Onassis Cardiac Surgery Center

BACKGROUNDTranexamic acid (TXA) is widely used as an antifibrinolytic agent to reduce bleeding in cardiac and extracorporeal circulation settings. Neurological adverse effects, including seizures and myoclonus, are rare and not well documented in patients supported by extracorporeal membrane oxygenation (ECMO).CASE SUMMARYWe report the case of a 52-year-old male with ST-elevation myocardial infarction and severe left ventricular dysfunction, who was transferred to our intensive care unit department under veno-arterial (VA)-ECMO support and continuous renal replacement therapy (CRRT). To maintain ECMO oxygenator function and due to decreasing fibrinogen levels, endovenous one gram TXA twice a day was administered and within hours after the second dose, the patient developed generalized myoclonic jerks. A non-contrast brain computed tomography revealed no acute or chronic abnormalities, and neurological evaluation attributed the findings to TXA as the most likely cause due to TXA overdose. Following discontinuation of TXA, the symptoms resolved within 48 hours.CONCLUSIONThis case highlights a rare neurological complication associated with TXA overdose, occurring in patient with VA-ECMO and CRRT. Clinicians should remain vigilant for such adverse effects in this context.

BACKGROUND Given its associations with high morbidity and mortality, type A aortic dissection requires urgent surgical intervention. Patients with Marfan syndrome present additional complexity due to underlying connective tissue abnormalities that warrant multiple thoracic aortic operations. The "arch-first" technique was developed to allow single-stage open extensive replacement of the thoracic aorta while maintaining continuous antegrade cerebral perfusion, thereby minimizing brain ischemia. In the current endovascular era, the frozen elephant trunk - a hybrid technique combining a conventional surgical graft for arch reconstruction with an integrated distal stent-graft - has gained popularity in management of these cases, displacing extensive open approaches. However, for specific patient populations, the arch-first technique remains a suitable approach. CASE REPORT This report describes 6 patients (5 men, 1 woman; aged 24-73 years) who were treated between June 2022 and June 2025 through application of the arch-first technique in complex clinical scenarios, highlighting its benefit in providing effective single-stage management of extensive thoracic aortic pathology. Although no patient experienced neurological deficits, 50% (3/6) required prolonged mechanical ventilation due to the invasiveness of the procedure. CONCLUSIONS The arch-first technique represents an effective surgical strategy for single-stage extensive thoracic aortic replacement, offering reliable cerebral protection and reduced neurological risk in complex aortic disease cases, particularly those involving patients with Marfan syndrome and in reoperation settings. Despite its invasive nature and potential for pulmonary morbidity, the arch-first technique remains a valuable option for selected patients. Further multicenter studies are needed to compare its outcomes with frozen elephant trunk and hybrid approaches.

Abstract Background The Greek National Network of Precision Medicine in Cardiology consists of a consortium of public sector hospitals, forensic services and genetic testing institutes. Aim This network aims to prevent sudden death in young people and study hereditary cardiovascular diseases in Greece. Method Two large national registries have been established, one for patients with hereditary heart diseases and one for sudden deaths in young people. A National Registration Platform has been created. Those registries lead to the evaluation of families with hereditary diseases or with sudden death in young people and to the identification of people within the families who suffer from hereditary cardiovascular disease (CV) and are not aware of it. At the same time, it identifies areas of the country with clusters of inherited CV diseases. Results Within the framework of the network, as a pilot project, we present the results of our own hospital which has tested 2.500 patients with inherited heart diseases and has performed 316 genetic tests on patients diagnosed with hereditary disease. Of the 316 patients, 42 tested positive for pathogenic (P) genetic variation, 74 positive for a likely pathogenic (LP) variant, and 72 for variant of unknown significance. The percentage of genes with the detected variants is shown in Figure 1. Out of the 116 families with P/LP variants, 88 families had at least the proband tested at our center and an average of 2.5 family members were also screened. From 233 screened relatives of probands with P/LP variants, 149 (64%) were found positive for the proband's variant. Clinical evaluation revealed typical or subclinical disease in 35% of the relatives, while 29% of them were phenotype negative. At the same time, areas with a founder effect phenomenon were identified in the country, specifically in Crete [hypertrophic cardiomyopathy (HCM) and ATTR inherited amyloidosis], Attica (HCM), Central Greece (PLN cardiomyopathy) and the Cyclades (Naxos disease-JUP cardiomyopathy). Also nests of rare hereditary diseases such as Cohen disease in Fourni of Ikaria and Wilson disease in Kalymnos, as well as areas of the Peloponnese and the island of Ios with neuromuscular diseases that also have cardiovascular involvement. Conclusion Greece, due to its islands and isolated areas, is a natural park of rare cardiovascular diseases. The Greek National Network of Precision Medicine in Cardiology constitutes an added value for the country's health services by identifying areas that need special interventions as well as populations that we have not been able to identify until now.Genetic profile of patients

