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Introduction: There is a lack of studies in the literature directly investigating the relationship between atrial tachycardia (AT) and left atrial (LA)/left atrial appendage (LAA) thrombus, and current guidelines do not provide strong recommendations regarding the use of transesophageal echocardiography (TEE) before AT catheter ablation. This study aims to elucidate the relationship between AT and the presence of LA/LAA thrombus and contribute to the literature on the use of TEE before AT catheter ablation. Methods: This single‐center retrospective observational study screened patients who underwent TEE between February 10, 2019, and February 10, 2023. Patients were assigned to the AT patient and control groups. TEE was conducted to exclude thrombus in the AT ablation group. The control group included patients who underwent TEE for interatrial septum evaluation and had LA imaging during TEE but did not have atrial arrhythmia. To mitigate bias between the AT patient group and the control group, they were randomized 1:1 using propensity‐score matching (PSM). Following randomization, each group consisted of 49 patients. Results: All analyses were conducted after PSM. There were no statistically significant differences between the AT patient and control groups in terms of baseline clinical characteristics and echocardiographic features. Additionally, no significant differences were found between the blood viscosities calculated at low and high shear rates in both groups. The study revealed a significant difference between the two groups in the presence of LA spontaneous echo contrast (SEC) (24.5% in AT group vs 0% in Control group, p =.001), but not in the presence of thrombi (8.2% in AT group vs 0% in Control group, p =.117). Conclusion: Compared to the control group, the presence of SEC was significantly higher in the AT patient group. The increased frequency of SEC in AT patients suggests the hypothesis that AT may contribute to LA stasis. The routine use of TEE before AT catheter ablation remains controversial, despite the presence of LA thrombus and SEC in the AT patient group. The clinical assessment of thrombus presence before the procedure must be conducted on a patient‐specific basis. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 38-year-old woman with recurrent palpitations and no structural heart disease, who presented with a documented wide QRS complex tachycardia (WCT) with negative precordial concordance. It discusses the differential diagnosis of the tachycardia mechanism and the management approach, including electrophysiologic study and radiofrequency ablation.

The article describes the case of a 67-year-old diabetic man with ischemic cardiomyopathy presented with a recurrent defibrillator shock. Topics discussed include medical history of the patient, importance of the introduction of premature ventricular complexes (PVC) during wide complex tachycardias (WCT), and ventriculoatrial (V-A0 responses of the tachycardia.

The article presents a case of a 58-year-old male experiencing recurrent episodes of paroxysmal palpitation to discuss the mechanism of a wide QRS tachycardia with short and long ventriculoatrial interval in the presence of atriofascicular (AF) accessory pathway (AP). Also cited are the patient's spontaneous sustained wide complex tachycardia (WCT) with left bundle branch block (LBBB) morphology, and the differential diagnosis of regular WCT like atrial flutter or atrial tachycardia (AT).

Catheter ablation of the slow pathway is the recommended treatment for atrioventricular nodal reentrant tachycardia (AVNRT) in children. Both radiofrequency ablation (RF) and cryoablation (CA) have been used for this purpose. In this report, we describe our experience during the transition period from RF to CA for the treatment of pediatric AVNRT. Between January 2012 and August 2021, a retrospective evaluation was conducted of the clinical features, procedural outcomes, and follow-ups of pediatric AVNRT patients who underwent catheter ablation at a pediatric electrophysiology center. The catheter ablation outcomes of 89 pediatric AVNRT patients were evaluated: 29 patients were ablated using RF (RF group) and 60 patients were ablated using CA (CA group). No significant difference was found between the groups in terms of gender, age, weight, and success and recurrence rates. The procedure duration and total lesion numbers were statistically significantly lower in the RF group compared with the CA group (86.67 ± 45.8 and 156.1 ± 37.7 min; p = 0.01, 4 [3–6] and p < 0.01, 8 [7–9] lesions, respectively). Catheter ablation was successful in all patients. There were no permanent complete atrioventricular blocks in both groups. A total of six patients (6.8%) developed recurrences. The cryoablation of pediatric AVNRT is a safe and effective procedure with comparable acute and mid-term follow-up success rates compared with RF, even during a period of transition from RF to CA. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 28-year-old woman undergoing an electrophysiology study (EPS). Topics include episodes of palpitations with documented narrow (NCT) and wide QRS complex tachycardia (WCT); and dissociation of HB potential from ongoing tachycardia favor AVNRT with BBB aberrancy.

The article presents a case study of a 59-year-old man who had rapid palpitations and documented supraventricular tachycardia (SVT) unresponsive to metoprolol therapy. He was diagnosed with an accessory pathway (AP) conduction, with the pathway being a bystander, and as orthodromic tachycardia (ORT) with posteroseptal AP. Also noted is the possibility of resetting even if no change in subsequent cycle length is seen during tachycardia.

A 32‐year‐old woman underwent radiofrequency catheter ablation of narrow QRS tachycardia that was terminated with intravenous adenosine. [ABSTRACT FROM AUTHOR]

The termination of tachycardia may provide important clues toward the mechanism of the tachycardia and that close vigilance may clinch the diagnosis before proceeding to other pacing maneuvers. [ABSTRACT FROM AUTHOR]

Abstract: Exercise-induced monomorphic ventricular tachycardia originating in the right ventricular outflow tract without evidence of structural heart disease can be idiopathic or can be the harbinger of structural abnormalities such as arrhythmogenic right ventricular dysplasia. Recently, the so-called variant Brugada syndrome has been reported in very few cases in the literature and is much less electrophysiologically defined in terms of its clinical significance. We present the case of a 21-year-old man with exercise-induced monomorphic ventricular tachycardia (left bundle-branch block/right axis deviation), without detectable structural heart disease, with evidence of J point and ST-segment elevation in electrocardiogram leads II, III, and aVF after intravenous administration of propafenone. This is followed by a brief discussion on the new concept of “variant Brugada syndrome,” drug-induced electrocardiographic changes, normal-variant repolarization abnormality, and idiopathic right ventricular outflow tract tachycardia. [Copyright &y& Elsevier]

In this prospective study, we set out to determine whether analysis of heart rate variability (HRV) in patients with exercise induced ventricular tachycardia (EIVT) and normal coronary arteries would reveal increased sympathetic nervous system activity. From January 1996 to December 2001, we compared 16 patients with EIVT and normal coronary arteries with an age- and sex-matched control group. Analysis of HRV showed that parameters indicative of parasympathetic activity were lower in our study group than in our control group: standard deviation of the mean of qualified NN intervals (SDNN), 81.6 ± 14.5 vs 139.3 ± 11.0, P <0.001; root mean square of successive differences (RMSSD), 22.3 ± 4.8 vs 36.3 ± 6.6, P <0.001; number of NN intervals that differed by more than 5 ms from the adjacent interval, divided by the total number of NN intervals (PNN50), 4.8 ± 1.5 vs 10.2 ± 3.1, P <0.001; and high-frequency component (HF), 28.7 ± 2.5 vs 32.4 ± 3.9, P <0.05. Conversely, parameters indicative of sympathetic activity were higher in patients with EIVT low-frequency component (LF), 71.2 ± 5.0 vs 52.0 ± 5.8, P <0.001; and absolute low/high frequency component ratio (LF/HF), 2.7 ± 0.2 vs 1.6 ± 0.2, P <0.001. There was a positive correlation between E/Wand LF (r=0.79, P <0.001) and between EIVT and LF/HF... [ABSTRACT FROM AUTHOR]