Tuesday, March 26, 2019

Pacemakers malfunction

emDocs - March 26, 2019 - David Bussé D -  Edited by: Santistevan J and Long B
"ED Approach to Pacemaker Malfunction
  • Suspect pacemaker malfunction with complaints of lightheadedness, fatigue, palpitations, hiccups, confusion, dyspnea, muscle twitches, and syncope.
  • The history should elicit whether the patient has any underlying problems leading to pacemaker malfunction. These include ACS, trauma, medication changes, or recent device reprogramming [1, 2].
  • Patients are given cards with the device’s type, model, manufacturer, and the date the device was implanted.
  • Ask patients to provide their pacemaker card.
  • The physical exam should begin with a review of vital signs, mental status, and cardiopulmonary status. Note signs of infection, migration, or trauma at the implant site [2, 7]. Also look for JVD, cannon A waves, pectoral muscle twitching, and new cardiac murmurs/rubs.
  • Obtain an ECG to determine whether an unstable bradycardia is present. Compare it to prior ECGs, looking particularly at axis changes [2].
  • The ECG of a single ventricle-paced patient will show ventricular pacer spikes and a LBBB with left axis deviation due to the placement of the electrode in the RV [7].
  • Biventriculrar pacers capturing the LV free wall demonstrate a dominant R wave in V1 and a QS complex in lead I, indicating a wavefront propagating away from the LV6.
  • ST segments and T-waves should be discordant with the QRS.
  • Obtain PA and lateral chest radiographs to check for lead dislodgement, fracture, or pneumothorax. Should a patient be unable to produce the pacer card, an overpenetrated chest radiograph can be used to determine the device maker by identifying the company symbol [1, 7].
  • Obtain serum measurements of electrolytes and any cardiotoxic drugs in addition to cardiac biomarkers in the appropriate setting. Metabolic derangements including hypothyroidism, acidosis, and hypokalemia can alter the threshold potential required for pacing [2].
  • Management is dictated by the patient’s symptoms and hemodynamic status. Transcutaneous pacing pads should be placed on the patient in an anterior-posterior configuration whenever malfunction is suspected [1, 2, 7]. Apply standard ACLS protocols should a patient be bradycardic with symptoms of hypoperfusion.
  • When hemodynamically stable, interrogate the pacemaker. Interrogation yields information on battery life, sensing and pacing thresholds (under/oversensing), integrity of the lead system (lead fracture), and recordings of cardiac rhythm [1, 6, 7]. Interrogation can indicate proper functioning or presence of arrhythmias that help risk stratify the patient.
  • Interrogation involves radiofrequency communication with the pacemaker by placing a wand over the device. The wand is attached to a programmer that performs the interrogation, and is specific to each device company."