ICD Introduction 2004

去顫器之適應症 – 中央健保局

• 嚴重心室頻脈、心室顫動導致猝死可能或昏迷。

• 反覆發作之持續性心室頻脈。• 高危險性臟血管疾病或遺傳性疾病，且臨

床合併心室快速不整脈，無法藥物控制者。

去顫器之非適應症 - 中央健保局

• 末期心臟衰竭，無法藥物控制又非心臟移植對象者。

• 猝死可能經急救後，無意識恢復者。• 末期疾病患者且存活不足六個月者。

植入式心臟去顫器在台灣 - 2004

• 首例於 1995

• 至今共 300 多例 75%

20%

5%

ICD vs. Drugs: Life Expectancy

Larsen GC, Pauker SG, et al. J Am Coll Cardiol. 1992;19(6):1323-1334.

0

1

2

3

4

5

6

7

ConventionalAntiarrhythmic

Therapy

ICD Therapy

LifeExpectancy

Estimate(No. Years))

Amiodarone

2.5

3.9

6.1

ICD Implantation

Lead Measurements

Parameter Acute Lead System Chronic Lead System

Ventricular capture threshold

< 1V < 3V

Pacing impedance 200-1000 Ohms 200-1000 Ohms

Defibrillation impedance

< 80 Ohms < 80 Ohms

Filter R-wave amplitude

> 5mV (Sinus rhythm) > 3mV (sinus rhythm)

Slew rate > 0.75V/sec 0.45V/sec

Medtronic Programmer

9790 Programmer

DFT: defibrillation threshold

DFT Testing

Inventor of ICD

Michel Mirowski, M.D.

1924-1990

GEM III DR / Marquis DR

GEM® III DR ICD - Held in Hand

Volume: 39.5 ccMass: 77 gThickness 13.5 mm

Guidant ICD System

St. Jude ICD

33 cc 70 gm 1.3cm

Evolution of ICD

ICD Generator

Audiotranducer

Microcircuitry

Magnet switch

Telemetry

High voltageoutput Sense

amplifier

Pace output

ms

Battery

HV capacitor

HVO circuit

3-6 V 10-mAsec

750V 30-A

Biphasic Polarity

ReversedPolarity

Initial Polarity

Tilt =65%

Tilt =65%

Vi=

750V

V2=92V

V1=263V

D1=7 ms

Longivity of ICD

• 5 years background monitoring

• 5 years pacing (single chamber, 100% pacing)

• 200 shocks

Life of ICD Battery

BOL (3.2-3.3 V)

ERI (2.5V) EOL (2.3-2.4 V)

Cel

l Vol

tage

(V

)

Time (months)

BOL: beginning of lifeERI: elective replacement indicatorEOL: end of life

ICD Lead

silicone

polyurethane

P/S electrodes

RV defibrillation electrode

RA/SVC defibrillation electrode

Silver

MP35NPl-Ir

Operation of ICD System

Monitor RhythmPost-shock Bradycardia

Cardioversion

AntiTachycardia Pacing DefibrillationTachycardia

BradycardiaAntibradycardia

Pacing

Burst / Ramp

Quick look report page 2

Anti-Tahcycardia Pacing

Redetection

Attempt 1 with 3 pulses Attempt 2 with 4 pulses

300ms

300ms

300ms

300ms

300ms

Burst

300ms

292ms

284ms

Ramp Burst

Ramp

Sensing Threshold

1.0 mV

4.0 mV

2.0 mV **

Detection Algorithm

Rate

Duration

Redetection Duration

Post-Shock Duration

90-200 bpm

1-60 sec

1-15 sec

1-60 sec

110-220 bpm

1-30 sec

1-15 sec

1-30 sec

PARAMETER VT-1 ZONE VT ZONE VF ZONE

130-250 bpm

1-15 sec

1 sec

1 sec

Tachycardia Detection

• Rate detection zones– Automatic gain / threshold control

• Detection enhamcements / Tachycardia discrimination– Sudden onset– Interval stability– Dual chamber detection– Automatic morphology analysis

