Pacemaker Malfunction Due to Atrial and Ventricular Leads Switched in the Header: Two Faces of the Same Mistake?

Abstract

Case 1A 65-year-old patient was referred for pacemaker implantation due to sick sinus syndrome. The implantation of a DDDR pacemaker (Kappa 901, Medtronic, Minneapolis, MN, USA) was uneventful, and two straight active fixation leads were introduced and placed, one in the right atrial appendage and the other in the right ventricular outflow tract. During implantation, immediately after the leads were connected to the pacemaker, a change in heart rhythm was observed from a sinus rhythm of 75 bpm with a first degree atrioventricular (AV) block to an apparently atrial paced rhythm of 125 bpm (Fig. 1). It was soon established that the atrial lead was placed in the ventricular port (VP) and the ventricular lead was placed in the atrial port. The situation was easily and promptly resolved. Case 2A 77-year-old man with a symptomatic second and third degree atrioventricular block underwent DDD pacemaker implantation (Kairos D, Biotronik, Berlin, Germany). The procedure was uneventful, with an apparently good, fully paced rhythm of 60 bpm at the end of the procedure. However, several hours after implantation the patient suffered a syncopal attack. The electrocardiogram (ECG) (Fig. 2) obtained at that time indicated periods of asystole with occasional ventricular capture following the atrial pacing spike. The pacemaker was reprogrammed to the AAI pacing mode and the symptoms resolved. The next day, after confirming under fluoroscopy that the leads were appropriately positioned in the heart, the pacemaker pocket was opened and, as expected, the leads were found to be incorrectly positioned (switched) in the pacemaker header. After correction there were no further sequelae and the patient remained asymptomatic during the subsequent 7 years of followup.What was the mechanism of such different presentations despite the same nature of the problem in these two cases ? DiscussionAccidental reversal of the atrial and ventricular leads in the pacemaker header is a rare and embarrassing complication, and is therefore probably underreported. Consequently, the observed clinical manifestations are poorly documented with only two case reports published. 1,2 A similar mistake with the proximal and distal defibrillator coil terminal pins erroneously switched in the header was also reported. 3 In the first case, the initial thought was that the pacemaker was inadvertently reprogrammed from the default program (DDD, lower rate 60/min, sensed AV delay 120 ms) to either AAIR or DDDR with a long AV delay and the sensor accelerated the pacing rate due to device movement during placement in the pacemaker pocket. However, since the fast paced rhythm did not slow down in the following few minutes, an alternative explanation was sought. Both the QRS-spike and the spike-QRS intervals were constant during the arrhythmia with the QRS-spike interval being equal to the sensed AV delay. This strongly suggested that the pacing spike came from the ventricular channel and was coupled with both the preceding and the following QRS. Such a situation can be pr...

Is it a typical crosstalk: Need for re‐implantation?

“…In the present case, dyssynchronization between the atrial and ventricular beats resulted in abnormal pacing spikes detected on the surface electrocardiogram, and it is a potentially life‐threatening condition. Previous case reports have suggested that this condition might be caused by crosstalk, dislocation of the leads, or inappropriate switching of the connection of the atrial and ventricular leads to the head of the generator [2–5]. Fluoroscopic examination revealed that dislocation of the atrial lead had been causing ventricular capture due to its proximity to the tricuspid valve, causing the ventricular capture to be sensed by the ventricular lead.…”

Pacemaker‐mediated tachycardia: What is the mechanism?

“…Nor was an impact of sensing assurance algorithms on the occurrence of oversensing ever reported, to the best of this author's knowledge. Apart from adding to our understanding of ELT mechanisms, this case prompts a reflection on the multitude of electrocardiographic manifestations of the lead position in an inappropriate heart chamber: from asystole and blocks to ELTs …”

“…Pacemaker‐mediated tachycardia with spikes after the QRS complexes and the QRS‐spike interval equal to the programmed AV delay interval should raise a strong suspicions of an orthodromic endless loop tachycardia (ELT), also known as “reversed” ELT. This is a rare arrhythmia that occurs when pacing leads are reversed in the pacemaker ports (i.e., the atrial lead in the ventricular port and the ventricular lead in the atrial port) and a slow 1:1 native AV conduction . During ortho‐ELT, QRS is sensed in the atrial channel and triggers pacing in the ventricular channel.…”

“…This is a rare arrhythmia that occurs when pacing leads are reversed in the pacemaker ports (i.e., the atrial lead in the ventricular port and the ventricular lead in the atrial port) and a slow 1:1 native AV conduction. 1 However, the ventricular potential amplitude was probably fluctuating and was periodically below the default sensitivity threshold, as at the end of implant when no oversensing was evident. Therefore, it seems likely that sensing assurance played a role by ensuring stable oversensing and perpetuation of this ortho-ELT.…”

“…Apart from adding to our understanding of ELT mechanisms, this case prompts a reflection on the multitude of electrocardiographic manifestations of the lead position in an inappropriate heart chamber: from asystole and blocks to ELTs. 1,5…”