Atrio‐ventricular synchronous pacing with a single chamber leadless pacemaker: Programming and trouble shooting for common clinical scenarios

Figures

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  Figure 1. Micra AV accelerometer signals and their relationship to surface ECG wave. AM, atrial mechanical; AV, atrioventricular; ECG, electrocardiography; PVAB, post ventricular atrial blanking; VE, end of ventricular ectopy

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  Figure 2. (A) The A4 signal falling below threshold which resulted in undersensing and lack of atrial tracking (see text for detail). (B) Next, A4 threshold was adjusted which resulted in A4 sensing and AM marker on the device channel. (C) AV synchrony established as evident by AM and VP). AM, atrial mechanical; VP, ventricular pacing

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  Figure 3. (A) Rhythm strip showing sinus rhythm with complete heart block and intermittent atrial sensing and tracking. (B) Accelerometer signal showing the A4 signal (red arrow) falling in the A3 sensing window, resulting in undersensing. (C) The A3 window end was shortened and A4 (red arrow) is now sensed. (D) AV synchrony established after programming change. AV, atrioventricular

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  Figure 4. (A) Sinus tachycardia tracked. Accelerometer signals show A3 and A4 merger (A7)(circled). Threshold (horizontal white line) set low enough to detect A4 but high enough to avoid A3. A7 sensing occurs in the A3 window due to the fast atrial rate. (B) Sinus rate slows resulting in the A3 and A4 separating (circled). The auto A3 window end self‐adjusted to keep A3 covered up and A4 (red arrow) tracked. (C) Rhythm strip shows AV synchrony. AV, atrioventricular; PVAB, post ventricular atrial blanking

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  Figure 5. (A) Rhythm strip shows sinus rhythm with complete heart block and junctional escape rhythm. No RV pacing or AV synchrony seen since the device mode switched to VVI + (backup VVI 40) (see text for detail). (B) Mode switch turned off. Partial AV synchrony restored. Some P waves are undersensed due to Wenckebach behavior and some P waves falling in the PVAB period. AV, atrioventricular; ECG, electrocardiography; PVAB, post ventricular atrial blanking; RV, right ventricle; VE, end of ventricular ectopy