Emergency pacemaker and ICD issues

Emergency related Pacemaker and ICDs Issues

Anne-Marie de Vries, January 2015

Contents

1. Clinical case2. Introduction pacemaker / Cardiac Resynchronisation Therapy

(CRT) / Implantable Cardiac Defibrillator (ICD)3. Implant related complications4. Pacing system malfunction5. ED management6. Magnet7. Back to case8. Demo-interrogation (by Medtronic)9. Patient experience (ICD)

Clinical case

ECG

ECG

ECG

Introduction

• Components and lead position

• Pacemakers modes

• Pacemaker/CRT/ICD indications

Pacemaker components and lead position

• Basic components: pulse generator and lead(s)

• Pulse generator; hard and software, battery (5-10 years)

• Leads:conductor, electrode, fixation mechanism, terminal

connector pin, insulator

Lead position

• Atrial leads in the right atrial appendage

• Right atrial septum position to suppress AF

• Right ventricular leads are traditionally placed in the right

ventricular apex, however RVOT or inter-ventriculair position to

avoid dyssynchrony

• Left ventriculair lead via coronary sinus to free left lateral or

posterior left ventriculair wall

• Final position depends on venous cardiac anatomy, avoidance of

phrenic nerve stimulation, location of myocardial scar

Lead fixation

Pacemaker modes

5 Letter code:

I = Chambers paced

II = Chambers sensed

III = Response to sensing

IV = Programmability, rate modulation

V = Multi-site pacing

A= Atria T=Triggered

V=Ventricle I=Inhibited

D=Dual Chamber (A+V) R=rate modulation

O=none

Table 2 NASPE pacemaker code

Pacemaker modes

• ED physicians most likely deal with AAIR, VVIR, DDD

and DDDR

• Rate response modality detect physiological changes;

minute ventilation, QT interval, stroke volume

Indications

• Continuous amendments for pacemaker indications

several categories)

• Most recent guideline ACC/AHA/HRS guideline

pacemaker, ICD and CRT implantation 2008 (update

2012 on CRT)

Pacemaker indication

• Sinus node dysfunction;

Symptomatic SSS

DDDR*

• Acquired AV block;

- III and Mobitz II degree block

- Dual chamber pacing preferrable

• Chronic bifascicualr or trifascicular block

Syncope risk varies based on presence of AV block and

pacemaker indication depends of HV intervals (EP-study)

CRT

• Systolic heart failure due intra- and inter-ventriculair dyssynchrony

• Dyssynchrony occurs independent from QRS duration

• Dyssynchrony determined by Echocardiographic parameters; TDI

and speckle tracking imaging

• In patients with systolic heart failure significant reduction in NYHA

class*(PATH-HF, MUSTIC SR, MIRACLE, COMPANION,CARe-

HF,MIRACLE-ICD,CONTAK-CD,RHYTHM-ICD)

• Non-responders to CRT; 10-40% non LBBB (QRS <130 msec,

RBTB)

TDI (Tissue Dopler Imaging)

Speckle tracking imaging

ICD; indications 2012 ACCF/AHA/HRS guidelines

Level of Evidence: A:

LVEF<35% due to prior MI who are at least 40 days post MI (NYHA II-III)

LV dysfunction due to prior MI, LVEF < 30%, NYHA I

Survivors of Cardiac arrest due to VF or hemodynamically unstable sustained

VT after evaluation to define the cause of event and excluding any reversible

causes

Level B

Non-ischeamic DCM LVEF < 35%, NYHA II-III

Non sustained VT due to prior MI, LVEF < 35% or inducible VF/FT on EPS

Structural heart disease and spontaneous sustained VT

Syncope of undetermined origen with clinically relevant HD sign sustained VT

or VF induced at EPS

LQTS patients who experience syncope and/or VT while on b-Blockers

Implant-related complications

1. Pocket hematoma2. Infection3. Lead dislodgement4. Pneumothorax/hematothorax5. Venous thrombosis6. Pacemaker syndrome7. Triscupid regurgitation8. Twiddler syndrome9. Pericardial effusion, perforation

Pocket hematoma

• Post procedural bleeding and pocket hematoma are relatively

common complications (on oac)

• Hematoma’s are generally treated conservatively unless large or

very painful they need surgical intervention (increased rate of

infection)

Infection

• About 0.2% (retrospective studie) of surgical site infection

(swelling, dehiscencion, erosion)

• However, fever of unknown origin an implanted device should

always be considered as a source of infection

• BC, Echogardiographic Dx

• Long term IVAB (Stahp A), device removal and lead extraction.

