case_images: PMC10666049_01
case_images: Electrocardiogram showing spontaneous P wave activity followed by unipolar ventricular stimulation spikes that most of the times are ineffective (blue arrows) and rarely result in ventricular capture (green arrows).
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case_images: F1
case_images: The electrocardiogram revealed a complete AV block due to intermittent loss of capture of the ventricular lead (Figure 1).
case_images: Procedural fluoroscopy images showing leadless PM's position at the level of the lower interventricular septum, just before device deployment. RAO, right anterior oblique; LAO, left anterior oblique.
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case_images: PMC10666049_01_fcvm-10-1287506-g002.jpg
case_images: F2
case_images: The device was implanted at the level of the lower interventricular septum, as shown in Figure 2, since the mid-septum was difficult to access.
case_images: Electrocardiogram showing unipolar atrial stimulation by the transvenous pacemaker followed by a ventricular spike generated by the leadless pacemaker that leads to ventricular capture with a fixed atrioventricular delay, resulting in atrioventricular synchrony. One ventricular and one atrial ectopic beat are also present.
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case_images: F3
case_images: With these settings, the transvenous PM was responsible for rate-responsive atrial stimulation, while the leadless PM allowed for atrial triggered ventricular stimulation (Figure 3).
case_images: Post-procedural chest x-Ray showing a dual chamber transvenous pacemaker and a MICRA  AV leadless pacemaker implanted at the interventricular septum.
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case_images: F4
case_images: At day one after implantation, a chest x-ray showed no signs of displacement (Figure 4) and the leadless PM interrogation revealed satisfying parameters: stimulation threshold of 0,25 volts at a pulse width of 0,24 ms and an impedance 870 ohms.
case_images: MICRA  AV window. Lead DI shows a sharp and high-amplitude signal that corresponds to the atrial pacing stimulus. An atrial mechanical event is sensed during the A3 (passive ventricular filling phase)/A4 (active ventricular filling) window, marked as AM on the stip. After the predefined atrioventricular delay, the pacing stimulus is delivered (VP). The amplitude of the recorded atrial signal has been automatically decreased to adapt to the sensing of the high amplitude far-field atrial pacing stimulus. Nevertheless, the atrial activity is well recognized by the accelerometer and the resulting atrioventricular synchrony is effective. VE, defines the end of the A3 window; AM, presumed atrial mechanical contraction (A4 signal/A-wave); VP, ventricular pacing.
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case_images: PMC10666049_01_fcvm-10-1287506-g005.jpg
case_images: F5
case_images: AV synchrony rate of 88% at one month (Figure 5) and 85% at six months (Table 1). An AAI-R mode setting was maintained for the transvenous PM.