In order to bring you the best possible user experience, this site uses Javascript. If you are seeing this message, it is likely that the Javascript option in your browser is disabled. For optimal viewing of this site, please ensure that Javascript is enabled for your browser.
Did you know that your browser is out of date? To get the best experience using our website we recommend that you upgrade to a newer version. Learn more.

We use cookies to optimise the design of this website and make continuous improvement. By continuing your visit, you consent to the use of cookies. Learn more

Highlights from the new ESC Guidelines on Cardiac Pacing and Resynchronization Therapy (version 2013)

This article is written by the author for the newsletter of the Council for Cardiology Practice.
It reflects the opinion of the author.

Six years after the last ESC Guidelines for cardiac pacing and resynchronization therapy (2007), 18 Task Force members, 26 ESC Committee for Practice Guidelines members and 26 reviewers contributed to a practical, new and short guideline on cardiac pacing and cardiac resynchronization therapy (CRT). With only 40 pages the document outlines an innovative classification of bradyarrhythmias by mechanism and also focuses on the strength of indications for CRT mainly in the presence or absence of left bundle branch block.

Arrhythmias


The document contains 65 recommendations: 30 for pacing indications (ten less compared with ESC 2007 guidelines) and 15 for CRT indications (ten more compared with ESC 2007 guidelines).

Among these 65 recommendations:

  • 23 (35%) are Class I
  • 21 (32%) Class IIa
  • 11 (17%) Class IIb
  • and 10 (15%) Class III

In regard to levels of evidence:

  • 6 (9%) have A level
  • 32 (48%) B level
  • and 28 (42%) C level

After a short preamble, the document is divided in two sections: 1. Indications for pacing and 2. Indications for cardiac resynchronization therapy.

In both sections, after the indications, specific modes of pacing recommendations are suggested and clinical perspectives are recommended at the end of each chapter.

1. Indications for pacing

The first innovation is the classification of bradyarrhythmias according to mechanism i.e. the clinical presentation because it is more useful for selecting patients for permanent cardiac pacing therapy than their aetiology.

The first fourteen pages divide the pacing indications in three main groups:

  • persistent bradycardia,
  • intermittent bradycardia with electrocardiographic documentation,
  • and suspected intermittent bradycardia (not yet documented).

In the diagnosis of bradyarrhythmia the document highlights how it is usually made from a standard ECG when persistent, and from a standard ECG or more prolonged ECG recordings [ambulatory monitoring or implantable loop recorder (ILR)] when intermittent. When a bradycardia is suspected but not documented, provocative testing or an electrophysiological study (EPS) may be required.

Since there is no defined heart rate below which treatment is indicated, correlation between symptoms and bradyarrhythmia is essential when deciding on the need for cardiac pacing therapy. This can be difficult to establish in patients with competing mechanisms for their symptoms. In general, an attempt to obtain ECG documentation during syncope (symptom-arrhythmia correlation) is warranted (see below).

1A. Pacing is indicated in patients with persistent bradicardia (sinus bradycardia or AV block):

  • When symptoms can clearly be attributed to bradycardia due to sinus arrest or AV block
  • With third- or second-degree type 2 AV block irrespective of symptoms
  • May be indicated when symptoms are likely to be due to bradycardia, even if the evidence is not conclusive

1B. Pacing is indicated in patients with intermittent documented bradycardia (sinus bradycardia or AV block):

  •  Who have documented symptomatic bradycardia due to sinus arrest or AV block
  • With third- or second-degree type 2 AV block irrespective of symptoms
  • Should be considered in patients ≥40 years with recurrent, unpredictable reflex syncopes and documented symptomatic pause/s due to sinus arrest or AV block or the combination of the two

1C. Pacing is indicated in patients with syncope and suspected (undocumented ) bradycardia:  

  • Alternating BBB and in patients with BBB and positive EPS defined as HV interval of ≥70 ms, or second- or third-degree His-Purkinje block demonstrated during incremental atrial pacing or with pharmacological challenge.
  • With dominant cardioinhibitory carotid sinus syndrome and recurrent unpredictable syncope.
  • May be considered in selected patients with unexplained syncope and BBB.
  • May be indicated in patients with tilt-induced cardioinhibitory response with recurrent frequent unpredictable syncope and age >40 years after alternative therapy has failed

2. Indications for cardiac resynchronization therapy (CRT)

Based on current guideline criteria only a small proportion of patients with heart failure (HF) (perhaps 5–10%) have cardiac dyssynchrony and are therefore indicated for CRT but this is still a large number of patients. Cardiac dyssynchrony is complex and multifaceted. Prolongation of the AV interval delays systolic contraction, inter- and intra-ventricular conduction delays lead to asynchronous contraction of LV wall regions (ventricular dyssynchrony). Cardiac resynchronization therapy (CRT) helps to restore AV, inter- and intra-ventricular synchrony, improving LV function, reducing functional mitral regurgitation and inducing LV reverse remodelling.

The Task Force reviewed the profuse literature and ascertained how the strength of indications for CRT focuses mainly on the presence or absence of left BBB. A spectrum of response to CRT, as with most other treatments, is recognized: the beneficial effects of CRT may be greater in females, patients with non-ischaemic cardiomyopathy and patients with QRS duration >150 ms (the longer the QRS duration, the greater the benefit).

Recommendations are divided in three different issues:

  • Patients with sinus rhythm
  • Patients with atrial fibrillation
  • and in case of an upgrade or “de novo“ implantation of CRT in patients with a brady indication for pacing

2A. Indications for CRT in patients with heart failure and low ejection fraction in sinus rhythm

  • CRT is recommended in chronic HF patients and LVEF ≤35% who remain symptomatic in NYHA functional class II, III and ambulatory IV despite adequate medical treatment and who have LBBB with QRS duration >120 ms on ECG
  • CRT should be considered in chronic HF patients and LVEF ≤35% who remain in NYHA functional class II, III and ambulatory IV despite adequate medical treatment and who have non-LBBB with QRS duration >150 ms. If QRS duration is 120-150ms, the benefits are uncertain.
  • CRT in patients with chronic HF with QRS duration <120 ms is not recommended.

2B. Different recommendations are given for patients with atrial fibrillation

These patients are subdivided into patients with an indication for CRT and patients with an indication for AV junction ablation.

B1. Patients with HF, wide QRS and reduced LVEF: 

  • B1A. CRT should be considered in chronic HF patients, intrinsic QRS≥120 ms and LVEF ≤35% who remain in NYHA functional class III and ambulatory IV despite adequate medical treatment, provided that a  biventricular pacing as close to 100% as possible can be achieved.
  • B1B. AV junction ablation should be added in case of incomplete biventricular pacing.

B2. Patients with uncontrolled heart rate who are candidates for AV junction ablation CRT should be considered in patients with reduced LVEF. 

2C. Different recommendations are given for an upgrade or “de novo“ implantation of CRT in patients with a brady indication for pacing

C1. Upgrade from conventional PM or ICD. CRT is indicated in HF patients with LVEF <35% and high percentage of ventricular pacing who remaining NYHA class III and ambulatory IV despite adequate medical treatment.

C2. “De novo” CRT implantation. CRT may be considered in HF patients, reduced EF and expected high percentage of ventricular pacing in order to decrease the risk of worsening HF.

Finally the Task Force suggests a clinical guidance to the choice between CRT-P or CRT-D in primary prevention. The rate of complications in the CRT implant is not low, so in the decision process for indication for pacing/CRT and for the choice of the best modality attention should be paid to a careful evaluation of the risk of complications. In general the risk of complications is higher when implanting more complex devices and for re-intervention and upgrades.