Automatic Gain Control

0.43 mV

3.44 mV

“Fast AGC” exponential decay within a dynamic range, using sinus template

Maximum sensitivity for dynamic range

“Slow AGC” using one of 12 dynamic ranges

8:1 (6:1 in atrium)

Separately programmable maximum sensitivity for device

0.27 mV

Detection Enhancement - OnsetVF

VT

VF

VT

Analysis Analysis

1 2

1. Gradual transition, Onset not met2. Duration ends, therapy inhibited

1 2

1. Abrupt transition, Onset met2. Duration ends, therapy initiated

Pivot interval

600600

Onset = 175 ms

Stage 2 is met4 of 4 comparisons (intervals to baseline average)are > Onset threshold.

Largest CL decrease is > Onset threshold

Stage 1 is met

572 456 785 410400 405 412

VT VT VT VTVS VS VTVS VS VS VT VTVT

Detection met

Baseline Avg.

Detection Enhancement - Stability

VT Detect//

//

Stability = 10 ms

7 8 9 10 9 9 10 88 8 9 9

Duration metStable (9 < 10)Initiate ATP therapy

DurationStability Analysis

Variance (ms)

Weighted average

Detection Enhancement – A & V Rate

Duration met, gradual

Ventricle

Atrium

Detection metStart Duration

V Rate > A Rate170 bpm > 90 bpm

A Rate

V Rate

Initiate therapy

A V Algorithm

VS VSVS

AS AS

50% of R-R interval

Junctional Anterograde Retrograde

AS

Concurrent Processing

//

//

P.S. Stability

P.S. Sustained Rate DurationDuration

V Rate < A Rate

Stability

A > AFib Rate Threshold

Tachy episode

declared (8/10)

P.S. AFib Rate Threshold

P.S. Duration

TREAT

Sudden

Unstable

AFib Rate Threshold False

V Rate > A Rate True

Onset

P.S. V Rate > A Rate

Programming – Tachycardia Detection

Patient Alert Programming Screen

Quick Look Programming Screen

Episode Data

Sesing Integrity Counter Programming Screen

Quick look report page 1

Quick look report page 2

Quick look report page 3

VF episode EGM

VF episode EGM

VF episode report page 1

VF episode report page 2

VF episode EGM

PR Logic in GEM® DR inappropriately detected for Sinus Tachycardia due to PR interval > 50% of RR interval.

PR Logic withheld using the Sinus Tach criteria for 17 beats before eventually delivering inappropriate VT therapy.

PR Logic™ (before enhancement)In Patient with Long PR interval

GEM® III’s new programmable 1:1 VT-ST boundary at nominal setting will perform identically to GEM DR in Sinus Tach episodes with PR interval > 50% of RR interval.

PR Logic at nominal settings inappropriately detected for same Sinus Tachycardia episode with Long PR interval.

VT-ST boundary 50%

Nominal PR Logic™ (VT-ST boundary at 50%)In Patient with Long PR interval

GEM® III DR appropriately withholds therapy for Sinus Tachycardia with a Long PR interval when 1:1 VT-ST boundary is programmed to 66%.

Enhanced PR Logic appropriately withholds detection for patients with a long PR interval.

VT-ST boundary 66%

Enhanced PR Logic™ (VT-ST boundary at 66%) In Patient with Long PR interval

Enhanced PR Logic™ PerformanceTheoretical Performance with Programmable VT-ST

boundary**

*18 beat self-terminating run: double tach in VT zone & regularity unmet

Positive PredictiveValue:95.2%

True Positive:711 episodes

False Positive:36 episodes

False Negative:1 episode*

(non-sustained)

True Negative:218 episodes

VT/VF SVTActual Rhythm

SV

TV

T/V

F

100% sensitivity (sustained

VT/VF)

85.8%incremental specificity

Det

ecte

d R

hyth

m

1919

**By programming the VT-ST boundary in GEM® III, 19 of the 22 inappropriate therapies would now be correctly withheld (1 patient’s P-wave fell in Junctional zone and would not be reclassified)