Shock reducing strategies in devices

10-10-2020

Raja Selvaraj, JIPMER

ICDs designed to treat VF

ICDs were designed to prevent sudden death from VF

Multiple functions of ICD

Bradycardia pacing
Anti-tachycardia pacing
Cardioversion
Defibrillation

But current devices are not restricted to treatment of VF alone

Shocks prevalence

A third of patients after 5 years
About a fifth are inappropriate

A significant proportion of patients with ICD get a shock

"Shock paradox"

Shocks worsen quality of life
Myocardial damage occurs with shocks
Shocks increase mortality

Term used to denote that ICD patients with shocks do worse than those without Paradoxically, we are not happy when the ICD delivers a shock

Increased mortality

Sweeney MO, Sherfesee L, DeGroot PJ, Wathen MS, Wilkoff BL. Differences in effects of electrical therapy type for ventricular arrhythmias on mortality in implantable cardioverter-defibrillator patients. Heart Rhythm. 2010 Mar;7(3):353-60. doi: 10.1016/j.hrthm.2009.11.027. Epub 2009 Dec 2. PMID: 20185109.

2000 + patients from 4 trials - PAINFREE rx, PAINFREE rx II, EMPIRIC and PREPARE Shocked VA episodes are associated with increased mortality

Not all shocks save lives

Ellenbogen KA … , Kadish A; Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) Investigators. Are implantable cardioverter defibrillator shocks a surrogate for sudden cardiac death in patients with nonischemic cardiomyopathy? Circulation. 2006 Feb 14;113(6):776-82.

When deaths and shocks are counted together, they are twice that of deaths in patients without ICD. Data from Definite. The gap is the non fatal NSVT that is treated

Shocks

Inappropriate shocks
Unnecessary, appropriate shocks
Necessary appropriate shocks

Inappropriate - not for VA Appropriate - for VA Unnecessary - non fatal / self terminating VA

Strategies to reduce shocks

Control of ventricular arrhythmias
- Drugs
- Ablation
Choosing the right device ?
Device programming

Control of arrhythmias

ICD is not a treatment for VT

Not for VT storm
Not in presence of recurrent VT

Medical management

Control VA before implant
Heart failure treatment, AAD, beta blockers after implant
Sotalol useful to reduce shocks (1)
Amiodarone - Better than beta blocker alone or Sotalol - OPTIC trial (2)

Pacifico A et al. Prevention of implantable-defibrillator shocks by treatment with sotalol. d,l-Sotalol Implantable Cardioverter-Defibrillator Study Group. N Engl J Med. 1999;340:1855–62. doi: 10.1056/NEJM199906173402402.
Connolly SJ et al. Comparison of beta-blockers, amiodarone plus beta-blockers, or sotalol for prevention of shocks from implantable cardioverter defibrillators: the OPTIC Study: a randomized trial. JAMA. 2006;295:165–71. doi: 10.1056/NEJM199906173402402.

Ablation

SMASH-VT (1)
- 128 pts with secondary prevention ICD randomised to ablation vs no additional therapy (1)
- 24 months - less shocks (12% vs 31%)
VTACH (2)
- ICM with VT - icd alone or icd with ablation (2)
- more freedom from VT with ablation

Reddy VY et al. Prophylactic catheter ablation for the prevention of defibrillator therapy. N Engl J Med. 2007;357:2657–65. doi: 10.1056/NEJMoa065457.
Kuck KH et al. Catheter ablation of stable ventricular tachycardia before defibrillator implantation in patients with coronary heart disease (VTACH): a multicentre randomised controlled trial. Lancet. 2010;375:31–40. doi: 10.1016/S0140-6736(09)61755-4.

Choosing a device. Will a dual chamber device reduce shocks ?

Dual chamber may have better detection

Friedman et al. Dual-Chamber Versus Single-Chamber Detection Enhancements for Implantable Defibrillator Rhythm Diagnosis. The Detect Supraventricular Tachycardia Study. Circulation. 2006;113:2871–2879. https://doi.org/10.1161/CIRCULATIONAHA.105.594531

Some studies supported intuitive feeling that dual chamber devices should allow better detection

Difference is small in real world

Atrial sensing problems may contribute to inappropriate detection in dual chamber devices
Improved algorithms with single chamber devices
Reduction in inappropriate shocks is only for slower rhythms
Better understanding of device programming - less inappropriate therapies

Gilliam FR et al. Real world evaluation of dual-zone ICD and CRT-D programming compared to single-zone programming: the ALTITUDE REDUCES study. J Cardiovasc Electrophysiol. 2011;22:1023–9. doi: 10.1111/j.1540-8167.2011.02086.x.

