A 69-year-old female presented to the emergency department with a two-hour history of persistent palpitations. An ECG showed a highly regular narrow QRS tachycardia with P waves. She was ultimately diagnosed with focal atrial tachycardia after an adenosine challenge. Focal atrial tachycardia is a regular, narrow complex, supraventricular tachycardic rhythm that is often paroxysmal and self-resolving. When this rhythm persists, it can eventually lead to tachycardia-induced cardiomyopathy. Narrow QRS complex tachycardia has a broad differential that encompasses many benign and dangerous rhythms. This report highlights the challenges and potential diagnostic pitfalls that can occur while trying to diagnose and evaluate tachydysrhythmias with presenting P-waves. We discuss the management strategies and propose a diagnostic algorithm to aid in the diagnosis of tachydysrhythmias.

Paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal re-entry tachycardia (AVNRT), are commonly treated with vagal maneuvers. The modified Valsalva maneuver, combining forced expiration with postural change, has shown higher success rates. A 44-year-old woman with recurrent PSVT underwent a modified Valsalva maneuver under ECG monitoring. The maneuver induced a 10-second asymptomatic polymorphic VT that resolved spontaneously. Echocardiography and labs were normal, and electrophysiology confirmed AVNRT. The patient was successfully treated with cryoablation. The modified Valsalva maneuver is generally safe. However, in rare cases it can induce ventricular tachycardia through autonomic, hemodynamic, or re-entry-related mechanisms. The modified Valsalva maneuver remains a first-line treatment for PSVT, but initial use should be ECG monitored. If polymorphic VT or other ventricular arrhythmias occur during the maneuver, further electrophysiological evaluation is warranted, and ablation should be considered for confirmed PSVT.

Introduction: Palpitations are one of the most common cardiovascular complaints, affecting approximately 6% to 11% of the general population. Since palpitations often occur sporadically and resolve before medical evaluation, diagnosing the underlying rhythm disturbance requires documentation via an electrocardiogram (ECG) recorded during the symptomatic episode. The standard tool for this purpose has long been the 24-h Holter monitor, which has significant limitations, with diagnostic yields as low as 10% to 15%. Objective: This study aims to evaluate the feasibility and diagnostic yield of single-lead ECG recordings from smartwatches in patients presenting with palpitations. Methods: From 1 May 2023 to 1 May 2025, we conducted a prospective, real-world cohort study among consecutive adults referred to the University Hospital of Ferrara-based arrhythmia outpatient clinics for evaluation of palpitations. Eligibility required patients to be ≥21 years of age, report palpitations for which ambulatory documentation was clinically indicated, and already own a compatible smartwatch capable of single-lead ECG. Participants were trained to record a 30-s single-lead ECG at the onset of symptoms. Tracings were transmitted securely and independently reviewed by two blinded electrophysiologists. Results: Fifty-nine patients were enrolled (mean age 52 years, 64% male). Thirty-one patients (52%) transmitted at least one smartwatch-derived electrocardiographic tracing. Seventy-seven smartwatch tracings were received. Of these, 73 (95%) were interpretable; 57 (78%) showed an arrhythmia, whereas 16 (22%) demonstrated normal sinus rhythm. Four recordings (5%) were non-interpretable. From the 57 arrhythmic tracings, 44 distinct arrhythmic diagnoses were identified. Paroxysmal atrial fibrillation (AF) accounted for 16 episodes. Other diagnosed arrhythmias included atrial flutter (n = 6), paroxysmal supraventricular tachycardia (PSVT) (n = 4), premature atrial complexes (PAC) (n = 6), premature ventricular complexes (PVC) (n = 9), inappropriate sinus tachycardia (n = 12), and second-degree atrioventricular (AV) block type I (n = 4). Conclusions: Smartwatch-based ECG monitoring in symptomatic patients is feasible and provides a high diagnostic yield for a broad spectrum of arrhythmias. Unlike large-scale population screening approaches, which generate vast datasets with limited clinical benefit, a symptom-driven strategy applied to carefully selected, educated, and motivated patients proves both clinically valuable and organizationally sustainable. Indeed, the mean number of tracings transmitted per patient was low (1.3), confirming the clinical and operational sustainability of this patient-triggered, real-world approach.

Etripamil (CARDAMYST[TM]) is an intranasal L-type calcium channel blocker (CCB) developed by Milestone Pharmaceuticals for the treatment of symptomatic paroxysmal supraventricular tachycardia (PSVT) and is under investigation for atrial fibrillation with rapid ventricular rate (AF-RVR). It received its first approval on the 12 December 2025 in the USA for the conversion of acute symptomatic PSVT episodes to sinus rhythm in adults. Additional global regulatory filings of etripamil for PSVT in adults, a phase II trial of etripamil in pediatrics, and a phase III trial for AF-RVR are in progress. This article summarizes the milestones in the development of etripamil leading to this first approval for PSVT.

Atrioventricular nodal reentrant tachycardia (AVNRT) is a common paroxysmal supraventricular tachycardia, often treated with slow pathway (SP) ablation. Rarely, iatrogenic AV block occurs. In the present case, a 50-year-old male underwent SP ablation for recurrent symptomatic AVNRT. The procedure was complicated by long-lasting 2:1 nodal atrioventricular (AV) block. Cardioneuroablation (CNA) targeting the inferior paraseptal ganglionated plexus was attempted during the same procedure. Bi-atrial ablation suddenly restored a sustained 1:1 AV conduction. Follow-up at two months showed normal AV conduction without arrhythmia documentation. This case demonstrates, for the first time, the use of CNA to treat acute iatrogenic nodal AV block during index SP ablation. It highlights CNA's potential to restore nodal function and avoid pacemaker implantation, potentially expanding its clinical indications beyond functional bradyarrhythmias.

Arrhythmias are among the most common cardiac complications during pregnancy, occurring in women with or without underlying structural heart disease. Early recognition and timely management are crucial to achieving the best possible maternal and fetal outcomes. Supraventricular arrhythmias are particularly frequent during pregnancy. Wolff-Parkinson-White (WPW) syndrome is a rare pre-excitation disorder characterized by the presence of an accessory pathway and can occasionally lead to life-threatening arrhythmias. The exact prevalence of WPW syndrome predisposing to supraventricular tachycardia (SVT) in pregnancy is not known. We present a case of a 28-year-old woman in her second trimester of pregnancy presenting with sudden-onset palpitations. She was hemodynamically stable on presentation, and her electrocardiogram (ECG) recording demonstrated SVT with a heart rate of 226 beats per minute. After a failure of vagal maneuvers, she was successfully treated with intravenous adenosine. Her subsequent ECG was consistent with WPW syndrome with delta waves. This case highlights the complexities in managing a case of SVT in pregnancy with WPW syndrome during its acute phase and follow-up. With pregnancy being a risk factor for an arrhythmogenic state, the presence of an accessory pathway may further increase the risk of fatal arrhythmia. Management should be approached keeping both maternal and fetal outcomes in perspective.