BACKGROUND:Rate-dependent left bundle branch block (LBBB) during exercise testing is traditionally considered a potential marker of coronary artery disease (CAD), yet the long-term prognosis remains uncertain. This study assessed the long-term outcomes of patients presenting with rate-dependent LBBB during exercise testing. METHODS:In this retrospective single-centre cohort study, all bicycle exercise tests performed between 2000 and 2022 were reviewed. Patients with transient LBBB developing during exercise and resolving during recovery were included. Baseline characteristics, diagnostic work-up, and long-term outcomes were collected. The primary endpoint was progression to permanent LBBB. Secondary endpoints included new-onset left ventricular systolic dysfunction, cardiac implantable electronic device (CIED) implantation, and all-cause mortality. RESULTS:Among 46,089 patients undergoing 51,220 exercise tests, 68 patients (0.15%) exhibited rate-dependent LBBB. Median age was 59.7 years (54.6-68.4) and 59.4% were male. CAD was present in 29.4%, while baseline heart failure was present in 11.8%. Rate-dependent LBBB occurred at a median heart rate of 126 bpm. During a median follow-up of 12.8 years (8.7-20.2), permanent LBBB developed in 36 patients (52.9%), with cumulative incidence of 46.5% at 10 years. New-onset systolic dysfunction occurred in 12 patients (17.6%), most often after or concurrent with permanent LBBB. CIED implantation was required in 12 patients (17.6%). All-cause mortality was 29.4% (8.1% at 10 years), with age as only independent predictor. CONCLUSIONS:Rate-dependent LBBB is uncommon but frequently progresses to permanent LBBB and is associated with subsequent systolic dysfunction. These findings suggest that rate-dependent LBBB may represent an early manifestation of intrinsic conduction system disease.
INTRODUCTION:High-sensitivity cardiac troponins enable early rule-out of myocardial infarction (MI), but their effect on diagnostic specificity remains uncertain. We evaluated rates of type I MI and obstructive coronary artery disease (CAD) among patients triaged using the Suspected Acute Myocardial Infarction in Emergency (SAMIE) pathway. METHODS:A retrospective cohort study was conducted on patients presenting with chest pain to an Australian Health Service Emergency Department between February 2023 and December 2024. Patients were classified as low-risk (troponin <5 ng/L), intermediate-risk (troponin ≥5 ng/L and Δ troponin <3 ng/L), or high-risk (troponin ≥5 ng/L and Δ troponin ≥3 ng/L or above sex-specific thresholds). All patients underwent expedited outpatient review through a rapid-access cardiac clinic. The primary outcome was type I MI within 30 days. Secondary outcomes included positive stress echocardiography and obstructive CAD on invasive coronary angiography. RESULTS:Among 355 patients (mean age 59.4 ± 17.5 years), 64 (18.0%) were low-risk, 121 (34.1%) intermediate-risk, and 170 (47.9%) high-risk. The 30-day type I MI rate was 0.6% (two events), both occurring in the SAMIE high-risk group. Rates of obstructive CAD and positive stress echocardiography were similar across risk categories. CONCLUSIONS:Among a selected cohort managed through a structured rapid-access chest pain outpatient service, 30-day type I MI rates were low across all SAMIE risk categories. Both events occurred in the SAMIE high-risk group. Given the small number of events, these findings should be considered hypothesis-generating and require validation in larger prospective studies.
Cardiovascular medicine continues to move towards precision-based, individualised patient care, supported by novel biomarkers, refined imaging protocols, and multidisciplinary risk assessment. The studies featured in this issue of Acta Cardiologica span cardio-oncology, structural heart disease, immune and proteomic biomarkers, sepsis-related cardiac dysfunction, arrhythmia management, and vascular disease. Collectively, they underscore the growing importance of individualised diagnostic and therapeutic strategies across the cardiovascular spectrum, from cancer-related heart failure to conduction system pacing and cardiac arrest prevention.
Cardiovascular medicine continues to move towards mechanistically informed, individualised patient care, supported by refined genetic, biochemical, and imaging tools. The studies featured in this issue of Acta Cardiologica span the genetic basis of accessory pathway formation, biomarker-guided risk stratification in infective endocarditis, the substrate and predictors of atrial fibrillation recurrence, the valvular-right ventricular interplay in mitral stenosis, cardiovascular safety in surrogate pregnancy, age-related differences in acute myocardial infarction, nutritional-inflammatory risk stratification in coronary intervention, and inflammation-driven sarcopenia in heart failure. Collectively, they illustrate how integrating molecular, biochemical, and structural data continues to refine diagnostic and therapeutic decision-making across the cardiovascular spectrum.
