ThermoCool SmartTouch catheter for percutaneous radiofrequency ablation in atrial fibrillation

Study component

Description

Objectives/hypotheses

To compare the prevalence, characteristics and predictors of pulmonary vein reconnections (PVRs) and the clinical outcome between contact force (CF) guided and conventional circumferential pulmonary vein isolation (CPVI) of atrial fibrillation (AF).

Study design

Randomised controlled trial.

Randomisation was performed in a 1:1 fashion based on a computer generated list of random numbers, in permuted blocks of 4, according to the presence or absence of the CF information during ablation and the sequential order of the CPVI.

Setting

Single centre (Japan). Patients were enrolled from April 2013 to April 2014.

Inclusion/exclusion criteria

Inclusion criteria: consecutive patients scheduled to undergo an initial CPVI of symptomatic paroxysmal or persistent AF refractory to or intolerant of at least 1 antiarrhythmic drug, using a 3.5 mm tip externally irrigated ablation catheter equipped with a CF sensor (ThermoCool SmartTouch).

Exclusion criteria: age of less than 20 years or more than 80 years, long‑standing persistent AF with a duration of more than 1 year, left atrium (LA) diameter of greater than 55 mm in the parasternal long‑axis view on transthoracic echocardiography, substrate modification of the LA in addition to CPVI, and previous cardiac surgery.

Primary outcomes

PVRs

Procedural time

Mean CF

Predictors of PVRs

Arrhythmia‑free survival rate at 12 months

Statistical methods

Comparative analysis between the CF and blind groups was performed using Student's t test, Mann–Whitney's U test, or chi²‑test. The coefficient of variation was used to compare the variability in the distribution.

Patients included

120 patients enrolled were randomly assigned to undergo CF‑guided CPVI with target CF of 20 g (n=60), or CPVI with operators blinded to CF information (n=60).

Results

The CF group had fewer PVRs, a lower incidence of persistent PVRs, and a shorter procedural time for the CPVI than the blind group.

The mean CF was higher in the CF group than the blind group, with the most significant difference observed along the posterior right‑sided PVs and anterior left‑sided PVs.

In logistic regression models, the mean CF was a negative predictor of PVRs along the P‑RPVs and A‑LPVs in the blind group, while no significant predictor was identified in the CF group or elsewhere in the blind group.

The arrhythmia‑free survival rate at 12 months was lower in the blind group, however, was not significant.

Conclusions

The authors concluded that CF‑guided CPVI could reduce PVRs and the procedural time and could be particularly beneficial along regions where a relatively low CF tends to be applied: the P‑RPVs and A‑LPVs.

Abbreviations: A‑LPVs, anterior‑left pulmonary veins; AF, atrial fibrillation; CF, contact force; CPVI, circumferential pulmonary vein isolation; g, grams; LA; left atrium; n, number of patients; P‑RPV, posterior‑right pulmonary veins; PV, pulmonary vein; PVRs, pulmonary vein reconnections.

ThermoCool SmartTouch (CF) group

Blind (non‑CF) control group

Analysis

Randomised

n=60

n=60

–

Efficacy

n=60

n=60

–

Primary outcome:

Incidence of PVRs/patient (mean±SD)

0.67±0.91

1.16±1.16

p=0.007

Incidence of persistent PVRs

13.2%

41.2%

p<0.001

Selected secondary outcomes:

Procedural time (min; IQR)

50.0 (42.0–60.5)

56.0 (47.5–70.5)

p=0.019

Mean CF (g)

18.0

16.1

p<0.001

Arrhythmia survival rate at 12 months (%)

89.9

88.2

p=0.624

Safety

n=60

n=60

–

Patients reporting serious adverse events

5% (3/60)

1.6% (1/60)

p=0.309

Air embolism during procedure

1.6% (1/60)

–

–

Femoral arteriovenous fistula

1.6% (1/60)

–

–

Late cardiac tamponade

1.6% (1/60)

–

–

Femoral haematoma

–

1.6% (1/60)

–

Abbreviations: CF, contact force; g, grams; IQR, interquartile range; min, minutes; n, number of patients; PVRs, pulmonary vein reconnections; SD, standard deviation.

