AVNRT ablation represented 18% of all procedures (2808 procedures, the third most common ablation target after AF and CTI). This was a highly significant reduction vs 2019, with 960 fewer procedures. This was the ablation target treated in the highest number of centers (n = 95), with an average of 29.3 ± 21 (range, 1-97) procedures/center and a 96% success rate. The most commonly used ablation catheter was the conventional 4-mm catheter (93%). The use of other types of catheters and energy sources was negligible.

The use of nonfluoroscopic navigation systems continued to increase, reaching 31% (from 25% in 2019), and up to 79% of navigation system-guided procedures were fluoroscopy free. The reported complication rate was 0.5%, which included 7 permanent atrioventricular blocks, 3 transient blocks, 1 pneumothorax, and 4 vascular complications.

AP ablation remained the fourth most frequently treated substrate (10%), despite a significant drop in 2020 (1539 procedures vs 2024 in 2019). This ablation target was treated in the vast majority of centers (94 of 97), with an average of 16.2 ± 12.2 (range, 1-54) procedures/center and a 90% success rate. Just 18.2% of the APs showed anterograde conduction exclusively, whereas 39.5% were concealed APs and 42.3% had bidirectional conduction. In addition, left APs continue to not only be the most frequent (47.6%), but also the most successful (98.5%), followed by inferoseptal (29.5%; 92.3% success rate), para-Hisian/anteroseptal (12.1%; 78.4% success rate), and right ventricular free wall (10.8%; 94.7% success rate).

Once again, 4-mm catheters were the most commonly used catheters (57%), followed by irrigated catheters (24%). Contact forcesensing technology continues to gain traction (12.3% in 2020 vs 7.1% in 2019).

Epicardial ablation was performed in 36 procedures and, in the case of left APs, retroaortic access was used in 60%. There were 21 complications (1.4%): 9 pericardial effusions, 8 vascular, 2 embolic phenomena, 1 bilateral pulmonary embolism after left AP ablation, and 1 catheter entrapment in the mitral subvalvular apparatus requiring surgery.

The use of mapping systems continued to grow, reaching almost half of procedures (48.7%), with 35.6% of them performed without fluoroscopy.

In total, 471 FAT procedures (3%) were reported, with an increase in the number of centers (n = 79) and an 80% success rate. Most (74%) were located in the right atrium, with a 92.2% success rate. In addition, 123 procedures were performed in the left atrium, with a slightly lower success rate (89.1%). The tendency continued for lower use of conventional irrigated tip catheters (144 procedures; 30.5%) due to an increase in contact forcesensing catheters (215 procedures; 45.6%). The data showed a notable increase in the use of mapping systems (71.5%) and 21.4% of the total were performed without fluoroscopy. Ten complications (2%) were reported; the most notable were 3 vascular complications (0.6%) and 4 pericardial effusions (0.8%).

CTI continues to be the second most commonly treated ablation target (3188 procedures; 21%). This substrate was treated in 94 centers, with a mean of 33.9 procedures/center and a mean success rate of 96%. The catheter of choice continues to be the conventional irrigated tip catheter (46.7%), whereas the use of contact forcesensing technology remains the second most common option (27%). The use of 8-mm catheters was unchanged (23.5%). Mapping system use showed a marked increase (42.7%), as well as zero-fluoroscopy interventions (25.2%). A total of 20 complications (0.6%) were reported, including 11 vascular, 2 pericardial effusions, 2 atrioventricular blocks, 1 embolism, and 1 myocardial infarction. One death was reported, but the cause was not specified.

MAT continues to be one of the least common ablation targets, despite being treated in 73 centers; 582 procedures were reported (4%). The most frequent subtype was that occurring after AF ablation (47.9%). Less frequent were MATs in congenital heart diseases (17.2%) or after arteriotomy (16%). It had the lowest success rate of all procedures (81.4%). The use of mapping systems was stable (81.6%), although there was a slight decrease in zero-fluoroscopy procedures (55 procedures; 9.4%). Contact forcesensing technology (71.9%) predominated over conventional irrigated catheters (10.2%). After AF, it was the supraventricular arrhythmia with the highest complication rate (14 cases; 2.4%); notable complications were 4 femoral vascular complications and 6 pericardial effusions.

In total, 750 AVN ablations (4.9%) were reported by 84 centers. The success rate was 95%. Most of the procedures were performed with conventional 4-mm catheters (399 procedures; 53.2%) or conventional irrigated catheters (212 catheters; 28.3%). The use of 8-mm catheters fell once again (n = 110; 14.6%). Four nonsevere complications were reported (0.5%): 3 vascular and 1 embolism.

