Background: New-onset postoperative atrial fibrillation (nPOAF) is a common complication after cardiac surgery (30– 50%), being associated with unfavorable long-term outcomes. Using the Society of Thoracic Surgeons National Adult Cardiac Database, we used machine learning (ML) to predict nPOAF and related 30-day outcomes following mitral valve (MV) surgery. A total of 27,856 MV operations were performed at 910 centers between 7/1/2017 and 6/30/2020 on patients without AF or a prior permanent pacemaker. The primary endpoint was nPOAF postoperatively. ML tech‑ niques utilized included penalized logistic regression, gradient boosting, decision trees, and random forests. Results: The overall incidence of nPOAF was 35.4% and that of new pacemaker insertion was 5.6%. Patients who developed nPOAF were older (67 ± 10 vs 60 ± 13 years), had more mitral valve stenosis (14.1% vs 11.7%), and hyperten‑ sion (72.1% vs 63.3%). They underwent more mitral valve replacement (39.1% vs 32.7%) and coronary artery bypass grafting (23.9% vs 16%). For predicting nPOAF, ML methods offer sensitivity, specificity and precision superior to logis‑ tic regression. The accuracy rate was identical with penalized and non-penalized logistic regression (0.672). Conclusions Predicting nPOAF and its short-term sequelae following MV surgery remains highly challenging.Machine learning methods offer a moderate degree of improvement in predicting nPOAF even in large national-level studies, in the absence of multi-modal data, such as real-time wearables data, electrocardiograms, heart rhythm moni‑ toring, or cardiac imaging.

Background: The relationship between sinus node dysfunction and atrial fibrillation (AF) has been well known. The reversibility of sinus node dysfunction is indeed a critical factor in determining the treatment strategy in patients with tachycardia–bradycardia syndrome (TBS). We aimed to assess the clinical outcome of choosing catheter abla‑ tion as the initial treatment in tachycardia–bradycardia syndrome and predictive factors leading to the implantation of a permanent pacemaker (PPM) in these patients. Methods: Patients with TBS who had been taken AF catheter ablation from 2012 to 2021 were reviewed, and 113 patients were enrolled. Patients were divided into two groups based on whether a “sinus pause episode of more than 3 s unrelated to tachyarrhythmia” coexists (Group I, n = 20) or not (Group II, n = 93). Results: Compared to Group II, baseline characteristics showed that Group I was comprised of more female gender (p = 0.043), with hypertension (p = 0.033), and with enlarged left atrium (p = 0.003). An average three-year follow-up found that eight patients (8/113, 7%) were implanted PPM (5/20, 25% in Group I vs. 3/93, 3.2% in Group II, p = 0.001).Using a multivariate model, a “sinus pause episode unrelated to tachyarrhythmia” was strongly associated with PPM implantation after catheter ablation in patients with TBS (HR 6.765, 95% CI 1.355–33.763, p = 0.020). Only four out of 113 patients (3.5%) progressed to persistent or permanent AF. Conclusions After catheter ablation as the initial treatment in TBS, only 7% underwent PPM implantation, and an iso‑ lated sinus pause was a predictive factor for requiring PPM implantation. In addition, even in patients who undergo catheter ablation with subsequent PPM implantation, we can expect to improve the clinical outcome associated with a reduced AF burden.