Study component

Description

Objectives/hypotheses

To compare procedure parameters and outcomes between contact force‑guided and non‑contact force‑guided circumferential pulmonary vein isolation (CPVI).

Study design

Randomised controlled trial.

Setting

Single centre (Japan). Dates of patient enrolment were not reported.

Inclusion/exclusion criteria

Inclusion criteria: consecutive patients undergoing CPVI for AF.

Exclusion criteria: not reported.

Primary outcomes

Contact force.

Procedure and fluoroscopy times.

Residual conduction gaps.

Freedom from any tachyarrhythmias at 6 months.

Statistical methods

Statistical analysis of the categorical variables in the 2 groups was made by Fisher's exact test or chi‑squared test. Statistical analysis of the continuous variables in the 2 groups was made by paired t test, analysis of variance, or Kruskal–Wallis test. All tests were 2‑tailed with p<0.05 considered significant.

Patients included

CPVI was conducted using ThermoCool SmartTouch catheter in all patients, however patients were randomly assigned to a contact force‑guided ablation group (CF information provided, n=19) or non‑contact force‑guided ablation group (CF information blinded, n=19).

Results

The mean±SD contact force observed in the contact force‑guided and non‑contact force‑guided groups were 11.1±4.3 g and 5.9±4.5 g respectively, for left side CPVI, and 12.1±4.8 g and 9.8±6.6 g respectively, for right side CPVI (both p<0.001).

The procedure time for CPVI in the contact force‑guided and non‑contact force‑guided groups were 59±16 min and 96±39 min, respectively (p<0.001).

The total number of residual connection gaps was 2.8±1.9 in the contact force‑guided group and 6.3±3.0 in the non‑contact force‑guided group (p<0.001).

At the 6 month follow‑up, 94.7% of patients in the contact force‑guided group and 84.2% in the non‑contact force‑guided group were free from any atrial tachyarrhythmias (p=0.34).

Conclusions

The authors concluded that the contact force‑guided CPVI was effective in reducing procedure time and additional touch‑up ablation. It may also improve long‑term outcomes, although further evidence is needed in this regard.

Abbreviations: AF, atrial fibrillation; CF, contact force; CPVI, circumferential pulmonary vein isolation; g, grams; min, minutes; n, number of patients; SD, standard deviation.

ThermoCool SmartTouch group

Non‑contact force control group

Analysis

Randomised

n=19

n=19

–

Efficacy

n=19

n=19

–

Primary outcome:

Contact force (g; mean±SD)

Left:

11.1±4.3

Left:

5.9±4.5

p<0.001

Right:

12.1±4.8

Right:

9.8±6.6

p<0.001

Selected secondary outcomes:

Procedure time (min; mean±SD)

59±16

96±39

p<0.001

Total number of residual conduction gaps (mean±SD)

2.8±1.9

6.3±3.0

p<0.001

Freedom from any atrial tachyarrhythmias at 6 months

94.7%

Paroxysmal only: 100%

84.2%

Paroxysmal only: 84.0%

p=0.34

p=0.11

Safety

n=19

n=19

–

Fluoroscopy time (s; mean±SD)

9±20

22±63

p=not significant

Major complications

None

None

–

Abbreviations: g, grams; min, minutes; n, number of patients; s, seconds; SD, standard deviation.

Study component

Description

Objectives/hypotheses

To determine if contact force sensing using the SmartTouch catheter with Advance Catheter Location (ACL) software reduces fluoroscopy times and radiation exposure during atrial fibrillation (AF) ablation when compared to procedures performed without them.

Study design

Retrospective cohort study.

Setting

Single high‑volume academic teaching hospital (UK).

AF ablations performed between 2009 and 2014 were included in study.

