Importance of the Activation Sequence of the His or Right Bundle for Diagnosis of Complex Tachycardia Circuits.

In this review, we emphasize the unique value of recording the activation sequence of the His bundle or right bundle branch (RB) for diagnoses of various supraventricular and fascicular tachycardias. A close analysis of the His to RB (H-RB) activation sequence can help differentiate various forms of supraventricular tachycardias, namely atrioventricular nodal reentry tachycardia from concealed nodofascicular tachycardia, a common clinical dilemma. Furthermore, bundle branch reentry tachycardia and fascicular tachycardias often are included in the differential diagnosis of supraventricular tachycardia with aberrancy, and the use of this technique can help the operator make the distinction between supraventricular tachycardias and these other forms of ventricular tachycardias using the His-Purkinje system. We show that this technique is enhanced by the use of multipolar catheters placed to span the proximal His to RB position to record the activation sequence between proximal His potential to the distal RB potential. This allows the operator to fully analyze the activation sequence in sinus rhythm as compared to that during tachycardia and may help target ablation of these arrhythmias. We argue that 3 patterns of H-RB activation are commonly identified-the anterograde H-RB pattern, the retrograde H-RB (right bundle to His bundle) pattern, and the chevron H-RB pattern (simultaneous proximal His and proximal RB activation)-and specific arrhythmias tend to be associated with specific H-RB activation sequences. We show that being able to record and categorize this H-RB relationship can be instrumental to the operator, along with standard pacing maneuvers, to make an arrhythmia diagnosis in complex tachycardia circuits. We highlight the importance of H-RB activation patterns in these complex tachycardias by means of case illustrations from our groups as well as from prior reports.

Natural History of Arrhythmia After Successful Isolation of Pulmonary Veins, Left Atrial Posterior Wall, and Superior Vena Cava in Patients With Paroxysmal Atrial Fibrillation: A Multi-Center Experience.

Background We evaluated long-term outcome of isolation of pulmonary veins, left atrial posterior wall, and superior vena cava, including time to recurrence and prevalent triggering foci at repeat ablation in patients with paroxysmal atrial fibrillation with or without cardiovascular comorbidities. Methods and Results A total of 1633 consecutive patients with paroxysmal atrial fibrillation that were arrhythmia-free for 2 years following the index ablation were classified into: group 1 (without comorbidities); n=692 and group 2 (with comorbidities); n=941. We excluded patients with documented ablation of areas other than pulmonary veins, the left atrial posterior wall, and the superior vena cava at the index procedure. At 10 years after an average of 1.2 procedures, 215 (31%) and 480 (51%) patients had recurrence with median time to recurrence being 7.4 (interquartile interval [IQI] 4.3-8.5) and 5.6 (IQI 3.8-8.3) years in group 1 and 2, respectively. A total of 201 (93.5%) and 456 (95%) patients from group 1 and 2 underwent redo ablation; 147/201 and 414/456 received left atrial appendage and coronary sinus isolation and 54/201 and 42/456 had left atrial lines and flutter ablation. At 2 years after the redo, 134 (91.1%) and 391 (94.4%) patients from group 1 and 2 receiving left atrial appendage/coronary sinus isolation remained arrhythmia-free whereas sinus rhythm was maintained in 4 (7.4%) and 3 (7.1%) patients in respective groups undergoing empirical lines and flutter ablation (P<0.001). Conclusions Very late recurrence of atrial fibrillation after successful isolation of pulmonary veins, regardless of the comorbidity profile, was majorly driven by non-pulmonary vein triggers and ablation of these foci resulted in high success rate. However, presence of comorbidities was associated with significantly earlier recurrence.

Vagal Reactions During Laser Balloon Ablation in Patients with Paroxysmal Atrial Fibrillation.

Radiofrequency and cryoballoon applications around the pulmonary veins (PVs) could provoke a vagal reflex (VR) by modulating the intrinsic cardiac autonomic nervous system (ICANS).This study aimed to investigate the incidence, timing, and clinical impact of a VR provoked by a laser balloon application for a PV isolation (PVI).A total of 92 consecutive paroxysmal atrial fibrillation (PAF) patients underwent a laser balloon PVI of PAF. Acute changes in the heart rate and blood pressure were recorded. The heart rate variability (HRV) was tested by Holter ECGs before and at three months following the ablation. Three hundred forty-five out of 363 PVs were successfully isolated (97%) with laser balloon applications. A VR such as sinus bradycardia (26.1%), transient sinus arrest (9.8%), transient atrioventricular block (1.1%), or a blood pressure reduction (8.7%) was observed during the laser balloon applications for the PVI. The follow-up ended at 12 months. The HRV attenuation was comparable before and at three months after the ablation procedure between that with and without a VR (P = 0.14). The PAF recurrence rate was also comparable between the two groups (P = 0.882).The laser balloon PVI often provoked a VR, however, the modulation of the ICANS was temporary and for up to three months as measured by the HRV changes after the ablation, and the freedom from any atrial fibrillation recurrence was comparable regardless of the occurrence of a VR.