Abstract Background/Introduction Left atrium LVAs are associated with impaired myocardial substrate and are known to contribute to the persistence of atrial fibrillation (AF). Understanding the significance of LVAs not only aids in refining ablation strategies but also enhances patient selection and risk stratification. Thus, identifying patients with LVA by using non-invasive methods such as a predictive risk score is an important endeavor. Purpose We sought to create and validate a simple and easy to use risk score as a clinical tool for identifying LVAs in patients undergoing AF catheter ablation. Methods Consecutive patients who underwent radiofrequency pulmonary vein isolation (PVI) for paroxysmal or persistent AF were included in this study. A sequential high-density 3D bipolar voltage map was constructed in all patients during sinus rhythm (SR), guided by a 3D electroanatomic mapping system. The cutoff value for LVA was defined as a bipolar voltage ≤ 0.5 mV measured in SR. LVA as percentage of the mapped left atrial surface in SR was also calculated. A novel low voltage area (LVA) prediction score, the P.A.L.A.H. risk score, was established. It includes P wave duration (PWD) on an electrocardiogram (PWD>120ms -1pt), Age (age >65 y/o-1pt, age>75y/o-2 pts), Left atrial diameter (LAD) (LAD>40mm-1pt), Arterial Hypertension (Arterial Hypertension- 1pt), Heart Failure (HF) (HF-2pt). Patients in the study were categorized into five distinct groups based on their P.A.L.A.H. score, which ranged from 0 to 5. Results One hundred and four consecutive patients (104) were included in our study [(age: 60.12±11.05 years; 50 men (48%)]. Sixty patients (60; 57.7%) suffered from paroxysmal AF. The highest P.A.L.A.H. score recorded was 5 (2.1±1.40). Regarding the LVA, significant differences between each value of P.A.L.A.H score and LVA value (p<0.0001) and LVA percentage (p<0.0001) were recorded (Figure 1,2). Conclusion(s) The P.A.L.A.H. score was significantly associated with the presence and extent of LVAs in patients undergoing AF catheter ablation. This relationship suggests that the P.A.L.A.H. score may serve as an important tool for risk stratification and clinical decision-making.P.A.L.A.H. score and LVAs percentage P.A.L.A.H. score and LVA value

Cardiac resynchronization therapy (CRT) represents a cornerstone in the management of patients with heart failure and electrical dyssynchrony, improving symptoms, reducing hospitalizations, and prolonging survival. CRT can be delivered via a pacemaker (CRT-P) or an ICD (CRT-D). Despite its widespread use, the mortality benefit of CRT-D over CRT-P remains uncertain, as no head-to-head randomized trials have been designed to directly compare the two modalities, making device selection a frequent clinical dilemma. In practice, CRT-D accounts for 70-80% of CRT implantations in developed countries, yet solid evidence demonstrating its superiority over CRT-P is lacking. Specific patient groups, including those with non-ischemic cardiomyopathy, advanced age, multiple comorbidities, or limited life expectancy, may derive limited incremental benefit from CRT-D, which should be balanced against device costs and specific risks such as lead failure and inappropriate shocks. The present review aims to provide a comprehensive comparison between CRT-D and CRT-P, focusing on the existing body of evidence, criteria for patient selection, comparative clinical outcomes, and risk-benefit considerations for clinical decision-making.

AimsThe feasibility and safety of the lattice-tip catheter for ventricular arrhythmia (VA) ablation in humans remain largely unknown. This study aimed to assess feasibility, safety profile as well as patient outcomes after VA ablation with a lattice-tip catheter in a multicentre European registry.Methods and resultsAll 18 European centres using the AFFERA system in September 2024 agreed to participate. Clinical, procedural, and follow-up data (minimum 3 months) were systematically collected and analysed. A total of 126 patients (18% female; mean age 59 ± 16 years) underwent VA ablation using the lattice-tip catheter during the inclusion period. Ablation indications included ventricular tachycardia (VT) in 99, premature ventricular complexes (PVCs) in 23, and ventricular fibrillation (VF) in 4 patients. Major and minor acute complications were observed in 7 (6%) and 18 (14%) procedures, respectively. They included thrombo-embolic event (n = 2), major bleeding (n = 2), ventricular fibrillation induction (n = 1), tamponade due to epicardial access (n = 1), and cardiogenic shock due to prolonged VT mapping (n = 1). Within the first month post-procedure, three patients died [from multi-organ failure (n = 2) and sepsis (n = 1)], two had worsening heart failure, one myocardial infarction, one sepsis, and one major gastro-intestinal bleeding. After a mean follow-up of 5.6 ± 3.7 months, absence of recurrence was 78% for PVC, 70% for VT, and 100% for VF.ConclusionIn this complex population with refractory VA, ablation using the lattice-tip catheter appears feasible and relatively safe. In the absence of large, randomized trials, exhaustive registry is of key importance to ensure safety and efficacy of new catheter technologies.