Re-insertion of device contralateral

Heamato- and pneumothorax

• About 1.5% pneumothorax (subclavian puncture)

• Hemothorax due to unintentional arterial puncture

• Avoidance with fluoroscopic insertion techniques or axillary

vein cannulation

Thrombosis

• Subclavian or brachio-chephalic venous thrombosis is a very

common event after pacemaker implantation with an

incidence of 2-22% from several days to up to 9 years after

implantation

• Often an asymptomatic occurrence shown on a venogram

during lead revision

• Symptomatic patients show typical manifestations of acute

DVT (swelling) or even vena cava superior syndrome

• PE is an uncommon event

• Therapy ranges from heparinisation/warfarin unto

percutaneous angioplasty or open surgery

Pacemaker syndrome

• Intolerance to ventricular pacing in the absence of

atrioventricular synchrony (“the AV dyssynchrony syndrome”)

• Ventricular pacing leads to suboptimal AV dyssynchrony

regardless of the pacing mode

• Symptoms result from the loss of physiological timing of atrial

and ventricular contractions

• Symptoms are a constellation of features due to decreased

cardiac output, loss of atrial contribution to ventricular filling,

loss of total peripheral resistance response, non physiological

pressure waves

• Patient needs adjustment of generator or lead to better

coordinate timing of atrial and ventricular contraction

Triscupid regurgitation

• Some patients present with R sided cardiac failure

• mechanism; impingement or adherence to leaflets,

perforation, impairment of valve closure due to entanglement,

, scar formation of thrombosis

• Or due to ventricular dyssynchrony

• Dx is made by 3D-TTE

Twiddler Syndrome

• Lead dislodgement due to a patient’s own compulsive

manipulation of generator causing the leads to become retracted

or coiled around the generator

• Dx ismade by radiographic appearance

• Dacron pouches

• Subpectoral pouches

Pacing system malfunction

• Generator malfunction in 4.6/1000 pacemakers and 20.7/1000

ICDs, most often due to battery malfunction

• Lead failure often due to insulation breaks, however this is a late

complication

• Pacemaker malfunction is a rare cause of syncope (8/162

patients in a retrospective study)

• An assesment of pacemaker malfunction should consist of ECG,

radiology, patients acid-base status (VBG), medication use and

interrogation (lead problems can result in very high impedance)

Lead dislodgement

• Usually after recent implantation, however up to 3 months after

implant is possible

• Undersensing, failure to capture or change in DFTs

• Telemetry, device interrogation

• Obtain a CXR in 2 directions (compare with previous CXR)

• Malposition near phrenic nerve or diaphragm may cause

hiccougs or muscle twitching

• Seldom leads may cause perforation and tamponade (TTE)

Pacing system malfunction

1. Failure to capture

2. Failure to sense

3. Failure to pace

4. Electromagnetic interference

Failure to capture

• Failure to deliver a pacing stimulus without subsequent

depolarisation

• Functional failure to capture when myocardial tissue is in

refractionary state

• Pathological failure to capture due to numerous conditions;

myocardial disease, electrolyte disturbances (Potassium !), anti-

arrhythmic drugs (Class Ic and QTc lengthening)

• Latency; might be confused with failure to capture; obtain a

multichannel recording recording (interrogation)

• Lead dislodgement, perforation and fracture, increasing DFT

may all lead to failure to capture

Failure to sense

• On myocardial depolarisation a signal is send via the lead wire

and filtered by the generator

• Undersensing could be caused by a change in morphology or

vector of the depolarisation front

• PVC, BBB or VTs may need exceed the sensing threshold

(depending on the programming)

