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Taquicardia por marcapasos. pptx.pptx
- 1. Pacemaker-mediated tachycardia (PMT) Enrique Sanchez Hiza 3rd year Clinical Cardiology felow
- 2. Introdution • A pacemaker-mediated tachycardia (PMT) can be defined as any condition in which a pacemaker paces the ventricles at rates that are inappropriately fast. • Can occur in patients who have dual-chamber pacemakers (reentry) 1) A rate response setting that is too sensitive 2) Tracking of atrial noise (such as what may occur with electromagnetic interference) 3) Inappropriate pacemaker manipulation with rate response turned on 4) Tracking of an atrial tachyarrhythmia related to upper rate settings.
- 3. Etiology • The pacemaker has to be in a pacing configuration where it senses the atrium and paces the ventricle (DDD mode). • Event that dissociates the P wave from the QRS complex and triggers the tachycardia (premature ventricular or atrial contraction, intermittent loss of atrial sensing or capture) • There has to be retrograde conduction through either the AV node or an accessory pathway. • The ventriculoatrial (VA) conduction needs to be long enough that it is able to be sensed by the atrial lead, meaning that it lasts beyond the atrial refractory period.
- 4. Epidemiology • The cornerstone mechanism is retrograde VA conduction • 30-80% of patients with pacemakers • It is more common in patients with sick sinus síndrome 80% and AV block 35% • 6% of all patients with pacemakers had at least one documented episode of pacemaker mediated tachycardia.
- 7. History and Physical Presentation: Palpitations, chest pain, dizziness, syncope, or even worsening of heart failure symptoms. In many cases, however, patients are asymptomatic. Physical Examination: The examination may be normal and only show tachycardia. In cases where the arrhythmia persists for prolonged times, hypotension or signs of heart failure may be evident.
- 8. Evaluation Ecg or Holter Interrogation
- 9. Pseudomalfunction • Frequency (PMT) • A-V interval/refractory periods • Mode Malfunction
- 10. Pathophysiology • A dual-chamber pacemaker programmed DDD • Retrograde (V→A) conduction with an atrial activation time that is longer than the programmed postventricular atrial refractory period (PVARP). • A ventricular-paced beat or a properly timed premature ventricular contraction (PVC) conducts retrograde via the AV node (or an accessory pathway, if present) to the atrium.
- 12. 1. Loss of AV synchrony due to ventricular extrasystoles. 2.Retrograde detection is activated 3.AV interval begins 4.The AV interval is prolonged 5.Synchronous ventricular stimulation with retrograde P
- 15. PVARP • Its function is to prevent the sensing of retrograde QRS that could trigger a PMT. • The initial portion is the PAVBI • In PVARP, intrinsic events can be sensed and identified as (Ar), so they do NOT modify pacemaker intervals or their synchrony. • An As in this period does not initiate an AV delay (AVD) • PVARP must be programmed to a value greater than the maximum AV delay (AVD)
- 17. Mode Anti-PMT • The pacemaker will automatically extend the PVARP up to 400 msec, after 8 consecutive events.
- 18. Response to ventricular premature beats • Solution: The pacemaker will classify as ventricular extrasystole any event sensed in the ventricle (Vs), without a previous atrial event and that is preceded by another ventricular event. • PVARP is extended to 400 msec.
- 23. Prognosis Long term prognosis is typically not affected by PMT. It is easily treatable, and recurrence can be prevented. It is important to note that long-standing episodes can cause a worsening of heart failure due to the hemodynamic effects of tachycardia in reducing diastolic filling time
Editor's Notes
- 2.- due to reentry. Una configuración de respuesta de frecuencia que es demasiado sensible Seguimiento del ruido auricular (como lo que puede ocurrir con la interferencia electromagnética) Manipulación inapropiada del marcapasos con respuesta de frecuencia activada Seguimiento de una taquiarritmia auricular relacionada con ajustes de frecuencia máxima.
