Daily Cardiology Research Analysis
Three impactful cardiology studies stood out today: a randomized trial showed epicardial ablation markedly reduces ventricular fibrillation recurrences in high-risk Brugada syndrome; a large multicenter cohort demonstrated cardiovascular MRI phenotyping outperforms societal recommendations for predicting malignant arrhythmias in suspected cardiac sarcoidosis; and a proteomics-based risk score significantly improved atrial fibrillation prediction over clinical and genetic models.
Summary
Three impactful cardiology studies stood out today: a randomized trial showed epicardial ablation markedly reduces ventricular fibrillation recurrences in high-risk Brugada syndrome; a large multicenter cohort demonstrated cardiovascular MRI phenotyping outperforms societal recommendations for predicting malignant arrhythmias in suspected cardiac sarcoidosis; and a proteomics-based risk score significantly improved atrial fibrillation prediction over clinical and genetic models.
Research Themes
- Catheter ablation outcomes in inherited arrhythmia syndromes
- Imaging-based risk stratification for device therapy decisions
- Proteomics for cardiovascular risk prediction
Selected Articles
1. Epicardial ablation in high-risk Brugada syndrome to prevent ventricular fibrillation: results from a randomized clinical trial.
In a single-center randomized trial of 40 high-risk Brugada syndrome patients (all with ICDs), epicardial catheter ablation significantly increased freedom from ventricular fibrillation recurrence (96% vs 50%) over approximately 4 years, with one major procedural pericardial effusion. No arrhythmic deaths occurred.
Impact: This is the first randomized evidence supporting epicardial ablation to reduce VF recurrences in high-risk Brugada syndrome, moving beyond observational data.
Clinical Implications: For high-risk Brugada patients with prior cardiac arrest or appropriate ICD therapies, referral to experienced centers for epicardial substrate ablation should be considered to reduce VF recurrences and ICD shocks, with attention to pericardial complications.
Key Findings
- Freedom from VF recurrence was 96% after epicardial ablation vs 50% in controls (P<0.001).
- One pericardial effusion requiring pericardiocentesis occurred; no arrhythmic deaths were observed.
- Major ICD-related complications occurred in 33% across the cohort, underscoring the burden of device therapy.
Methodological Strengths
- Randomized controlled design with clinically meaningful primary endpoint (VF recurrence).
- Long mean follow-up (~4 years) capturing sustained effects.
Limitations
- Single-center, small sample size and 2:1 randomization may limit generalizability.
- Open-label design; potential selection and performance biases.
Future Directions: Multicenter randomized trials with larger samples should validate effectiveness, safety, and impact on hard outcomes (appropriate ICD therapies, hospitalizations) and identify optimal patient selection.
AIMS: Epicardial ablation for Brugada syndrome (BrS) has shown promise in reducing ventricular fibrillation (VF), but its role remains controversial due to the lack of randomized trials. This study evaluates the efficacy of catheter ablation in high-risk BrS patients. METHODS AND RESULTS: This prospective, single-centre, randomized (2:1) study enrolled BrS patients with cardiac arrest (CA) or appropriate ICD therapies. All patients had an ICD and were randomized to undergo epicardial ablation (ablation group) or no ablation (control group). Enrolment began in September 2017 and prematurely terminated in February 2024. The primary endpoint was freedom from VF recurrences. Secondary endpoints included procedure safety, ICD-related complications, and quality-of-life assessment. Forty patients (83% male, mean age 43.7 ± 12.1) were randomized: 26 in the ablation group and 14 in the control group. Thirty-six patients received appropriate ICD therapies before enrolment: 24 (92%) in the ablation group and 12 (86%) in the control group. One patient in the ablation group experienced a post-procedural pericardial effusion requiring pericardiocentesis. Thirteen patients (33%) had major ICD-related complications. After a mean follow-up of 4.0 ± 1.7 years, freedom from VF recurrence was 96% (25/26) in the ablation group and 50% (7/14) in the control group (P < 0.001). No unexplained or arrhythmic deaths occurred during follow-up. CONCLUSION: Epicardial catheter ablation was associated with a reduction in VF recurrence compared with ICD therapy alone. These findings support the use of epicardial ablation in high-risk BrS patients. CLINICALTRIALS.GOV: ID NCT03294278.
