Daily Cardiology Research Analysis
Three impactful cardiology studies stand out today: a randomized trial shows conduction system pacing better preserves left ventricular ejection fraction than right ventricular pacing; an individual patient data analysis links longitudinal blood pressure to outcomes across heart failure phenotypes in a non-linear, EF-specific manner; and a prospective study suggests upgrading pacing-induced cardiomyopathy patients to left bundle branch area pacing yields greater LVEF improvement than biventricul
Summary
Three impactful cardiology studies stand out today: a randomized trial shows conduction system pacing better preserves left ventricular ejection fraction than right ventricular pacing; an individual patient data analysis links longitudinal blood pressure to outcomes across heart failure phenotypes in a non-linear, EF-specific manner; and a prospective study suggests upgrading pacing-induced cardiomyopathy patients to left bundle branch area pacing yields greater LVEF improvement than biventricular pacing.
Research Themes
- Conduction system pacing to preserve ventricular function
- Blood pressure targets across heart failure phenotypes
- Upgrading pacing strategy in pacing-induced cardiomyopathy
Selected Articles
1. Prospective randomized trial of conduction system pacing vs right ventricular pacing for patients with atrioventricular block; Prague CSP trial.
In a 249-patient randomized trial of atrioventricular block, conduction system pacing preserved LVEF better than right ventricular pacing (−2% vs −4%) and reduced the frequency of ≥10% LVEF decline, with no difference in 1-year composite clinical events. CSP required longer procedural and fluoroscopy times but had similar complication rates.
Impact: This pragmatic RCT provides high-quality evidence that CSP better preserves ventricular function than RVP, informing pacing strategy selection for patients with atrioventricular block.
Clinical Implications: For patients with AV conduction disease requiring pacing, consider CSP (His bundle or left bundle branch area pacing) to minimize LVEF decline, while counseling on slightly longer procedure times.
Key Findings
- CSP led to a smaller LVEF decline versus RVP at 12 months (−2% vs −4%, P=0.03).
- LVEF decrease ≥10% occurred more often with RVP than CSP (16% vs 5%, P=0.01).
- No significant difference in composite clinical outcomes (CV death, CRT upgrade, HF hospitalization) at 1 year.
- CSP had longer procedural and fluoroscopy times; complication rates were similar.
Methodological Strengths
- Randomized, intention-to-treat design with balanced baseline characteristics.
- Clinically meaningful endpoints including LVEF change and composite clinical events.
Limitations
- Modest sample size and 12-month follow-up limit power to detect differences in hard outcomes.
- Heterogeneity within CSP techniques (His bundle, left bundle branch area, deep septal pacing) may dilute specific effects.
Future Directions: Larger, longer RCTs comparing CSP modalities with RVP and CRT on clinical outcomes (HF hospitalization, mortality), remodeling, and cost-effectiveness are warranted.
BACKGROUND: Conduction system pacing (CSP) replaces right ventricular pacing (RVP) in bradycardia patients. OBJECTIVE: To compare CSP vs RVP in patients with pacemaker indication due to atrioventricular conduction disease. METHODS: This study randomized patients to CSP or RVP in 1:1 ratio and followed them for 12 months. CSP received either His bundle pacing or left bundle branch area pacing; The primary end point was a change in the left ventricular ejection fraction (LVEF). The combined composite clinical end point consisted of cardiovascular death, cardiac resynchronization therapy upgrade, or hospitalization for heart failure. RESULTS: Of 249 patients, 125 were randomized to RVP and 124 to CSP; there were no differences between clinical parameters. In CSP, 10 patients received His bundle pacing, 96 left bundle branch area pacing, 15 deep septal pacing, and 3 RVP. Procedural and fluoroscopy times were longer in CSP vs RVP (63 vs 40 and 7 vs 3 minutes; P < .001). In the intention-to-treat analysis, the LVEF decline in CSP was smaller than RVP (-2% vs -4%, P = .03), and a LVEF decrease ≥ 10% occurred more often in RVP 19 (16%) than CSP 6 (5%), P = .01. There was no difference in the composite clinical outcome between RVP and CSP (9 vs 4, P = .15). There was also no difference in procedural complications (9 in RVP vs 2 in CSP, P = .09). CONCLUSION: In patients with severe conduction disease, CSP led to a smaller LVEF decline than RVP after 1 year of pacing. Both pacing methods had similar rates of clinical end points and procedural complications.
2. Longitudinal blood pressure and cardiovascular outcomes in heart failure: An individual patient data pooling analysis of clinical trials.
Across 28,406 trial participants with HF, longitudinal BP exhibited EF-specific non-linear risk patterns: J-shaped in HFrEF (low SBP harmful, high SBP neutral) and U-shaped in HFmrEF/HFpEF (both low and high SBP harmful). Low SBP consistently portended worse outcomes.
Impact: This large IPD analysis refines BP targets in HF by EF phenotype, challenging one-size-fits-all BP strategies and informing individualized blood pressure management.
Clinical Implications: Avoid excessive BP lowering in HFrEF and recognize that both hypotension and uncontrolled hypertension carry risk in HFmrEF/HFpEF; time-updated BP monitoring should guide individualized targets.
Key Findings
- In HFrEF, low SBP increased composite risk (HR 1.71), while high SBP did not significantly change risk.
- In HFmrEF/HFpEF, both low SBP (HR 1.74) and high SBP (HR 1.77) increased risk, indicating a U-shaped association.
- Time-dependent BP modeling across eight trials supports EF-specific, non-linear BP-risk relationships.
