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................................................................................ or previous cardiovascular implantable electronic device (CIED) infection]. Observational data showed that a leadless pacemaker was a safe pacing alternative in patients with previous device infection and explant, and in patients on chronic haemodialysis. Whereas observational data indicate high efficacy and low complication rates with leadless pacemakers,50 there are currently no data from RCTs documenting the long-term safety and efficacy of leadless vs. standard transvenous pacemakers, and therefore the indication for a leadless pacemaker should be carefully considered on a case by case basis. The absence of long-term data on leadless pacemaker performance and limited data on retrievability and end-of-life strategy449 require careful consideration before selecting leadless pacemaker therapy, especially for younger patients (e.g. with a life expectancy >20 years).

8 Indications for pacing in specific

conditions

8.1 Pacing in acute myocardial infarction

In patients with acute MI, significant bradyarrhythmia may occur due to autonomic influences or damage of the conduction system by ischaemia and/or reperfusion. The right coronary artery supplies the sinus node in 60% and the AVN and His bundle in 90% of patients.451,452 AVB is located above the His bundle in most patients with inferior infarction, but is usually infra-Hisian and preceded by intraventricular conduction disturbances in anterior infarction.451,453457 The incidence of high-degree AVB in patients with ST-segment elevation MI has declined to 34% in the primary percutaneous coronary intervention era.458460 High-degree AVB is most frequent in inferior or inferolateral infarctions.455,458461 Patients with high-degree AVB have higher clinical risk and larger infarctions especially when AVB complicates an anterior infarction.458460,462,463 New-onset intraventricular conduction disturbance is also associated with larger infarctions.464467 Sinus bradycardia and AVB at presentation can be vagally mediated and may respond to atropine.455,468 Revascularization is recommended in patients with AVB who have not yet received reperfusion therapy.469 AVB may require temporary pacing in the presence of refractory symptoms or haemodynamic compromise, but most often resolves spontaneously within a few days and only a minority of patients require permanent pacing.451,454,456,458,462 In patients with persistent intraventricular conduction abnormalities and transient AVB in whom permanent pacing was recommended in the past, there is no evidence that permanent cardiac pacing improves outcome.454,470 These patients frequently have HF and poor LV function, and should be evaluated for ICD, CRT-P, or CRT- D rather than conventional pacing if an early device implantation is considered.471

If AVB does not resolve within 10 days, a permanent pacemaker should be implanted. In the absence of robust scientific data, the waiting period before pacemaker implantation has to be decided individually. It may last up to 10 days but can be shortened to 5 days depending on the occluded vessel, time delay, and success of revascularization. Conditions favouring consideration of earlier pacemaker implantation include unsuccessful or late revascularization, anterior MI, bifascicular block or AV block before MI, and progression of AV block within the first days after MI. Sick sinus syndrome after occlusion of the right coronary artery resolves in most cases. If revascularization is incomplete, pacemaker implantation can usually still be postponed and implantation only be performed if symptoms due to sinus bradycardia persist.

8.2 Pacing after cardiac surgery and

heart transplantation 8.2.1 Pacing after coronary artery bypass graft and valve surgery AVB may occur in 14% of cases after cardiac surgery and in 8% after repeat valve surgery.472476 SND may occur after right lateral atriotomy or transseptal superior approaches to the mitral valve.473,474

Recommendations for using leadless pacing (leadless pacemaker)

Recommendations Classa Levelb

Leadless pacemakers should be considered as an alternative to transvenous pacemakers when no upper extremity venous access exists or when risk of device pocket infection is particularly high, such as previous infection and patients on haemodialysis.45,4750,450 IIa B Leadless pacemakers may be considered as an alternative to standard single-lead ventricular pacing, taking into consideration life expectancy and using shared decision-making.45,4750 IIb C

aClass of recommendation. bLevel of evidence. ESC 2021 Recommendations for cardiac pacing after acute myocardial infarction

Recommendations Classa Levelb

Implantation of a permanent pacemaker is indicated with the same recommendations as in a general population (section 5.2) when AVB does not resolve within a waiting period of at least 5 days after MI. I C In selected patients with AVB in the context of anterior wall MI and acute HF, early device implantation (CRT-D/CRT-P) may be considered.471 IIb C Pacing is not recommended if AVB resolves after revascularization or spontaneously.454456,458 III B

AVB = atrioventricular block; CRT-D = defibrillator with cardiac resynchronization therapy; CRT-P = cardiac resynchronization therapy-pacemaker; MI = myocardial infarction. aClass of recommendation. bLevel of evidence. ESC 2021

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