2. Prediction of ventricular arrhythmic outcomes in suspected cardiac sarcoidosis: a comparison of cardiovascular magnetic resonance phenotyping vs. societal recommendations for implantable cardioverter-defibrillator placement.
In 1,514 patients with suspected cardiac sarcoidosis, CMR phenotyping identified risk of fatal or life-threatening ventricular arrhythmias more accurately than societal ICD recommendations. High-risk phenotypes had 5-/10-year incidences of 24%/35%, whereas low-risk phenotypes had 0.7%/2.6%; discrimination by CMR was superior (AUC up to 0.861).
Impact: This large multicenter study demonstrates that CMR-based phenotyping can better stratify ventricular arrhythmic risk than current guideline frameworks, directly informing ICD decision-making.
Clinical Implications: In suspected cardiac sarcoidosis, integrating CMR phenotyping into risk assessment may refine primary prevention ICD selection beyond societal recommendations, potentially reducing both under- and over-implantation.
Key Findings
- CMR high-risk phenotype had 5- and 10-year ventricular arrhythmic incidences of 24.0% and 35.0%, respectively.
- Low-risk CMR phenotype had very low event rates (0.7% at 5 years; 2.6% at 10 years).
- CMR phenotyping outperformed societal recommendations with AUC 0.861 (5 years) and showed the highest adjusted subdistribution hazard ratio (19.8).
Methodological Strengths
- Large multicenter cohort with median 4.5-year follow-up (up to 10 years).
- Robust statistical analysis including discrimination metrics and competing risk modeling.
Limitations
- Observational design; potential residual confounding and referral bias.
- Heterogeneity in imaging protocols and clinical management across centers.
Future Directions: Prospective studies integrating CMR phenotyping into clinical pathways should test its impact on ICD implantation decisions, outcomes, and cost-effectiveness.
BACKGROUND AND AIMS: Implementing societal recommendations for primary prevention implantable cardioverter-defibrillators (ICDs) in cardiac sarcoidosis requires an accurate diagnosis. However, cardiac sarcoidosis diagnostic schemes are inconsistent and often produce conflicting results. This study aimed to compare the discriminative accuracy of cardiovascular magnetic resonance imaging (CMR) phenotyping with the societal recommendations for predicting long-term ventricular arrhythmic outcomes in patients with suspected cardiac sarcoidosis, regardless of their diagnostic status. METHODS: This multicentre study included patients with histology-supported sarcoidosis who underwent CMR for suspected cardiac involvement and were ineligible for secondary prevention ICDs. The study outcome was a composite of fatal or life-threatening ventricular arrhythmias. Outcomes were compared based on eligibility for ICDs by societal recommendations and CMR phenotyping. RESULTS: Among 1514 patients, 84 experienced the study outcome during a median follow-up of 4.5 years and a maximum follow-up of 10 years. The high-risk CMR phenotype was associated with higher 5- and 10-year incidences of the outcome (24.0% and 35.0%, respectively) compared with those who met societal recommendations. Patients with low-risk phenotypes had lower incidences (0.7% and 2.6%). Cardiovascular magnetic resonance imaging phenotyping outperformed societal recommendations in discriminative accuracy, with areas under the curve of 0.861 and 0.776 for 5- and 10-year outcomes, respectively. Additionally, CMR phenotyping had the highest adjusted subdistribution hazard ratio (19.8) for the study outcome. CONCLUSIONS: In patients with suspected cardiac sarcoidosis, CMR phenotyping showed greater discriminative accuracy than societal recommendations for predicting fatal or life-threatening ventricular arrhythmias, suggesting that it may be more effective at identifying candidates for primary prevention ICDs.
