Machine learning and radiomics for ventricular tachyarrhythmia prediction in hypertrophic cardiomyopathy: insights from an MRI-based analysis.

BACKGROUND: Myocardial fibrosis is often detected in patients with hypertrophic cardiomyopathy (HCM), which causes left ventricular (LV) dysfunction and tachyarrhythmias. PURPOSE: To evaluate the potential value of a machine learning (ML) approach that uses radiomic features from late gadolinium enhancement (LGE) and cine images for the prediction of ventricular tachyarrhythmia (VT) in patients with HCM. MATERIAL AND METHODS: Hyperenhancing areas of LV myocardium on LGE images were manually segmented, and the segmentation was propagated to corresponding areas on cine images. Radiomic features were extracted using the PyRadiomics library. The least absolute shrinkage and selection operator (LASSO) method was employed for radiomic feature selection. Our model development employed the TabPFN algorithm, an adapted Prior-Data Fitted Network design. Model performance was evaluated graphically and numerically over five-repeat fivefold cross-validation. SHapley Additive exPlanations (SHAP) were employed to determine the relative importance of selected radiomic features. RESULTS: Our cohort consisted of 60 patients with HCM (73.3% male; median age = 51.5 years), among whom 17 had documented VT during the follow-up. A total of 1612 radiomic features were extracted for each patient. The LASSO algorithm led to a final selection of 18 radiomic features. The model achieved a mean area under the receiver operating characteristic curve of 0.877, demonstrating good discrimination, and a mean Brier score of 0.119, demonstrating good calibration. CONCLUSION: Radiomics-based ML models are promising for predicting VT in patients with HCM during the follow-up period. Developing predictive models as clinically useful decision-making tools may significantly improve risk assessment and prognosis.

Comprehensive analysis of recurrence factors in cryoballoon AF ablation: integrating clinical, biomarkers, and echocardiographic parameters.

Atrial fibrillation (AF) poses substantial challenges in cardiovascular diseases, impacting patient health and economic burdens. Understanding the mechanical effects of AF on the left atrium (LA) and assessing the influence of treatment modalities on LA functions are critical. This study aims to assess the efficacy of echocardiographic and biochemical parameters in predicting AF recurrence following second generation cryoballoon ablation (CB-2). Ninety-two patients with symptomatic AF, treated with CB-2 at Istanbul University-Cerrahpasa, Faculty of Medicine, Department of Cardiology, were prospectively examined from January 2021 to July 2023. The study endeavors to develop a predictive model for AF recurrence, investigating the relationship between echocardiographic measurements and serum biomarkers with recurrence. The follow-up duration for echocardiographic assessments and biochemical analyses was systematically documented. The study revealed a significant enhancement in LA mechanical functions during echocardiographic follow-ups three months post-procedure. Specifically, LA strain parameters emerged as significant predictors of recurrence (LAsr: 95%CI 1.004-1.246, p = 0.047; LAsct: 95%CI 1.040-1.750, p = 0.024). Biochemical analyses demonstrated a correlation between elevated PRO-BNP levels and an increased risk of recurrence (95%CI 1.000-1.003, p = 0.012). Moreover, specific biomarkers such as MYBPHL, which demonstrated increased levels post-procedure, were deemed indicative of atrial damage, suggesting potential additional atrial substrate modification beyond PVI. Consequently, improvements in LA function post-cryoballoon ablation and biochemical markers have surfaced as potential indicators for predicting AF recurrence. This study elucidates the effectiveness of CB-2 in treating AF and its impact on LA functions. Notably, LA strain measurements and PRO-BNP levels have emerged as reliable indicators for predicting recurrence. Beyond clinical implications, our research establishes a foundation for a deeper understanding of the role of CB-2 in AF management and factors associated with recurrence.

The impact of ticagrelor therapy on CABG-related bleeding in patients with STEMI managed with pPCI and following on-pump CABG.

Patients on double antiplatelet treatment who need early in-hospital coronary artery bypass grafting (CABG) are at high risk of major bleeding. In this study, we aimed to investigate the impact of ticagrelor preloading on CABG related bleeding in patients with ST-segment elevation myocardial infarction (STEMI) initially managed with primary percutaneous coronary intervention (pPCI). Patients with the diagnosis of STEMI who were managed with pPCI and underwent subsequent early (4-7 days following pPCI) or delayed (> 7 days following pPCI) on-pump CABG surgery were included. All study patients were preloaded with ticagrelor 180 mg prior to pPCI procedure. Patients' demographics, clinical variables, and short-term cardiovascular outcomes were recorded. This is a retrospective study which included 98 patients. Fifty-four (54%) patients underwent early and 44 (45%) patients underwent delayed CABG surgery. CABG-related bleeding occurred in 22 (22.4%) patients. There was no significant difference with respect to total ticagrelor dose and timing of the surgery between patients with or without CABG-related bleeding (p: 0.165 and p: 0.142). Multivariate analyses demonstrated that only preoperative hemoglobin level < 10.9 and use of mechanical cardiac support devices were independent predictors of CABG-related bleeding [OR: 3719, p: 0.009 and OR: 11,698, p: 0.004, respectively].There were three deaths within the 30 days of surgery, all occurring in patients with CABG-related bleeding. However, CABG-related bleeding was not associated with long-term cardiovascular events during the follow-up. Our results indicated that discontinuation of ticagrelor therapy 3 days prior to surgery is sufficient to avoid CABG-related bleeding. Moreover, early CABG following STEMI does not increase the risk of long-term cardiovascular events.