- Intro: There are several factors that are integral to the initiation and maintenance of pacemaker mediated tachycardia 1.- This is why this form of tachyarrhythmia does not happen in single-chamber pacemakers or with other pacing modes like VVI or AAI. 2.- There needs to be an event that dissociates the P wave from the QRS complex and triggers the tachycardia.
- 1.- Because shows ventricular pacing at or slightly below the upper rate limit, with atrial sensing and A-V association. 2.- Performing device interrogation and examining the telemetered intracardiac electrograms. This will show retrograde conduction with atrial sensed beats following ventricular paced beats, whereas in normal situations, the atrial sensed beats should precede ventricular pacing.
- there are 6 types of problems 1.- Underdetection 2.- overdetection 3.- absence of capture 4.- absence of exit 5.- Pseudomalfunction 6.- Malfunction
- 3.- If the atrial depolarization occurs after the set PVARP, but before the next timed atrial-paced beat, ventricular pacing will be triggered at the programmed AV interval. PMT results from retrograde conduction of a ventricular beat through the AV node (or if present, an accessory pathway). This typically happens when there is a premature ventricular beat that disrupts the normal cycle and separates the P wave from the QRS complex, thus serving as a triggering event for the tachycardia. When retrograde conduction of this ventricular beat takes place, the resulting earlier than normal atrial activation is sensed by the atrial lead, specifically if the atrial refractory period (PVARP) is passed. This earlier sensing of the P wave subsequently leads to ventricular activation with subsequent ventricular pacing after the set period of AV delay. If the retrograde conduction persists, a reentrant circuit will form with continuous ventricular activation. In many instances, the PVARP varies so that it shortens with rate. This can make PMT more likely. The AV interval can be programmed to change with the rate. This tends to reduce the risk of PMT. Depending on the pacemaker programming and the VA conduction, the rate of the PMT may vary, but it is bounded by (and generally occurs near or at) the programmed upper rate limit. La PMT resulta de la conducción retrógrada de un latido ventricular a través del nódulo AV (o si está presente, una vía accesoria). Esto suele ocurrir cuando hay un latido ventricular prematuro que interrumpe el ciclo normal y separa la onda P del complejo QRS, sirviendo así como un evento desencadenante de la taquicardia. Cuando tiene lugar la conducción retrógrada de este latido ventricular, el cable auricular detecta la activación auricular resultante antes de lo normal, específicamente si se pasa el período refractario auricular (PRAPV). Esta detección temprana de la onda P conduce posteriormente a la activación ventricular con estimulación ventricular posterior después del período establecido de retraso AV. Si persiste la conducción retrógrada, se formará un circuito de reentrada con activación ventricular continua. En muchos casos, el PRAPV varía y se acorta con la frecuencia. Esto puede hacer que la PMT sea más probable. El intervalo AV se puede programar para cambiar con la frecuencia. Esto tiende a reducir el riesgo de PMT. Según la programación del marcapasos y la conducción VA, la frecuencia de la TMM puede variar, pero está limitada por (y generalmente ocurre cerca o en) el límite de frecuencia superior programado.
- Any disturbance that causes loss of AV synchrony can facilitate retrograde conduction and potentially PMT, for example ventricular premature beats, atrial non-capture, atrial undersensing and oversensing.
- INTRO: It is activated by a Vs or Vp in the DDD, DDI and VDD modes. postatrial ventricular blanking period PAVBI postventricular atrial refractory period PVARP
- postventricular atrial refractory period PVARP postatrial ventricular blanking period PAVBI periodo d cegamiento ventricular posauricular. It is a period of ventricular sensing that complements the period of post-atrial ventricular blanking and functions only after atrial stimulation (Ap) Retardo AV sensado. By increasing this PVARP, it is possible that, if there are retrograde P waves, they fall within the refractory period and, therefore, do not start an AVDS interval (sensed AV delay)
- Post ventricular atrial refractory period Turn on PMT function. This solution was designed to interrupt pacemaker-mediated tachycardias
- Post ventricular atrial refractory period. AVDE: Retardo auriculoventricular AV estimulado Vs: ventricule sensed