Table 1.
The clinical characteristics and summary of included studies
| First author | Country of origin | Year | Study type | Participant description | Exclusion criteria | Total population | Male (%) | Mean age (years) | fQRS definition | fQRS (n) | Mean duration of follow‐up (months) | Outcome definition | Conclusion by authors |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| de Asmundis et al. | Belgium | 2017 | Prospective cohort study | Spontaneous or drug induced type 1 Brugada pattern ECG | Underlying structural cardiac abnormalities | 289 | 70 | 45 ± 16 | Abnormal fragmentation within the QRS complex as≥4 spikes in I or ≥8spikes in V1, V2, and V3 | 50 | 121.2 ± 55.2 | VF or SCD | fQRS was associated with VF/SCD |
| Calò et al. | Italy | 2016 | Prospective cohort study | Spontaneous type 1 Brugada pattern ECG | History of VF or aborted SCD | 347 | 78.4 | 45 ± 13.1 | Fragmentation within the QRS complex, with ≥4 spikes in a single lead or ≥8 spikes in V1, V2, and V3 | 85 | 48 ± 38 | VF or SCD | fQRS was associated with VF/SCD |
| Conte et al. | Belgium | 2016 | Prospective cohort study | Spontaneous or drug induced type 1 Brugada pattern ECG who underwent ICD therapy | Underlying structural cardiac abnormalities | 176 | 67 | 40.7 ± 16.7 | Abnormal fragmentation within the QRS complex as ≥4 spikes in I or ≥8 spikes in V1, V2, and V3 | 29 | 95.2 ± 51.10 | Appropriate ICD shock to VF/sVT | fQRS was not associated with a higher rate of appropriate ICD shock |
| Maury et al. | France | 2013 | Retrospective cohort study | Spontaneous or drug induced type 1 Brugada pattern ECG | N/A | 325 | 79.4 | 47 ± 13 | Fragmented QRS in V1 to V3 | 8 | 48 ± 34 | SD | fQRS was associated with SDs |
| Morita et at. | Japan | 2017 | Retrospective cohort study | Spontaneous type 1 Brugada pattern ECG | Low quality of ECG recording and lack of ECG recording of V1 and V2 | 456 | 95 | 46.5 ± 14 | (1) ≥4 positive spikes in one of the leads V1 through V3 or (2) ≥8 positive spikes in all of V1, V2, and V3 | 229 | 89.5 ± 62.1 | VF | Patients with fQRS had a shorter time to arrhythmic events |
| Priori et al. | Italy | 2012 | Prospective cohort study | Patients ≥18 years old with spontaneous or drug induced type 1 Brugada pattern ECG who never had cardiac arrest and sVT | Structural cardiac abnormalities or cardiac diseases | 308 | 80 | 45 ± 12 | ≥ 2 spikes within the QRS complex in V1 to V3 | 25 | 36 ± 8 | VF or appropriate ICD | fQRS was associated with arrthymia events |
| Sakamoto et al. | Japan | 2015 | Case‐control study | Spontaneous or drug induced type 1 Brugada pattern ECG | Taking antiarrhythmic drugs, abnormality in either the right or left ventricular morphology and/or function | 129 | 94.6 | 52 ± 12 | (1) ≥4 positive spikes in one of the leads V1 through V3 or (2) ≥8 positive spikes in all of V1, V2, and V3 | 9 | 49.24 | VF | fQRS was not associated VF |
| Take et al. | Japan | 2012 | Retrospective cohort study | Spontaneous or drug induced type 1 Brugada pattern ECG with history of syncope | History of VF due to ischemic heart disease | 84 | 97.6 | 47 ± 12 | Fragmented QRS in V1 to V3 | 37 | 48 ± 48 | VF or appropriate ICD | fQRS was associated with the occurrence of VF |
| Tokioka et al. | Japan | 2014 | Retrospective cohort study | Spontaneous or drug induced type 1 Brugada pattern ECG | N/A | 246 | 95.9 | 47.6 ± 13.6 | Abnormal fragmentation within the QRS complex as ≥4 spikes in I or ≥8 spikes in V1, V2, and V3 | 78 | 45.1 ± 44.3 | VF or SCD | VF/SCD episodes were more frequently observed in patients with fQRS than in those without fQRS |
ECG, electrocardiogram; ERP, early repolarization pattern; fQRS, fragmented QRS; ICD, implantable cardioverter defibrillator; N/A, not applicable; SCD, sudden cardiac death; SD, sudden death; sVT, sustained ventricular tachycardia; VF, ventricular tachycardia.