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Micro Volt T Wave Alternans (MTWA). ( Analytic Spectral Method). Microvolt T-Wave Alternans. What is TWA? Published Clinical Data and ongoing trials Suggested Clinical use protocols How is an alternans test performed? How is the test interpreted?. T-Wave Alternans. Visible. - PowerPoint PPT Presentation
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Micro Volt T Wave Micro Volt T Wave Alternans (MTWA)Alternans (MTWA)
( Analytic Spectral Method)
Microvolt T-Wave AlternansMicrovolt T-Wave Alternans
What is TWA?
Published Clinical Data and ongoing trials
Suggested Clinical use protocols
How is an alternans test performed?
How is the test interpreted?
T-Wave AlternansT-Wave Alternans
VisibleVisible
Microvolt LevelMicrovolt Level
Predicts immediate Predicts immediate (VT/VF).(VT/VF).
Measured with Measured with proprietary spectral proprietary spectral method at heart rates. method at heart rates.
Predicts ~2 year VT/VF.Predicts ~2 year VT/VF.
T-Wave AlternansT-Wave Alternans
Even Beats
Odd Beats
MeanValt
Valt
100
120
140
160
180
200
0 20 40 60 80 100 120
Beat Number
T W
ave
Am
plit
ude
Beat Series
128 Beats
FFT
Spectrum
Alternans
0
10
20
30
40
50
0.0 0.1 0.2 0.3 0.4 0.5
Frequency (Cycles/Beat)Sp
ectr
um
(
V2 )
Resp
Noise
Spectral Method Spectral Method Detection of Microvolt TWADetection of Microvolt TWASpectral Method Spectral Method Detection of Microvolt TWADetection of Microvolt TWA
Smith, Clancy, Valeri, Ruskin, and Cohen. Circulation 1988;77:110-121
High Risk Groups for SCDHigh Risk Groups for SCD
High Coronary High Coronary RiskRisk
Post M IPost M I
Heart Failure/Heart Failure/E F < 35%)E F < 35%)
Previous Previous VF / VTVF / VT
Syncope /Syncope /Heart DiseaseHeart Disease
00 100100 200200 3003005050
(thousands)(thousands)(millions)(millions)
Population SizePopulation Size
00 1010 2020 505011 22 55
SCD Percent / YearSCD Percent / Year Total SCD / YearTotal SCD / Year
00 101011 22 55 2020
(percent)(percent)
Sudden Death Risk FactorsSudden Death Risk Factors
MTWA / Electr. Instability
LVEF/ MI Trigger
Do we need a better risk stratification Do we need a better risk stratification method?method?
Microvolt T-Wave AlternansMicrovolt T-Wave Alternans
What’s TWA
Published Clinical Data (all clinical data published are based on Analytic Spectral Method)
Ongoing trials
Suggested Clinical Use Protocols
How is an alternans test performed?
How is the test interpreted?
MGH / MIT StudyMGH / MIT Study
EP StudyAlternans Test
0
20
40
60
80
100
0 4 8 12 16 20
Months
Arr
hyth
mia
-free
Sur
viva
l (%
)
Negative
Positive
0
20
40
60
80
100
0 4 8 12 16 20
Months
Arr
hyth
mia
-free
Sur
viva
l (%
)
Negative
Positive
Rosenbaum, Jackson, Smith, Garan, Ruskin and Rosenbaum, Jackson, Smith, Garan, Ruskin and Cohen Cohen N Engl J Med N Engl J Med 1994;330:235-2411994;330:235-241
Multi-Center Regulatory Study Multi-Center Regulatory Study Prediction of VT/VF, ICD Firing and Total Prediction of VT/VF, ICD Firing and Total MortalityMortality
Gold MR, et al. A Comparison of TWA, SAECG, EP for Arrhythmia Risk Stratif. JACC Vol 36,7,2000.
50
60
70
80
90
100
0 2 4 6 8 10 12 14
Alternans Test
RR =13.9P<0.001
Months
Eve
nt
Fre
e S
urv
ival
TWA +
TWA -
50
60
70
80
90
100
0 2 4 6 8 10 12 14
EP Study
RR=4.7P=0.001
MonthsE
ve
nt
Fre
e S
urv
iva
l
EP +
EP -
Syncope SubstudySyncope Substudy
Bloomfield DM, Gold MR, Anderson KP, Wilber DJ, El-Sherif N, Estes NAM, Groh WJ, Kaufman ES, Greenberg ML, Rosenbaum DS, Dabbous O, Cohen RJ. AHA, 1999.
