Heart Failure
Conditions
Keywords
DFT, Congestive Heart failure (CHF), ICD
Brief summary
When implantable cardiac defibrillators are implanted (ICDs), the defibrillation threshold (DFT), of the amount of energy required to effectively terminate life-threatening arrhythmias is determined. The device is then programmed to discharge a larger amount of energy in order to provide a safety margin. In some patients, the DFT is so high, that an adequate safety margin is not programmable. Placement of a defibrillation lead in the azygos vein has been found to be helpful in these patients. This goal of this trial is to attempt to quantify the average reduction in the DFT (if any) that results from the addition of the azygos lead.
Detailed description
Patients undergoing placement of an ICD for the primary or secondary prevention of sudden cardiac death will be asked to participate. Patients will undergo implantation of a standard right ventricular ICD lead at the time of ICD implantation. In addition, patient will receive another high voltage ICD lead placed in the azygos vein as has been previously described in the literature (1). After sedating the patient, the DFT will be determined using a binary search algorithm. This consists of testing the device at a given output for the first shock after inducing ventricular fibrillation (VF). Should the shock fail, external defibrillation will be attempted, as is the standard method for performing DFT testing. As per the standard method of DFT testing, VF will be induced a second time, with the shock strength dependent on the success of the first shock. If the first shock was unsuccessful, the second will be at a higher output. If the first shock was successful, the second will be at a lower output. A third shock will then be delivered, based on the success or failure of the preceding shock to define the DFT. Of note, as the device can be programmed to give multiple shocks for one episode, VF will not necessarily need to be induced each time. For example, VF could be induced, and the device programmed to give a 20 Joule (J) shock followed by a 23J shock if not successful, thus limiting the number of VF inductions required. DFT testing will be done using both the standard configuration of high voltage leads as well as using the azygos lead. We hypothesize that using the azygos lead will result in a lower DFT.
Interventions
DEVICEStandard configuration vs. azygos coil
Addition of an azygos vein defibrillation coil instead of a standard SVC coil.
Sponsors
Medtronic
Washington University School of Medicine
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Single group undergoing crossover in therapy (defibrillation testing with two different device configurations).
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Any patient undergoing elective placement of an ICD for the primary or secondary prevention of sudden cardiac death is eligible.
Exclusion criteria
include any contraindication to endovascular ICD implantation which includes but is not limited to; active infection, occluded venous access, or inability to perform DFT testing secondary to the inability to sedate the patient or hemodynamic compromise.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Difference in the DFT With an Azygos Vein Coil Versus the Standard SVC Coil. | During the course of the implant procedure and testing | Defibrillation threshold will be estimated by repeat defibrillation testing using an azygos coil and using an SVC coil (and compared). The outcome measure quoted below is the mean DFT using the azygos coil vs. the mean DFT using the standard configuration. |
Countries
United States
Participant flow
Recruitment details
Patients undergoing Implantable Cardioverter-Defibrillator (ICD) implantation in the electrophysiology laboratory were recruited. Both outpatients (recruited from the electrophysiology clinic) and inpatients (recruited from Barnes-Jewish Hospital) were included.
Participants by arm
| Arm | Count |
|---|---|
| Standard SVC Coil vs. Azygos Coil The DFT with the standard SVC coil vs. DFT with the azygos vein coil in place.
Azygos vein coil: Addition of an azygos vein defibrillation coil instead of a standard SVC coil. | 25 |
| Total | 25 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | inability to implant azygos coil | 3 | 3 |
| Overall Study | Inability to sedate for DFT testing | 1 | 0 |
Baseline characteristics
| Characteristic | Standard SVC Coil vs. Azygos Coil |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 6 Participants |
| Age, Categorical Between 18 and 65 years | 19 Participants |
| Region of Enrollment United States | 25 participants |
| Sex: Female, Male Female | 7 Participants |
| Sex: Female, Male Male | 18 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 25 |
| other Total, other adverse events | 1 / 25 |
| serious Total, serious adverse events | 0 / 25 |
Outcome results
Primary
Difference in the DFT With an Azygos Vein Coil Versus the Standard SVC Coil.
Defibrillation threshold will be estimated by repeat defibrillation testing using an azygos coil and using an SVC coil (and compared). The outcome measure quoted below is the mean DFT using the azygos coil vs. the mean DFT using the standard configuration.
Time frame: During the course of the implant procedure and testing
Population: All enrolled patient who were able to undergo azygos coil implant and defibrillation testing.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Standard Configuration vs. Azygos Coil | Difference in the DFT With an Azygos Vein Coil Versus the Standard SVC Coil. | DFT wtih Azygos coil | 10.4 Joules | Standard Deviation 7.7 |
| Standard Configuration vs. Azygos Coil | Difference in the DFT With an Azygos Vein Coil Versus the Standard SVC Coil. | DFT with Standard Configuration | 12.2 Joules | Standard Deviation 8.61 |
Comparison: The null hypothesis is that there is no difference between the DFT using the azygos coil vs. the standard configuration.~Paired t-test (two-tailed), used due to construction of study with DFT determined in both configurations in each patient, yields p=0.103p-value: 0.103t-test, 2 sided