --- VVIR + AV nodal ablationChronic AF --- VVIR + AV nodal ablation

Paroxysmal AF ( usually in sinus rhythm between Paroxysmal AF ( usually in sinus rhythm between episodes) --- Dual-chamber pacemaker with mode episodes) --- Dual-chamber pacemaker with mode switchingswitching

Stroke prevention strategyStroke prevention strategy Percutaneous LA appendage transcatheter Percutaneous LA appendage transcatheter

occlusion (PLAATO)occlusion (PLAATO)

Involves insertion of an occlusion device by catheter into Involves insertion of an occlusion device by catheter into the LA appendage via trans septal puncturethe LA appendage via trans septal puncture


http://cardiologysearch.blogspot.in/A circular mapping catheter is in the ostium of the left A circular mapping catheter is in the ostium of the left lower PV and an ablation catheter with a large-tip lower PV and an ablation catheter with a large-tip

electrode is recording a PV potential from the nearby electrode is recording a PV potential from the nearby

strandstrand. .

http://cardiologysearch.blogspot.in/During radiofrequency ablation near Lasso-8 During radiofrequency ablation near Lasso-8 recording site, the sharp PVPs are seen in the recording site, the sharp PVPs are seen in the first two beats but are absent during the last first two beats but are absent during the last

two beatstwo beats



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IntroductionIntroduction

Paroxysmal AFParoxysmal AF Short lasting < 1 hourShort lasting < 1 hour Long lasting >1; < 48 hours Long lasting >1; < 48 hours AF interspersed with periods of sinus rhythm & usually AF interspersed with periods of sinus rhythm & usually

terminates spontaneouslyterminates spontaneously Persistent AFPersistent AF Occur between 2days - weeksOccur between 2days - weeks Intervention is needed to restore the sinus rythumIntervention is needed to restore the sinus rythum Chronic or permanent AFChronic or permanent AF Persists for months to yearsPersists for months to years No spontaneous conversion No spontaneous conversion Interventions to restore sinus rythum are either Interventions to restore sinus rythum are either

ineffectual or not triedineffectual or not tried



Type – IType – I --- Activation consisted of single, broad --- Activation consisted of single, broad wavefronts propagating without conduction delay & either wavefronts propagating without conduction delay & either only short arcs of conduction block or small areas of slow only short arcs of conduction block or small areas of slow conduction that did not disrupt the main course of conduction that did not disrupt the main course of propagationpropagation

Type – IIType – II --- Activation consisted of either the presence of --- Activation consisted of either the presence of 2 wavelets or of single wave (with either considerable 2 wavelets or of single wave (with either considerable conduction block or slow conduction or both)conduction block or slow conduction or both)

Type – IIIType – III --- Activation was characterized by 3 or more --- Activation was characterized by 3 or more wavelets combined with areas of slow conduction & wavelets combined with areas of slow conduction & multiple arcs of conduction blockmultiple arcs of conduction block

As the fibrillation changed from type I to III, AFs frequency As the fibrillation changed from type I to III, AFs frequency & irregularity increased, creating a higher incidence of & irregularity increased, creating a higher incidence of continuous electrical activity & reentrycontinuous electrical activity & reentry



Familial AF Familial AF • Genetic predisposition – is a hypothesisGenetic predisposition – is a hypothesis

• Defect linked to Defect linked to chromosome 10qchromosome 10q (21 of 49 members (21 of 49 members from 3 spanish families presented with AF)from 3 spanish families presented with AF)

• Missense mutation in the Missense mutation in the lamin A/C genelamin A/C gene (In DCM – (In DCM – associated with AF)associated with AF)

• Missense mutationMissense mutation Arg663His Arg663His ( In specific phenotype of ( In specific phenotype of HCM – associated with 47% of AF)HCM – associated with 47% of AF)



Rate control in atrial fibrillationRate control in atrial fibrillation


Rate control in atrial fibrillationRate control in atrial fibrillation






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Health & Medicine

Atrial fibrilation