AF became consolidated as the most frequently treated ablation target, with 4513 procedures and increases from 23% in 2017 to 26% in 2018, 28% in 2019, and 30% in 2020. Although the mean number of procedures remained above 50 ablations/center (55.7 ± 44.5), the median was lower (44; range, 1-222). The acute success rate was 96%. Figure 6 shows the distribution of centers by annual AF ablation volume in 2020. Of the 81 centers undertaking AF ablation, 45 (55.5%) performed between 1 and 50 procedures (18 of these centers performed fewer than 25). Just 13 centers exceeded 100 procedures/y (16%), 3 of which performed more than 150 and only 1 more than 200.

Figure 6.

A: changes in the point-by-point and cryoablation techniques since 2013. B: distribution of centers by number of ablation procedures for atrial fibrillation (AF).

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Paroxysmal AF ablation comprised 60.8%, persistent AF comprised 33.9%, and long-standing (>1 year) persistent AF comprised 5.1%.

The predominant target continued to be electrical isolation of the pulmonary veins (94.5%) and the data showed a fall in the treatment of other ablation targets (51 fractionated electrogram ablations and 107 superior vena cava isolations). Left atrial lines were placed in 192 procedures (4.3%). Other targets were limited (24 atrial appendage isolations and 8 rotor ablations and ablations of low-voltage areas or extrapulmonary foci).

Although the most commonly used technique continued to be point-by-point radiofrequency (2369 procedures; 55.4%), the use of cryoablation increased (2144 procedures; 44.6%). Figure 6 shows the changes over time in procedures performed with the point-by-point technique vs cryoablation since 2013. In contrast to previous years, the use of other techniques was not reported.

Irrigated catheters with contact forcesensing technology were the catheter of choice (84.8%). Steerable sheaths were reported in 56% of procedures undertaken with radiofrequency. Although 43.3% of centers are equipped with intracardiac echocardiography, it was used in only 18 centers (441 procedures; 9.7% of AF procedures). Six centers reported zero-fluoroscopy procedures (n = 75).

The number of complications was stable (159; 3.5%), with only 1 death, which was attributed to septic shock. In addition, 43 vascular complications were recorded (0.9%), as well as 50 pericardial effusions (1.1%), 35 phrenic nerve palsies (0.7%), and 11 embolisms (0.2%) as the most noteworthy events.

In total, 649 IVT ablation procedures were performed in 620 patients, representing 4% (similar to 2019), although there was a notable decrease in the number of procedures vs the 807 in 2019. The number of centers treating this ablation target was unchanged (n = 88), with an average of 7.4 ± 5.8 (range, 1-23) procedures/center and an 83.7% success rate.

Of these, 298 procedures involved VT of the right ventricular outflow tract, 97 involved VT of the left ventricular outflow tract, 64 involved VT of the aortic root, 32 were fascicular tachycardias, 32 were epicardial tachycardias, 4 had an origin in the pulmonary artery, and 72 were in other locations, such as the papillary muscles, mitral annulus, and right ventricular moderator band.

The use of mapping systems predominated (82%); 18% were zero-fluoroscopy procedures. Ablation was preferentially performed with contact forcesensing technology (66.2%), whereas 24.3% used conventional irrigated catheters. Other types of catheters or energy sources were limited (4-mm nonirrigated tip, 4.8%; cryoablation, 0.3%).

There were 25 complications (3.9%): 14 vascular, 10 pericardial effusions, and 1 sedative-induced respiratory acidosis. One death was reported, caused by delayed cardiac tamponade on the ward.

For this ablation target, 422 procedures were performed in 381 patients. This represents a fall of more than 100 procedures vs 2019, although the number of centers undertaking this type of ablation was largely unchanged (64 vs 66 in 2019). The mean number of procedures/center was 6.6 ± 5.1 (range, 1-22). Most procedures were performed with mapping systems (92%) and with irrigated tip ablation catheters (94.1% in total and 80% with contact forcesensing technology). An increase was seen in the number of zero-fluoroscopy procedures (5%). The overall success rate was 85.3%. Retroaortic access was used in 55.4% and transseptal in 49.8%. The combined endocardial/epicardial approach fell to 11.1%, whereas an exclusively epicardial approach was used in 2.1%.

The main strategy was ablation of the substrate (71.1%). The reported complication rate was 7.3% (similar to that of the previous year): 9 vascular, 7 pericardial effusions, 4 embolic phenomena, 2 atrioventricular blocks, and 1 death of a patient with refractory arrhythmic storm and cardiogenic shock.