Cryoballoon pulmonary vein isolation-mediated rise of sinus rate in patients with paroxysmal atrial fibrillation.

BACKGROUND: Modulation of the cardiac autonomic nervous system by pulmonary vein isolation (PVI) influences the sinoatrial nodal rate. Little is known about the causes, maintenance and prognostic value of this phenomenon. We set out to explore the effects of cryoballoon PVI (cryo-PVI) on sinus rate and its significance for clinical outcome. METHODS AND RESULTS: We evaluated 110 patients with paroxysmal atrial fibrillation (AF), who underwent PVI using a second-generation 28 mm cryoballoon by pre-, peri- and postprocedural heart rate acquisition and analysis of clinical outcome. Ninety-one patients could be included in postinterventional follow-up, indicating that cryo-PVI resulted in a significant rise of sinus rate by 16.5% (+ 9.8 ± 0.9 beats/min, p < 0.001) 1 day post procedure compared to preprocedural acquisition. This effect was more pronounced in patients with initial sinus bradycardia (< 60 beats/min.) compared to patients with faster heart rate. Increase of rate was primarily driven by ablation of the right superior pulmonary vein and for a subset of patients, in whom this could be assessed, persisted ≥ 1 year after the procedure. AF recurrence was neither predicted by the magnitude of the initial rate, nor by the extent of rate change, but postprocedural sinus bradycardia was associated with higher recurrence of AF in the year post PVI. CONCLUSIONS: Cryo-PVI causes a significant rise of sinus rate that is more pronounced in subjects with previous sinus bradycardia. Patient follow-up indicates persistence of this effect and suggests an increased risk of AF recurrence in patients with postprocedural bradycardia.

Prospective multicentric validation of a novel prediction model for paroxysmal atrial fibrillation.

BACKGROUND: The early recognition of paroxysmal atrial fibrillation (pAF) is a major clinical challenge for preventing thromboembolic events. In this prospective and multicentric study we evaluated prediction scores for the presence of pAF, calculated from non-invasive medical history and echocardiographic parameters, in patients with unknown AF status. METHODS: The 12-parameter score with parameters age, LA diameter, aortic root diameter, LV,ESD, TDI A', heart frequency, sleep apnea, hyperlipidemia, type II diabetes, smoker, ß-blocker, catheter ablation, and the 4-parameter score with parameters age, LA diameter, aortic root diameter and TDI A' were tested. Presence of pAF was verified by continuous electrocardiogram (ECG) monitoring for up to 21 days in 305 patients. RESULTS: The 12-parameter score correctly predicted pAF in all 34 patients, in which pAF was newly detected by ECG monitoring. The 12- and 4-parameter scores showed sensitivities of 100% and 82% (95%-CI 65%, 93%), specificities of 75% (95%-CI 70%, 80%) and 67% (95%-CI 61%, 73%), and areas under the receiver operating characteristic (ROC) curves of 0.84 (95%-CI 0.80, 0.88) and 0.81 (95%-CI 0.74, 0.87). Furthermore, properties of AF episodes and durations of ECG monitoring necessary to detect pAF were analysed. CONCLUSIONS: The prediction scores adequately detected pAF using variables readily available during routine cardiac assessment and echocardiography. The model scores, denoted as ECHO-AF scores, represent simple, highly sensitive and non-invasive tools for detecting pAF that can be easily implemented in the clinical practice and might serve as screening test to initiate further diagnostic investigations for validating the presence of pAF. Prospective validation of a novel prediction model for paroxysmal atrial fibrillation based on echocardiography and medical history parameters by long-term Holter ECG.

The effect of left atrial remodeling after cryoballoon ablation and radiofrequency ablation for paroxysmal atrial fibrillation.