Inclusion/exclusion criteria

Inclusion criteria: patients with persistent or paroxysmal AF.

Exclusion criteria: not reported.

Primary outcomes

Total fluoroscopy time, radiation dose.

Secondary outcomes: procedure duration, total ablation time, cardiac complications.

Statistical methods

Comparisons between groups were performed with an unpaired Student's t‑test or, where normal distribution could not be assumed, the Mann–Whitney U test. Categorical variables were compared with a Chi²‑test.

A p value of <0.05 was considered statistically significant.

Patients included

n=510 SmartTouch group: AF ablations delivered via the unidirectional D or F curve ThermoCool SmartTouch catheter coupled with CARTO 3.1 software which includes additional ACL feature.

n=1,005 control group: AF ablations delivered via the ThermoCool and ThermoCool Celsius catheters coupled with CARTO‑XP and EnSite NavXsoftware.

Both paroxysmal and persistent AF was treated with wide area circumferential ablation with lesions placed 1–2 cm outside the pulmonary vein (PV) ostia. An additional strategy for persistent AF patients included the following: complex or fractionated electrograms targeted throughout the left and right atrium. If remained in AF linear lesions were added at the mitral isthmus and roof. If patients had a history of typical atrial flutter, a cavotricuspid isthmus line was added. If at any point AF developed into atrial tachycardia, this was mapped and ablated. If sinus rhythm was not restored following these lesions, electrical cardioversion was performed.

Results

The SmartTouch group had a significantly lower fluoroscopy time (9.5 vs. 41 min, p<0.001), radiation doses (1,044 vs. 3,571 mGy cm², p<0.001) and shorter procedural time (195 vs. 240 min p<0.001) when compared to the control group.

There was no difference in the rate of cardiac complications across groups.

Conclusions

SmartTouch CF‑sensing catheter use with ACL during AF ablation significantly reduces fluoroscopy times by 77%, radiation dose by 71% and procedural time by 19% but does not improve overall safety or the risk of cardiac complications.

Abbreviations: ACL, advanced catheter location; AF, atrial fibrillation; CF, contact force; cm, centimetres; mGy, milligrays; min, minutes; PV, pulmonary vein.

ThermoCool SmartTouch Group

Non‑contact force control group

Analysis

Randomised

n/a

n/a

–

Efficacy

n/a

n/a

–

Safety

n=510

n=1,005

–

Primary outcome:

Median fluoroscopy time

(min; IQR)

All patients:

9.5 (9.8)

All patients:

41 (28.8)

p<0.0001

Subgroup analysis – Paroxysmal AF subgroup: 8 (6.5)

Subgroup analysis – Paroxysmal AF subgroup: 33 (113)

p<0.0001

Persistent AF subgroup: 10.5 (11.3)

Persistent AF subgroup: 47.5 (33.0)

p<0.0001

No statistical difference in fluoroscopy times or radiation dose was observed for de novo vs. redo ablation procedures in paroxysmal AF (p=0.22) or persistent AF (p=0.50) patients.

Median radiation dose

(mGy cm²; IQR)

All patients:

1043.5 (1050)

All patients:

3571 (4527)

p<0.0001

Subgroup analysis –

Paroxysmal AF subgroup:

923 (976)

Subgroup analysis – Paroxysmal AF subgroup:

2467 (2791)

p<0.0001

Persistent AF subgroup: 1037.5 (2594.4)

Persistent AF subgroup: 2501.5 (2451.0)

p<0.0001

Median total procedure time

(min; IQR)

All patients:

195 (60)

All patients:

240 (130)

p<0.0001

Subgroup analysis – Paroxysmal AF subgroup: 200 (95)

Subgroup analysis – Paroxysmal AF subgroup: 240 (130)

p<0.0001

Persistent AF subgroup: 238 (67.5)

Persistent AF subgroup: 288 (135)

p<0.0001

Median total ablation time (min; IQR)

All patients:

51.5 (46.0)

All patients:

