Pacemakers - Managing and troubleshooting Flashcards
Mgmt of diaphragmatic pacing
- Reduce output
- Use ventricular pacing (rather than atrial pacing), given that atrial wires are often closer to the phrenic nerve.
- Reposition of pacing wires
Patient recently underwent transneous pacing wire/pacemeker insertion
Clinical findings: Chest discomfort, shortness of breath or evidence of pericarditis Progressive hypotension and tachycardia Elevated jugular venous pressure and pulsus paradoxus Muffled heart sounds and pericardial rub
Chest x-ray: enlarged cardiac silhouette
Echocardiography: pericardial fluid with right ventricular diastolic collapse.
- Importantly, the pacing wire/pacemaker lead should not be immediately removed, as it may be “plugging the hole” and preventing further development of a pericardial effusion or tamponade.
- It should be removed under close observation, typically in the surgical OR.
1. IV access, telemetry, monitors (blood pressure, heart rate, oxygen saturation)
2. Volume resuscitation
3. Aspiration / Drainage: Pericardiocentesis, correcting coagulation and await 3-4 days for the hole to scar down and thrombose. Following this, lead repositioning should then be attempted.
What does it mean if my patient develops a new right bundle branch block during pacing after implantation of a permanent transvenous pacemaker?
- A typical paced QRS morphology from a right ventricular lead resembles a left bundle-branch block morphology (with minor differences). However, the finding of a right bundle branch block morphology, or tall R-wave in V1, suggests left-sided pacing.
- This can occur if the right ventricular lead is advanced inadvertently into the coronary sinus, or the right ventricular lead is advanced through a patent foramen ovale / atrial septal defect into the left ventricle.
- In both cases, the pacing wire will capture the left ventricle and should be repositioned.
What is the effect of paced rhythms on an ECG’s ability to detect an acute myocardial infarction?
As with an intrinsic left bundle branch block, ventricular pacing results in depolarization and repolarization abnormalities that can confound the ECG’s ability to detect an acute myocardial infarction.
Criteria used to identify MI in patients with LBBB or a pacemaker?
Smith-Modified Sgarbossa Criteria
* Concordant ST elevation ≥ 1 mm in ≥ 1 lead
* Concordant ST depression ≥ 1 mm in ≥ 1 lead of V1-V3
* Proportionally excessive discordant STE in ≥ 1 lead anywhere with ≥ 1 mm STE, as defined by ≥ 25% of the depth of the preceding S-wave
Hemodynamically unstable patient
You are called to see a patient post-permanent transvenous pacemaker insertion with a pericardial effusion with concern for ventricular lead perforation. What do you do?
- bedside echocardiogram can demonstrate tamponade physiology and the patient should undergo urgent pericardiocentesis or be taken immediately to the operating room.
- If the echocardiogram does not demonstrate tamponade physiology and the pacemaker interrogation demonstrates that the pacemaker is functioning well, then the pericardial effusion is likely due to microperforation during lead insertion and can be treated conservatively if not large.
Hemodynamically stable patient
You are called to see a patient post-permanent transvenous pacemaker insertion with a pericardial effusion with concern for ventricular lead perforation. What do you do?
If the patient is hemodynamically stable, one should obtain a 12-lead ECG and chest x-ray to evaluate for changes in lead position. A CT scan of the chest with contrast may also be helpful when looking for lead migration or perforation with contrast extravasation.
Pacemaker mgmt in a patient who is pacing dependent and will undergo a procedure utilizing electrocautery.
- In such cases, the pacemaker can be programmed to AOO, VOO or DOO depending on whether there is an intact atrioventricular conduction. This should be re-evaluated or re-programmed as soon as electrocautery is not needed.
- Another option is to place a magnet over the generator for the pacemaker- a magnet will cause the pacemaker to default to an asynchronous mode (e.g. VOO or DOO).
Do patients with permanent transvenous pacemakers or epicardial leads require endocarditis antibiotic prophylaxis for procedures?
Patients with pacemakers or defibrillators are considered negligible risk and do not require endocarditis antibiotic prophylaxis prior to procedures.
Antibiotic prophylaxis prior to invasive dental or oral procedures; which patients?
●Prosthetic cardiac valve or valve repair with prosthetic valve material.
*Prosthetic heart valve (surgical or transcatheter)
*Cardiac valve repair with prosthetic material (including annuloplasty rings or clips)
●Durable mechanical circulatory support device (ventricular assist device or artificial heart).
●Previous, relapsed, or recurrent IE.
●Certain types of congenital heart disease including:
*Unrepaired cyanotic congenital heart disease (patients with palliative shunts and conduits are still considered unrepaired).
*Completely repaired congenital heart defect with prosthetic material or device, during the first six months after surgical or transcatheter placement.
*Repaired congenital heart disease with residual defect at the site or adjacent to the site of a prosthetic patch or prosthetic device.
*Prosthetic pulmonary artery valve or conduit (surgical or transcatheter; eg, Melody valve and Contegra conduit).
●Cardiac transplant recipients who develop cardiac valvulopathy.
Antibiotic prophylaxis regimen
My patient has a permanent transvenous pacemaker (placed 1month ago) and requires an MRI. What do I do?
MRI is contraindicated in patients with a new pacemaker implantation (within 4-6 weeks) as this may cause dislodgement of the leads, even in MRI compatible devices. In such cases, the MRI is typically deferred until after the waiting/recovery period. However, if there are any concerns, an appropriate consultation should be obtained to determine if imaging would be reasonable.
