Management of Post-Management of Post-Cardiac Surgery Cardiac Surgery

Ventricular ArrhythmiasVentricular Arrhythmias

Salah Eldin Atta, MDSalah Eldin Atta, MDConsultant Electrophysiology,Consultant Electrophysiology,

SBCC, Al-Dammam, KSASBCC, Al-Dammam, KSA

Associate Professor of Cardiology, Associate Professor of Cardiology,

Assiut University, EgyptAssiut University, Egypt

Objectives:Objectives: Importance and Epidemiology of Importance and Epidemiology of

Ventricular Arrhythmias after cardiac Ventricular Arrhythmias after cardiac surgery.surgery.

Aetiology and mechanisms.Aetiology and mechanisms. Diagnosis and Risk assessment Diagnosis and Risk assessment Acute management of different types of Acute management of different types of

post operative Ventricular Arrhythmiaspost operative Ventricular Arrhythmias Long term management.Long term management.

Why to bother about postoperative Why to bother about postoperative Ventricular Rhythms/Arrhythmias?Ventricular Rhythms/Arrhythmias?

Indicator of irritability in the ventricles that Indicator of irritability in the ventricles that may be an alarm of a serious aetiology.may be an alarm of a serious aetiology.

Haemodynamic effects due to loss of atrial Haemodynamic effects due to loss of atrial kick, and dys-synchrony in the contraction kick, and dys-synchrony in the contraction which can significantly decrease cardiac which can significantly decrease cardiac output specially with ↑ rate.output specially with ↑ rate.

Evidence of relation to worse outcome.Evidence of relation to worse outcome.

EPIDEMIOLOGIC FEATURESEPIDEMIOLOGIC FEATURES Venricular ectopy, including non sustained Venricular ectopy, including non sustained

ventricular tachycardia (NSVT) is seen in about ventricular tachycardia (NSVT) is seen in about 50% of patients during and after cardiac 50% of patients during and after cardiac surgery but are not related to mortality if with surgery but are not related to mortality if with good LV function.good LV function.

Conversely, Sustained VT and ventricular Conversely, Sustained VT and ventricular fibrillation occur rarely after cardiac surgery fibrillation occur rarely after cardiac surgery (0.4 - 1.4% reported in various studies) but are (0.4 - 1.4% reported in various studies) but are life threatening and affects outcome. life threatening and affects outcome. (Raimondo et al, J Am Coll Cardiol 2004, Yeung et al 2004)

Time of initial episode of postoperative ventricular tachycardia ,Yeung et al, 2004

General factors prediposing to post cardiac surgery VT

• Hemodynamic instability • Electrolyte-abnormalities• Metabolic disturbances • Drugsa)Sympathomimetics, inotropes b) Antiarrhythmics. • Sepsis, Tissue trauma, inflammation or

indwelling catheters.

Three main Categories of Cardiac surgeries related to post-op. VT in the following order:

1. Coronary Artery Bypass Surgery (CABG).

2. Surgery for Valvular Heart Disease.

3. Surgery for Congenital Heart Disease.

age > 65 years, female gender, body mass index < 25 kg/m2, unstable angina, moderate or poor LV function, and the need

for inotropes and an intra-aortic balloon pump. On pump duration, Off-pump surgery showed

a substantial but non-significant protective effect against VT/VF (Raimondo et al JACC 2004).

1-Risk Factors of Post CABG 1-Risk Factors of Post CABG Ventricular ArrhythmiasVentricular Arrhythmias

The most likely and reversible cause is residual myocardial ischemia

Inadequate myocardial protection, myocardial reperfusion. Transmural re-entry, oxygen free radicles and Ca overload causing enhanced automaticity or triggered activity are possible mechanisms.

grafting a non-collateralized occluded vessel supplying an infarcted zone may help survival of purkinje cells at scar borders that may create re-entry circuits (Steinberg et al 1999) .

Causes of Post CABG Causes of Post CABG Ventricular ArrhythmiasVentricular Arrhythmias

Recurrent VT after aortic or mitral valve Recurrent VT after aortic or mitral valve surgery is rare but often due to reentry in a surgery is rare but often due to reentry in a region of ventricular scar and is bimodal in region of ventricular scar and is bimodal in prersentation with either early postop. or prersentation with either early postop. or years later occurrence.years later occurrence.

The scars are often, but not always, located The scars are often, but not always, located in proximity to a valve annulus. Scars are in proximity to a valve annulus. Scars are usually 2ry to the original disease but may be usually 2ry to the original disease but may be related to the procedure. (Ekardt et al 2007) related to the procedure. (Ekardt et al 2007)

2- VT after valve surgery2- VT after valve surgery

Commonest aetiology of sudden death in postop. children between the ages of 1 and 16y is Postoperative tetralogy of Fallot and the incidence ↑ over years (1.6%) (Wren 1996).

