Daily Cardiology Research Analysis
A randomized trial shows left bundle branch area pacing is non-inferior to biventricular pacing for cardiac resynchronization, potentially reshaping device strategy. A prospective, protocolized investigation identifies pulmonary and cardiac causes as dominant etiologies of in-hospital cardiac arrest and exposes low agreement with presumed causes. Stress CMR robustly predicts major adverse events in diabetics and non-diabetics alike, supporting broader risk stratification beyond symptoms.
Summary
A randomized trial shows left bundle branch area pacing is non-inferior to biventricular pacing for cardiac resynchronization, potentially reshaping device strategy. A prospective, protocolized investigation identifies pulmonary and cardiac causes as dominant etiologies of in-hospital cardiac arrest and exposes low agreement with presumed causes. Stress CMR robustly predicts major adverse events in diabetics and non-diabetics alike, supporting broader risk stratification beyond symptoms.
Research Themes
- Conduction system pacing versus biventricular pacing for CRT
- Protocolized etiologic workup after in-hospital cardiac arrest
- Stress CMR for long-term prognostication in diabetes
Selected Articles
1. Conduction system pacing vs. biventricular pacing for cardiac resynchronization: the CSP-SYNC randomized single centre study.
In a single-centre randomized trial of 62 CRT candidates, left bundle branch area pacing achieved non-inferior improvement in LVEF versus biventricular pacing (14.0% vs 8.5% at 6 months), with similar reductions in LVESV and improvements in functional status. Temporal remodeling and HF hospitalization rates were comparable across arms.
Impact: This randomized comparison directly informs device strategy, suggesting conduction system pacing can match conventional BiV pacing for CRT efficacy. It addresses a current practice shift with controlled evidence.
Clinical Implications: LBBAP may be considered an effective alternative to BiV for CRT in eligible patients, influencing lead selection and operator training while potentially simplifying venous anatomy constraints.
Key Findings
- Non-inferior LVEF improvement at 6 months with LBBAP vs BiV (14.0% vs 8.5%; non-inferiority P<0.001).
- Comparable decreases in LVESV and improvements in 6-minute walk test and NYHA class across groups.
- Similar trends in LV remodeling and heart failure hospitalizations between strategies through 12 months.
Methodological Strengths
- Randomized allocation with prespecified primary endpoint (LVEF change at 6 months).
- Multiple clinical and echocardiographic secondary endpoints including 12-month assessments.
Limitations
- Single-centre, small sample size (n=62) limits generalizability and power for safety endpoints.
- Non-inferiority design without blinding; trial registration and CONSORT adherence not specified.
Future Directions: Larger multicentre RCTs should confirm clinical outcomes, durability, and safety, and define patient subgroups most likely to benefit from LBBAP.
AIMS: There are limited prospective randomized studies comparing left bundle branch area pacing (LBBAP) and biventricular (BiV) pacing for cardiac resynchronization therapy (CRT). The study tested whether LBBAP is non-inferior to BiV pacing in patients with Class I indication for CRT. METHODS AND RESULTS: The CSP-SYNC study is an investigator-initiated, randomized, single-centre study. Sixty-two patients were randomized 1:1 to LBBAP or BiV. The primary study endpoint was the change in left ventricular ejection fraction (LVEF) at 6 months. Secondary endpoints included changes in echo and clinical parameters after 6 months and 12 months. Thirty-one patients were randomized to each arm. Most patients were males (71%), and 32% had ischaemic cardiomyopathy. At 6 months, similar improvement of LVEF was observed in the LBBAP group compared to the BiV group [14.0% (95% confidence interval (CI): 11.2-16.8) in LBBAP vs. 8.5% (95% CI: 5.6-11.2) in BiV] with a mean intergroup difference of 5.6% (95% CI: 1.6-9.5; P < 0.001 for non-inferiority). Both groups showed comparable decrease in LVESV [-64 mL (95% CI: -78 to -50) vs. -40 mL (95% CI: -54 to -25) respectively, mean difference -24 mL (CI 95%: -44 to -4); P < 0.001 for non-inferiority] and changes in 6-min walk test (P < 0.001 for non-inferiority) and NYHA class (P = 0.011 for non-inferiority). Temporal trends of LV remodelling and heart failure hospitalization rates were also comparable. CONCLUSION: In patients with a Class I indication for CRT, LBBAP was non-inferior to BiV pacing in improving LVEF and provided similar structural and electrical remodelling.
2. Why do patients develop in-hospital cardiac arrest? A prospective clinical observational study (WHY-IHCA).
In a prospective, protocolized IHCA workup including post-mortem imaging when no ROSC occurred, pulmonary (30%) and cardiac (29%) etiologies predominated. Hypoxia (21%) and myocardial ischemia (11%) were the most frequent subcategories, and agreement between presumed and expert-adjudicated causes was low.
Impact: Establishes a reproducible etiologic pathway for IHCA, demonstrating that protocolized imaging and testing improve cause attribution and challenge initial bedside assumptions.
Clinical Implications: Hospitals should consider standardized IHCA etiologic protocols, including early whole-body imaging and toxicology, and caution reliance on initial presumed causes to guide secondary prevention and quality review.
Key Findings
- Pulmonary (30%) and cardiac (29%) etiologies predominated among 150 IHCA cases.
- Hypoxia (21%) and myocardial ischemia (11%) were the leading subcategories.
- Low concordance between presumed and expert-adjudicated causes (kappa 0.16–0.42); expert panel unknown only 7% vs presumed unknown 26%.
Methodological Strengths
- Prospective, protocolized, and comprehensive etiologic investigation including post-mortem imaging.
