Results are expressed as mean ± standard deviation or median [interquartile range], depending on the distribution of the variable. Continuous quantitative variables were analyzed using analysis of variance or the Kruskal-Wallis test, whereas qualitative variables were analyzed using the chi-square test. Linear regression models were used to analyze the number of implantations and devices implanted per million population, the total number of implantations, and the number of implantations for primary prevention in each center.

In 2019, 172 hospitals performing ICD implantation participated in the registry. This figure is similar to that of 2018 (173) but slightly lower than that of 2017 (181, the highest number recorded since registry formation). Data from the 172 hospitals are shown in table 1; 106 were publicly-funded health centers. Figure 1 shows the total number of implantation centers, the rate per million population, and the total number of implantations by autonomous community according to the data sent to the registry. In 2019, 23 centers implanted ≥ 100 devices, 74 implanted between 11 and 99 devices, 76 ≤ 10, and 31 only 1.

Figure 1.

Distribution of implantation activity by autonomous community in 2019: number of implantation centers/rate per million population/total number of implantations. Mean rate = 149 implantations/million population.

(0.34MB).

In 2019, the total number of implantations (first and replacements) was 7003, representing an increase vs 2018 (6421). The total number of implantations reported to the registry and those estimated by Eucomed in the last 10 years are shown in figure 2. Accordingly, the data for 2019 show the highest number of ICD implantations in Spain in registry history (7389 in 2019, 7077 in 2018, and 6429 in 2017 according to Eucomed data).

Figure 2.

Total number of implantations notified and number estimated by Eucomed from 2010 to 2019. Eucomed, European Confederation of Medical Suppliers Associations; ICD, implantable cardioverter-defibrillator.

(0.18MB).

The overall implantation rate was 149/million population for the registry but 157/million population according to Eucomed data. This figure is higher than that of the previous year (137 implantations/million population in 2018) but much lower than the mean ICD implantation rate in Europe (303 implantations/million population in 2019). Changes in the implantation rate per million population during the last 10 years according to registry and Eucomed data are shown in figure 3.

Figure 3.

Total number of implantations notified per million population and number estimated by Eucomed from 2010 to 2019. Eucomed, European Confederation of Medical Suppliers Associations; ICD, implantable cardioverter-defibrillator.

(0.17MB).

The name of the hospital performing the procedure was recorded in 99.7% of forms (table 1). Most procedures (6364, 91%) were performed in publicly-funded health centers.

This information was available in 6127 forms sent to the SEC (85.7% of the devices included in the registry). First implantations comprised 4551, representing 74.3% of the total (71.5% in 2018, 71.4% in 2017, 66.8% in 2016, and 71.8% in 2015). The rate of first implantations per million population was 96.8 (83.4 in 2018, 76.5 in 2017, 65.5 in 2016, and 75.1 in 2015).

The mean age of all patients undergoing ICD implantation or replacement was 62.1 ± 13.8 (4-97) years in 2019 vs 62.4 ± 13.5 (7-97) years in 2018, 62.3 ± 13.4 (6-90) years in 2017, 62.7 ± 13.4 (6-90) years in 2016, and 62.8 ± 13.3 (6-89) years in 2015. The mean age of patients at first implantation was 60.8 ± 13.8 years. As in previous years, patients were overwhelming male: they represented 82.1% of all patients and 83.0% of first implantations.

The most frequent underlying cardiac condition in first implantation patients was ischemic heart disease (52.3%), followed by dilated cardiomyopathy (25.2%), hypertrophy (8.4%), primary conduction abnormalities (Brugada syndrome and long QT syndrome) (3.2%), valve diseases (1.8%), and arrhythmogenic right ventricular cardiomyopathy (1.3%) (figure 4).

Figure 4.

Type of heart disease prompting implantation (first implantations). ARVC, arrhythmogenic right ventricular cardiomyopathy; Others, patients with more than 1 diagnosis.

(0.15MB).