The site of the ventricular tachycardia was found by intraoperative mapping to be due to re-entry in the right ventricular outflow tract, and related to the use of a he use of a right ventricular outflow tract patch, right ventricular outflow tract patch, right ventricular outflow tact aneurysms and pulmonic insufficiency. (Harrison et al 1997)

3- Ventricular Arhythmia post 3- Ventricular Arhythmia post congenital heart Surgerycongenital heart Surgery

Diagnosis and Treatment(When and How to interfere?)

Ventricular arrhythmias include:

1- Premature ventricular contractions (PVCs).

2- Non sustained Ventricular Tachycardia.

3- Sustained Ventricular Tachycardia (Monomorphic or polymorphic).

4- Incessant VT and Electerical Storm.

4- Ventricular Fibrillation.

PREMATURE VENTRICULAR PREMATURE VENTRICULAR COMPLEXES (PVCs)COMPLEXES (PVCs)

The impulse arise in one ventricle, so no P The impulse arise in one ventricle, so no P wave and wide QRS > 120ms.wave and wide QRS > 120ms.

T wave is large ,opposite in direction to T wave is large ,opposite in direction to QRS.QRS.

Compensatory or noncompensatory pauseCompensatory or noncompensatory pause Fixed or variable coupling interval.Fixed or variable coupling interval.

Significance of PVC’sSignificance of PVC’s

Less important if already present pre-Less important if already present pre-operatively and monomorphic.operatively and monomorphic.

Very Frequent PVC’s can decrease Very Frequent PVC’s can decrease cardiac output.cardiac output.

Can lead to more serious ventricular Can lead to more serious ventricular arrhythmias, such as VT or VF.arrhythmias, such as VT or VF.

The significance of the causes behind The significance of the causes behind the PVC’s.the PVC’s.

When to be concerned about When to be concerned about PVC’s?PVC’s?

1. When they Occur at the rate of or greater than 8 per minute.

2. Polymorphic (Multifocal) PVCs

3. R - on - T PVCs

4. Bigeminy PVCs (every other beat is a PVC)

5. Runs of two (2) or more PVCs in a row.

Management of PVC’s and NSVTManagement of PVC’s and NSVT

Simple PVC’s usually do not require RxSimple PVC’s usually do not require Rx Exclude and manage any precipitating Exclude and manage any precipitating

cause (Ischaemia, Electrolytes, Sepsis)cause (Ischaemia, Electrolytes, Sepsis) Frequent PVC’s can be suppressed by Frequent PVC’s can be suppressed by

atrial pacing.atrial pacing. If symptom producing can be If symptom producing can be

suppressed with beta blockers or safe suppressed with beta blockers or safe AA.AA.

VENTRICULAR VENTRICULAR TACHYCARDIATACHYCARDIA

VT consists of at least three or VT consists of at least three or more consecutive PVCs at a rate more consecutive PVCs at a rate of 100bpm.of 100bpm.

Types:- Nonsustained <30s Types:- Nonsustained <30s sustained > 30s.sustained > 30s.

Rhythm- Regular / slightly Rhythm- Regular / slightly irregular irregular

Rate 100 to 250 / minRate 100 to 250 / min

Algorithm for wide complex tachycardia diagnosis Algorithm for wide complex tachycardia diagnosis from ESC guidelines 2010from ESC guidelines 2010

AV dissociationAV dissociation

FUSION & CAPTURE BEATSFUSION & CAPTURE BEATS Diagnostic of VTDiagnostic of VT Seen in VT of lower rates(< 160)Seen in VT of lower rates(< 160) Capture beat- sinus beat Capture beat- sinus beat Fusion beat- hybrid beat due to occasional Fusion beat- hybrid beat due to occasional

sinus & ventricular activation capturing the sinus & ventricular activation capturing the ventricles together.ventricles together.

QRS Duration and AXISQRS Duration and AXIS

QRS >140ms good indicator of VTQRS >140ms good indicator of VT QRS 120- 140 ms only 50% have VT (Wellens et QRS 120- 140 ms only 50% have VT (Wellens et

al) al) RBBB with left axis deviation is of little helpRBBB with left axis deviation is of little help LBBB with extreme LAD ( northwest) axisLBBB with extreme LAD ( northwest) axis Extreme axis is rarely seen in SVT with aberrancy.Extreme axis is rarely seen in SVT with aberrancy. Concordance in the precordial leads and QRS Concordance in the precordial leads and QRS

morphology criteria (wellens criteria and Brugada morphology criteria (wellens criteria and Brugada criterial)criterial)

CONCORDANCE of QRS in precordial leads (60%)CONCORDANCE of QRS in precordial leads (60%)

If not Sure of the diagnosis, consider If not Sure of the diagnosis, consider

the wide complex tachycardia as VT the wide complex tachycardia as VT

and manage accordingly.and manage accordingly.