3. Proteomic Signatures for Risk Prediction of Atrial Fibrillation.
Using 51,680 participants with 1,459 plasma proteins, a 165-protein risk score improved AF prediction beyond CHARGE-AF, NT-proBNP, and polygenic risk, increasing the C-index from 0.771 to 0.816 and achieving a 5.4% net reclassification improvement at a 5-year 5% risk threshold. Findings replicated in ARIC.
Impact: This study establishes externally validated proteomic signatures that significantly enhance AF risk prediction, opening avenues for biomarker-guided screening and prevention.
Clinical Implications: If translated, proteomic risk scoring could identify individuals for intensified monitoring or preventive interventions beyond clinical and genetic risk, but implementation will require platform standardization and cost-effectiveness analyses.
Key Findings
- A 165-protein score (from 1,459 proteins) yielded HR 2.20 per 1-SD increase for incident AF in testing.
- Adding the protein score increased the C-index from 0.771 to 0.816 and improved net reclassification by 5.4%.
- External validation in ARIC confirmed improved AF risk stratification.
Methodological Strengths
- Very large cohort with internal training/testing split and external replication.
- Rigorous lasso-penalized Cox modeling combined with clinical, biomarker, and genetic risk.
Limitations
- Observational design; potential residual confounding and cohort-specific biases.
- Generalizability beyond UK/US cohorts and platform/batch effects require evaluation.
Future Directions: Prospective trials should test proteomic score-guided screening/prevention strategies and assess cost-effectiveness and health equity impacts.
BACKGROUND: Proteomic signatures might improve disease prediction and enable targeted disease prevention and management. We explored whether a protein risk score derived from large-scale proteomics data improves risk prediction of atrial fibrillation (AF). METHODS: A total of 51 680 individuals with 1459 unique plasma protein measurements and without a history of AF were included from the UKB-PPP (UK Biobank Pharma Proteomics Project). A protein risk score was developed with lasso-penalized Cox regression from a random subset of 70% (36 176 individuals, 54.4% women, 2155 events) and was tested on the remaining 30% (15 504 individuals, 54.4% women, 910 events). The protein risk score was externally replicated with the ARIC study (Atherosclerosis Risk in Communities; 11 012 individuals, 54.8% women, 1260 events). RESULTS: The protein risk score formula developed from the UKB-PPP derivation set was composed of 165 unique plasma proteins, and 15 of them were associated with atrial remodeling. In the UKB-PPP test set, a 1-SD increase in protein risk score was associated with a hazard ratio of 2.20 (95% CI, 2.05-2.41) for incident AF. The C index for a model including CHARGE-AF (Cohorts for Heart and Aging Research in Genomic Epidemiology Atrial Fibrillation), NT-proBNP (N-terminal B-type natriuretic peptide), polygenic risk score, and protein risk score was 0.816 (95% CI, 0.802-0.829) compared with 0.771 (95% CI, 0.755-0.787) for a model including CHARGE-AF, NT-proBNP, and polygenic risk score (C-index change, 0.044 [95% CI, 0.039-0.055]). Protein risk score added to CHARGE-AF, NT-proBNP, and polygenic risk score resulted in a risk reclassification of 5.4% (95% CI, 2.9%-7.9%) with a 5-year risk threshold of 5%. In the decision curve, the predicted net benefit before and after the addition of protein risk score to a model including CHARGE-AF, NT-proBNP, and polygenic risk score was 3.8 and 5.4 per 1000 people, respectively, at a 5-year risk threshold of 5%. External replication of a protein risk score in the ARIC study showed consistent improvement in risk stratification of AF. CONCLUSIONS: Protein risk score derived from a single plasma sample improved risk prediction of AF. Further research using proteomic signatures in AF screening and prevention is needed.