Left ventricular systolic function data were provided in 68.6% of forms. In the total patient group, left ventricular ejection fraction was > 50% in 17.9% of patients, from 41% to 50% in 9.5%, from 36% to 40% in 8.8%, from 31% to 35% in 20.7%, and ≤ 30% in 43.1% (figure 5). The distribution was similar when patients were grouped by first implantations and by replacements.

Figure 5.

Left ventricular ejection fraction of patients in the registry (total and first implantations).

(0.09MB).

The New York Heart Association (NYHA) functional class was recorded in 44.7% of forms. Most patients were in NYHA class II (56.2%), followed by NYHA III (24.9%), NYHA I (17.7%), and NYHA IV (1.3%). The distribution for this variable was also very similar in the overall and first implantation groups (figure 6).

Figure 6.

New York Heart Association (NYHA) functional class of total and first implantation patients.

(0.06MB).

The baseline cardiac rhythm was recorded in 68.4% of forms. It was primarily sinus rhythm (78.3%), followed by atrial fibrillation (17.1%) and pacemaker rhythm (4.2%). The remaining patients had other rhythms (eg, atrial flutter and other arrhythmias).

The clinical arrhythmia prompting device implantation was reported in 68.8% of forms submitted to the registry. For first implantations, most patients had no documented clinical arrhythmias (63.7%), whereas 14.3% showed sustained monomorphic ventricular tachycardia, 9.7% had nonsustained ventricular tachycardia, and 11.2% had ventricular fibrillation. In total, patients with no documented clinical arrhythmia comprised 60.8% (figure 7). The most frequent presentation in both the total implantation group and the first implantation group (41.3% of completed responses) was asymptomatic (in more than half of patients), followed by syncope, sudden cardiac death, and other symptoms (figure 8).

Figure 7.

Distribution of arrhythmias prompting implantation (total and first implantations). NSVT, nonsustained ventricular tachycardia; PVT, polymorphic ventricular tachycardia; SMVT, sustained monomorphic ventricular tachycardia; VF, ventricular fibrillation.

(0.07MB).

Figure 8.

Clinical presentation of the arrhythmia in the registry patients (first implantations and total). SCD, sudden cardiac death.

(0.07MB).

Information on the electrophysiological studies performed before ICD implantation was provided in 62.7% of forms. These studies were performed in 324 patients (7.4%), mainly in those with ischemic heart disease or dilated cardiomyopathy and in 38.7% of patients with Brugada syndrome. Sustained monomorphic ventricular tachycardia was the most common induced arrhythmia (44.8%), followed by ventricular fibrillation (24.1%), nonsustained ventricular tachycardia (11.2%), and, to a lesser extent, other arrhythmias (5.4%). No arrhythmia was induced in 14.6% of the electrophysiological studies.

Information on clinical history has been recorded since 2011, permitting establishment of the profile of patients undergoing ICD implantation in Spain.

Answers to some of these questions were provided in 68.8% of forms. The most pertinent information regarding cardiovascular risk and history is that hypertension was recorded in 54.4% of patients, hypercholesterolemia in 35.1%, smoking in 25.6%, diabetes mellitus in 28.9%, history of atrial fibrillation in 26.8%, family history of sudden cardiac death in 8.6%, renal failure in 12.6%, and history of stroke in 5.8%.

The QRS interval was recorded for 42.1% of first implantations (mean, 124.1 ms). In 30.8% of the patients, it was > 140 ms, and 86.1% of these patients had a resynchronization-defibrillator device (ICD-cardiac resynchronization therapy [CRT]).