42 (48.8)

p=0.802

Subgroup analysis – Paroxysmal AF subgroup: 43 (40)

Subgroup analysis – Paroxysmal AF subgroup: 35 (45)

p=0.685

Persistent AF subgroup:58 (58)

Persistent AF subgroup: 55.4 (58.3)

p=0.701

Cardiac complications

Pericardial effusion: 0.98%^a (5/510)

Pericardial effusion: 1.49%^a

(15/1005)

No statistical comparison reported

Cardiac tamponade: 0.78% (4/510)

Cardiac tamponade: 0.99% (10/1005)

Abbreviations: AF, atrial fibrillation; CF, contact force; cm, centimetres; IQR, interquartile range; mGy, milligray; min, minutes.

^aCalculated by the external assessment centre, not explicitly reported in study.

Study component

Description

Objectives/hypotheses

To determine if the use of a contact force sensing catheter is associated with lower fluoroscopy times and improved freedom from arrhythmia in the medium‑term following first time paroxysmal and non‑paroxysmal atrial fibrillation (AF) ablation.

Study design

Retrospective cohort study.

Patients having ablation procedures between 2010 and 2012 were included in the study.

Setting

Four high‑volume hospitals (UK).

Inclusion/exclusion criteria

Inclusion criteria: patients undergoing first time radiofrequency AF ablation using 3.5 mm tipped open‑irrigated catheters who had never previously undergone any left atrial ablation, and who completed at least 6 months follow‑up.

Exclusion criteria: none reported

Primary outcomes

Freedom from AF. AF defined as any ≥30 s period of atrial tachyarrhythmia (fibrillation, flutter or tachycardia) by symptoms and all electrocardiogram (ECG) recordings, at all follow‑ups after a 3‑month blanking period.

Secondary outcomes: procedural fluoroscopy time, procedural complications. Complications were predefined as: death during admission or directly related to procedure, atrioesophageal fistula, sternotomy, pericardial drainage, PV stenosis, phrenic palsy, stroke, transient ischemic attack, atrioventricular block requiring permanent pacing, and femoral complication defined as significant by detection of atriovenous fistula or pseudoaneurysm, or requirement for intervention, blood transfusion, or readmission.

Statistical methods

Differences between populations were evaluated with Pearson's Chi²‑test. For categorical data, Mann–Whitney U test where ordinal with >2 categories, and Student's t‑test for continuous data. Univariate relationship to outcome were evaluated within Pearson's Chi²‑test or Fisher's exact test for categorical data, Mantel–Haenszel test of trend where ordinal with >2 categories, and Student's t‑test for continuous data. Tests were performed 2‑tailed with p<0.05 considered statistically significant.

As well as the use of a contact force sensing catheter, 19 possible explanatory variables were assessed as potential predictors of outcome.

For the primary outcome, possible univariate explanatory variables were entered into multivariate stepwise binary logistic regression analyses in order of univariate significance, with primary outcome the dependent variable. Variables with p<0.05 in the presence of other selected variables were retained in the final model, and the c‑statistic calculated.

For the secondary outcome, non‑categorical possible univariate explanatory variables were entered into a multiple regression analysis in order of univariate significance, with secondary outcome the dependent variable. Variables with p<0.05 in the presence of other selected variables were retained in the final model, and the r² calculated.

Patients included

Patients were selected by case‑matching within each of the 3 AF types (paroxysmal, persistent, long‑lasting persistent). Cases used the ThermoCool SmartTouch catheter and were matched 1:2 ratio to controls utilising a non‑contact force‑sensing catheter (undefined). In the control group, surround flow catheter technology was used in a minority of procedures, 9.8% (39/400) by a single operator.

CF group: n=200 (including 92 paroxysmal and 108 non‑paroxysmal AF).

Non‑CF group: n=400 (including 184 paroxysmal and 216 non‑paroxysmal AF).

