Rhythm Disorders

Cardiac Pacemakers:

• A review of cardiac pacing
  • Modes of cardiac pacing
  • Definitions of different pacing modes
• Examples of different pacing modes
  • DDD pacemakers
    • DDD timing diagram in sinus rhythm with an AV delay of 80ms.
    • DDD mode showing atrial and ventricular pacing and atrial sensing and venticular pacing.
    • DDD mode showing ventricular tracking of atrial fibrillation
    • DDI timing diagram in sinus rhythm and with one PVC with an AV delay of 80ms.
    • DDI pacing at a lower rate of 50/min
    • DDD pacemaker recorded on a 12 lead EKG. Patient has a severe intraventricular conduction abnormality
    • DDD pacemaker at its upper rate limit in a patient with atrial fibrillation/flutter
    • DDD pacemaker failing to sense a P wave
    • DDD pacemaker the effect of a PVC on the timing cycles
    • DDD pacemaker timing diagram with atrial lead pacing the ventricle
    • A patient with atrial tachycardia with an intra-atrial recording from his pacemaker
    • Ladder diagrams and tracings while in DDI mode and complete heart block.
    • DDD pacer set at 70/min. but atrial pacing at 75/min due to conduction with a PR interval shorter than the A/V interval set on the pacemaker.
    • Recording from the atrial lead of a patient with atrial fibrillation
  • Atrial pacing
    • AAI with ladder diagram
    • AAI pacing 12 lead with a patient with Right Ventricular dysplasia taking Flecainide for ventricular tachycardia.
    • A series of electrocardiograms from a 78 year old woman who was implanted with a VVI pacemaker in 1991. The patient developed congestive heart failure five years later due to pacemaker syndrome which was corrected by switching to atrial pacing.
    • A patient with an atrial pacer that did not seem to pace properly.
    • Two rhythm strips from a patient with an AAI.R pacemaker with atrial sensing of the QRS due to a prolonged PR interval.
    • 12 lead electrocardiogram of a patient with right ventricular dysplasia and paced rhythm
    • A rhythm strip from a patient that shows AAI pacing competing with and resetting the patient's nodal rhythm.
    • Atrial pacing with competition from an accelerated ventricular rhythm causing fusion complexes
    • An irregular rhythm with an atrial pacemaker.
  • Ventricular Pacing
    • VVI with ladder diagram
    • Ventricular paced rhythm with atrial flutter
    • VVI pacing in patient with first degree A/V block
    • Ventricular paced rhythm with atrial flutter after A/V nodal ablation.
    • The effect of an acute myocardial infarction on the EKG of VVI pacing
    • Failure to pace or a recording artifact? This is a recording from a patient with a Medtronic implantable defibrillator which also functions as a VVI pacemaker.
    • Lead failure in a recently replaced VVI pacemaker.
    • Escape/capture bigemini
    • A rate responsive pacemaker with a respiratory sensor
    • A recording showing rate hysteresis
    • pacing during ventricular fibrillation and failure to capture after a 360 joule shock.
• Pacing conduction patterns
  • A 12 lead electrocardiogram from a patient with a lead pacing the left ventricle.
  • Tracings from a the same patient with right atrial appendage stimulation, R.V. septal and apical stimulation.
  • A tracing from a patient with Mobitz I AV block where the AV conduction stops with VDD pacing even with a long sensed to paced interval of 300ms.
• Pacemaker interactions
  • A patient with two pacemakers, a DDD and a VVI .R which is at end of life
  • Myopotential inhibition of a VVI.R pacemaker
  • Suppression of a VVI pacemaker with an external pacemaker
• Pacemaker Pacing Artifacts:
  • Bipolar ventricular paced rhythm with atrial flutter after A/V nodal ablation.
  • Unipolar ventricular paced rhythm with atrial flutter
• Pacemaker Follow-up:
  • Unusual rhythms
    • Bigemini with magnet over the pacemaker
    • Bigemini with atrial threshold testing
    • conversion of atrial flutter with rapid atrial pacing followed by nodal rhythm
  • Threshold Testing
    • 3 lead rhythm strip with DDD pacemaker and normal magnet response
    • Pulse amplitude threshold testing for a ventricular pacemaker
    • Atrial threshold testing
      • Atrial threshold testing in a DDD pacer using the AAI mode
      • Atrial threshold testing in a model 2102 pacemaker
    • PVCs interfering with ventricular threshold testing
    • The effect of a long AV interval on atrial threshold testing of a DDD Pacer
    • Threshold testing inducing asystole in a 21 year old patient with congenital complete heart block.
    • Two pacemakers, DDD and VVI with atrial capture in one and ventricular in the other
  • Strength duration curves
    • A strength/duration curve from an atrial lead.
    • A strength/duration curve from a ventricular lead.
  • Time dependent capture
  • Pacemaker system failure:
    • Pacemaker pacing failure and Mobitz II A/V block in a patient with a history of Torsade de Pointe and three degree heart block.
    • A patient with a failing ventricular lead due to a subclavian crush.
  • Trans-telephonic EKG recordings
    • Trans-telephonic pacemaker check failure to capture
    • Trans-telephonic pacemaker check: Failure to capture. A patient in the high Arctic.
    • Trans-telephonic pacemaker check at the MUHC (instructions)
  • Trans-telephonic Audio recordings
    • The EKG and sound of a Medtronic VVI.P pacemaker with the magnet applied near the end of the recording
  • Recording of end of life indication with magnet applied to VVI pacemaker
  • A pacemaker that required inversion of the programming head for programming. The pacemaker could not be programmed in the usual manner in the pacemaker clinic. The pacemaker was implanted correctly with the conducting window toward the skin, but was a left-sided model which differed from the previous x-ray outline of the right-sided model. Having to invert the programming head suggests a problem with the programming head, inverted implantation of the pacemaker, or because the pacemaker electronics are functioning as a contra-lateral pacemaker.
  • Lecture on pacemaker follow-up November 1998