Reasons why practically there is no benefit in Reduces trial, advantage was for VT < 170 and 170-200

DATAS trial

334 patients
Randomised to SC-ICD, DC-ICD or simulated SC-ICD (DC programmed as SC)
Lower rate of significant clinical events with DC-ICD
But none of primary endpoints different (not enough statistical power)

Almendral J et al. Dual-chamber defibrillators reduce clinically significant adverse events compared with single-chamber devices: results from the DATAS (Dual chamber and Atrial Tachyarrhythmias Adverse events Study) trial. Europace. 2008;10:528–35. doi: 10.1093/europace/eun072.

RAPTURE

RCT of 100 patients
DC-ICD did not reduce inappropriate shocks

Friedman PA et al. A prospective randomized trial of single- or dual-chamber implantable cardioverter-defibrillators to minimize inappropriate shock risk in primary sudden cardiac death prevention. Europace. 2014;16:1460–8. doi: 10.1093/europace/euu022.

So generally consider dual ICD only when there is a pacing indication

Programming

Most important strategy to reduce shocks is appropriate programming

Focused update 2019

Stiles MK, Fauchier L, Morillo CA, Wilkoff BL; ESC Scientific Document Group. 2019 HRS/EHRA/APHRS/LAHRS focused update to 2015 expert consensus statement on optimal implantable cardioverter-defibrillator programming and testing. Europace. 2019 Sep 1;21(9):1442-1443. doi: 10.1093/europace/euz065. PMID: 31090914.

Brady programming

Manufacturer specific guidelines are available. We will use Abbott as example

Not focus of this talk, but frequently made mistake. DAVID trial

VF detection

Note high rate cut off to identify VF

PAINFREE 2

FVT 188-250 bpm
Randomised to ATP or shock
ICM and NICM, primary and secondary prevention
72% of VT in this zone could be terminated with ATP
Improved quality of life with ATP

Wathen MS et al. Prospective randomized multicenter trial of empirical antitachycardia pacing versus shocks for spontaneous rapid ventricular tachycardia in patients with implantable cardioverter-defibrillators: Pacing Fast Ventricular Tachycardia Reduces Shock Therapies (PainFREE Rx II) trial results. Circulation. 2004;110:2591–6. doi: 10.1161/01.CIR.0000145610.64014.E4.

PAINFREE key trial to assert that VA up to 250 can respond to ATP

VT detection

Note high NID / long detection interval

MADIT-RIT

1500 patients - 3 arms
standard programming / VT > 200 / 60 sec delay > 170, 12 sec > 200
First inappropriate therapy

Moss AJ et al. Reduction in inappropriate therapy and mortality through ICD programming. N Engl J Med. 2012;367:2275–83. doi: 10.1056/NEJMoa1211107.

High rate therapy vs delated therapy vs conventional therapy

MADIT-RIT

ATP for "VF"

Personal experience

An example from our patient. Fast VT at rate 230 bpm in VF zone ATP terminates on very first paced beat

Shocks for VF

ATP for VT

ATP for VT. Use burst. Use more than one sequence

PREPARE trial

ATP for FVT (182-250 bpm) in primary prevention ICDs
Cohort of 700 patients
Historic controls (EMPIRIC and MIRACLE-ICD)
First shock in 12 mths reduced from 17% to 9%

Wilkoff BL et al. Strategic programming of detection and therapy parameters in implantable cardioverter-defibrillators reduces shocks in primary prevention patients: results from the PREPARE (Primary Prevention Parameters Evaluation) study. J Am Coll Cardiol. 2008;52:541–50. doi: 10.1016/j.jacc.2008.05.011.

PITAGORA

206 pts randomised to ramp or burst for fast VT
Better success with burst (75% vs 56%)

Gulizia MM et al. A randomized study to compare ramp versus burst antitachycardia pacing therapies to treat fast ventricular tachyarrhythmias in patients with implantable cardioverter defibrillators: the PITAGORA ICD trial. Circ Arrhythm Electrophysiol. 2009;2:146–53. doi: 10.1161/CIRCEP.108.804211.

Discriminators

Morphology reliable and good sens / spec Other discriminators not very specific

SVT time out

Noise rejection / Lead integrity alerts

Turn on manufacturer specific algorithms for noise rejection / lead integrity checks Low frequency attenuation - attenuates amplitude of t wave

Summary

ICD is not a treatment for VT
Dual chamber ICD does not appear justified for better discrimination
Ensure good R wave and small T wave
Program high VF rate - 250 bpm
Long detection interval for VT
ATP - during charging for VF, more than one attempt for VTs

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Shock reducing strategies in devices 10-10-2020 Raja Selvaraj, JIPMER