Results

The use of a contact force‑sensing catheter independently predicted clinical success in ablation for paroxysmal AF (HR 2.24 [95% CI: 1.29 to 3.90], p=0.004) but not non‑paroxysmal AF (HR 0.73 [0.41 to 1.30], p=0.289) in multivariate analysis.

Among all cases, the use of contact force‑sensing catheters was associated with reduced fluoroscopy time in multivariate analysis (reduction by 7.7 [5.0 to 10.5] min, p<0.001).

Complication rates were similar in both groups.

Conclusions

At medium‑term follow‑up, contact force‑sensing catheter technology is associated with significantly improved outcomes for first‑time catheter ablation of paroxysmal AF, but not non‑paroxysmal AF. Fluoroscopy time was lower when contact force‑sensing technology was employed in all types of AF ablation procedures.

Abbreviations: AF, atrial fibrillation; CF, contact force; CI, confidence interval; ECG, electrocardiogram; HR, hazard ratio; min, minutes; s, seconds.

ThermoCool SmartTouch group

Non‑contact force control group

Analysis

Randomised

n/a

n/a

–

Efficacy

n=200

n=400

–

Primary outcome: Procedural success

Paroxysmal: 59% (54/92)

Paroxysmal: 46% (85/184)

p=0.05

Non‑paroxysmal: 43% (46/108)

Non‑paroxysmal: 43% (92/216)

p=1.00

The use of a contact force sensing catheter independently predicted clinical success in ablation for paroxysmal AF (HR 2.24 [95% CI: 1.29 to 3.90], p=0.004) but not non‑paroxysmal AF (HR 0.73 [95% CI: 0.41 to 1.30], p=0.289) in multivariate analysis.

Safety

n=200

n=400

–

Fluoroscopy time (min; mean±SD)

26.6±15.1

34.7±18.7

p<0.0001

Among all cases, the use of contact sensing catheters was associated with reduced fluoroscopy time in multivariate analysis (reduction by 7.7 [95% CI: 5.0 to 10.5] min, p<0.001).

Complications

Overall complications: 3.5% (7/200)

Overall complications: 17 (4.25%)

p=0.163

Complication related to ablation: 1% (2/200)

Complication related to ablation: 2.25% (9/400)

p=0.158

Pericardial drains: 1.0%^a (2/200)

Pericardial drains: 1.25%^a (5/400)

Femoral complications: 2.0%^a (4^a/200)

Femoral complications: 1.75%^a (7/400)

Transient ischemic attack: 0.50%^a (1/200)

Atrioesophageal fistula leading to death: 0.25%^a (1/400)

Stroke: 0.25%^a (1/400)

Pulmonary vein stenosis: 0.25%^a (1/400)

Phrenic palsies: 0.50%^a (2/400)

Abbreviations: min, minutes; n, number of patients.

^aCalculated by EAC, not explicitly reported in study.

Pulmonary vein isolation using "contact force" ablation: The effect on dormant conduction and long‑term freedom from recurrent atrial fibrillation – A prospective study (Andrade et al. 2014)

ThermoCool SmartTouch ablation

Non‑contact force guided ablation

Analysis

Design

Prospective non‑randomised controlled study.

The purpose was to study the utility of CF‑guided ablation using the ThermoCool SmartTouch catheter on immediate and long‑term outcomes, when compared to non‑CF‑guided ablation using the standard ThermoCool catheter.

Efficacy

n=25

n=50

–

Primary outcome:

Dormant conduction

Patients: 4 (16%)

Patients: 26 (52%)

p=0.0029

Pulmonary vein pairs: 4 (8%)

Pulmonary vein pairs: 35 (35%)

p=0.0004

Selected secondary outcomes:

Procedural time

(min; mean±SD)

235.4±89.9

179.1±59.1

p=0.0038

Ablation time (min; mean±SD)

58.8±22.1

56.4±24.0

p=0.5857

Freedom from recurrent atrial arrhythmias at 1 year

88%

66%

log rank p=0.047

Safety

n=25

n=50

–

Fluoroscopy time

(min; mean±SD)

71.9±19.1

36.5±18.6

p=0.0001

Patients reporting serious adverse events

Not reported

Not reported

Complications included^a:

Tamponade requiring drainage: 1

Groin hematomas: 2

Cerebral thromboembolic event with full recovery: 1

Atrioventricular fistula requiring surgical repair: 1

^a complications were not attributed to 1 or the other intervention groups.