Background: New-onset postoperative atrial fibrillation (nPOAF) is a common complication after cardiac surgery (30– 50%), being associated with unfavorable long-term outcomes. Using the Society of Thoracic Surgeons National Adult Cardiac Database, we used machine learning (ML) to predict nPOAF and related 30-day outcomes following mitral valve (MV) surgery. A total of 27,856 MV operations were performed at 910 centers between 7/1/2017 and 6/30/2020 on patients without AF or a prior permanent pacemaker. The primary endpoint was nPOAF postoperatively. ML tech‑ niques utilized included penalized logistic regression, gradient boosting, decision trees, and random forests. Results: The overall incidence of nPOAF was 35.4% and that of new pacemaker insertion was 5.6%. Patients who developed nPOAF were older (67 ± 10 vs 60 ± 13 years), had more mitral valve stenosis (14.1% vs 11.7%), and hyperten‑ sion (72.1% vs 63.3%). They underwent more mitral valve replacement (39.1% vs 32.7%) and coronary artery bypass grafting (23.9% vs 16%). For predicting nPOAF, ML methods offer sensitivity, specificity and precision superior to logis‑ tic regression. The accuracy rate was identical with penalized and non-penalized logistic regression (0.672). Conclusions Predicting nPOAF and its short-term sequelae following MV surgery remains highly challenging.Machine learning methods offer a moderate degree of improvement in predicting nPOAF even in large national-level studies, in the absence of multi-modal data, such as real-time wearables data, electrocardiograms, heart rhythm moni‑ toring, or cardiac imaging.

Background: The relationship between sinus node dysfunction and atrial fibrillation (AF) has been well known. The reversibility of sinus node dysfunction is indeed a critical factor in determining the treatment strategy in patients with tachycardia–bradycardia syndrome (TBS). We aimed to assess the clinical outcome of choosing catheter abla‑ tion as the initial treatment in tachycardia–bradycardia syndrome and predictive factors leading to the implantation of a permanent pacemaker (PPM) in these patients. Methods: Patients with TBS who had been taken AF catheter ablation from 2012 to 2021 were reviewed, and 113 patients were enrolled. Patients were divided into two groups based on whether a “sinus pause episode of more than 3 s unrelated to tachyarrhythmia” coexists (Group I, n = 20) or not (Group II, n = 93). Results: Compared to Group II, baseline characteristics showed that Group I was comprised of more female gender (p = 0.043), with hypertension (p = 0.033), and with enlarged left atrium (p = 0.003). An average three-year follow-up found that eight patients (8/113, 7%) were implanted PPM (5/20, 25% in Group I vs. 3/93, 3.2% in Group II, p = 0.001).Using a multivariate model, a “sinus pause episode unrelated to tachyarrhythmia” was strongly associated with PPM implantation after catheter ablation in patients with TBS (HR 6.765, 95% CI 1.355–33.763, p = 0.020). Only four out of 113 patients (3.5%) progressed to persistent or permanent AF. Conclusions After catheter ablation as the initial treatment in TBS, only 7% underwent PPM implantation, and an iso‑ lated sinus pause was a predictive factor for requiring PPM implantation. In addition, even in patients who undergo catheter ablation with subsequent PPM implantation, we can expect to improve the clinical outcome associated with a reduced AF burden.

A 16-year-old man presented with short VA supraventricular tachycardia and 2:1 atrioventricular ratio. The correct maneuvers allowed us to guide not only the mechanism but also the probable location of the atrioventricular block.

Background: Bundle branch reentrant ventricular tachycardia is a unique type of VT that employs both bundles and the ventricular septum as integral components of a re-entrant circuit. It is usually observed in dilated cardiomyopathy, and its circuit depends exclusively on the specialized conduction system.Case presentation A 67-year-old man with a history of Fabry disease, and atrial fibrillation ablation, was admitted for a wide QRS tachycardia at 150 bpm, with an LBBB. Pharmacological therapy failed to stop the arrhythmia. Intracardiac recordings confirm the diagnosis. His Bundle recordings are essential, and Atrioventricular (AV) dissociation is typically present. The method used to induce left BBRVT is right ventricle apex stimulation. An electrophysiological study showed an AV dissociation a long HV sequence and a similar QRS morphology between VT and sinus rhythm. An overdrive stopped it. The same arrhythmia reappears and is restored to sinus rhythm by electrical cardioversion.We decided to implant an Implantable Cardiac defibrillator (ICD) with a backup pacing for secondary prevention and to ablate the right bundle branch. Conclusion BBRVT is a rare entity that is underreported. Pharmacological therapy is usually inefficient. An ICD is recommended for secondary prevention and can provide backup pacing, frequently required after catheter ablation to prevent the development of AV block or an excessive prolonged HV interval. Catheter ablation of the bundle branch is the first-line therapy.