- Expert panel adjudication with predefined main and subcategories.
Limitations
- Single-centre study limits generalizability; moderate sample size.
- No long-term outcomes beyond etiologic determination; potential adjudication subjectivity despite panel process.
Future Directions: Multicentre validation of protocolized IHCA workups and evaluation of their impact on secondary prevention, outcomes, and resource utilization.
BACKGROUND: No previous study has described in-hospital cardiac arrest (IHCA) aetiologies prospectively through a protocolised investigation. In this study, we investigated IHCA aetiologies in both IHCA patients achieving return of spontaneous circulation (ROSC) as well as IHCA patients not achieving ROSC. METHODS: Adult IHCA patients were included at Aarhus University Hospital in Denmark. In patients with ROSC, the investigation consisted of blood tests including toxicology, echocardiography, and whole-body computed tomography (CT). In patients without ROSC, the investigation consisted of blood tests including toxicology and whole-body CT and magnetic resonance imaging (MRI). The primary outcome was the IHCA aetiology as determined by a four-person expert panel using pre-defined main- and subcategories. Secondary outcomes included the presumed cause as determined by cardiac arrest team leaders as well as the discrepancy between presumed and expert panel causes. RESULTS: 150 patients were included, and 71 (47 %) achieved ROSC. Expert panel aetiologies (with between-expert ranges) were determined as cardiac in 29 % (27-29 %) and pulmonary in 30 % (25-32 %) of cases. Myocardial ischaemia and hypoxia were the most prevalent specific subcategories in 11 % (10-15 %) and 21 % (14-23 %) of cases, respectively. The cause was deemed unknown in 7 % (0-14 %) of cases, and presumed causes were deemed unknown in 26 % of cases. Agreement between presumed and expert panel causes was low (Kappa: 0.16-0.42 across experts). CONCLUSION: The predominant aetiologies of IHCA are pulmonary and cardiac. A protocolised investigation, including post-mortem investigations, aided in disclosing IHCA aetiologies. Presumed causes are often unknown and often differ from expert panel causes.
3. The role of stress cardiovascular magnetic resonance in patients with Diabetes Mellitus.
In 2,718 propensity-matched patients followed a median 6.5 years, stress CMR markers—ischemia or LGE extent ≥3 segments—were strong, independent predictors of MACE (HR 7.14 and 5.03, both p<0.001) with similar prognostic value in diabetics and non-diabetics. Asymptomatic diabetics had event rates comparable to symptomatic patients.
Impact: Demonstrates robust, symptom-agnostic prognostic utility of stress CMR, supporting broader risk stratification in diabetes beyond symptom-based referral.
Clinical Implications: Stress CMR can guide intensity of preventive therapy in diabetics irrespective of symptoms; however, randomized trials are needed to assess whether CMR-guided strategies improve outcomes.
Key Findings
- Propensity-matched cohort of 1,359 diabetics and 1,359 non-diabetics; median follow-up 6.5 years with 14.2% MACE.
- Ischemia or LGE extent ≥3 segments independently predicted MACE (HR 7.14 and 5.03; both p<0.001).
- Prognostic value did not differ by diabetes status; asymptomatic diabetics had similar event rates to symptomatic patients.
Methodological Strengths
- Large, two-centre cohort with propensity-score matching and long follow-up.
- Hard clinical endpoints (CV death and non-fatal MI) with robust hazard estimates.
Limitations
- Observational design with potential residual confounding and referral bias.
- Only two centres; no randomized assessment of CMR-guided management.
Future Directions: Randomized trials to test CMR-guided prevention strategies in diabetics, including asymptomatic individuals, and cost-effectiveness analyses.
OBJECTIVES: The aim of this study was to evaluate the prognostic value of stress perfusion cardiovascular magnetic resonance (CMR) in diabetic versus non-diabetic patients, and then in symptomatic versus asymptomatic diabetics. BACKGROUND: Diabetic individuals are at increased risk of coronary atherosclerosis. A significant percentage of diabetics fail to perceive the typical symptoms of myocardial ischemia. Screening methods such as coronary computed tomography (CCTA) or single-photon emission computed tomography (SPECT) have not shown clear benefits in asymptomatic diabetics. The role of stress CMR in this population is not well established. METHODS: Between 2008 and 2018, all consecutive diabetic and non-diabetic patients without known cardiovascular disease referred for stress perfusion CMR in two tertiary centers were included. Propensity-score matching was used to create a cohort of diabetic versus non-diabetic patients with similar baseline characteristics. All patients were followed for the occurrence of major adverse cardiovascular events (MACE), defined as cardiovascular death or non-fatal myocardial infarction. Diabetic patients were categorized into symptomatic and asymptomatic patients. RESULTS: Out of 3,485 eligible patients, 1,359 diabetics and 1,359 non-diabetics (mean age 69±12 years, 57.4% women) with similar propensity scores were included. Over a median follow-up period of 6.5 (5.9-8.9) years, 386 (14.2%) experienced MACEs. Kaplan-Meier analysis for the occurrence of MACE indicated that the extent of ischemia or late gadolinium enhancement (LGE) involving ≥ 3 segments were independent predictors of the occurrence of MACEs (hazard ratio, HR: 7.14 [95% CI, 5.01-10.02]; and HR: 5.03 [95% CI, 3.47-7.29]; both p<0.001, respectively), with no significant differences between diabetics and non-diabetics. Asymptomatic diabetics (n=255) showed similar event rates as symptomatic patients (p=0.98). CONCLUSION: Stress CMR provides valuable prognostic information in diabetic patients, irrespective of symptoms. Further assessment is needed to determine whether stress CMR should be a standard screening tool for diabetic patients.