Reduced residual conduction gaps and favourable outcome in contact force‑guided circumferential pulmonary vein isolation (Itoh et al. 2015)

ThermoCool SmartTouch ablation

Non‑contact force guided ablation

Analysis

Design

Prospective non‑randomised controlled study.

The study assessed the safety and efficacy of CF‑guided CPVI and compared the residual conduction gaps and long‑term outcomes in patients undergoing CPVI by the ThermoCool SmartTouch catheter and EZ Steer ThermoCool catheter.

Efficacy

n=50

n=50

Primary outcome:

Total number of residual gaps (mean±SD)

2.7±1.7

6.3±2.7

p<0.05

Selected secondary outcomes:

–

–

–

Procedural time

(min; mean± SD)

160±30

245±61

p<0.001

Freedom from any atrial tachycardia (including AF recurrence) at 12 months

94% (47/50)

78% (39/50)

Log rank p=0.02

Freedom of AF recurrence at 12 month

96% (48/50)

82% (41/50)

Log rank p=0.02

Safety

n=50

n=50

–

Fluoroscopy time

(min; mean±SD)

17±8

54±27

p<0.001

Complications

None reported

None reported

–

Comparison of contact force‑guided procedure with non‑contact force‑guided procedure during left atrial mapping and pulmonary vein isolation: impact of contact force on recurrence of atrial fibrillation (Makimoto et al. 2015)

ThermoCool SmartTouch ablation

Non‑contact force guided ablation

Analysis

Design

Prospective non‑randomised controlled study

The aim of the study was to evaluate the impact of contact force visualisation on the incidence of low and high CF during left atrial mapping and pulmonary vein isolation.

Efficacy

n=35

n=35

–

Primary outcome:

Contact force (% at each force category)

Low (<10 g): 13%

Low (<10 g): 38%

p<0.001

High (≥40 g): 1.5%

Excessive high (>100 g): none

High (≥40 g): 11%

Excessive high (>100 g): 0.5%

p<0.0001

Recurrence of AF or atrial tachycardia

9 patients

12 patients

p value: NS

Selected secondary outcomes:

Total procedural time

(min; mean±SD)

133±42

152±33

p=0.04

Ablation time

(min; mean±SD)

Right PV:

819±150

Right PV:

824±268

p=0.92

Left PV:

786±213

Left PV:

794±255

p=0.88

Safety

n=35

n=35

–

Total fluoroscopy time

(min; mean±SD)

13.5±6.6

15.7±6.5

p=0.16

Total fluoroscopy dose

(cGy; mean±SD)

2047±973

2281±1229

p=0.38

Complications

None reported

None reported

–

Real‑time contact force sensing for pulmonary vein isolation in the setting of paroxysmal atrial fibrillation: procedural and 1‑year results (Marijon et al. 2014)

ThermoCool SmartTouch ablation

Non‑contact force guided ablation

Analysis

Design

Prospective single‑centre non‑randomised controlled study

The study aimed to establish whether continuous CF monitoring during PVI using the ThermoCool SmartTouch catheter could be associated with lower rate of AF recurrence and better maintenance of sinus rhythm, when compared with a conventional ablation catheter (EZ Steer ThermoCool).