Methodological Strengths
- Large individual patient data set (n=28,406) from eight trials with time-updated BP analyses.
- Multivariable Cox models and EF-stratified evaluation enhance clinical interpretability.
Limitations
- Post hoc pooling across heterogeneous trials may introduce residual confounding.
- BP categorized by tertiles may not directly translate to clinical thresholds.
Future Directions: Prospective studies to test EF-tailored BP targets and evaluate outcome effects of individualized BP management strategies.
AIMS: Previous analyses of the relationship between blood pressure (BP) and heart failure (HF) outcomes have primarily used baseline values rather than longitudinal measurements. We aimed to elucidate associations between longitudinal BP and clinical outcomes in patients with HF with reduced ejection fraction (HFrEF), mildly reduced ejection fraction (HFmrEF), and preserved ejection fraction (HFpEF). METHODS AND RESULTS: We conducted a comprehensive analysis of 28 406 patients from eight trials, evaluating time-dependent BP categorized by tertiles and per 10 mmHg increments in BP on outcomes. The primary endpoint was the time to the first occurrence of a composite endpoint comprising cardiovascular death or HF hospitalization. Multivariate Cox regression analysis revealed a J-shaped relationship between BP and the composite outcome in HFrEF. Specifically, compared with the middle-level systolic BP (SBP), low SBP was associated with a higher risk of the composite endpoint (hazard ratio [HR] 1.71, 95% confidence interval [CI] 1.60-1.82; p < 0.001) and high SBP showed a non-significant change in risk (HR 1.07, 95% CI 0.97-1.18; p = 0.187). Conversely, a U-shaped relationship was observed in HFmrEF and HFpEF. Low SBP was linked to a higher risk of the composite endpoint (HR 1.74, 95% CI 1.47-2.07; p < 0.001), and high SBP similarly increased the risk (HR 1.77, 95% CI 1.45-2.17; p < 0.001). CONCLUSIONS: The relationship between BP and HF outcomes is non-linear and closely tied to left ventricular ejection fraction. Low SBP consistently predicts a poor prognosis, whereas high SBP is associated with an increased risk in HFmrEF and HFpEF but not in HFrEF.
3. Effectiveness of upgrading to left bundle branch area pacing compared with biventricular pacing in patients with right ventricular pacing-induced cardiomyopathy.
In a prospective two-center cohort of 78 PICM patients, upgrading to LBBAP resulted in greater 6-month LVEF improvement than BiVP, especially with true LBBP, while longer-term clinical events were similar after adjustment.
Impact: Addresses a pressing clinical question on optimal upgrade strategy for PICM and supports physiologic pacing as a compelling alternative to CRT in selected patients.
Clinical Implications: Consider LBBAP—preferably LBBP—when upgrading PICM patients to maximize LVEF recovery, while recognizing that hard clinical outcomes may be similar to BiVP over ~2 years.
Key Findings
- LVEF improvement at 6 months was greater with LBBAP versus BiVP (9.59% vs 4.91%; P=0.008).
- Within LBBAP, LBBP outperformed LVSP for LVEF gain (10.62% vs 6.47%).
- Adjusted clinical outcomes over a mean 20.5 months were similar between LBBAP and BiVP.
Methodological Strengths
- Prospective, two-center enrollment with predefined echocardiographic endpoints.
- Adjusted analyses for confounders and comparison of LBBP vs LVSP subtypes.
Limitations
- Nonrandomized design with potential selection bias and residual confounding.
- Modest sample size limits power for clinical outcomes.
Future Directions: Randomized trials comparing LBBAP and BiVP in PICM with longer follow-up to assess remodeling, arrhythmic risk, and patient-reported outcomes.
BACKGROUND: Pacing-induced cardiomyopathy (PICM) occurs in some patients requiring a high burden of right ventricular pacing (RVP). Whether left bundle branch area pacing (LBBAP) might be superior to biventricular pacing delivering cardiac resynchronization therapy remains unclear. OBJECTIVE: The present study aimed to evaluate the effectiveness of LBBAP compared with BiVP in patients with PICM. METHODS: This prospective, 2-center observational study enrolled consecutive patients with PICM who underwent upgrading to either LBBAP or BiVP. LBBAP was further classified into left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP). The primary end point was the change in left ventricular ejection fraction (LVEF) from baseline to 6-month follow-up. Other echocardiographic parameters, N-terminal pro-B-type natriuretic peptide levels, New York Heart Association functional class, and clinical events (all-cause mortality, heart failure hospitalization, and malignant ventricular arrhythmias) were evaluated during follow-up. RESULTS: In total, 78 patients were included in the final analysis (33% patients with LVEF < 35%), including 40 patients with LBBAP (30 with LBBP and 10 with LVSP) and 38 patients with BiVP. At the 6-month follow-up, LVEF improvement was significantly greater in patients with LBBAP than those with BiVP (9.59 ± 7.48% vs 4.91 ± 7.73%; P = .008), and higher in LBBP than LVSP (10.62 ± 7.28% vs 6.47 ± 7.57). During a mean follow-up duration of 20.5 ± 12.5 months, clinical outcomes did not differ between BiVP and LBBAP groups (26.3% vs 17.5%; adjusted hazard ratio = 1.57 [0.55-4.48], P = .395) after adjustment for confounders. CONCLUSIONS: PICM upgrading to LBBAP or BiVP demonstrated similar clinical outcomes, but upgrading to LBBAP was associated with greater improvement in LVEF.