Sudden Cardiac Death
Conditions
Keywords
ICD, Defibrillation, ULV, Tuned
Brief summary
The objective of this study is to compare the ULV (Upper Limit of Vulnerability)/DFT (Defibrillation Threshold) efficacy between the 2.5, 3.5 and 4.5 ms membrane time constant based biphasic defibrillation waveforms. This comparison will result in identifying the optimal membrane time constant when programming the tuned defibrillation waveform.
Detailed description
Sudden cardiac death (SCD) continues to be a significant cause of cardiac mortality with annual deaths ranging from 250,000 to 400,000 in the United States. Accordingly, implantable cardioverter-defibrillators (ICD's) have proven to be an important therapeutic option for patients susceptible to SCD. Successful therapy and generator longevity are greatly dependent on proper defibrillation threshold (DFT) determination. All modern ICD's utilize a biphasic waveform for defibrillation. It has been clearly shown that biphasic waveforms reduce the energy required for internal defibrillation of the heart. However, there is no consensus on which pulse widths are best for defibrillation. St. Jude Medical ICD's (implantable cardioverter defibrillators) have programmable pulse widths, which allow the physician multiple options in dealing with ICD patients. By implanting ICD's with programmable pulse widths, this study utilizes the Tissue RC Resistance/Capacitance) model to try to identify the optimal pulse widths. To determine the efficacy of an optimal membrane time constant estimate for the tuned waveform, defibrillation testing must be performed. Upper limit of vulnerability (ULV) has been proposed as an alternative means of predicting the DFT and it has been shown that ULV guided DFT testing can achieve a defibrillation success rate of 95%.
Interventions
DEVICEImplantable Cardioverter Defibrillator (ICD), Cardiac Resynchronization Therapy (CRT-D)
Patients that are indicated for an ICD or CRT-D receive one of these devices.
Sponsors
Abbott Medical Devices
Study design
Allocation
RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Patient is a candidate for ICD/CRT-D implantation. * Patient has a compatible transvenous defibrillation lead system. * Patient has had an echocardiogram, MUGA, or cath procedure within 6 months of ICD/CRT-D implant. * Patient is able to tolerate ULV guided DFT testing.
Exclusion criteria
* Patient has a mechanical valve in the tricuspid position. * Patient has epicardial defibrillation electrodes. * Patient is pregnant. * Patient is less than 18 years old.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Defibrillation Thresholds (DFTs) (3.5 ms Waveform) | Implant |
| DFT (2.5 ms Waveform) | Implant |
| DFT (4.5 ms Waveform) | Implant |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Group 1 | 217 |
| Total | 217 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Final DFTs were not obtained | 96 |
Baseline characteristics
| Characteristic | Group 1 |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 129 Participants |
| Age, Categorical Between 18 and 65 years | 88 Participants |
| Age, Continuous | 67 years STANDARD_DEVIATION 14 |
| Region of Enrollment United States | 217 participants |
| Sex: Female, Male Female | 57 Participants |
| Sex: Female, Male Male | 160 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 0 / 217 |
| serious Total, serious adverse events | 0 / 217 |
Outcome results
Primary
Defibrillation Thresholds (DFTs) (3.5 ms Waveform)
Time frame: Implant
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Group 1 | Defibrillation Thresholds (DFTs) (3.5 ms Waveform) | 427 Volts | Standard Error 11 |
Primary
DFT (2.5 ms Waveform)
Time frame: Implant
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Group 1 | DFT (2.5 ms Waveform) | 454 Volts | Standard Error 11 |
Primary
DFT (4.5 ms Waveform)
Time frame: Implant
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Group 1 | DFT (4.5 ms Waveform) | 435 Volts | Standard Error 11 |