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10 11 12
TWA -
TWA +
RR = 4.4; P< 0.05
Eve
nt
Fre
e S
urv
i val
Months
EP -
EP +
Eve
nt
Fr e
e S
urv
i val
Months
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10 11 12
Frankfurt CHF Study Frankfurt CHF Study Preliminary Results in 81 patientsPreliminary Results in 81 patients
Klingenheben , Hohnloser SH. The Lancet Dec. 2000.
50
60
70
80
90
100
0 4 8 12 16 20 24
Alternans Test
TWA +
TWA -
Months
Eve
nt
Fre
e S
urv
ival
P<0.001
Non-Ischemic DCM StudyNon-Ischemic DCM StudyJACC 2003 JACC 2003 Results in 1 Results in 13737 patients patients
Kllingenheben T, Bloomfield, D, Cohen, R, Hohnloser, S;
JACC Vol 41 N.12 2003
Preditive value of MTWA Onset Heart Preditive value of MTWA Onset Heart
RateRate Kitamura JACC Jan 2002: 104 DCM patients pts
Tanno, Circulation, 2004; 109: 1854-1858 on 248 Tanno, Circulation, 2004; 109: 1854-1858 on 248 ischemic and non ischemic patients has found ischemic and non ischemic patients has found
similar resultssimilar results
Ikeda Post-MI StudyIkeda Post-MI Study
0
20
40
60
80
100
0 2 4 6 8 10 12
P = 0.0002
TWA -
TWA +
Eve
nt
Fre
e (%
)
Months
Ikeda, T,The American J. Cardiol Vol 89, Jan 1,2002
Post MI & MTWA (Large Multicenter Post MI & MTWA (Large Multicenter Study)Study)
Prospective study, 834 consecutive patients, infarct survivors, 7 Japanese centers.
Prognostic Indices: TWA, LP, EF, NSVT
Endpoint: SCD or resuscitated VF
Follow-up: 25 + 13 months
Design
Conclusions: These findings from a large prospective study demonstrate that TWA is a strong risk stratifier for sudden cardiac death after myocardial infarction.
Ikeda, T,The American J. Cardiol Vol 89, Jan 1,2002
850 pz. Post MI - 25 850 pz. Post MI - 25 SCD & VF SCD & VF EventEventss..( AJC Jan 2002)( AJC Jan 2002)
Sens. NPV RH
MTWA 22/24 (92%) 435/437(99%) 11
LVEF 14/25 (56%) 672/683(98%) 6
NSVT 12/25 (48%) 611/624(98%) 4
LP 11/22 (50%) 544/555(98%) 5
MTWA study in AthletesMTWA study in Athletes (F. Furlanello, G. Galanti,(F. Furlanello, G. Galanti, A. Michelucci, D. A. Michelucci, D.
Marangoni,Marangoni, R. Cappato) R. Cappato)
100 athletes ( no Organic Heart Disease)
48 healthy : 45 MTWA- 3 indeterm.
52 arrhythmic athletes
– 42 MTWA- (1 amiodaron) 3 indeterm.: 41 EP- (1 + amio)
– 7 MTWA+ : • 5 EP+: 2 ICD 1Myocarditis 1 Amio 1 RFCA• 1 EP- (but with NSVT)• 1 no EP25 months follow up : no events in TWA- 1 ICD multiple
discharges in TWA+
A.N.E. 2004 ;9(3):1-6
MTWA with Exercise in MTWA with Exercise in Pediatrics and Congenital Pediatrics and Congenital Heart Disease: Limitations and Heart Disease: Limitations and Predictive ValuePredictive Value
TWA is associated with pediatric and CHD diagnoses at high risk of serious events and may contribute, with other diagnostic tools, to management choices.(Pacing Clin Electrophysiol. 2006;29(7):733-741)
Antiarrhythmic Drug StudyAntiarrhythmic Drug Study 49 patients w/ Cardiomiopathy and VT/VF
Class I and III antiarrhythmic drug (Amiodarone 57%)
Study endpoint: Recurrence of VT/VF in 13 months
Result: PPV 67% NPV 71%
Conclusion: TWA significantly predicts reoccurrence of VT even on antiarrhythmic drug. TWA may be also a useful marker for evaluating the efficacy of antiarrhythmic drug
Koiki Sakabe A.N.E. 2001 6(3): 203-208
Beta Blocker StudyBeta Blocker Study 65 patients with prior VT
T-wave alternans measured atrial pacing at baseline and during beta blockade with metoprolol and d,I-sotalol
Both SOT and MET resulted in a reduced TWA Amplitude but not in a change of TWA Onset HR.
