All Portuguese centers responded to the survey in 2017 and 2018. In 2017, 22 electrophysiology centers were operating, of which 15 were in public hospitals (68%) and seven in private health institutions (32%). This represents a slight reduction in the overall number of active centers (compared to 25 in 2014) due to some private centers ceasing operation (there had been 11), while one more center opened in a public hospital (previously 14). In 2018, the number of centers remained unchanged, with one public center opening and one private center ceasing activity.

Sixteen of the country’s electrophysiology centers, including all of the private centers, were located in the greater Lisbon (n=11) and greater Porto (n=5) areas (Figure 1).

Figure 1.

Geographical distribution of public and private electrophysiology centers in Portugal.

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With regard to physical resources, in 2018 all centers were equipped with polygraphs (five centers had two polygraphs) and fluoroscopy systems (seven centers had two image intensifiers). Only one private center did not have a three-dimensional electroanatomical mapping system, while 12 centers (55%) had at least two such systems.

In terms of human resources, there were 33 electrophysiologists active in 2018, 18 of them also practicing in private institutions. The teams included at least two electrophysiologists in 13 centers (13%), two cardiopulmonary technicians in 18 centers (82%), and two nurses in 20 centers (91%). Human resources also included 15 physicians undergoing training for the subspecialty of cardiac electrophysiology. Eleven centers provided training for the internship in arrhythmology during training for the specialty of cardiology. Details of the human resources involved are presented in Figure 2.

Figure 2.

Human resources in electrophysiology centers in Portugal in 2018.

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In 2017, a total of 3407 electrophysiological procedures with ablation and 774 diagnostic electrophysiological studies (not followed by ablation) were performed. The number of ablations performed in 2016 was 2895, so the year-on-year growth in the number of ablation procedures performed was 18% (Figure 3).

Figure 3.

Changes in annual numbers of ablation procedures between 2006 and 2018.

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In 2017, seven centers (32% of the total) carried out more than 100 ablations, accounting for 77% of all such procedures (2623/3407). The four centers that performed more than 300 ablations accounted for 55% of these procedures (1857/3407). None of the centers performed fewer than 10 ablations/year (unlike in 2014, when this was the case in nine centers). The seven private centers performed 511 ablations, representing 15% of the total.

In 2018, 3653 ablations were performed (an increase of 8% over the previous year) and 673 diagnostic electrophysiological studies. The number of centers performing over 100 ablations increased to nine, and five centers performed over 300 ablations. The 13 centers that each performed fewer than 100 ablations accounted for 748 procedures, 20% of the total. In the six private centers 567 ablations were performed, 16% of the total.

The distribution by type of ablation for 2017 and 2018 is shown in Figure 4 and a comparative analysis for the period 2016-2018 is presented in Supplementary Figure S1. Distribution by center and type of ablation is presented in Figure 5 (for 2018) and in Supplementary Figure S2 (for 2017).

Figure 4.

Distribution of procedures by type of ablation in 2017 and 2018. AF: atrial fibrillation; AFl: atrial flutter; AP: accessory pathway; AVNRT: atrioventricular nodal reentrant tachycardia; AVRT: atrioventricular reentrant tachycardia; PVCs: premature ventricular contractions; VF: ventricular fibrillation; VT: ventricular tachycardia; WPW: Wolff-Parkinson-White syndrome.

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Figure 5.

Distribution of procedures by center and type of ablation in 2018. AF: atrial fibrillation; AFl: atrial flutter; AP: accessory pathway; AV: atrioventricular; AVNRT: atrioventricular nodal reentry tachycardia; PVCs: premature ventricular contractions; VF: ventricular fibrillation; VT: ventricular tachycardia; WPW: Wolff-Parkinson-White syndrome.

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AF ablation was the most frequently performed procedure and accounted for an increasing proportion of activity over the period under study, rising from 30% in 2016 to 36% in 2018. Conversely, the proportion of procedures for paroxysmal supraventricular tachycardias (atrioventricular nodal reentrant tachycardia and accessory pathway arrhythmias) fell from 40% in 2016 to 33% in 2018. Ablation of ventricular arrhythmias accounted for 6-7% of activity, a figure that did not vary significantly during the study period.