BACKGROUND: Cryoballoon ablation (CBA) and radiofrequency ablation (RFA) are the most common procedures used to treat refractory atrial fibrillation (AF) and are performed through pulmonary vein isolation (PVI). Studies have shown that CBA can approximately match the therapeutic effects of RFA against AF. However, few studies have investigated the difference between CBA and RFA of the effects on left atrial remodeling for paroxysmal AF. OBJECTIVE: Atrial remodeling is considered pivotal to the occurrence and development of AF, therefore we sought to assess the influence of atrial remodeling in patients with paroxysmal AF after CBA and RFA in this study. METHODS: In this nonrandomized retrospective observational study, we enrolled 328 consecutive patients who underwent CBA or RFA for refractory paroxysmal AF in May 2014 to May 2017 in our hospital. After propensity score matching, 96 patients were included in the CBA group, and 96 were included in the RFA group. Patients were asked to undergo a 12-lead electrocardiogram, a 24-h Holter monitor, and an echocardiogram and to provide their clinical history and symptoms at 6 months and 1, 2, and 3 years postprocedurally. Electrical remodeling of the left atrium was assessed by P wave dispersion (Pdis); structural remodeling was assessed by the left atrium diameter (LAD) and left atrial volume index (LAVI) during scheduled visits. RESULTS: As of January 2020, compared with baseline, at 1 year, 2 years, and 3 years after ablation, the average changes in Pdis (∆Pdis), LAD (∆LAD), and LAVI (∆LAVI) were significant in both the CBA and RFA groups. Six months after ablation, ∆Pdis, ∆LAD, and ∆LAVI were greater in the CBA group than in the RFA group. There was no significant difference between the two groups in AF/flutter recurrence, but the AF/flutter-free survival time of CBA group may be longer than RFA group after 2 years after ablation. A higher ∆Pdis, ∆LAD, or ∆LAVI at 1 year after ablation may increase AF/flutter-free survival. CONCLUSIONS: Although CBA and RFA are both effective in left atrial electrical and structural reverse-remodeling in paroxysmal AF, CBA may outperform RFA for both purposes 6 months after ablation. However, during long-term follow-up, there was no significant intergroup difference.

Ablation of paroxysmal and persistent atrial fibrillation in the very elderly real-world data on safety and efficacy.

BACKGROUND: The role and technique of catheter ablation of atrial fibrillation (AF) in the elderly is unclear. While in young patients pulmonary vein isolation (PVI) has evolved as first option, in older patients decision is often made in favor of drugs as higher complication rates and less benefit are suspected. Therefore, data on PVI of paroxysmal and persistent AF in these patients is still sparse but of eminent importance. HYPOTHESIS: PVI is comparably safe in the very elderly with similar recurrence and complication rates. METHODS: We enrolled all patients (n = 146) aged >75 years who underwent a first PVI over a period of 10 years (2009-2019) from our prospective single-center ablation registry. Mean follow-up time was 231 ± 399 days. RESULTS: Acute ablation success defined as complete PVI and sinus rhythm at the end of the ablation procedure was high (99%). Severe periprocedural complications occurred in 3.3% (stroke/TIA n = 2; 1.3%; pericardial effusion n = 3; 2%). In 4.6% of patients symptomatic sick-sinus-syndrome was unmasked after PVI resulting in pacemaker implantation. There were no deaths related to PVI. Recurrence rate of symptomatic AF was 37.3% resulting in a Re-PVI and/or substrate ablation in 32 pts (20.9%). During follow-up pacemaker implantation plus atrioventricular node ablation was performed in 10 pts (6.8%). There was a trend toward lower recurrence rates with single-shot devices (cryoballoon, multielectrode phased-radiofrequency ablation catheter) than with point-by-point radiofrequency while complication rates did not differ. CONCLUSION: PVI for AF is a feasible treatment option also in patients >75 years with a reasonable success and safety profile. Higher success rates occurred in patients treated with a single-shot device as compared to point-by-point ablation.

Comparative effects of intensive ganglionated plexus ablation in treating paroxysmal atrial fibrillation and vasovagal syncope.

BACKGROUND: Ganglionated plexus (GP) ablation is used to treat atrial fibrillation (AF) and vasovagal syncope (VVS). However, the comparative effects of GP ablation in treating paroxysmal atrial fibrillation (PAF) and VVS have not been well studied. OBJECTIVE: The purpose of this study was to investigate the effects of intensive GP ablation on PAF and VVS. METHODS: PAF and VVS patients were enrolled in this study. Pulmonary vein isolation (PVI) was performed in the PAF group, and additional ablation was performed at GP sites. Anatomic ablation of left atrial GPs was performed in the VVS group. The primary endpoint was freedom from AF or other sustained atrial tachycardia and syncope recurrence. RESULTS: A total of 195 patients were enrolled: 146 patients with PAF, including eight patients with combined VVS (PAF group), and 49 patients with VVS (VVS group). Vasovagal response (VR) was achieved in 78 (53.4%) patients in the PAF group and 48 patients (98.0%) in the VVS group (P < .05). During the 17.8 ± 10.5 (range, 3-42) month follow-up, 126 (86.3%) patients were free of AF in the PAF group, and 45 (91.8%) patients in the VVS group had no syncope recurrence and significantly improved symptoms. CONCLUSIONS: Anatomically guided intensive GP ablation showed efficient clinical outcomes for both groups of patients. Compared with PAF patients, VVS patients had more VR during ablation in the left atrium. Furthermore, VR during ablation indicated a better prognosis in PAF patients.

