Patient Education and Consent
Patients should be familiarized with the procedure and the possible complications, including those related to sedation given for the procedure.
Patient instructions
Patients should be made aware of the requirement for bedrest after the procedure is performed when vascular access is required. Written home care instructions should be provided to the patient as well.
Equipment
The equipment and personnel required for the safe application of these techniques in the electrophysiology laboratory is addressed in detail in a 2014 consensus statement released by the Heart Rhythm Society [14] as well as a 2020 joint consensus statement by the European Heart Rhythm Association (EHRA), HRS, Asia Pacific Heart Rhythm Society (APHRS), and the Latin American Heart Rhythm Society (LAHRS). [6]
As a rule, because of the potential to induce hemodynamically unstable arrhythmias, resuscitation equipment must be readily available. In addition, when performed invasively, a recording system and electroanatomical mapping system are typically used, as is a fluoroscopic imaging system. As with any procedure that involves sedation, supplemental oxygen, wall suction, and equipment to monitor heart rate, blood pressure, and oximetry are mandatory.
Patient Preparation
Patients should be kept on nothing by mouth (NPO) status for the procedure.
Anesthesia
As a rule, these procedures are safely performed with conscious sedation. Agents such as midazolam and fentanyl are commonly used for sedation, with adjunctive lidocaine for local anesthesia; 1% lidocaine is preferred, as it has been demonstrated that with higher concentrations and overly liberal infiltration, patients can achieve blood lidocaine levels high enough to alter the electrophysiologic properties of the heart. [15]
In some cases, general anesthesia or deep sedation may be preferred. When the expected procedural time is extensive, the rhythm being investigated is hemodynamically unstable, or the patient is unable to lie still, deeper levels of sedation make for a safer procedure. For small children and younger adolescents, general anesthesia is preferable.
When using deeper levels of sedation, the addition of beta agonists such as isoproterenol may be required to counteract the sympatholysis induced from deep sedation. Mechanical support, such as intra-aortic balloon pumps, may also be required in these cases.
Positioning
In most cases, these procedures are performed in an electrophysiology laboratory under fluoroscopic guidance with the patient in a supine position. Positioning is typically with the arms at the sides to allow for free movement of the imaging camera. When these techniques are performed via an existing pacemaker or implanted defibrillator, the patient is typically supine on a stretcher or bed, although, because no venous sheathes are involved, they may be in a reclining rather than supine position. In all cases, it is imperative that the positioning is such that loss of consciousness will not result in injury.
Monitoring & Follow-up
In the immediate postprocedural period, frequent monitoring of vital signs is mandatory. Typically, vital signs postprocedure are assessed every 15 minutes for the first hour and then every 30 minutes for the subsequent hour. With each assessment of the vital signs, the vascular access sites are checked for signs of bleeding, hematoma, or other vascular complications.
Patients who undergo a diagnostic electrophysiologic study without ablation or insertion of a cardiac rhythm management device afterward are typically discharged to home the same day after 4-6 hours of observation. When an ablation is performed or a device such as a pacemaker or defibrillator is inserted after an electrophysiologic study, the standard of care in most of the United States is overnight observation in a telemetry ward.
Preprocedural Planning
Prior to undertaking a study involving programmed stimulation, it is essential to begin with an understanding of what exactly is being investigated and what the clinical scenario is for each individual patient. Relevant information would typically include any electocardiographic (ECG), Holter, mobile cardiac outpatient telemetry (MCOT), or telemetry data that would give an appreciation of the cardiac chamber from which the suspected arrhythmia originates, the tachycardia cycle length, and the most likely mechanism of the arrhythmia (ie, automatic vs reentrant). Other details that can be gleaned from these data include the presence of other "nonclinical" arrhythmias that may be seen during the study but which differ from the one believed to be causing the particular issue being investigated.