• Break in wire insulation or Battery depletion may cause under

sensing

• Undersensing immediate after implantation may be caused by

dislodgement or perforation

• Again; Class Ic or HYPERKALEMIA

• Long blanking and refractory periods of a pacemaker can lead to

relatively or functional undersensing

Failure to pace

• Failure to deliver a stimulus to the heart

• Absence of pacing artefacts on intrinsic rates lower than the lower rate

of the device

• Causes; oversensing, partial lead fracture or insulation defects,

crosstalk

• Oversensing could be caused by retrograde P waves, t waves,

ventricular EADs or DADs skeletal myo-potentials (pectoralis,

diaphragm, rectus abdomens)

• External electromagnetic interference

• Blunt trauma to pulse generator, lead fracture, dislodgement or loose

connection

• Pacing artefacts may not be visible on 12 lead ECG and give a false

impression of failure to pace

• PACs or PVCs on a single telemetry lead can give a false impression of

failure to pace

Pacemaker tachycardia

• Also known as pacemaker re-entry tachycardia or endless-loop

tachycardia (like other re-entry dysrhythmias, pacemaker is now a part

of the re-entry circuit)

• only in patients with dual chamber devices

• An intrinsic premature complex is sensed by an atrial lead of the

pacemaker which responds by generating a ventricular impulse. The

ventricular impuls is retrogradely conducted via the AV node to the atria,

now the atrial lead senses the atrial impulse and generates a ventriculair

pulse (completed loop)

• This pacemaker re-entry tachycardia will not exceed the programmed

upper rate, however can be significant enough to cause symptoms

• Adenosine may not be effective where as magnet therapy will be

• NB ! pacemakers atrial sensing tresholds need to be adjusted

• NB ! Mode switch can cause the pacemaker to discontinue atrial

tracking when the atrial upper rate is exceeded

Pax

ED management

1. History

2. Physical examination

3. 12 lead ECG

4. VBG !!!

5. Radiology (CXR PA and lat)

6. Device interrogation/magnet function

ED Management

1. Hyperkalemia

2. Myocardial infarction (Sgarbossa)

Hyperkalemia

• Widened QRS complex (widened paced complexes)

• Severe hyperkalemia causes a sine wave following pacing

artefacts

• Elevation of pacing threshold; increased latency, intermittent

capture, or continuous loss of capture, loss of sensing

• Latency may be temporarily overcome by increasing the maximum

voltage of output HOWEVER treatment of hyperkaliema is a

priority

Acute myocardial infarction

• The depolarisation and depolarisation from ventricular paced

rhythms may complicate the diagnosis of acute MI (also in LBBB)

• ST and T waves shift in a discordant direction which can mask or

mimic AMI, “appropiate discordance”

• SERIAL ECGs show dynamic ST-segment changes

• 3 criteria used to Dx infarction in patients with LBBB are

• Concordant ST-elevation> 1 mm (score 5)

• Concordant ST-depression>1 mm in V1-V3 (score 3)

• Excessively discordant ST elevation > 5 mm (score 2) in leads

with a negative QRS complex

New or old LBBB ?

• “NEW developed LBBB” reflects AMI is NOT true ! Recognition goes

back to 1917 !

• New LBBB should be either due to a LARGE anterior or

anteroseptal infarction resulting in a large injury OR very focal lesion

just distal from the His bundel

• New or old, not always clearly visible in acute settings

• Patients with previous LBBB generally have underlying myocardial

or conduction system abnormalities predisposing to a larger risk

(older, hypertension, CHF)

• Historical studies do not make a fair differentiation in patients with

(L)BBB and ACS

• New studies show that in only 29% of new LBBB; ACS is present*

*Chang et al, Am J Emerg Med, 2009,; 27:916-21

The Ventriculair conduction system

Sgarbossa criteria

Criteria A Sgarbossa: (90% specifity): 5 point

Concordant ST-elevation> ANY 1mm in lead with a positive QRS

Criteria B Sgarbossa: (90% specifity): 3 point

Concordant ST- depression > 1 mm in ANY lead from V1-V3

Criteria C Sgarbossa: Excessively ST-elevation > 5mm score 2

(high sensivity, lower specifity, ratio of R vs > 20%)

> 3 points ; 90% specifity for ACS

Criteria from Sgarbossa based on a retrospective review from 17

patients from GUSTO-1

ECG ACS in LBTB

ICD trouble shooting

• Device and procedural complications (as with pacemakers)