Conclusion: There are comparable effects of SOT and MET. TWA can be assessed during ongoing therapy if target Heart Rate of 110bpm can be reached.
Klikenhaben J Am Coll Card 2001;38:2013-9.
Event Rates of EPS and TWAEvent Rates of EPS and TWA
Singly In Combination
EPS+ 25% EPS+, TWA+ 39%
TWA+ 25% EPS-, TWA+ 15%
EPS- 5% EPS+, TWA-12%
TWA- 1.5% EPS-, TWA- 0%
Rashba, Gold MR, et al. . Enhanced vulnerability using TWA and EP PACE 2002; 25(4,Part Ii): 523-750
MADIT IIMADIT II(HF post MI with EF < 30%)
This study will increase the number of ICD implanted from its current level of 60.000 by two fold to 120,000 (USA)- and
4 times in Europe.
SCD-Heft (EF <35%) will multiply again the number of implants ( Class II on
Guidelines)
Ikeda AHA 2002 prospective study on MADIT Ikeda AHA 2002 prospective study on MADIT II patientsII patients
Data published on 129 pts with Hohnloser on The Lancet 2003; Data published on 129 pts with Hohnloser on The Lancet 2003; 362:125-26362:125-26
VT and SD primary end points ;
1/25 negative TWA patient had Sustained VT but no SD or VF
TWA in MADIT II Population: Multi-Center TWA in MADIT II Population: Multi-Center CHF CHF StudyStudy
2% death rate (twa-) comparared to 10% in ICD arm 2% death rate (twa-) comparared to 10% in ICD arm of Madit IIof Madit II
0 6 12 18 24Months
70
80
90
100A
rrh
yth
Su
rviv
al TWA -
TWA +
TWA Ind
55 32 12
Pos vs. Neg: Hazard Ratio ~ , p < 0.05
45 22 15
Total number of subjects at risk:
64 21 13
Bloomfield, Daniel et alt Circulation 2004; 110:1885-1889
Bloomfield MADIT II PatientsBloomfield MADIT II Patients
Bloomfield, Circulation, 2004; 110: 1885-1889
Baravelli and Salerno : Predictive Baravelli and Salerno : Predictive Significance for SCD of Microvolt level T Significance for SCD of Microvolt level T wave Alternans in NYHA class II CHF wave Alternans in NYHA class II CHF patients: A Prospective studypatients: A Prospective study
Baravelli et al, International Journal of Cardiology, March 2005
ICD placed / life savedICD placed / life saved
MADIT II
MTWA negative
MTWA positive
MUSTT
18 (11 at 3 yrs )
-30%
5
4
Data extracted from Data extracted from D. Bloomfield Circulation D. Bloomfield Circulation 20042004
… … Jacc 2006, Vol 47 N. 2 Daniel Jacc 2006, Vol 47 N. 2 Daniel
Bloomfield…Bloomfield…
549 patients LVEF <40% (MADIT II and SCD-Heft included)
2 years follow up
End points: death and Sustained VT/VF than LVEF
“TWA was significantly better univariate and multivariate predictor of death and Sustained VT/VF”
MTWA is a Powerful Arrhythmic MTWA is a Powerful Arrhythmic Risk StratifierRisk Stratifier
Annual Spontaneous Ventricular Tachyarrhythmic Event Rates These rates were observed in prospective natural history MTWA studies in patients similar to patients in
MADIT-II and SCD-HeFT. Study Population N Follow-
Up (months)
MTWA+ MTWA- HR
Klingenheben, 2000
CHF (Prior MI and DCM)
107 18 16% 0%
Hohnloser, 2003 DCM 137 18 17% 4% 4 Kitamura, 2002 DCM 83 21 16% 2% 9 Adachi, 2001 DCM 82 40 11% 1% 12 Grimm, 2003 DCM
LVEF 0.45 263 72 3% 2% 1.5
Ikeda, 2000 Prior MI 102 13 30% 2% 16 Ikeda, 2002 Prior MI 834 24 4% 0.5% 8 Hohnloser et al, 2003
Prior MI LVEF 0.30
129 24
9%* 19%
0%* 3%
6
Chow, 2003 Prior MI LVEF 0.30
203 18 8% 1% 6
All All 1,811 8.4% 1.2% 7
*SCD and Cardiac Arrest only
Antonis A. Armoundas, Stefan Hohnloser, Takanori Ikeda, Richard J. Cohen, Nature Clinical Practice, October 2005
All Cause Mortality is Lower in MTWA Negative Patients All Cause Mortality is Lower in MTWA Negative Patients Who Did Not Receive ICDs than in Comparable Patients Who Did Not Receive ICDs than in Comparable Patients in the MADIT-II and SCD-HeFT Trials who Did Receive in the MADIT-II and SCD-HeFT Trials who Did Receive
ICDsICDsAnnual All Cause Mortality Rates
Upper portion of table involves prospective ICD studies. Lower part of table involves prospective MTWA studies in non-ICD patients with reported mortality endpoint analyses.