Background: The lead of left bundle branch area pacing (LBBAP) inserted into the muscular septum will make the transvenous lead extraction (TLE) of LBBAP more challenging and because in LBBAP ventricular lead (V lead) should be inserted into the part of the septum, damage to the vessel near the lead could occur. The case reports introduced the complications of LBBAP previously introduced, but not being considered in detail.Case presentation The two patients (76-year-old man, 90-year-old man) with a complete atrioventricular block (CAVB) undergoing the LBBAP procedure experienced complications related to the procedure. The complications were abrupt dysfunction of V lead and damage to the septal vein in the process of the procedure, respectively. Fortu‑ nately, they were discharged without any other complications. Conclusions A deliberate approach for the procedure would be needed as well as successful insertion appropriate for the protocol of LBBAP. And long-term follow-up of complications should be needed.

Background: Pheochromocytoma is a rare catecholamine-producing tumour originating from adrenal chromaffin cells. Classic clinical presentation includes headache, diaphoresis and palpitation. Syncope is uncommon and may result from hypotension or arrhythmia. We report a case of neurally mediated syncope in pheochromocytoma associated with cardiac repolarization abnormalities, a unique presentation of the disease.Case presentation This case report presents a 28 year-old woman, describing recurrent syncope usually preceded by prodromes such as headache, visual blurring, heart palpitations and psychomotor agitation. Firstly she was diagnosed with anxiety and depression, but there was no improvement of symptoms with psychiatric treatment. Previous Holter revealed long QT interval. Echocardiogram showed normal dimensions, preserved left ventricular function and no valvopathies. The patient was referred for a Head-up tilt test (HUTT) in order to investigate reflex syncope. The electrocardiogram (ECG) exhibited normal sinus rhythm and diffuse cardiac repolarisation abnormalities. HUTT was positive for vasodepressor type neurally mediated syncope and ECG showed U waves after a syncope episode.This electrocardiographic finding motivated further clinical investigation. The patient also described abdominal pain, increased abdominal volume, weight loss and blood pressure instability. Based on clinical history and ventricular repolarisation abnormalities uncovered by HUTT, pheochromocytoma was suspected. Urinary test was positive for catecholamines and the abdominal imaging revelead expansive lesion. She underwent surgery to remove the pheochromocytoma, confirmed by immunohistochemistry. Conclusions After surgery she had no recurrency of symptoms, remaining asymptomatic after six years of follow-up, suggesting a cause-effect relationship between neurally mediated syncope and pheochromocytoma.

WSWs have the potential to reliably and continuously screen for AFib and detect it in a timely manner.The inconclusive results produced by WSWs are a significant problem. Once the inconclusive results are rectified, WSWs may be used for widespread screening of AFib in those people who are at high risk of developing AFib.

Background: Atrial tachycardia poses challenges in patient management due to the associated risks of stroke and systemic embolism. While anticoagulation is recommended in atrial fibrillation (AF), its role in atrial tachycardia remains less defined. This prospective study aimed to evaluate the efficacy and safety of apixaban, a direct oral anticoagulant, in individuals diagnosed with left-sided atrial tachycardias. Methods: Patients diagnosed with left-sided atrial tachycardia (n = 439) were observed over 3 years. Baseline characteristics, medication regimens, and clinical outcomes were assessed. Apixaban-treated individuals (n = 213) received standard or reduced dosages, while the control group (n = 226) received standard care. Primary outcomes included stroke, systemic embolism, bleeding, and mortality rates. Results: Baseline characteristics were comparable between groups. The apixaban cohort showed a lower incidence of stroke (7.0% vs. 9.3%, p = 0.027) and decreased all-cause mortality (11.7% vs. 12.8%, p = 0.012) compared to controls.No significant differences were found in major bleeding or systemic embolization between groups. Conclusion Apixaban demonstrated a potential benefit in reducing stroke and mortality rates in patients with leftsided atrial tachycardia. While requiring further validation, these findings suggest a potential role for apixaban in anticoagulation strategies for atrial tachycardia management.