Structural and Functional Impact of Adrenoceptor Beta-1 Gene Polymorphism in Patients with Hypertrophic Cardiomyopathy and Response to Beta-Blocker Therapy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a genetically inherited cardiac disorder with diverse clinical presentations. Adrenergic activity, primarily mediated through beta-adrenoceptors, plays a central role in the clinical course of HCM. Adrenergic stimulation increases cardiac contractility and heart rate through beta-1 adrenoceptor activation. Beta-blocker drugs are recommended as the primary treatment for symptomatic HCM patients to mitigate these effects. METHODS: This prospective study aimed to investigate the impact of common ADRB-1 gene polymorphisms, specifically serine-glycine at position 49 and arginine-glycine at position 389, on the clinical and structural aspects of HCM. Additionally, the study explored the association between these genetic variations and the response to beta-blocker therapy in HCM patients. RESULTS: A cohort of 147 HCM patients was enrolled, and comprehensive assessments were performed. The findings revealed that the Ser49Gly polymorphism significantly influenced ventricular ectopic beats, with beta-blocker therapy effectively reducing them in Ser49 homozygous patients. Moreover, natriuretic peptide levels decreased, particularly in Ser49 homozygotes, indicating improved cardiac function. Left ventricular outflow obstruction, a hallmark of HCM, was also reduced following beta-blocker treatment in all patient groups. In contrast, the Arg389Gly polymorphism did not significantly impact baseline parameters or beta-blocker response. CONCLUSION: These results emphasize the role of the Ser49Gly polymorphism in the ADRB-1 gene in shaping the clinical course and response to beta-blocker therapy in HCM patients. This insight may enable a more personalized approach to managing HCM by considering genetic factors in treatment decisions. Further research with larger populations and longer follow-up periods is needed to confirm and expand upon these findings.

Impact of Preloading Strategy With Ticagrelor on Periprocedural Myocardial Injury in Patients With Non-ST Elevation Myocardial Infarction Undergoing Early Invasive Strategy.

ABSTRACT: Pretreatment with an oral P2Y12 receptor blocker (before coronary angiography) versus treatment in the catheterization laboratory has been a matter of debate in patients presenting with non-ST segment elevation myocardial infarction (NSTEMI). The primary aim of this study was to assess the impact of an immediate preloading strategy with ticagrelor on periprocedural myocardial injury in patients with NSTEMI treated with an early invasive strategy. NSTEMI patients who underwent coronary angiography and subsequent percutaneous coronary intervention (PCI) within 24 hours after hospital admission were divided into 2 groups: the first group (pretreatment group) included patients who received ticagrelor pretreatment as soon as possible after admission and the second group (no pretreatment group) included patients who received a loading dose of ticagrelor after coronary angiography. The pretreatment group included 232 patients, and the no pretreatment group included 87 patients. Male patients represented the majority of the patients. The 2 groups were similar in baseline characteristics, except for a greater incidence of hypertension ( P = 0.014) and higher hemoglobin levels ( P = 0.01) in the pretreatment group in comparison with the no pretreatment group. Patients in the ticagrelor pretreatment group had less myocardial injury until coronary angiography based on troponin measurements collected at 12 hours after admission ( P = 0.025). Patients in the ticagrelor pretreatment group also had fewer periprocedural myocardial injuries based on troponin measurements taken between 12 and 24 hours after the PCI ( P = 0.026 and P = 0.022, respectively). Our findings suggested that ticagrelor pretreatment reduces periprocedural myocardial injury in NSTEMI patients who underwent PCI within 24 hours after admission.

The Long-Term Impact of Ionizing Radiation on DNA Damage in Patients Undergoing Multiple Cardiac Catheterizations.

Ionizing radiation (IR) exposures have increased exponentially in recent years due to the rise in diagnostic and therapeutic interventions. A number of small-scale studies investigated the long-term effect of IR on health workers or immediate effects of IR on patients undergoing catheterization procedures; however, the long-term impact of multiple cardiac catheterizations on DNA damage on a patient population is not known. In this study, the effects of IR on DNA damage, based on micronuclei (MN) frequency and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as markers in peripheral lymphocytes, were evaluated in patients who previously underwent multiple cardiac catheterization procedures. Moreover, genetic polymorphisms in genes PARP1 Val762Ala, OGG1 Ser326Cys, and APE1 Asn148Glu as a measure of sensitivity to radiation exposure were also investigated in the same patient population. The patients who underwent ≥ 3 cardiac catheterization procedures revealed higher DNA injury in comparison to the patients who underwent ≤ 2 procedures, documented with the presence of higher level of MN frequency (6.4 ± 4.8 vs. 9.1 ± 4.3, p = 0.002) and elevated serum 8-OHdG levels (33.7 ± 3.8 ng/mL vs. 17.4 ± 1.9 ng/mL, p = 0.001). Besides, OGG1 Ser326Cys and APE1 Asn148Glu heterozygous and homozygous polymorphic types, which are related with DNA repair mechanisms, were significantly associated with MN frequency levels (p = 0.006 for heterozygous and p = 0.001 for homozygous with respect to OGG1 Ser326Cys, p = 0.007 for heterozygous and p = 0.001 for homozygous with respect to APE1 Asn148Glu). There was no significant difference in terms of PARP1 Val762Ala gene polymorphism between two groups.