Study Population N Follow-Up
(months) No ICD ICD
MADIT II2, 2002 Prior MI LVEF 0.30
1,232 20 13.2% 9.2%
SCDHeFT3, 2004 CHF LVEF 0.35
2,521 60 9.0% 6.5%
All 3,753 10.4% 7.4%
Study Population N Follow-Up (months)
Entire Population
MTWA-
Bloomfield9, 2003 Prior MI LVEF 0.30
177 24 7% 2%
Hohnloser et al17, 2003
Prior MI LVEF 0.30
129 24 10% 7%
Costantini et al, 2004
DCM LVEF 0.40
282 24 3% 0%
Grimm et al14, 2003
DCM LVEF 0.45
263 72 4% 2%
All 851 5.3% 2.0%
Antonis A. Armoundas, Stefan Hohnloser, Takanori Ikeda, Richard J. Cohen, Nature Clinical Practice, October 2005
Annualized Annualized mortality (%)mortality (%)TRIAL
OHD
FU(mo)
0
5
10
15
20
MADIT IIMADIT II11
ICM + EF < 0.30
20
SCD-HeftSCD-Heft22
ICM + NICM +EF < 0.35
60
TWA-CHFTWA-CHF33
ICM + EF < 0.40
24
TWA-CHFTWA-CHF44
NICM +EF < 0.40
24
HohnloserHohnloser55
ICM + EF < 0.30
ICD– 12.4%
ICD – 8.6% ICD+ 6.5%
TWA– 2.0% TWA- 0%
TWA- 7% ICD+ 9.2%
1. Moss et al. NEJM 2002;346:8772. Bardy et al. NEJM 2005;352:2253. Bloomfield et al Circulation. 2004;110:1885
AN
NU
AL
IZE
D M
OR
TA
LIT
Y (
%)
24
ChowChow66 - -
ICM + EF < 0.35
18 - 40
ICD- 5.6% ICD+ 5.3%
ICD- 14.7%
ICD+ 7.3%
TWA+TWA+
TWA-TWA-
4. Costantini et al. Circulation 2004;110:667 (Supp)5. Hohnloser et al Lancet 2003;362:1256. Chow et al. JACC 2006;47:1820
1 Year Total Mortality
Meta- Analysis on 2608 Meta- Analysis on 2608 patients in published trials.patients in published trials.
( JACC 2005;46:75-82 )( JACC 2005;46:75-82 )
Negative Predictive Value 97.2%
Positive Predictive Value 19.2%
ACC 2006 Investigator ACC 2006 Investigator awardaward
“Cost-effectiveness of ICD implantation including the initial cost of ICD implant, cost of MTWA testing, complications, ICD replacements, death rates, etc.”
The results of the simulations revealed an Incremental Cost Effectiveness Ratio of $88,700 per Quality Adjusted Life Year in the ICDs FOR ALL strategy as compared to the use of MTWA risk stratification. (JACC June 7 2006 ) and confirmed by Dr MOSS study (JACC 2006; 47:2310-2318)
CMS proposes Medicare coverage for T-wave alternans ICD risk-stratification test
Dec 30, 2005
Steve Stiles
Costs of Healthcare will go outside national budgets so that MEDICARE has DETERMINED that : “There is sufficient evidence to conclude that microvolt TWA testing using only the spectral analytic method can improve net health outcomes and is reasonable and necessary for patients who are candidates for ICD placement.“….
