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Background: Paroxysmal supraventricular tachycardia (PSVT) is a common episodic arrhythmia characterized by unpredictable onset and burdensome symptoms including palpitations, dizziness, chest pain, distress, and shortness of breath. Treatment of acute episodes of PSVT in the clinical setting consists of intravenous adenosine, beta-blockers, and calcium channel blockers (CCBs). Etripamil is an intranasally self-administered L-type CCB in development for acute treatment of AV-nodal dependent PSVT in a nonmedical supervised setting., Methods: This paper summarizes the rationale and study design of NODE-303 that will assess the efficacy and safety of etripamil. In the randomized, double-blinded, placebo-controlled, Phase 3 RAPID trial, etripamil was superior to placebo in the conversion of single PSVT episodes by 30 minutes post initial dose when administered in the nonhealthcare setting; this study required a mandatory and observed test dosing prior to randomization. The primary objective of NODE-303 is to evaluate the safety of symptom-prompted, self-administered etripamil for multiple PSVT episodes in real-world settings, without the need for test dosing prior to first use during PSVT. Secondary endpoints include efficacy and disease burden. Upon perceiving a PSVT episode, the patient applies an electrocardiographic monitor, performs a vagal maneuver, and, if the vagal maneuver is unsuccessful, self-administers etripamil 70 mg, with an optional repeat dose if symptoms do not resolve within 10 minutes after the first dose. A patient may treat up to four PSVT episodes during the study. Adverse events are recorded as treatment-emergent if they occur within 24 hours after the administration of etripamil., Results: Efficacy endpoints include time to conversion to sinus rhythm within 30 and 60 minutes after etripamil administration, and the proportion of patients who convert at 3, 5, 10, 20, 30, and 60 minutes. Patient-reported outcomes are captured by the Brief Illness Perception Questionnaire, the Cardiac Anxiety Questionnaire, the Short Form Health Survey 36, the Treatment Satisfaction Questionnaire for Medication and a PSVT survey., Conclusions: Overall, these data will support the development of a potentially paradigm-changing long-term management strategy for recurrent PSVT., Competing Interests: Conflicts of interest Sarah Omodele, Silvia Shardonofsky and David B. Bharucha are employees of Milestone Pharmaceuticals. Bruce S. Stambler received compensation as a consultant for Milestone Pharmaceuticals. Peter Noseworthy declares no conflict of interest. Hanh Bui declares no conflict of interest. A John Camm received compensation as a consultant for Milestone Pharmaceuticals; grants and personal fees from Boehringer Ingelheim, Bayer, Pfizer, Bristol-Myers Squibb, and Daiichi Sankyo; personal fees from Medtronic, Boston Scientific, Menarini, and Biotronik; and support from Anthos, Sanofi, Abbott, GlaxoSmithKline, and Johnson & Johnson. Benoit Coutu declares no conflict of interest. Maria Leonor Parody declares no conflict of interest. Samuel F Sears received compensation from Medtronic and Abbott as a consultant; he also received speaker compensation from Medtronic, Zoll, and Biotronik; serves as a quality-of-life consultant for Thyve, Tenaya, and Milestone Pharmaceutical. Narendra Singh declares no conflict of interest. Juan Agudelo Uribe declares no conflict of interest. John Vyselaar declares no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background and Objective: Patients with palpitations clinically suggestive of paroxysmal supraventricular tachycardia (PSVT) are often managed conservatively until ECG-documentation of the tachycardia, leading to high impact on life quality and healthcare resource utilization. We evaluated results of electrophysiological study (EPS), and ablation when appropriate, among these patients, with special focus on gender differences in management., Methods: BELIEVE SVT is a European multicenter, retrospective registry in tertiary hospitals performing EPS in patients with palpitations, without ECG-documentation of tachycardia or preexcitation, and considered highly suggestive of PSVT by a cardiologist or cardiac electrophysiologist. We analyzed clinical characteristics, results of EPS and ablation, complications, and clinical outcomes during follow-up., Results: Six-hundred eighty patients from 20 centers were included. EPS showed sustained tachycardia in 60.9% of patients, and substrate potentially enabling AVNRT in 14.7%. No major/permanent complications occurred. Minor/transient complications were reported in 0.84% of patients undergoing diagnostic-only EPS and 1.8% when followed by ablation. During a 3.4-year follow-up, 76.2% of patients remained free of palpitations recurrence. Ablation (OR: 0.34, P < .01) and male gender (OR: 0.58, P = .01) predicted no recurrence. Despite a higher female proportion among patients with recurrence, (77.2% vs 63.5% among those asymptomatic during follow-up, P < .01), 73% of women in this study reported no recurrence of palpitations after EPS., Conclusions: EPS and ablation are safe and effective in preventing recurrence of nondocumented palpitations clinically suggestive of PSVT. Despite a lower efficacy, this strategy is also highly effective among women and warrants no gender differences in management., Competing Interests: Conflict of interest None., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: Paroxysmal atrial fibrillation (AF) may progress to persistent AF. We studied the clinical correlates and the effect of rhythm-control strategy on AF progression., Methods: RecordAF was a worldwide prospective survey of AF management. Consecutive eligible patients with recent-onset AF were included and allocated to rate or rhythm control according to patient/physician choice. A total of 2,137 patients were followed up for 12 months. Atrial fibrillation progression was defined as a change from paroxysmal to persistent/permanent AF., Results: Progression of AF occurred in 318 patients (15%) after 1 year. Patients with AF progression were older; had a higher diastolic blood pressure; and more often had a history of coronary artery disease, stroke or transient ischemic attack, hypertension, or heart failure. Patients treated with rhythm control were less likely to show progression than those treated only with rate control (164/1542 [11%] vs 154/595 [26%], P < .001). Multivariable analysis showed that history of heart failure (odds ratio [OR] 2.2, 95% CI 1.7-2.9, P < .0001), history of hypertension (OR 1.5, 95% CI 1.1-2.0, P = .01), and rate control rather than rhythm control (OR 3.2, 95% CI 2.5-4.1, P < .0001) were independent predictors of AF progression. The propensity score-adjusted OR of AF progression in patients with rate rather than rhythm control was 3.3 (95% CI 2.4-4.6, P < .0001)., Conclusions: Although heart failure and hypertension are associated with AF progression, rhythm control is associated with lower risk of AF progression., (Copyright © 2012 Mosby, Inc. All rights reserved.)