The pathophysiological substrate of young-onset atrial fibrillation (yAF) is diverse, involving both genetic predisposition and an increasing burden of cardiovascular risk factors among younger populations. Despite its growing clinical relevance, the available literature on the role of catheter ablation (CA) in yAF remains limited. The aim of the present study was to assess the efficacy of CA in a cohort of patients with yAF undergoing first time CA. This was a single-center retrospective study. Patients with yAF (aged ≤ 45 years) who underwent first-time CA were compared against a 1:1 propensity-score matched cohort of older patients (> 45years), to assess arrhythmia recurrences in a follow-up period of 12-month. Logistic regression was used to compare differences with calculation of odds ratios (OR) with 95% confidence intervals (CI). 225/450 (50%) patients were included in the yAF group and 225/450 (50%) in the older group. The mean age in the yAF group was 39 ± 6 years [vs. 58 ± 7 in the older group], 76% were males and 79% had paroxysmal type of AF. The types of CA were radiofrequency (54%), cryoablation (44%), and pulsed field ablation (2.7%). Patients in the older group experienced significantly more arrythmia recurrences (63/225 [28%] vs 40/225 [18%], OR = 1.80, 95%CI = [1.15, 2.83], p = 0.01) in the 12-month follow-up period. In the initial (unmatched) cohort, age was significantly and linearly associated with AF recurrences at 12 months [OR = 1.02, 95%CI = (1,1.04), p = 0.025], with the Youden index maximizing at 59 years. In this propensity score matched cohort study, younger patients (≤ 45 years) with AF who underwent first-time CA, experienced significantly less arrhythmia recurrences in a 12-month follow-up period, off antiarrhythmic drugs compared to older individuals. Complication rates did not differ between groups. No association was found between the type of CA and the risk of recurrence.

Background/IntroductionThe widespread performance of catheter ablation for atrial fibrillation (AF) has significantly increased the incidence of complex atrial tachycardias (ATs) originating from a diseased or previously ablated myocardial substrate. Under these circumstances, extensive areas of fibrosis or lines of block may complicate the interpretation of activation maps and subsequently the successful diagnosis of the underlying mechanism of the AT. A novel ablation catheter, combining high density mapping and dual ablation properties has been recently released for the treatment of AF. The system has been proven highly effective for both the establishment of the diagnosis and the ablation of a variety of ATs in one of our previous studies.PurposeIn the current study we aimed to assess the performance of the novel system in the establishment of the diagnosis and the ablation efficacy in a challenging cohort of patients presented with complex ATs and history of previous catheter ablation.MethodsPatients with documented ATs and history of previous catheter ablation or surgery were included in the study. Cases of cavotricuspid isthmus dependent atrial flutters were excluded. Activation mapping was used for the establishment of AT mechanism. Confirmation with entrainment was performed, whenever appropriate. Accuracy of the activation mapping in diagnosis, acute ablation efficacy (termination of AT during ablation followed by non-inducibility) and procedural characteristics were the study endpoints. Bidirectional block of linear lesions was validated with pacing maneuvers and activation remap.Results11 patients were included (6 mitral flutters, 2 roof flutters, 2 focal/microreentry ATs and one macroreentrant AT involving the anterior wall of the left atrium). Proper diagnosis of the tachycardia mechanism was established by the activation map in all cases. In two cases with extensive atrial fibrosis, activation mapping revealed the area of a critical isthmus that led to immediate termination of the AT with one single lesion. Mean mapping time was 8.5±3.1 minutes with acquisition of 380.1±129 mean mapping points/minute. Mean ablation time was 40.2±22.7 seconds. Conversion to sinus rhythm during ablation was achieved in all cases with the exception of a mitral flutter that converted to cavotricuspid isthmus dependent atrial flutter. No major or minor complications occurred.ConclusionIn a cohort of patients with complex ATs and history of previous catheter ablation, the novel lattice tip catheter that combines high density mapping and dual ablation properties successfully suggested the underlying mechanism of the tachycardia by the pattern of activation in activation maps in all cases. The delivered lesions were highly effective with acute termination of ATs and achievement of bidirectional block in linear lesions.