The changes in first implantations by type of heart disease and presentation from 2015 are shown in table 2. These data were provided in 66.1% of forms in 2019. Ischemic heart disease was the most frequent reason for ICD implantation in Spain, accounting for 52.3% of first implantations in 2019. Among ischemic heart disease patients, the most common indication was primary prevention (68.1%). However, a considerable number of forms returned failed to note the reason or it was unclassifiable. The second most common reason for ICD implantation was dilated cardiomyopathy (25.2% of all first implantations) and the absolute number of first implantations increased in 2019 vs previous years (925 in 2019 vs 803 in 2018, 830 in 2017, 866 in 2016, and 964 in 2015). The recovery in the number of units implanted in patients with dilated cardiomyopathy reflects the increase in primary prevention indications (59.1% vs 44.2% in 2018 and 41% in 2017). For the less common heart diseases, the most frequent indications were primary prevention of hypertrophic cardiomyopathy, congenital valve diseases, arrhythmogenic right ventricular cardiomyopathy, and Brugada syndrome. However, in long QT syndrome, the indication was evenly split between primary prevention and secondary to sudden cardiac death (40.5% each).

The implantation indication was identified in 66.0% of forms. Most first implantations were indicated for primary prevention (65.1%), a similar proportion to 2018 (65.7%) and an increase vs the previous year (table 3).

The implantation setting and specialist performing the procedure were recorded in 72.3% of forms. At 85.4%, the predominant implantation location was the electrophysiology laboratory (83.1% in 2018 and 81.4% in 2012), followed by the operating room (12.3%). Electrophysiologists performed 82.06% of implantations (80.6% in 2018 and 81.0% in 2012); surgeons performed 7.4% (9.2% in 2018 and 14% in 2012), and both together performed 6%. Other specialists and intensivists were involved in 2.3% and 2.4%, respectively.

Generator placement was recorded for 56.4% of first implantations. Placement was subcutaneous in 95.6% of patients and subpectoral in the remaining 4.4%. These figures were 94.9% and 5.1%, respectively, for all devices implanted.

The types of device implanted are shown in table 4. This information was provided in 96.9% of forms submitted to the registry. In 2019, first implantations of subcutaneous defibrillators increased to 8.3% (6.0% in 2018, 5.3% in 2017, 6.4% in 2016, and 2.4% in 2015), largely due to a fall in the implantation of single-chamber defibrillators.

The most frequent reason for replacement was battery depletion (80.9%); complications prompted 7.4% of replacements (9.1% in 2018). Of the 827 replacements providing this information, 2.1% were performed before 6 months.

Information was available on lead status in 52.5% of forms; 2.86% were malfunctioning (44 forms) and they were extracted in 13.6% of the patients reporting this problem.

Information on device programming was provided in 64.9% of forms. The most widely used programming was VVI (52.7%), followed by DDD (28.1%), VVIR (6.3%), DDDR (6.6%), and others (6.3%), largely algorithms to prevent ventricular pacing.

Ventricular fibrillation induction was tested in 380 patients, representing 8.1% of the 4711 records providing this information (5.3% in 2018 and 6.7% in 2012). The mean number of shocks delivered was 1.1. Thus, in the vast majority of cases, the threshold was not calculated and device functioning simply tested.

Complication development was recorded in 75.0% of forms. There were 30 complications: 8 coronary sinus dissections, 1 tamponade, 1 pneumothorax, 7 deaths, and 12 unspecified. The mortality rate was 0.1%, similar to that of the last 3 years (0.2% in 2018, 0.09% in 2017, 0.02% in 2016, 0.07% in 2015, and 0.05% in 2014), although the number fortunately remains quite low.

The SEC is committed to the quality of cardiovascular care in Spain, as exemplified by the Spanish Implantable Cardioverter-defibrillator Registry, with its systematic publication of data since 2005.5 This consistency allows us to identify trends in ICD implantation, the types of devices used, and the characteristics of the patients undergoing ICD implantation in our country in recent years. The period evaluated shows a progressive increase in the number of ICD implantations, with periodic reductions in the 2011 to 2012 period and in 2017 vs previous years. The number of units implanted in Spain has increased in the last 2 years. Together with the slight decrease in the number of implantations in Europe in this period,11 this growth has reduced, albeit slightly, the major differences between Spain and the rest of Europe. While the rate of implantations per million population in Spain in 2010 was about half of the European average (116 vs 248), the difference from Europe reduced last year, with a rate of 157 implantations per million in 2019 (vs 152 in 2018 and 138 in 2017) vs a decrease in Europe from 311 in 2017 to 303 in 2019.

