TABLE 4.
Summary of findings.
| Outcomes effect measure follow-up |
Number of participants (studies) | Certainty of the evidence (GRADE) | Relative effect (95% CI) | Anticipated absolute effects |
|
| Risk with deferred ablation or no ablation | Risk difference with early ablation* | ||||
| Any appropriate ICD therapy–assessed with: odds ratio Follow-up: mean 23.4 months |
770 (6 RCTs) |
⊕⊕⊕○ Moderatea |
OR 0.53 (0.33 to 0.83) |
440 per 1,000 | 146 fewer per 1,000 (234 fewer to 45 fewer) |
| Appropriate ICD shocks–assessed with: odds ratio Follow-up: mean 24.2 months |
1,076 (8 RCTs) |
⊕⊕⊕○ Moderatea |
OR 0.52 (0.35 to 0.77) |
313 per 1,000 | 121 fewer per 1,000 (175 fewer to 53 fewer) |
| All-cause mortality–assessed with: odds ratio Follow-up: mean 24.2 months |
1,076 (8 RCTs) |
⊕⊕⊕○ Moderateb |
OR 0.91 (0.58 to 1.45) |
145 per 1,000 | 11 fewer per 1,000 (56 fewer to 52 more) |
| VT storm–assessed with: odds ratio Follow-up: mean 24.7 months |
796 (6 RCTs) |
⊕⊕⊕⊕ High |
OR 0.58 (0.39 to 0.85) |
213 per 1,000 | 77 fewer per 1,000 (117 fewer to 26 fewer) |
| CV mortality–assessed with: odds ratio Follow-up: mean 24.2 months |
1,076 (8 RCTs) |
⊕⊕⊕○ Moderateb |
OR 0.78 (0.49 to 1.22) |
94 per 1,000 | 19 fewer per 1,000 (46 fewer to 18 more) |
| CV hospitalizations–assessed with: odds ratio Follow-up: mean 24.3 months |
948 (7 RCTs) |
⊕⊕○○ Lowb |
OR 0.67 (0.49 to 0.92) |
356 per 1,000 | 86 fewer per 1,000 (143 fewer to 19 fewer) |
| Complications–assessed with: odds ratio Follow-up: mean 24.2 months |
1,076 (8 RCTs) |
⊕○○○ Very lowc |
OR 1.00 (0.44 to 2.26) |
158 per 1,000 | 0 fewer per 1,000 (80 fewer to 149 more) |
| QoL physical component–assessed with: mean difference Scale from: 0 to 100 Follow-up: mean 20 months |
198 (3 RCTs) |
⊕○○○ Very lowb,d,e |
– | The mean QoL physical component was 0 | MD 1.02 lower (3.6 lower to 1.56 higher) |
| QoL mental component–assessed with: mean difference Scale from: 0 to 100 Follow-up: mean 20 months |
198 (3 RCTs) |
⊕○○○ Very lowb,d,e |
– | The mean QoL mental component was 0 | MD 0.31 higher (2.43 lower to 3.04 higher) |
GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI, confidence interval; CV, cardiovascular; MD, mean difference; OR, odds ratio; ICD, implantable cardioverter-defibrillator; QoL, quality of life; VT, ventricular tachycardia.
Explanations:
aICD therapies as a possible surrogate measure of clinically relevant VT/FT.
bAlthough studies were conducted within a timespan of 15 years, three of them were conducted during the last 6 years and this outcome could have been modified by modern drug therapies.
cIn most studies ablation and ICD implantation were done within a narrow time window and it could be difficult to assign a potential complication to a single procedure. In the two studies comparing ablation to antiarrhythmic drugs, serious adverse events were significantly more frequent in the drug treatment arm.
dThe results were derived from approximately 48% of the pooled patient population of the three studies reporting QoL outcomes.
eHigh risk of attrition bias and high risk of bias in the measurement of the QoL outcomes for all three studies.