“ MTWA can identify which heart patients are at NEGLIGIBLE risk of sudden death, and who may therefore be able to avoid ICD implantation and its attendant RISK”.…..March 21, 2006
ICD risks :ICD risks : “Prophylactic Defibrillator Therapy Is Associated
With Increased Mortality in Microvolt T-Wave Alternans Negative Patients With Ischemic Cardiomyopathy” (ACC 2005 abstract). Data reported also in “Prognostic Utility of Microvolt T-Wave Alternans in Risk Stratification of Patients With Ischemic Cardiomyopathy” JACC Vol 47, No 9 2006, May 2nd
”Frequency and causes of implantable cardioverter-defibrillator therapies: is device therapy proarrhythmic?”Am J Cardiol 2006 April 15 .
ACC/AHA/ESC 2006 NEW ACC/AHA/ESC 2006 NEW Guidelines for VA & SCD patients Guidelines for VA & SCD patients
(August 2006)(August 2006)“ It is reasonable to use TWA for improving the
diagnosis and risk stratification of patients with Ventricular Arrhythmias (VA) or who are at risk for developing life threatening VA. Class IIa (Level of Evidence A)”
“ICD trials especially MADIT II have highlighted the need to develop novel tools in order to identify patients at highest risk of VA and SCD.”
Mtwa icd strategy (1)Mtwa icd strategy (1)
Clinical:
- class 2 applications (scd-heft)
- EF borderline
- help to increase the primary prevention application penetration ( only 10% ) for patients or doctors reluctant to ICD implantation (for possible ICD / quality of life complications)
- EP test cases of difficult interpretation
Mtwa icd strategy (2)Mtwa icd strategy (2)
Economic Efficiency:
- not acceptable costs per quality adjusted life year gain (50.000 $)
- budget limitation: not enough ICDs for all primary (Class I) prevention patients: A selection has to be made also according to the new 2006 guidelines suggestions.
New trials with device New trials with device implantation to validate the implantation to validate the
positive predictive valuepositive predictive value
ABCD TrialABCD TrialProtocolProtocol
MUSTT population:400 patients, 42 MUSTT population:400 patients, 42 CentersCenters
C A D /N S V T
T W A + /E P +IC D
T W A + /E P S -IC D
T W A -/E P +IC D
T W A -/E P -N O IC D
L V E F< 4 0%T W A /E P
MASTER Trial on Madit II MASTER Trial on Madit II PatientsPatients
Largest trial: 1800 patients
Post MI, EF<40% & Madit II & MTWA
ICD implanted in all MADIT II patients
60 Centers US: Start September 2003
CARISMA Northen Europe CARISMA Northen Europe study:study:• Post MI, EF <40%, Loop recorder Post MI, EF <40%, Loop recorder implantedimplanted
•10 Centers, 400 Patients: end enrollement 10 Centers, 400 Patients: end enrollement Dec. 200Dec. 20044
Comparison to Other Risk Comparison to Other Risk MarkersMarkersPrediction of Arrhythmia-Free SurvivalPrediction of Arrhythmia-Free Survival
Comparison to Other Risk Comparison to Other Risk MarkersMarkersPrediction of Arrhythmia-Free SurvivalPrediction of Arrhythmia-Free Survival
0 5 10 15
Relative Risk
Armoundas et al,
1998
Hohnloser et al,
1998
Gold et al, 1999
Klingenheben etal, 2000
NSVT
HRV
SAECG
TWA
*
*
*
*
* p < 0.01
Microvolt T-Wave AlternansMicrovolt T-Wave Alternans
What’s TWA
Published Clinical Data and ongoing trials
Suggested Clinical Use Protocols
How is an alternans test performed?
How is the test interpreted?
