Dr. Michele Brignole,
The implantable loop recorder (ILR) is a new powerful diagnostic tool for diagnosis of unexplained syncope. The European Society of Cardiology and European Heart Rhythm Association have recently published documents containing recommendations on the appropriate use of ILRs. Data from literature suggest that, in clinical practice, ILRs might be underused in patients with unexplained syncope in relation to the standard proposed by guidelines.
Little is known on the prevalence of ILR in the clinical practice for patients with unexplained syncope. Solano et al (1) have estimated that 5% of all patients referred to two tertiary centres for the evaluation of syncope and 28% of those with unexplained syncope had received an ILR after complete work-up. In the multicentre ESGSY2 study, of 269 patients referred to the Emergency Department, 1% were implanted with an ILR (2). In the multicentre SUP study, of 700 patients referred to specialised syncope facilities, 4% finally received ILR implantation (3).
The European Society of Cardiology and European Heart Rhythm Association have recently published documents containing recommendations on the appropriate use of ILRs in patients with syncope (4,5). In both documents, the recommendations for ILR in patients with unexplained syncope are similar; they are reported in table 1.
Table 1 Indications for ILR in patients with unexplained syncope
Class I recommendations. ILR is indicated in:
Class II A recommendations. ILR may be indicated:
Class II B recommendations. ILR may be indicated:
In the multicentre, prospective and observational SUP study (3), the real world practice of 9 Italian hospitals equipped with a Syncope Unit was photographed. Among 700 consecutive patients investigated for syncope, the diagnosis remained unexplained in 159 cases at the end of full conventional work-up. In an ad-hoc sub-study (6), authors compared the prevalence of ILR actually implanted (as per indication of the physician investigator) with that estimated using restricted criteria based on Class I recommendations of the recently published ESC (4) and EHRA (5) guidelines. The implant of ILR was considered potentially appropriate when the patient had one of these characteristics:
These criteria are probably more restrictive than those of class I of the guidelines because, contrary to guideline recommendations, patients without cardiac disease were included only if they had had ³ 3 episodes of syncope in the previous two years and age ³ 40 years. Of 159 patients with unexplained syncope, 110 (69%) had appropriate criteria for implantation of ILR according to guidelines. On the contrary, ILR had been actually implanted in 28 (18%) patients, p<0,0001 versus estimated criteria (Table 2). Seven (25%) of these patients had potentially inappropriate ILR implantation according to the adopted criteria. Table 2. Relationship between observed and estimated ILR indications
Total patients with unexplained syncope
Observed ILR implanted
Observed ILR not implanted
Estimated ILR potentially indicated
ILR not indicated
In the SUP study (3), the observed incidence of implanted ILR was 30 per million inhabitants per year (95% confidence interval 23–39), a figure which is very similar to that of 34 per million inhabitants per year calculated by Solano et al (1) in patients with unexplained syncope. These figures seem therefore to be representative of the real world practice in Italy. On the contrary, the estimated incidence according to predefined criteria based on class I indications of the EHRA and ESC guidelines (4,5) is 118 ILRs per million inhabitants per year (95% confidence interval 103–134). How much the dissemination of the guidelines will be able to fill the gap between the observed and estimated incidence is a matter for future studies.
The conclusion of this study was that there is discrepancy between clinical practice and standardised class I indications for ILR in patients with unexplained syncope. Two thirds of patients with unexplained syncope had potentially appropriate indications for implantation of ILR. The estimated indications were four times higher than those observed.
1- Solano A, Menozzi C, Maggi R, Donateo P, Bottoni N, Lolli G, Tomasi C, Croci F, Oddone D, Puggioni E, Brignole M. Incidence, diagnostic yield and safety of the implantable looop-recorder to detect the mechanism of sincope in patients with and without structural heart disease. Eur Heart J 2004; 25: 1116-1119
2- Brignole M, Menozzi C, Bartoletti A, Giada F, Lagi A, Ungar A, Ponassi I, Mussi C, Maggi R, Re G, Furlan R, Rovelli G, Ponzi P, Scivales A. A new management of sincope: prospective systematic guideline-based evaluation of patients referred urgently to general hospital. Eur Heart J 2006; 27: 76-82
3- Brignole M, Ungar A, Casagranda I, Gulizia M, Lunati M, Ammirati F, Del Rosso A, Sasdelli M, Santini M, Maggi R, Vitale E, Morrione A, Francese G. M, Vecchi M.R, Giuli S, Giada F. Prospective multicentre systematic guideline-based management of patients referred to the Syncope Units of general hospital. Europace 2010: 12, 109–118
4- Moya A, Sutton R, Ammirati F, Blanc JJ, Brignole M, Dahm JB, Deharo JC, Gajek J, Gjesdal K, Krahn A, Massin M, Pepi M, Pezawas T, Ruiz Granell R, Sarasin F, Ungar A, van Dijk G,Walma E, Wieling W. Guidelines for the Diagnosis and Management of Syncope (Version 2009) Eur Heart J 2009; 30: 2631–2671
5- Brignole M, Vardas P, Hoffman E, Huikuri H, Moya A, Ricci R, Neil Sulke N, Wieling W. Indications for the use of diagnostic impalantable and external ECG loop recorders. Europace 2009;11: 671-687 6- Vitale E, Ungar A, Maggi R, Francese M, Lunati M, Colaceci R, Del Rosso A, Castro A, Santini M, Giuli S, Belgini L, Casagranda I, Brignole M. Discrepancy between clinical practice and standardized indications for an implantable loop recorder in patients with unexplained syncope Europace 2010; 12: 1475-1479
Michele Brignole, MD FESC Department of Cardiology, Ospedali del Tigullio, Lavagna, Italy. Elena Vitale, MD Department of Emergency, Ospedale Antonio, Biagio e Cesare Arrigo, Alessandria, Italy.
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