Bradycardia and a pectoralis twitch in a pacemaker patient
Bradycardia and a pectoralis twitch in a pacemaker patient
Ms. K, age 50 years, was obese with a past medical history significant for hypertension and hypercholesterolemia. Her family history was positive for CAD, arrhythmias, bradycardia, and bigeminy. Two years earlier, she had received a dual-chamber permanent pacemaker (PPM) and an implantable cardioverter defibrillator (ICD).
Ms. K had also been diagnosed with Bell's palsy (with right-sided residual paralysis), glucose-6-phosphate dehydrogenase deficiency, and dilated cardiomyopathy. She underwent hemodialysis three days a week to treat end-stage renal disease. Multiple hemodialysis catheters had been placed.
1. Patient presentation
During a dialysis session, Ms. K experienced bradycardia and noted that her pacemaker appeared to have no capture. She reported no chest pain, shortness of breath, or syncope. However, the patient told clinicians that she occasionally felt her pectoralis muscle twitch. Since this episode occurred in a dialysis unit, referral was the only course of action available. Unfortunately, the patient decided to wait.
A few weeks later, Ms. K presented to another hospital with complaints of a painful sensation in her chest wall. Routine chest x-ray showed the PPM/ICD lead tip outside the heart silhouette and perforating the right ventricular (RV) apex into the left pleural space (Figure 1). CT scan confirmed the position of the RV lead. Interrogation of the PPM/ICD demonstrated failure of the ventricular lead to capture, failure to sense, and normal impedance.
2. Treatment course
To ensure a safe surgical procedure, Ms. K was admitted for evaluation prior to PPM-ICD laser lead extraction and re-insertion of the lead via left mini-thoracotomy. Lung sounds were clear to auscultation bilaterally. The heart had a regular rate and rhythm. Arteriovenous fistulae, patent and with a positive thrill, were noted in the patient's right upper extremity. The remainder of Ms. K's preoperative physical examination was noncontributory.
In the operating room, transesophageal echocardiography was established intra-operatively. The patient underwent a left anterior minimally invasive thoracotomy, laser extraction of the right atrial (RA) and RV leads, repair of the ventricular perforation, and re-insertion of new RA and RV leads (Figure 2). Despite the perforation through the myocardium and the pericardium, there was no evidence of a pericardial effusion. Ms. K tolerated the procedure well. The new leads were interrogated, demonstrating excellent impedance and pacing thresholds. The defibrillator demonstrated voltage defibrillation twice on testing. The patient was extubated and transferred to the recovery room without incident. Hemodialysis was performed the following morning, and she was discharged home.
Approximately 3%-7% of implantable cardiac devices develop complications.1 Pacemaker lead perforations are classified either as immediate (occurring up to one month after implantation) or delayed (occurring later than one month).2 A delayed perforation of the RV typically requires astute recognition and immediate intervention. The most common manifestations of delayed perforation include hemopericardium (with or without cardiac tamponade), diaphragm or pectoral muscle stimulation, loss of stimulation properties, and pneumothorax.3
As happened with Ms. K, patients may not present with chest pain or shortness of breath, although they may note such symptoms as inappropriate shocks. The subacute nature of the presentation requires the clinician to obtain a thorough history.
Interrogation of the ICD will reveal changes in the pattern of the pacing threshold, impedance, and R-wave amplitude. Evaluation with chest x-ray, CT scan, and echocardiography are part of the diagnostic confirmation process.
Delayed perforation occurs in 0.1%-0.8% of pacemakers and 0.6%-5.2% of ICDs.4 Increase in the number of delayed perforations has been attributed to surgeons' and cardiologists' use of thinner active-fixation leads and the increased stiffness of newer manufacured pacemaker leads.5 A thin-walled dilated ventricle with impaired function may be a contributing factor, as is the experience level of the individual performing the device insertion. Major risk factors associated with cardiac perforation include advanced age, female gender, BMI <20, steroid use, and anticoagulation therapy.6
To prevent perforation, clinicians should consider other areas of lead placement within the RV (e.g., the septum or outflow tract). Note, however, that the data on septal-lead placement, reliability, and longevity are limited. Consider leaving a loop of the lead in the ventricle so that the lead does not become strained during deep inhalation. Finding the proper balance between too much and not enough slack will help prevent complications.
4. Other considerations
The FDA's Code of Federal Regulations (Title 21—Food and Drugs—Part 803—Medical Device Reporting) requires hospitals and other facilities to report deaths and serious injuries associated with the use of medical devices.7 Even if the patient is not harmed, adverse events should be reported. This helps identify significant trends earlier and allows the institution of corrective actions, minimizing patients' exposure to risk.
Dr. Kleinschmidt is a physician assistant in cardiothoracic surgery and Dr. Ciuffo is a cardiac surgeon, both in New York City.
1. Ellenbogen KA, Wood MA, Shepard RK. Delayed complications following pacemaker implantation. Pacing Clin Electrophysiol. 2002;25:1155-1158.
2. Satpathy R, Hee T, Esterbrooks D, Mohiuddin S. Delayed defibrillator lead perforation: an increasing phenomenon. Pacing Clin Electrophysiol. 2008;31:10-12.
3. Oba J, Aoki O, Takigami K, et al. Surgical treatment of ventricular and pericardial perforation by a permanent pacing lead: a case report. J Cardiol. 2005;45:69-73.
4. Khan MN, Joseph G, Khaykin Y, et al. Delayed lead perforation: a disturbing trend. Pacing Clin Electrophysiol. 2005;28:251-253.
5. Danik SB, Mansour M, Singh J, et al. Increased incidence of subacute lead perforation noted with one implantable cardioverter-defibrillator. Heart Rhythm. 2007;4:439-442.
6. Krivan L, Kozák M, Vlasínová J, Sepsi M. Right ventricular perforation with an ICD defibrillation lead managed by surgical revision and epicardial leads—case reports. Pacing Clin Electrophysiol. 2008;31:3-6.
7. U.S. Food and Drug Administration. CFR—Code of Federal Regulations Title 21.