Diagnosis and Treatment Diagnosis and Treatment ModelModelDiagnosis and Treatment Diagnosis and Treatment ModelModel
High Risk PatientsHigh Risk PatientsHigh Risk PatientsHigh Risk Patients
Stress test with the CH 2000Stress test with the CH 2000Stress test with the CH 2000Stress test with the CH 2000
Electrophysiology StudyElectrophysiology StudyElectrophysiology StudyElectrophysiology StudyCoronary AngiographyCoronary AngiographyCoronary AngiographyCoronary Angiography
ICD, ablation, drugsICD, ablation, drugsICD, ablation, drugsICD, ablation, drugsCABG or AngioplastyCABG or AngioplastyCABG or AngioplastyCABG or Angioplasty
IschemiaIschemia T-wave AlternansT-wave Alternans
C A D L o o k fo r o th er C a u seso f S y n co p e
E P L V E F 0 .4 0
IC D L o o p R eco rd er C o n sid er IC D
+ -
+ -
+ - - +
T W A
P atien ts w ith K n ow n H eart D isease an dU n exp la in ed S yn cop e
Suggested Suggested protocolsprotocols
S tress T est w ith T W A
T W A +A ctiv e Isch em ia
T W A +N o A ctiv e Isch em ia
T W A -N o A ctiv e Isch em ia
T W A -A ctiv e Isch em ia
T rea t Isch em ia
R ep ea t T W A
E P
T rea t Isch em ia
T W A +
IC D ?
+ -
P a tien ts w ith Isch em ic H ea rt D isea se a n d L V E F 0 .4 0
Microvolt T-Wave AlternansMicrovolt T-Wave Alternans
What’s TWA
Published Clinical Data and ongoing trials
Suggested Clinical Use Protocols
How is an alternans test performed?
How is the test interpreted?
Heart Rate Dependence Heart Rate Dependence of TWAof TWAHeart Rate Dependence Heart Rate Dependence of TWAof TWA
VT PATIENTVT PATIENT
H
HHHH
J
J
J
J
JJ0
10
20
30
40
AL
TE
RN
AN
S (
V
HEART RATE (BPM)80 100 120 140
CONTROLCONTROL
Rosenbaum, et al
Measurement of TWA with Measurement of TWA with CH-2000 CH-2000
Full featured stress system
3 Pretest Lead checks
14 leads standard stress test option
Proprietary Diagnostic Screen Grid
New HearTwave IINew HearTwave II
Designed for best MTWA testing.
Windows XP operating system
Includes ECG monitoring
Upgradeable to full Stress test
Methods to increase Heart Methods to increase Heart RateRate
Treadmill or Ergometer
Pharmacologic (Dobutamine)
Pacing:
Atrial
AV Sequetial with AV delay of 180 msec
AV Simultaneous….
MTWA in Atrial Fibrillation MTWA in Atrial Fibrillation patientspatients
Microvolt T-wave alternans during exercise and pacing in patients with acute myocardial infarction. PACE 2005;28:Suppl 1:S193-7.:
“Simultaneous V+A pacing can be used to assess TWA also in patients with atrial fibrillation and impaired AV nodal conduction. This approach also eliminates retrograde atrial activation and/or random sinus activity at descending portion of the T wave, which may obscure the TWA analysis during ventricular pacing. The data obtained with V+A pacing were similar to those measured during the bicycle exercise and A pacing “
ECG (Segment)ECG (Segment)
ImpedanceImpedance
RespirationRespiration
ECG (Center)ECG (Center)
Noise ReducedNoise Reduced
Adaptive cancellation reduces noise due to patient movement
Adaptive cancellation reduces noise due to patient movement
Noise ReductionNoise Reduction
High-Resolution ElectrodesHigh-Resolution ElectrodesMake noninvasive test feasibleMake noninvasive test feasibleHigh-Resolution ElectrodesHigh-Resolution ElectrodesMake noninvasive test feasibleMake noninvasive test feasible
Microvolt T-Wave AlternansMicrovolt T-Wave Alternans
What’s new?
How are EPs using the test clinically?
How is an alternans test performed?
How is the test interpreted?
Positive TWA TestPositive TWA Test (automatic interpretation)(automatic interpretation)
HeartRate
T-WaveAlternans
• Sustained Alternans• Valt 1.9 µV• Alternans ratio 3• Positive HR threshold
• Onset HR < 110 bpm
Negative TWA Test Negative TWA Test (automatic interpretation)(automatic interpretation)
HeartRate
T-WaveAlternans
• No Sustained Alternans
• HR of > 105 achieved
www.alternans.owww.alternans.orgrg
All updated information on T Wave Alternans