Background: The circadian onset patterns and cycle lengths of atrial tachyarrhythmias (AT) were determined in a group of patients with persistent atrial fibrillation., Methods: Fifteen patients, mean age 63 +/- 14 years and 80% male, were implanted with the Jewel AF atrial defibrillator (Medtronic, Minneapolis, Minn) for persistent atrial fibrillation only. Onset times of AT and median onset atrial cycle lengths were determined from device memory., Results: Over a follow-up period of 23.3 +/- 7 months, 227 episodes of persistent AT were treated by patient-activated atrial defibrillation. The peak onset of persistent AT was nocturnal, with 74% of episodes initiating between 8 pm and 8 am. Eighty-seven percent of the patients experienced an additional 403 paroxysmal AT episodes. These episodes showed a "double-peaked" pattern with the least number of episodes occurring between midnight and 8 am. The mean onset atrial cycle length of persistent AT was significantly shorter than the paroxysmal AT episodes (200 +/- 37 ms vs 240 +/- 39 ms, P <.005). The atrial cycle lengths at arrhythmia onset of both paroxysmal and persistent AT episodes also demonstrated circadian variation., Conclusion: There is a circadian distribution of onsets for persistent AT with predominance at night. Patients with persistent AF have >1 type of atrial arrhythmia with differences in the onset patterns and atrial cycle lengths, suggesting different triggers and onset mechanisms.

Background: The relation between abnormalities in the signal-averaged P wave and atrial size has not been determined in patients with paroxysmal atrial fibrillation (PAF) without structural heart disease., Methods: Signal-averaged electrocardiograms of P waves were recorded in 38 patients with idiopathic PAF and 34 control subjects. Filtered P-wave duration (FPD) and root-mean-square voltages for the last 20 ms of the vector magnitude were measured. Atrial volume was calculated by cine magnetic resonance imaging., Results: FPD was longer (131.7 +/- 10.9 ms vs 120.8 +/- 8.6 ms, P <.0001) and root-mean-square voltage was lower (2.89 +/- 1.29 microV vs 3.62 +/- 1.48 microV, P <.05) in the PAF group than in control subjects. However, the various atrial volumes were similar in the 2 groups. In controls, FPD was significantly correlated with left (r = 0.593, P <.0001) and total (r = 0.492, P <.005) atrial volume but not with right atrial volume. In patients with PAF, no significant correlations were found between FPD and any of the atrial volumes. Elderly patients with PAF (age > or =60 years) showed longer FPD than younger patients with PAF (139.2 +/- 9.4 ms vs 125.6 +/- 8.0 ms, P <.0001)., Conclusions: FPD is influenced by the left and total atrial volumes in the normal heart without PAF. Prolonged FPD seems to be a useful predictor of idiopathic PAF among patients without atrial enlargement, especially in the elderly.

Background: The prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses are well known electrophysiologic characteristics in patients with paroxysmal atrial fibrillation (PAF)., Methods: To search for possible electrocardiographic markers that could serve as predictors of idiopathic PAF, we measured the maximum P-wave duration (P maximum) and the difference between the maximum and the minimum P-wave duration (P dispersion) from the 12-lead surface electrocardiogram of 60 patients with a history of idiopathic PAF and 40 age-matched healthy control subjects., Results: P maximum and P dispersion were found to be significantly higher in patients with idiopathic PAF than in control subjects. A P maximum value of 110 msec and a P dispersion value of 40 msec separated patients from control subjects, with a sensitivity of 88% and 83% and a specificity of 75% and 85%, respectively., Conclusions: P maximum and P dispersion are simple electrocardiographic markers that could be used for the prediction of idiopathic PAF.