This ablation target exhibited the lowest drop in the number of procedures, with a total of 247 in 231 patients (19 fewer than in 2019); there was also no change in the number of centers treating this target (n = 51). The mean number of procedures/center was 4.8 ± 4.4 (range, 1-28) and the success rate was 82.6%. This type of ablation was applied to the following ablation targets: nonischemic dilated cardiomyopathy (122 procedures; 84.4% success), arrhythmogenic cardiomyopathy (31 procedures; 81% success); congenital heart diseases (28 procedures; 100% success); hypertrophic cardiomyopathy (13 procedures; 84.6% success); bundle-branch VTs (9 procedures; 100% success); and 29 miscellaneous procedures, which included myocarditis, Chagas disease, valvular heart disease, Brugada syndrome, and noncompaction cardiomyopathy. Retroaortic access was used in 41.3% and transseptal in 31.6%. The exclusively epicardial approach was used in 11.7%, whereas the combined endocardial/epicardial approach was used in 18.6%. Twelve complications were reported (4.9%): 5 pericardial effusions, 2 atrioventricular blocks, 1 vascular, 1 phrenic nerve palsy, 1 pericarditis, and 2 deaths caused by cardiac perforations with tamponade.

In 2020, almost half of all procedures were performed with mapping system support (7408 procedures; 49%). These systems were most frequently used in VTs in structural heart disease (92%), followed by MAT and IVT (both, 82%). Nonetheless, compared with 2019, the ablation targets showing the greatest proportional increase were CTI (+11%), FAT (+8%), and AVNRT (+6%). In addition, and in line with the trends of previous years, the number of fluoroscopy-free procedures increased again, reaching 2146 (14%). The 3 ablation targets most commonly treated without fluoroscopy were CTI (25%), AVNRT (24%), and FAT (21%). Figure 7 illustrates the proportions of procedures for each ablation target that were conducted with a navigation system or without fluoroscopy.

Figure 7.

Percentage of procedures performed with a mapping system and without fluoroscopy in 2019 and 2020. AF, atrial fibrillation; AP, accessory pathway; AVN, atrioventricular node; AVNRT, atrioventricular nodal reentrant tachycardia; CTI, cavotricuspid isthmus; FAT, focal atrial tachycardia; IVT, idiopathic ventricular tachycardia; MAT, macroreentrant atrial tachycardia; VT-AMI, ventricular tachycardia associated with acute myocardial infarction; VT-NAMI, ventricular tachycardia not associated with acute myocardial infarction.

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In total, 243 ablations were reported in pediatric patients. This represents a slight increase in the percentage vs the total (1.6%), although the number fell in absolute terms (43 fewer than in 2019). In total, 37 centers reported ablation procedures in pediatric patients (2 fewer than in 2019). However, no center performed more than 50 procedures. One center undertook 44 procedures, whereas another 5 performed between 10 and 20.

APs continue to be the most frequently treated substrate (171 procedures; 70.4%), representing 11.1% of all AP ablations.

AVNRT was the second most frequently treated ablation target (47 procedures; 19.3%), followed by FAT (12 procedures; 4.9%), MAT (6 procedures; 2.5%), CTI (4 procedures; 1.7%), and VTI (3 procedures; 1.2%). Figure 8 shows the distribution by ablation target and as a percentage of the total number of procedures.

Figure 8.

Distribution of pediatric procedures by ablation target and as a proportion with respect to the total number of procedures. AP, accessory pathway; AVNRT, atrioventricular nodal reentrant tachycardia; CTI, cavotricuspid isthmus; FAT, focal atrial tachycardia; IVT, idiopathic ventricular tachycardia; MAT, macroreentrant atrial tachycardia.

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A total of 80 laboratories (82%) provided specific data on the effects of the pandemic on their clinical practice. In 2020, the laboratories were closed due to the pandemic for an average of 47 ± 33 days. In addition, 72 electrophysiologists (18%) had to self-isolate or were infected with SARS-CoV-2, and 111 SARS-CoV-2-infected patients underwent procedures. The most frequently applied changes to clinical practice included preadmission PCR tests, same-day discharge for simple procedures (in centers that did not do so already), the implementation of shift work, the dedication of a laboratory to SARS-CoV-2 patients in centers with more than 1 available laboratory, and same-day admission (12.5%) or discharge (9%) for complex procedures (only recorded for centers that did not do so before the pandemic). These last 2 measures were largely adopted by high-volume centers.