Publish in this journal
Journal Information
Vol. 67. Issue 1.
Pages 65-66 (January 2014)
Vol. 67. Issue 1.
Pages 65-66 (January 2014)
Scientific letter
Full text access
Do Inappropriate Implantable Cardioverter-defibrillator Shocks Generate Additional Costs?
¿Las descargas inapropiadas de desfibriladores automáticos implantables generan costes adicionales?
Damià Pereferrer Kleinera,??
Corresponding author
, Antoni Sicras Mainarb, Roger Villuendas Sabatéa, Oscar Alcalde Rodrígueza, Carles Labata Salvadora, Antoni Bayes-Genisa
a Unidad de Arritmias, Servicio de Cardiología, Hospital Universitari Germans Trias i Pujol, Badalona, Barcelona, Spain
b Dirección de Planificación, Hospital Municipal de Badalona, Badalona, Barcelona, Spain
Article information
Full Text
Download PDF
Tables (2)
Table 1. Use of Hospital Resources as a Function of Causes of Inappropriate Discharge
Table 2. Distribution of Health Care Costs as a Function of Causes of Inappropriate Discharge
Show moreShow less
Full Text
To the Editor,

The efficacy of implantable cardioverter-defibrillators in preventing sudden death has been amply demonstrated.1 However, inappropriate discharge (ID) remains a therapeutic complication with negative consequences for prognosis and quality of life. Undoubtedly, IDs use up health care resources but no studies have attempted to quantify this cost. We present an analysis of the economic cost of ID-related medical attention in our center.

Between 2003 and 2011, we implanted cardioverter-defibrillators in 227 patients. Antitachycardia pacing therapy was programmed with 2 or 3 zones and overdrive pacing therapy. In the follow-up, the electrophysiologist analyzed each arrhythmic event. ID were defined as those applied in situations other than ventricular tachycardia or ventricular fibrillation, as well as in ventricular tachycardia/ventricular fibrillation appearing after inappropriate pacing in supraventricular or sinus tachycardia. Dubious cases were resolved by consensus. Prolonged episodes, which the device considers as more than one, were considered a single clinical episode.

Analysis was based on clinical episodes. We considered costs directly related with the medical attention received for each episode (extra visits to the clinic, emergency room visits, hospitalization, interventions, and length of in-hospital stay). We also determined the possible effect of IDs on the useful life of devices, taking into account that ID episodes can present as multiple shocks when a shock does not revert the cause that triggered it. The items and associated costs were obtained from the relevant regional government of Catalonia decree (SLT/42/2012).2

Median follow-up was 2.5 years (0 days to 8.5 years), and 27 patients (11.9%) presented with an ID. In total, 42 clinical ID episodes were recorded. Incidence was 0.08 episodes per patent/year. The most frequent cause was nonventricular tachycardia (66.7%). Overdetection of T waves caused 16.7% of episodes and electrical noise detection, 11.9%. In 19% of episodes, more than 5 shocks were received.

Tables 1 and 2 show resources used in the 42 episodes and their estimated economic cost, grouped as a function of ID cause. Twenty episodes led to medical examinations in the emergency room or outpatient clinics. Another 20 episodes were diagnosed in subsequent routine check-ups. These were single shock episodes, mostly for nonventricular tachycardia. The 2 remaining episodes occurred in patients hospitalized for another cause and the attention they received was not included as a cost. Eight episodes led to hospitalization. Hospitalizations were classified as a function of the diagnosis-related groups (DRG). Seven DRG 115 patients (implantation or replacement of generator or defibrillator electrode) and 1 DRG 544 patient (heart failure with major complications) were hospitalized. The DRG was the criterion used to determine the cost of hospitalization. Mean in-hospital stay was 4.4 days. Seven patients underwent reinterventions with ID, due to broken electrode (3), electrode displacement (2) and T wave overdetection (2). Total expense attributable to these incidents for all 42 episodes was €118 135.

Table 1.

Use of Hospital Resources as a Function of Causes of Inappropriate Discharge

ID causes  Episodes  Emergency room  Ambulatory  Admissions  Intervention  Replacement 
Rapid atrial fibrillation  12 
Supraventricular tachycardia  11 
Sinus tachycardia 
T wave detection 
Electrode displacement 
Broken electrode 
Inhibition therapy failure 
Total  42  12  14 

ID, inappropriate discharge.

Table 2.

Distribution of Health Care Costs as a Function of Causes of Inappropriate Discharge

  Episodes, n  Attends emergency room  Attends out-patient clinic  Admission without intervention (GRD 544)  Admission with intervention (GRD 115)  Mean per episode 
Unit cost  —  185  143  10 845  14 724   
ID episodes
Rapid atrial fibrillation  12  370  286      55 
Supraventricular tachycardia  11  185  429      56 
Sinus tachycardia  555  429      197 
T wave detection  185  572  10 845  29 448  5864 
Electrode displacement  185  143    29 448  9925 
Broken electrode  555    44 172  14 909 
Inhibition therapy failure  185  143      328 
Total  42  2220  2002  10 845  103 068  2813 

DRG, diagnosis-related groups; ID, inappropriate discharge.

Unless otherwise indicated, values express €.

Forty-nine devices were indicated for replacement due to low battery levels, 12 in the ID group and 37 in the non-ID group. Mean device life was 4.2 (2.2) years and 5.2 (1.6) years, respectively (P=.03). Mean device cost of the 227 implantations was €20 810 per unit. The 19.2% reduction in device life represents a mean cost of €3996 per device with ID.

We must remember that the economic value of the resources used was determined by our context at the time of the study, and this may differ in other situations. Furthermore, our calculation was based on the use of specific health care resources but we did not consider costs associated with the undoubtedly unfavorable effects of shocks—particularly inappropriate shocks—on psychosocial factors, quality of life, and overall mortality.

Our study found the economic cost of ID-related medical attention is distributed unequally; 42.8% of episodes were treated without using any of the resources studied and 96.4% of total costs were related to the 8 in-hospital episodes. We must distinguish between the cost of ID episode-related medical attention as such, and the cost of treating the cause. The first is low, since half of the episodes did not generate extra visits and were diagnosed at subsequent routine check-ups; moreover, diagnosis and therapeutic decision-making took place at a single visit. We put the cost of this at a mean €100 per episode. Treatment of ID-causes gives rise to costs that differ greatly as a function of these causes. Most are treated by reprogramming and/or adjusting medication, at no additional cost. However, 19% of episodes required hospitalization and reintervention, with high costs attributable more to the complication causing the ID than to ID itself (mean €14 239). Moreover, ID shortens the useful life of devices, at an estimated mean cost of some €4000 per device with ID.


Study financed by Medtronic.

D.P. Zipes, A.J. Camm, M. Borggrefe, A.E. Buxton, B. Chaitman, M. Fromer, et al.
ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines.
J Am Coll Cardiol, 48 (2006), pp. e247-e346
Orden SLT/42/2012, de 24 de febrero, por la que se regulan los supuestos y conceptos facturables y se aprueban los precios públicos correspondientes a los servicios que presta el Instituto Catalán de la Salud; DOGC núm. 6079 (02/03/2012). Available at: [accessed 8 Feb 2013].
Copyright © 2013. Sociedad Española de Cardiología
Revista Española de Cardiología (English Edition)

Subscribe to our newsletter

View newsletter history
Article options
es en

¿Es usted profesional sanitario apto para prescribir o dispensar medicamentos?

Are you a health professional able to prescribe or dispense drugs?