Defibrillation and Cardioversion:

• External Cardioversion/defibrillation
  • Recording of a series of shocks for Atrial Flutter
  • Sinus pause post cardioversion for atrial fibrillation
  • An irregular rhythm after cardioversion for atrial fibrillation
  • pacing during ventricular fibrillation caused by cardioversion and failure to capture after a 360 joule shock.
• Implantable Defibrillators
  • Recording from a device during a spontaneous episode of ventricular fibrillation.
  • P.A. chest film of a patient with an implantable defibrillator and an epicardial patch and S.V.C. spring electrode.
  • Threshold Testing
    • Defibrillation threshold testing of an implantable defibrillator (successful) followed by ventricular paced rhythm.
    • Defibrillation threshold testing of an implantable defibrillator (successful) followed by sinus rhythm.
    • Defibrillation threshold testing of an implantable defibrillator (successful) followed by sinus rhythm. Recorded using an external defibrillator.

EKG Recordings:

• An electrocardiogram from a patient with a cardiac myoplasty stimulator.
• A problem with atrial capture with a dual chamber pacemaker with a long A/V interval.
• A patient post pacemaker implant. for syncope
• A rate responsive pacemaker with respiratory sensor An ECG strip from the pacemaker clinic.
• A patient post DDD pacemaker implant ECG strip and images from a patient post DDD pacemaker implant.
• Patient with perforation of a temporary transvenous pacemaker Three EKGs and X-ray

X-ray images associated with devices:

• Defibrillators:
  • A 68 year old patient with a DDD.R defibrillator
  • A 65 year old woman with a DDD.R defibrillator with an atrial lead in an unusual place.
  • A patient with an implantable defibrillator and a dual chamber pacemaker.
  • CINE frames of Atrial J lead in patient with Implantable defibrillator
• Pacing and Defibrillation Leads
  • Chest x-ray series from a patient with a fractured ventricular lead
  • Chest X-ray of patient with a pacemaker with a poor pacing threshold and lead compression at the site of the suture sleeve
  • X-ray frame of a patient with permanent and temporary cardiac pacing wires. The atrial lead is prolapsing across the tricuspid valve
  • X-ray frame of a patient with a temporary catheter in the high right atrium and coronary sinus.
  • Lateral chest film of a patient with a screw-in atrial lead in the lower atrial septum.
  • PA and Lateral chest film from a patient with a ventricular pacing wire in the middle cardiac vein.
  • A patient with mitral and tricuspid annuloplasty rings and an atrial lead in the lower right atrium.
  • A patient with a ventricular lead in a posterior position of the right ventricle.
  • A pacemaker system with a poor pacing threshold before and after repositioning the ventricular lead. The patient also has a prosthetic mitral valve and tricuspid annuloplasty ring the allows the visualization of the position of the two valve rings.
  • A patient with a failing ventricular lead due to a subclavian crush.
  • A patient after a DDD.R implant with a displaced active fixation atrial lead
• Pacemakers
  • A patient with two right ventricular pacing wires.
  • Chest X-ray from a patient with two pacemakers
  • A pacemaker that required inversion of the programming head for programming. The pacemaker was implanted with the conducting window against the muscle.
  • Patient with repaired Patent Foramen Ovale with VVI.R pacemaker
  • Dextrocardia with atrial and ventricular leads and VVI pacemaker
• Complications
  • A patient with a peumotharax post pacemaker lead implant.
  • Pneumothorax post pacemaker implant

Questions From the WEB

• Pacemaker syndrome