Despite the increase in ICD implantations in 2019, the rate of implantations in Spain continues to be lower than expected given the scientific evidence endorsed in the clinical practice guidelines.1–3 The impact of the underuse of ICD therapy was reflected in a recently published Swedish study12 that showed that, between 2000 and 2016, an ICD was ultimately implanted in only 10% of patients with an ICD indication for primary prevention of sudden cardiac death (according to ESC guidelines). ICD implantation was associated with mortality reductions of 27% in the first year of follow-up and of 12% at 5 years. The Implantable Cardioverter-defibrillator Registry also shows a clear underuse of ICD therapy in Spain and highlights the importance of new measures to increase ICD use in patients who would benefit from this approach.

The latest registry data confirm the increase in primary prevention indication observed in recent years, with a 65.1% rate of prophylactic implantations (table 3), which once again brings us slightly closer to the European average. The rate of prophylactic implantations has increased by 9.2% in the last 10 years. Other European registries also show that primary prevention is the leading indication for ICD implantation, with rates of about 80%.13,14

Regarding the types of devices implanted in Spain, the data show a stabilization in the percentage of primary ICD-CRT implantations after the progressive decrease detected in previous years (31.4% in 2019 vs 30.6% in 2018, 31.5% in 2017, and 32.1% in 2016). The percentage of first implantations of single- and dual-chamber ICDs fell in 2019. The decline in single-chamber devices can be explained by the increase in the percentage of first implantations of subcutaneous ICDs (8.3% in 2019 vs 6.0% in 2018 and 5.3% in 2017). Undoubtedly, the results of the Praetorian study presented in the latest meeting of the Heart Rhythm Association, which determined that subcutaneous ICDs are not inferior to transvenous ICDs, will increase the use of subcutaneous ICD in the coming years.15,16

The most frequent indication in 2019 was once again ischemic heart disease (52%), followed by dilated cardiomyopathy (25.2%). Dilated cardiomyopathy as a percentage of the heart disease prompting the ICD implantation stabilized in 2019 after the decline seen in previous years. This fall was largely due to lower use of ICD therapy in the primary prevention of sudden cardiac death, which fell drastically in Spain after the publication of the DANISH study.17 This phenomenon was also seen to a greater or lesser extent in other European countries.18 We do not consider this decline justified based on the available data, for various reasons. First, more than half of the patients in the DANISH study had a cardiac resynchronization device, which partly limits the value of the results for patients without resynchronization indication. Second, a clear benefit was found in patients younger than 70 years, which represent the overwhelming majority of implantations in Spain.6,7 Third, the results of 2 meta-analyses once again showed a consistent benefit of ICDs in this patient population, with a 25% reduction in the relative risk of death.19,20 Finally, the only guidelines published after the results of the DANISH trial maintain the indication for ICD implantation for primary prevention in patients with dilated cardiomyopathy (class I, level of evidence A).1

There were no changes from previous registries in the epidemiological characteristics of the patients. Patients with severe ventricular dysfunction and in NYHA II and III continue to predominate. No changes were seen either in the specialist performing the implantation and most procedures were once again performed in the electrophysiology laboratory.

As in previous years, the data from the 2019 registry once again show differences in the implantation rates per million population of the various autonomous communities. Several communities showed higher than average rates: Cantabria (255), Principality of Asturias (200), Aragon (180), Galicia (175), the Basque Country (172), Valencian Community (166), Castile-La Mancha (165), Chartered Community of Navarre (162), Castile and León (157), Extremadura (156), and Community of Madrid (156). Below average were Catalonia (135), the Region of Murcia (128), La Rioja (126), Andalusia (121), the Balearic Islands (121), and the Canary Islands (116). A generalized increase was seen in the rate of implantations per million population in 2019. Only the Principality of Asturias (200 vs 214 in 2018), Extremadura (156 vs 168 in 2018), and the Canary Islands (116 vs 118 in 2018) had lower implantation rates per million population vs 2018. The difference between the communities with the highest and lowest implantation rates continue to be marked, which is difficult to explain in terms of the theoretically homogeneous Spanish health system. These differences are not explained by income level or population density or by the different incidences of ischemic heart disease and heart failure among the autonomous communities. This situation might call into question the equity of our health care system in an area as important as that of the prevention of sudden cardiac death.