In 2017, AF ablation was performed in 17 centers, totaling 1017 procedures (76% in public hospitals and 24% in private centers). The mean number of AF ablations was 60 and the median was 25, with considerable variation between centers (11 centers performed <50 ablations, 73% of which performed <25 procedures) (Table 1). The four centers that performed >100 procedures were responsible for 73% of all AF ablations (n=738). In 2018, 1222 AF ablations were performed in 18 centers, which represented a year-on-year increase of 20%. The mean number of AF ablations in these centers rose to 68 and the median rose to 36. The largest increase was seen in low- and medium-volume centers, the proportion of procedures performed in the four centers with most AF ablations falling to 62% (n=763) (Table 1).

In 2017 and 2018, 63% (n=1216) of patients who underwent AF ablation were male, 60% (n=1232) were aged 50-69 years and 74% (n=1380) had paroxysmal AF (Table 2). The procedure was a first ablation in 81% of cases (n=1715). The most commonly used technique during the study period was point-by-point radiofrequency ablation guided by electroanatomical mapping (61% of procedures), but the use of cryoablation increased by 87%, rising from 128 procedures in 2017 to 239 in 2018.

Clinically relevant complications were reported in 18 patients (0.8%), mainly tamponade or hemopericardium requiring pericardiocentesis (n=14; 0.7%) and vascular access complications requiring intervention (n=11; 0.5%). No deaths or cases of stroke, infective endocarditis or atrioesophageal fistula were reported.

In 2017, ablation of VT (idiopathic, including premature ventricular contractions [PVCs], or secondary to structural heart disease) was performed in 15 centers, totaling 215 procedures (6% of all ablations). One procedure was also performed to ablate the arrhythmogenic substrate in a case of Brugada syndrome.

Eight centers performed fewer than 10 V T ablations, while the five centers that performed over 20 procedures were collectively responsible for 66% of all VT ablations (n=142) (Table 3). Three centers performed ablations of VT or ventricular fibrillation (VF) using an epicardial or endo-epicardial approach, in a total of 14 procedures.

Of the total of VF/VT ablations, 92% were performed in public centers, including 97% of those in cases of structural heart disease.

In 2018, the number of procedures increased by 16% (to 249), due to a rise in idiopathic VT ablations (from 108 in 2017 to 146 in 2018). In 2018, VF/VT ablations were performed in 19 centers, with a mean of 13 procedures (median six). Five centers performed epicardial or endo-epicardial VT ablations, in a total of 22 procedures.

The clinical characteristics of patients undergoing VF/VT ablation are presented in Table 4. Of the 464 V T ablations carried out in 2017 and 2018, 55% (n=254) were performed for idiopathic VT or frequent PVCs, 34% (n=156) for VT in ischemic heart disease, 8.8% (n=40) in non-ischemic dilated cardiomyopathy (post-myocarditis, hereditary, sarcoidosis, amyloidosis or unknown etiology), and 1.1% (n=5) in the setting of arrhythmogenic right ventricular cardiomyopathy. One procedure was performed in a patient with hypertrophic cardiomyopathy and another to ablate the arrhythmogenic substrate in a case of Brugada syndrome (Figure 6).

Figure 6.

Distribution of ventricular tachycardia ablations by etiology in 2017 and 2018. ARVD: arrhythmogenic right ventricular cardiomyopathy; DCM: dilated cardiomyopathy; HCM: hypertrophic cardiomyopathy.

Information on etiology of heart disease was available for 456 patients undergoing ventricular tachycardia ablation (98% of these procedures).

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Ablations of idiopathic VT were performed with a similar frequency in both sexes (Table 4). However, patients undergoing VT ablation in structural heart disease were predominantly male (92% men vs. 8% women; p<0.001). The number of VT ablations in non-ischemic dilated cardiomyopathy, although still low, rose between 2017 and 2018 from 15 to 25 procedures, while VT ablations in ischemic heart disease fell from 84 to 72.

In 2017 and 2018, a total of 36 V T ablations were performed using an epicardial or endo-epicardial approach, more often in patients with non-ischemic dilated cardiomyopathy (n=22; 61%) (Table 5). Although an epicardial approach was significantly more likely to be used in non-ischemic dilated cardiomyopathy than in ischemic heart disease (55% vs. 5%; odds ratio: 22.6; 95% confidence interval: 8.8-58.2; p<0.0001), it should be noted that epicardial mapping was performed in eight patients with ischemic heart disease, as well as in all five patients with arrhythmogenic right ventricular cardiomyopathy who underwent VT ablation and in the patient with Brugada syndrome.

Clinically relevant complications were reported in 15 cases, a complication rate of 3.2% (Table 6). The most frequent complication was tamponade or hemopericardium requiring pericardiocentesis (n=12; 2.6%) and one death was reported as a procedural complication (0.2%).