Efficacy

n=30

n=30

Primary outcome:

Procedural PVI success

80% (25/30)

37% (11/30)

p<0.0001

Acute PV reconnection (within 20 min)

10.0%

16.7%

–

Selected secondary outcomes:

RF ablation time

(min; mean±SD)

45.2±18.0

65.4±22.0

p=0.01

AF recurrence at 12 months

(95% CI)

10.5% (1.38 to 22.4)

35.9% (12.4 to 59.4)

Log rank p=0.04

Safety

n=30

n=30

–

Fluoroscopy time

(min; mean±SD)

20.1±4

26.7±5

p<0.01

Total radiation dose

(Gy∙cm²; mean±SD)

41.6±10

56.7±14

p=0.02

Immediate procedural complications

Local hematoma: 1

Pericardial effusions: 2

Local hematoma: 1

Arteriovenous fistula: 1

Pericardial effusions: 1

–

Clinical impact of an open‑irrigated radiofrequency catheter with direct force measurement on atrial fibrillation ablation (Martinek et al. 2012)

ThermoCool SmartTouch ablation

Non‑contact force guided ablation

Analysis

Design

Prospective non‑randomised controlled study

The study aimed to assess the impact of direct catheter force measurements on acute procedural parameters during RFCA using either a standard catheter (Navistar ThermoCool) or a CF‑guided catheter (ThermoCool SmartTouch).

Efficacy

n=25

n=25

Primary outcome:

Acute pulmonary vein reconnection

12% (3/25)

36% (9/25)

p=0.095

Selected secondary outcomes:

RF ablation time

(min; mean±SD)

39.0±11.0

50.5±15.9

p=0.007

Procedure time

(min; mean±SD)

154±39

185±46

p=0.022

Total energy delivered (W; mean±SD)

58,510±14,655

70,926±19,470

p=0.019

Safety

n=25

n=25

–

Complications

AV fistula: 1

Pericardial tamponade: 1

AV fistula: 1

Pseudo‑aneurysm: 1

Minimal pericardial effusion: 1

–

Fluoroscopy time

(min; mean±SD)

23.6±13.1

28.6±17.4

p=0.312

Which is the best catheter to perform atrial fibrillation ablation? A comparison between standard ThermoCool, SmartTouch, and Surround Flow catheters (Sciarra et al. 2014)

Design

Prospective non‑randomised controlled trial

The aim of this study was to analyse the impact of the SmartTouch and Surround Flow catheters on catheter ablation of paroxysmal AF in terms of feasibility and acute efficacy when compared to the conventional ThermoCool catheter.

ThermoCool SmartTouch (STc)

ThermoCool SF (SFc)

Conventional ThermoCool catheter (TCc)

Analysis

Efficacy

n=21

n=21

n=21

–

Primary outcome:

Isolated PVs

83 (98%)^a

80 (96%) ^a

81 (96%) ^a

p=NS

PVs isolated at 30 min after procedure

95%

95%

89%

p=0.05

AF recurrence

5 (23.8%)

5 (23.8%)

7 (33.3%)

–

Selected secondary outcomes:

RF ablation time(min; mean±SD)

30±14

30±9

41±13

STc vs. TCc p=0.013

SFc vs. TCc p<0.01

STc vs. SFc p=NS

Total procedure time

(min; mean±SD)

140±53

170±51

181±53

STc vs. TCc p<0.001

SFc vs. TCc p=NS

STc vs. SFc p<0.001

Safety

n=21

n=21

n=21

–

Fluoroscopy time

(min; mean±SD)

20±10

21±13

34±18

STc vs. TCc p<0.001

SFc vs. TCc p=0.02

STc vs. SFc p=NS

Complications

None

Mild groin haematoma: 1

None

–

Abbreviations: AF, atrial fibrillation; CF, contact force; CI, confidence interval; cm, centimetres; CPVI, circumferential pulmonary vein isolation; g, grams; Gy, grays; min, minutes; n, number of patients; NS, not significant; PV, pulmonary veins; RF, radiofrequency; RFCA, radiofrequency cardiac ablation; SD, standard deviation; SFc, SmartTouch SF catheter; STc, SmartTouch catheter; TCc, ThermoCool catheter; W, watts.

^a Percentages calculated by EAC as 98.8%, 95.2% and 96.4% for the STc, SFc and TCc groups respectively.