The purpose of this study is to determine whether administration of a pectoral nerve blocks (Pecs I and II) with 0.25% bupivacaine are more effective as compared to placebo to provide analgesia for cardiac implantable electronic device (CIED) placement in cardiac electrophysiology lab

Cardiovascular implantable electrical device (CIED) is a generalized term for pacemakers, implantable cardiac devices (ICDs) and cardiac resynchronization therapy (CRT) devices. CRT is a modality of cardiac pacing that provides simultaneous pacing of left ventricle (LV) and right ventricle (RV) as biventricular (BiV) pacing (CRT-pacemaker or CRT-P), or by a combined CRT-implantable-defibrillator (CRT-D). The indication for pacemaker implantation in a patient is abnormal cardiac electrical conduction such as sinus node dysfunction or high-grade atrioventricular block. CRT is indicated for patients with symptomatic heart failure with left bundle branch block. Patients undergoing CIEDs often have multiple other associated comorbidities such as pulmonary disease, chronic kidney disease etc. which places them at a high-risk for undergoing these procedures.

Every year, more than 500,000 CIEDs are implanted in the United States alone. These procedures are being done with increasing frequency in patients with arrhythmias, heart failure and other risk factors for sudden cardiac death. Opioid prescription usage and persistent use of opioids after CIED procedures remains very high. In the context of current opioid crisis, there is a growing need to find alternatives to optimize pain and limit opioid usage in the patient population.

The current standard practice for CIED placement is either under monitored anesthesia care (MAC) or general anesthesia. MAC is sedation and is usually performed using benzodiazepines, opioids, and propofol. Deleterious effects of opioids during sedation include respiratory or hemodynamic compromise, particularly in this high-risk patient population with low reserve. General anesthesia is invasive requiring endotracheal intubation and positive pressure ventilation, which can also compromise cardiorespiratory function. Finally, some patients with obesity or obstructive sleep apnea may have low tolerance to sedation and opioid use in procedures involving tunneling of leads or deeper chest wall tissue dissection. Despite procedural sedation or general anesthesia, patients generally continue to require pain medications postoperatively due to residual pain from the procedure.

Nerve blocks involve injection of local anesthetic around peripheral nerves or their branches to interrupt pain and other sensory signals thus alleviating pain. Pectoralis or Pecs block is one such nerve block and has recently been effectively in increasing evidence for various surgeries and procedures on chest wall. Few case reports in adult population undergoing pacemaker, ICD and CRT placement also emphasize the utility of these blocks especially in patients who are critically ill. Preliminary studies have shown lower sedation requirements and higher patient and proceduralist satisfaction with use of PEC block in these patients.

Moreover, there is no large study has evaluated the utility of PECs block in this patient population undergoing CIED insertion and there remains a need to investigate their utility in a systematic study.

There are two components to a Pecs block: Pecs I block that targets the lateral and medial pectoral nerves, suppliying both pectoral muscles (major and minor, and Pecs II block that targets the anterior and lateral division of the thoracic intercostal nerves T2-T6, the long thoracic nerve (C5-C7) which supplies the serratus anterior muscle and the thoracodorsal nerve (C6-C8) which innervates the latissimus dorsi muscle. Thus, combination of both Pecs I and II blocks can provide a widespread analgesic coverage and has been previously studied for analgesia for breast surgeries and also in thoracic trauma. It is a promising option considering its efficacy and ease of administration and may prove to be a useful analgesic technique in patients undergoing CIED insertion or replacement. The block is devoid of the systemic adverse events associated with opioids and hemodynamic complications associated with general anesthesia. It is a relatively superficial block and is therefore safe even on patient on antiplatelet therapy. It could prove useful in reducing intra-procedure analgesic requirement in the acute setting of postoperative pain as well as preventing chronic pain and has the potential to become the standard of care for analgesia in CIED procedures.

Inclusion Criteria:

• Patients 18 years of age or older
• Undergoing CIED placement in electrophysiology lab
• Booked with anesthesia service for the procedure.

Exclusion Criteria:

• Current participation in another interventional study
• Use of mechanical circulatory support device
• Emergent procedures
• Patients receiving other modalities of regional anesthesia like intrathecal morphine
• Chronic opioid use for chronic pain conditions with tolerance (total daily dose of an opioid at or more than 30 mg morphine equivalent for more than one month within the past year)
• Current use of SSRI, TCA, anti-epileptics, gabapentin, or pregabalin as part of multimodal pain management
• Hypersensitivity to bupivacaine
• Hemodynamics related: Oxygenation outside of normal limits (defined as PaO2 < 60mmHg on an FiO2 of 1.0 or SpO2 < 85% within 30 minutes prior to drug administration), Received an infusion or bolus ≥ 0.05 mcg/kg/min of epinephrine o Received an infusion or bolus ≥ 0.50 mcg/kg/min of milrinone, Received an infusion or bolus ≥ 0.20 mcg/kg/min of norepinephrine o Significant clinician or nursing concern, Hemodynamically unstable (defined as HR > 120, SBP < 80, MAP < 50 within 30 minutes prior to drug administration)

Enrolled subjects will be randomized to one of the two study groups, in a 1:1 randomization ratio. Patients randomized to Group 1, or the bupivacaine group, will receive up to 25cc of 0.25% bupivacaine hydrochloride for the PECs blocks. In Group 2, patients will receive up to 25cc of normal saline. Use of placebo is a standard control procedure in clinical trials and will allow for the assessment of unbiased quantitative data on the efficacy across all treatment groups.