In 2019, the implantation rate in the countries participating in the Eucomed was 303 per million population (302 in 2018, 307 in 2017, and 316 in 2016), including ICDs and ICD-CRTs. For the first time since the Eucomed began publishing European implantation data, the Czech Republic, with 458 devices per million population, was the country with the highest implantation rate, overtaking Germany (457), which was the European country with the highest ICD implantation rate in previous years. One consistent finding is that Spain (157 implantations/million) is the country with the lowest number of implantations. Several countries showed higher than average rates: Italy (476), Denmark (391), the Netherlands (369), and Poland (327). Below average were Austria (266), Sweden (256), Belgium (250), Ireland (242), Finland (242), Norway (239), Switzerland (230), Portugal (226), France (223), Greece (213), the United Kingdom (212), Hungary (164), and, in last place, Spain (157). However, the difference in the implantation rate in Spain from the European average slightly decreased in 2019 (157 vs 303 compared with 152 vs 302 in 2018, 138 vs 307 in 2017, 144 vs 320 in 2016, and 138 vs 315 in 2015). As can be seen from these figures, only 2 countries in Europe have an ICD implantation rate per million population less than 200: Hungary and Spain.

The ICD-CRT implantation rate was 119 per million population (117 in 2018, 122 in 2017, 127 in 2016, and 124 in 2015). As in the overall group and for the first time, the Czech Republic (204 implantations) was the country with the highest number of implantations, surpassing Germany (188), the second country in terms of device implantations. In contrast, Spain stands out, unfortunately, as the country with the lowest implantation rate (53). The proportion of ICD-CRTs with respect to the total varies from 28% in Denmark and 31% in Ireland to 45% in the Czech Republic. The European average is 39%. Above the average are the Czech Republic, Finland, France, Germany, Hungary, Italy, Portugal, Switzerland, and the United Kingdom. Only Denmark has a rate below 30%. Spain has a proportion of 33%.21

These countries have the same regional differences14,22 seen in the Spanish registry, for reasons that are hard to explain. One possible explanation is the number of available arrhythmia units, but that does not explain the relationship, at least in Spain, because communities with the highest number of available units had lower implantation rates. Income does not seem to be factor because countries with lower incomes than Spain, such as Ireland, the Czech Republic, and Poland, show much higher implantation rates. Nor can these differences be explained by the prevalence of cardiovascular diseases or population age. Regardless, the implantation rate in Spain might reflect a lower degree of acceptance of and adherence to clinical practice guidelines, which has been linked to increased mortality in patients with cardiovascular disease. This situation, evident in successive registries, should compel us, electrophysiologists first and cardiologists second, to improve our ability to identify candidates for ICD implantations due to the major benefits of the therapy, which include reduced morbidity and mortality in at-risk patients.

The 2019 registry collected data on 95% of implantations, higher than in previous years but still below 2017, when the registry recorded data on 97% of all ICD implantations. As in previous years, completion of the different fields in the implantation form varied and was lower than desired. In addition, no follow-up data were collected from patients, which would permit more relevant clinical studies. Finally, the unequal completion of the data on ICD-associated complications and the absence of follow-up data probably underestimate the actual complication rate.

This registry is the 16th official report. The durability of this registry is a credit to all of the participating members of the Heart Rhythm Association of the SEC. In 2019, a website9 for the online completion of the implantation form for both ICDs and pacemakers was launched by the SEC in collaboration with the Spanish Agency for Medicines and Health Products. This website enables the real-time recording of both types of implantable heart devices. We hope that the availability of this website will improve the completion rate and quality of the registry. This platform will undoubtedly enable the performance of prospective studies and will boost the safety of patients with devices affected by any possible safety alerts in the coming years.