- To identify the mechanism of a wide complex tachycardia
- To induce VT as part of an ablation procedure or before a surgical procedure in which cryoablation may be used as an adjunct
- To determine whether VT is the cause of unexplained syncope
- To decide whether an ICD should be implanted, such as for patients with ischemic cardiomyopathy, ejection fraction ≤40%, and nonsustained VT
- Some operators will also use programmed stimulation in patients with Brugada syndrome to determine whether an ICD should be implanted.
- In rare cases, to assess the efficacy of antiarrhythmic therapy
- If there is no plan to treat the VT differently (ie, if life expectancy is <1 year and no ICD is to be implanted or no ablation is to be performed)
- Presence of mobile ventricular thrombus
- Patient or clinical factors that may preclude the procedure (concurrent infection, valvular abnormalities that prevent passage through the tricuspid valve to do the procedure, pericardial effusion or tamponade, acute severe heart failure)
- VT from reversible causes such as ischemia or hyperkalemia
- Sterile mask, gown, gloves
- Sterile prep solution for access site
- Sterile drapes
- Sterile introducer sheaths, wires, and introducer needles
- Lidocaine for local anesthesia
- Syringes and small-gauge (25- or 30-gauge) needles for subcutaneous infiltration of local anesthetic
- Ultrasound for vascular access (optional)
- Intracardiac catheters and cables
- Fluoroscopy system
- Three-dimensional mapping system (optional)
- Pacing stimulator
- ECG machine and ECG recording system
- Crash cart with intubation equipment, resuscitation drugs, external defibrillator, and pacing equipment
- Oxygen source and delivery system, if necessary (eg, nasal cannula, mask)
- Equipment for starting a peripheral IV, if necessary:
- IV catheter (20-gauge)
- Alcohol or other sterile prep swab
- Tape or transparent sterile dressing for securing IV
- Heparin lock for IV
- Gauze or bandage for IV site
- Medications for sedation, if necessary (eg, midazolam)
- Dressing for femoral access site
- Electrophysiology studies are used to assess cardiac conduction and rhythm abnormalities. Studies are carried out by insertion of intracardiac catheters via the femoral, subclavian, or internal jugular vein and sometimes in the femoral artery as well. A catheter for a diagnostic electrophysiology study is placed in the right ventricular (RV) apex and may be moved to the RV outflow tract also. Catheters may also be placed in the high right atrium (RA), coronary sinus, and/or His bundle region.
- Vascular access for catheter ablation via the femoral approach is described here. The femoral vein is located in the femoral triangle just medial to the femoral arterial pulsation, below the inguinal ligament.
||Clinical Pearls: Anatomic relations in the groin can be remembered as “NAVEL, pointing toward the navel.” From lateral to medial, they are Nerve, Artery, Vein, Empty space, Lymphatics.
- Relationships of the heart in the chest
- In situ, the right border of the heart is formed by the RA, superior vena cava (SVC), and inferior vena cava (IVC). The left atrium (LA) is the most posterior chamber of the heart and is not visible in the anteroposterior view in the cardiac silhouette.
- The left and right phrenic nerves are close to the left atrial (LA) appendage and the SVC, respectively.
- The right ventricle (RV) extends from the orifice of the tricuspid valve nearly to the cardiac apex, ascends to the left to become the infundibulum (or conus arteriosus), and then reaches the pulmonary orifice, supporting the cusps of the pulmonic valve.
- The left ventricle (LV) is posterior and leftward of the RV. The inflow is from the mitral valve to the apex, and outflow is through the LV outflow tract to the aortic valve.