Initial Management of Patients Receiving a Single Shock (IMPRESS)
Initial Management of Patients Receiving a Single Shock (IMPRESS)
The goal of this study is to determine the optimal treatment for patients who receive a
 single shock from their implantable cardioverter defibrillator (ICD). All participants in
 this study will be fitted with a special electrode vest to detect the origin of heart rhythm
 abnormalities and then they will undergo a procedure called Non-Invasive Programmed
 Stimulation (NIPS). This procedure involves sedating a participants with anesthesia and then
 using the participant's own ICD to try to stimulate the heart to go into ventricular
 tachycardia. If this procedure is unable to induce the participant into ventricular
 tachycardia, then the participant will just be managed with usual care and will not be placed
 on any additional medications and will not undergo an ablation. However, if the NIPS induces
 the ventricular tachycardia, the electrode vest will be used to determine the origin of the
 abnormal heart rhythm inside the heart. After a successful NIPS procedure, the participants
 will be randomly assigned to either be placed on medication therapy or undergo catheter
 ablation. The outcomes from all three groups will be compared and the researchers hope to
 better understand which participants are most likely to benefit from watchful waiting versus
 medication versus catheter ablation.
Patients with a history of ventricular tachycardia requiring defibrillation or who are at
 risk for developing ventricular tachycardia will undergo placement of an implantable
 cardioverter defibrillator (ICD) for purposes of prevention of sudden cardiac arrest. While
 the ICD is lifesaving, if a patient receives a shock from their ICD it is painful and the
 entire experience is very traumatic. Traditionally, the management of these patients who
 receive a single shock from their ICD is variable because it is not known if the patient will
 continue to experience further shocks or not. Some physicians will initiate antiarrhythmic
 medical therapy after only a single shock, whereas others will wait until the patient has
 recurrent ICD shocks before initiating therapy. All patients should be counseled to not drive
 for 6 months following a shock. Ventricular tachycardia ablation, a procedure involving
 placing catheters from the groin into the chambers of the heart to isolate the source of
 ventricular tachycardia and eliminate these foci through delivery of radiofrequency energy,
 is typically reserved for patients with multiple recurrent cases of ventricular tachycardia.
 While some studies have shown that ventricular tachycardia ablations can be done safely at an
 earlier course of the disease and this procedure has been demonstrated to reduce further ICD
 shocks, this practice is not commonplace.

 Patients who undergo a ventricular tachycardia ablation procedure, will initially have
 catheters placed into the ventricular chambers of the heart and these catheters will be used
 to stimulate the heart in an attempt to induce the ventricular tachycardia, a process known
 as programmed stimulation. One major limitation of a ventricular tachycardia ablation
 procedure is the need to be able to induce the ventricular tachycardia rhythm via programmed
 stimulation. If this rhythm cannot be induced then it is very difficult to perform the
 ventricular tachycardia ablation procedure. Non-invasive programmed stimulation (NIPS) is a
 means of performing programmed stimulation using the patient's own ICD and does not involve
 placing catheters into the heart.

 Aim: The aim of this study is to investigate if non-invasive programmed stimulation (NIPS)
 can be used to risk stratify patients determine if earlier intervention with either
 antiarrhythmic medications or ablation in patients with recurrent ventricular tachycardia
 that received ICD shocks would help decrease further ICD shocks and hospitalizations for
 ventricular arrhythmias.

 Primary hypothesis: Patients receiving a single ICD shock for ventricular tachycardia who
 undergo a non-invasive programmed stimulation (NIPS) that fails to induce any sustained
 ventricular tachycardia, are at low likelihood of experiencing recurrent ICD shocks within
 the next year.

 Secondary hypothesis: For patients receiving a single ICD shock for ventricular tachycardia
 who undergo non-invasive programmed stimulation (NIPS) that induces a sustained, monomorphic
 ventricular tachycardia rhythm, the performance of ventricular tachycardia ablation will
 reduce the incidence of recurrent ICD shocks within the next year, as compared to
 antiarrhythmic therapy alone.
Inclusion Criteria:

 -  18-80 years old, both males and females

 -  Single or dual chamber ICD or BiVentricular ICD in situ

 -  Ischemic or non-ischemic cardiomyopathy

 -  Receive a single shock from their ICD for monomorphic ventricular tachycardia

 Exclusion Criteria:

 -  ICD shock for polymorphic VT/VF or inappropriate shock

 -  Previous ventricular tachycardia ablation within 1 year

 -  NYHA Class IV heart failure or current inotrope therapy

 -  Ventricular tachycardia storm

 -  Listed for heart transplant or LVAD

 -  Pregnant as determined by urine pregnancy test prior to NIPS