Treatment Pts with clinically Pts with clinically stable monomorphic VT stable monomorphic VT

I- Exclude and treat the underlying causea. myocardial ischemia, reperfusionb. hypoxemiac. digitalis toxicity, epinephrine, aminophyline d. hypokalemia, hypomagnesaemiae. anemiaf. CHFg. Sepsis, feverh. acidosis i. bradycardiaj. anxiety

2- Pharmacological treatment of Pts 2- Pharmacological treatment of Pts with clinically stable VT with clinically stable VT

Amiodarone 150-300mg bolus over Amiodarone 150-300mg bolus over 10min. then1mg/min 6hrs, 10min. then1mg/min 6hrs, 0.5mg/min 18hrs, can be continued 0.5mg/min 18hrs, can be continued for several days.for several days.

Lidocaine 1 to 1.5 mg/kg bolus Lidocaine 1 to 1.5 mg/kg bolus every 5-10min to max 3mg/kgevery 5-10min to max 3mg/kg

Infusion 1-4mg/min, Procainamide Infusion 1-4mg/min, Procainamide 30mg/min to 17mg/kg.30mg/min to 17mg/kg.

till termination or becoming unstable.till termination or becoming unstable.

Management of unstable Management of unstable sustained ventricular tachycardiasustained ventricular tachycardiaPts with clinically unstable VT Pts with clinically unstable VT (angina, shock, cerebral hypoperfusion )(angina, shock, cerebral hypoperfusion ) Prompt DC shock within one minute. Prompt DC shock within one minute. High rt parasternal – apexHigh rt parasternal – apex Paddle size 8-12cm Paddle size 8-12cm Area of both paddles 50 sq.cmArea of both paddles 50 sq.cm Sync.-monophasic(200-360J) or Sync.-monophasic(200-360J) or

Biphasic (100-200JBiphasic (100-200J After conversion, AAD and correct After conversion, AAD and correct

cause.cause. If not reverted start ACLS protocol.If not reverted start ACLS protocol.

Incessant VT and electerical storm electerical storm : Defintion: Defintion:

Ventricular tachycardia that repeatedly Ventricular tachycardia that repeatedly recurs and persistsrecurs and persists for more than half of a for more than half of a 24-h period despite repeated attempts24-h period despite repeated attempts to to terminate the arrhythmia is designated terminate the arrhythmia is designated "incessant." "incessant."

Recurrence for >3 times/24 hrs of Recurrence for >3 times/24 hrs of sustained VT requiring interference is sustained VT requiring interference is referred to as electerical storm.referred to as electerical storm.

Incessant VT–VF managementIncessant VT–VF management Exclude the possibility of ongoing Exclude the possibility of ongoing

myocardial ischemia and correction of myocardial ischemia and correction of residual ischaemia, may need coronary residual ischaemia, may need coronary angiography. VT may be the only sign.angiography. VT may be the only sign.

Correct general reversible causes,Correct general reversible causes, Consider proarrhythmia if the VT became Consider proarrhythmia if the VT became

slower and incessant after AAD.slower and incessant after AAD.Treatment Treatment is directed at maintaining hemodynamic is directed at maintaining hemodynamic support untilsupport until the drug is excreted. Avoid the drug is excreted. Avoid combinations of AADs.combinations of AADs.

Intra-aortic balloon counter-pulsationIntra-aortic balloon counter-pulsation can can also be helpful for haemodynamic supportalso be helpful for haemodynamic support

Sedation and even general anesthesia Sedation and even general anesthesia quiets episodesquiets episodes and restores stability in and restores stability in some cases. some cases.

Implantable cardioverter defibrillator is not Implantable cardioverter defibrillator is not indicated for acute management of indicated for acute management of patients with electrical storms.patients with electrical storms.

Incessant VT and electerical storm electerical storm :

Catheter ablation is an important option for Catheter ablation is an important option for management of incessantmanagement of incessant monomorphic monomorphic VT and can be life-saving. VT and can be life-saving.

When hemodynamicWhen hemodynamic stability can be stability can be maintained, presence of the tachycardia maintained, presence of the tachycardia facilitatesfacilitates mapping to identify the source of mapping to identify the source of the arrhythmia.the arrhythmia.