• Arrhythmia related complications; inappropriate shocks,

appropriate shocks; ventricular storm and incessant tachycardia,

phantom shocks

• pro-arrhythmic effects

• Increased DFT (fibrosis, amiodarone),

• Heart-failure

• Phantom shocks

• Emotional and quality of life issues: anxiety, depression, fear for

Icd discharge, negative life style changes; unable to return to

work or to drive, decrease in physical activity

Inappropriate shocks in ICD patients

• Most often caused by SVTs or non sustained VTs

• Other causes; electromagnetic interference, inappropriate

sensing, ICD malfunction (lead fracture)

• Most inappropriate shocks are avoided with modern and

adequate ICD programming (high cut-off rates, arrhythmia

discrimination detection)

Appropriate shocks in ICD patients

• Increasing arrhythmia duration and ATP have diminished

delivered shocks (ATP terminates at least 90% of VTs)

• Electrical storm (definition in ICD carriers is 2 or more adequately

delivered shocks < 24 hours);

• Amiodarone loading, b Blockers (reduction of effects of sympatic

nerve system) and sometimes proceeding towards sedation. both

electrical storm and incessant VT indicate a worse prognosis due

to the underlying mechanism

Pro-arrhythmic effect of ICD

• Arrhythmogenic effect of implanted lead; irritation of local

myocardial tissue, fibrosis.

• Inserted in a prior scar site may induce reentry

• RV pacing causes interventricular and intraventricular

dyssynchrony

• “normal” bradycardia back up pacing may result in short-long

pacing sequence leading towards induction of VT

• Biventriculair pacing reduces SCD however may induce Vt due to

an abnormal sequence of depolarisation and depolarisation fronts

Magnet function

• Know where the magnet is located in your ED

• Know the effects of applying a magnet to a device

• Know the difference between a magnet application and

an electrical reset

• Most pacemakers and ICDs turn off the sensing mode

when a magnet is applied over the generator

• The pacemaker starts to pace in an asynchronous

mode in a fixed rate (Medtronic 65/min reflects EOL)

• Rarely a device may be programmed in a “magnet off”

setting

When to apply a magnet ?

1. To terminate a pacemaker mediated tachycardia

2. Inappropriate sensing (due to electromagnetic interference;

diathermy, MRI)

3. Over sensing due to lead problems

4. Stop ICD ATP or defibrillation shock therapy (backup

bradycardia pacing will still be provided).NB an alert sound will

be initiated when applying a magnet to a medtronic ICD (also on

lead and impedance problems or EOL)

ACLS in an ICD patient

• ICD and CRT-D patients should have same approach

• SHOCKS delivered are of NO risk for the MET-team

• If arrhythmia persists after a device defibrillation, attach patient to

anterior-posterior placed leads preferably 8 cm from generator

• Consider magnet placing to avoid unintentional device

defibrillation's

• Consider; increased DFTs due to ipsilateral pneumothorax

• `consider femoral access instead of subclavian due to often

thromboses veins (or in appropiate response of a pacemaker due

to wire interrogation)

More ?

go to: Medtronic Academy (for Physicians)

LIFTL Fellowship exam SAQ and SMACC 2014

Amal Mattu

ECG pedia

Back to clinical case

81 male

4/7 post dual chamber pacemaker insertion (pAF)

Re-currence of pre implantation dizziness, palpitations and

SOB

CXR: correct lead position

Interrogation: A not sensing, P wave in bipolar, re-programmed

to bipolar, treshold and impedence normal.

Loaded on amiodarone

Literature

1. Up to Date; Electrical storm and incessant ventricular tachycardia, Overview of

pacing in heart failure, implantable cardioverter defibrillators;

2. EMP: Managing Pacemaker related Complications and malfunctions in the ED

3. Cardiac Pacing and ICDs; 4th Edition, K.A Ellenbogen

4. A practical guide to cardiac pacing, 5th edition, H.Weston Moss

5. Electrofysiological Testing, 3d edition, R.N Fogoros

6. AHHF/AHA/HRS 2012 Guidelines for device based therapy

7. Medtronic Academy

8. LIFTL

9. Neeland et al, J am Coll Cardiol, 2012; 10;60 (2):96-105. “Evolving

considerations in the management of patients with LBTB and suspected AMI