The purpose of this study was to determine whether symptoms recorded at the time of transtelephonic ECG monitoring (TTEM) correlate with attacks of paroxysmal supraventricular tachycardia (PSVT) or paroxysmal atrial fibrillation (PAF). We studied 113 patients with these arrhythmias who made a total of 3319 TTEM calls during their participation in double-blind, placebo-controlled, crossover, multicenter trials of flecainide therapy. Among 49 patients with PSVT, 62.7% of symptomatic calls were associated with ECG-documented PSVT as compared with 6.8% of asymptomatic calls (p less than 0.001). Similarly, among 69 patients with PAF, 69% of symptomatic calls were associated with ECG-documented PAF compared with 10.6% of asymptomatic calls (p less than 0.001). Both in patients with PSVT and PAF, an attack of PSVT or PAF could be documented by ECG in more than 70% of the calls when patients complained of tachycardia, increased sweating, or dyspnea. The sensitivity of a symptomatic call was 91% for PSVT and 89% for PAF, and it was not influenced by flecainide therapy. However, flecainide therapy was associated with a decrease in the positive predictive value of symptomatic TTEM calls and an increase in false positive TTEM transmissions. We conclude that in patients with symptomatic PSVT or PAF, there is a temporal relationship between symptoms and the occurrence of ECG-documented attacks of PSVT or PAF. However, sole reliance should not be placed on the presence or absence of symptoms as a measure of drug failure or efficacy, and it is important to document the cardiac rhythm by TTEM at the time symptoms are recorded.

The efficacy of a single oral dose of flecainide to terminate paroxysmal supraventricular tachycardia (PSVT) was evaluated in 25 children and young adults. The subjects were selected from a group of 35 patients with recurrent attacks of PSVT evaluated by means of electrophysiologic study and intravenous electropharmacologic testing with flecainide. In all 25 patients the induced PSVT was stopped by intravenous flecainide and was then no longer inducible or nonsustained. All patients had normal hearts. At least 48 hours after acute intravenous testing, 25 patients underwent electrophysiologic study with a transesophageal catheter and PSVT was induced in all of them: atrioventricular reentrant tachycardia in 16 and atrioventricular nodal reentrant tachycardia in nine. During stable tachycardia, a single oral dose of flecainide (2.9 +/- 0.3 mg/kg; 2.5 to 3.3 mg/kg) was administered. This approach was effective for termination of PSVT in 22 patients. The mean plasma level of flecainide at cessation of tachycardia was 277 +/- 92 ng/ml (150 to 500 mg/ml). All 22 patients who responded were given a single oral dose of flecainide for recurrences of PSVT during follow-up. During a period of 12 +/- 7 months (2 to 27 months) a total of 134 spontaneous episodes of PSVT were reported, and 127 of these episodes were terminated with periodic management. Thus oral periodic flecainide seems useful for management of PSVT in selected patients.

Atrioventricular conduction patterns suggestive of dual A-V nodal pathways have been reported in patients with and without a history of paroxysmal A-V nodal re-entrant tachycardia (PSVT). The purpose of this study was to determine whether significant association exists between this conduction pattern and the occurrence of PSVT in man. The pattern of A-V conduction was evaluated at similar pacing rates in 13 patients with documented PSVT and 135 patients with PSVT. Patients without PSVT were divided into groups with normal PR intervals (106 patients), PR intervals of 120 msec. or less (12 patients), and PR intervals of 200 msec. or greater (17 patients). Evidence of dual A-V nodal pathways was found in seven of 13 patients with PSVT and nine of 135 patients without PSVT, including eight of 106 patients with normal PR intervals, none of 12 patients with short PR intervals, and one of 17 patients with PR intervals of 200 msec. or greater. The incidence of dual A-V nodal pathways was significantly greater (P less than 0.01) in patients with PSVT when compared with all other groups. In two of four patients with PSVT, propranolol was found to unmask evidence of dual pathways; no evidence of dual pathways was produced by propranolol in 23 patients without PSVT. The data show that the pattern of dual A-V nodal pathways is common only in patients with PSVT and is significantly less frequent in patients without PSVT regardless of the presence of short or long PR intervals. The results of this study establish a strong association between this conduction pattern and the occurrence of PSVT in man.

Atrial contractions can be reliably detected by subcostal M-mode echocardiography of the right atrial wall. Recognition of various rhythm disturbances, especially tachyarrhythmias, is facilitated in the simultaneously recorded nondiagnostic ECG. Differentiation between supraventricular tachycardias with aberration and ventricular tachycardia with atrioventricular dissociation is alleviated. However, this technique is of limited value in the diagnosis of ventricular tachycardia with retroconduction and is not useful in differentiating supraventricular tachycardias with wide QRS from ventricular tachycardia when atrial fibrillation coexists.