Incessant VT and electerical storm electerical storm :

3D mapping guided RF ablation of VT

However, 10% to 20% of patients have However, 10% to 20% of patients have reentry circuitsreentry circuits that are not successfully that are not successfully ablated. The location of some circuitsablated. The location of some circuits deep deep to the endocardium or in the epicardium, to the endocardium or in the epicardium, are importantare important causes for failure. causes for failure.

For patients with incessant VT, remainingFor patients with incessant VT, remaining

options then include arrhythmia surgery, options then include arrhythmia surgery, placement of a ventricularplacement of a ventricular assist device, or assist device, or cardiac transplantation. cardiac transplantation.

Incessant VT and electerical storm electerical storm :

Polymorphic VT Polymorphic VT Torsades de PointesTorsades de Pointes

VT characterized by VT characterized by QRS complexes of changing amplitude that QRS complexes of changing amplitude that

appear to twist around the isoelectric line & appear to twist around the isoelectric line & occur at rates of 200 to 250 /minoccur at rates of 200 to 250 /min

With Prolonged QT intervals generally With Prolonged QT intervals generally exceeding 500 msecexceeding 500 msec

U wave can also become prominent& U wave can also become prominent& merge with T wavemerge with T wave

ManagementManagement Correct electrolytes, IV K/magnesium Correct electrolytes, IV K/magnesium Temporary ventricular or atrial pacing+ Temporary ventricular or atrial pacing+

ICDICD Lidocaine, mexiletine or phenytoin can Lidocaine, mexiletine or phenytoin can

be triedbe tried K channel activating drugs pinacidil, K channel activating drugs pinacidil,

cromakalimcromakalim Cause of long QT should be treatedCause of long QT should be treated Consider ischaemia if without long QTConsider ischaemia if without long QT

Ventricular Fibrillation: A lethal arrhythmia: no coordinated electerical

activity in the heart, essentially there is no pulse or cardiac output.

Rhythm: none QRS: no clearly discernable QRS complex;

wave forms look chaotic. Two types:Two types:

Fine: can look like A-fib without QRS complexes, Fine: can look like A-fib without QRS complexes, amplitude of waves <3mm.amplitude of waves <3mm.

Coarse: generally more irregular, amplitude of waves Coarse: generally more irregular, amplitude of waves >3mm>3mm

Guidelines of CPR in the postoperative patient

Amiodarone Vs LidocaineAmiodarone Vs Lidocaine The ARREST and ALIVE triaLs, have Led to the The ARREST and ALIVE triaLs, have Led to the

expert consensus that ‘amiodarone shouLd be expert consensus that ‘amiodarone shouLd be considered as the first Line antiarrhythmic drug that considered as the first Line antiarrhythmic drug that shouLd be given to patients with VF/puLseLess VT shouLd be given to patients with VF/puLseLess VT that persists after 2–3 shocks pLus adequate CPR that persists after 2–3 shocks pLus adequate CPR and use of a vasopressor although only very short and use of a vasopressor although only very short term benefit could be proved.term benefit could be proved.

Lidocaine, may be used as an aLternative but onLy if Lidocaine, may be used as an aLternative but onLy if amiodarone is not avaiLabLe.amiodarone is not avaiLabLe.

Long term therapyLong term therapy Depends on LV function.Depends on LV function. MADIT I &II, MUSTT, SCD MADIT I &II, MUSTT, SCD

studies EF<35% ICDstudies EF<35% ICD Hybrid therapy ICD + drugs. Hybrid therapy ICD + drugs.

(AVID,CIDS)(AVID,CIDS) Beta-Blockers, Class III agents- Beta-Blockers, Class III agents-

amiodarone, sotalol amiodarone, sotalol (EMIAT,CAMIAT,GESICA trails), (EMIAT,CAMIAT,GESICA trails),

Radiofrequency ablation if Radiofrequency ablation if recurrent monomorphic VT.recurrent monomorphic VT.

ConclusionConclusion

Post CABG

Sust. Vent. Tachyarryth.

Ventricular Fibrillation

Defib. IV Amio,Lido

Identify/Treat ppt factors

No further AA therapyRecurrence

Defib, Use other IV drugs

UnsuccessfulContinue CPR as

guidelines

SuccessfulContinue the

drugs, consider long term ICD

Ventricular tachycardia

UnstableUse V-Fib Protocol

StableIV Amiodarone, Lido, BretyTreat Ppt factors, Defib0

RecurrenceUse VT recurr. Protocol,, IPB,

consider RF ablation and ICD.

No recurrenceNo further therapy

MANAGEMENT OF POST CABG VT/VF

No Recurrence