Enfoque en el diagnóstico diferencial de las taquicardias paroxísticas supraventriculares en el Laboratorio de electrofisiología / Differential diagnosis of paroxysmal supraventricular tachycardia at the electrophysiology laboratory

Resumen: Las taquicardias paroxísticas supraventriculares son arritmias frecuentes y producen importante morbilidad. El estudio electrofisiológico permite hacer el diagnóstico su mecanismo para luego realizar la ablación. El diagnóstico no siempre es sencillo y se debe recurrir a múltiples observaciones y maniobras para alcanzarlo. En la siguiente revisión se discuten los principales criterios usados para el diagnóstico del mecanismo de estas taquicardias durante un estudio electrofisiológico.

Abstract: Paroxysmal supraventricular tachycardias are frequently observed arrhythmias associated to significant morbidity. Electrophysiological study allows the diagnosis of the mechanisms underlying the arrhythmia leading toblation. The diagnosis is not always easy and multiple observations and maneuvers are required to uncover it. In the following review, the main criteria used to diagnose the mechanisms of these tachycardias during an electrophysiological study are discussed.

Usefulness of tissue Doppler-derived atrial electromechanical delay for identifying patients with paroxysmal atrial fibrillation.

BACKGROUND: Tissue Doppler imaging (TDI)-derived atrial electromechanical delay (AEMD) has been reported to be useful for detecting paroxysmal atrial fibrillation (PAF). However, its usefulness remains unknown when analyzed along with patients seemingly at high-risk for AF as controls. From this standpoint, we investigated whether AEMD would be of use for identifying patients with PAF. METHODS: We retrospectively analyzed TDI recordings to obtain AEMD in 63 PAF patients. Thirty-three patients with multiple cardiovascular risk factors (MRFs) but without history of AF and 50 healthy individuals served as disease and healthy controls, respectively. AEMD was defined as the time-interval between the electrocardiogram P-wave and the beginning of the spectral TDI-derived A' for the septal (septal EMD) and lateral (lateral EMD) sides of the mitral annulus. RESULTS: There was no significant difference in the left atrial volume index between PAF patients and disease controls (28 ± 9 mL/m2 vs. 27 ± 5 mL/m2). PAF patients had longer AEMD, particularly for the lateral EMD (75 ± 23 ms), compared with disease (62 ± 22 ms, P = 0.009) and healthy (54 ± 24 ms, P < 0.001) controls. Multivariate logistic regression analysis revealed that the lateral EMD (OR 1.25, 95%CI 1.03-1.52, P = 0.023), along with the left atrial volume index (OR 2.25, 95%CI 1.44-3.51, P < 0.001), was one of the significant independent associates of identifying PAF patients. CONCLUSIONS: This cross-sectional study indicates that even analyzed together with MRFs patients, AEMD remains useful for identifying patients at risk for AF. Our results need to be confirmed by a large-scale prospective study.

Common wearable devices demonstrate variable accuracy in measuring heart rate during supraventricular tachycardia.

BACKGROUND: Wearable devices are used as a noninvasive method of monitoring health. The accuracy of wearables for heart rate (HR) monitoring has been extensively studied in sinus rhythm, but evidence for tachyarrhythmias, particularly supraventricular tachycardia (SVT), is sparse. OBJECTIVE: The purpose of this study was to examine the accuracy of 4 common wearable devices-Apple Watch, Fitbit Charge HR, Garmin VivoSmart HR, and Polar A360-in measuring HR during paroxysmal SVT. METHODS: Data were gathered from 52 patients by placing 1 device on each wrist during an electrophysiological study at which SVT was induced. The device-measured HR was obtained by using the highest HR measured by the device during each SVT episode. This HR was compared with measurements from a 12-lead electrocardiogram (ECG), for which the rate during the last 5 seconds of SVT was averaged. RESULTS: For SVT episodes <15 seconds, the Apple, Fitbit, Garmin, and Polar devices registered an increase from baseline HR in 18.7%, 19.5%, 1.5%, and 37.7% of episodes, respectively. For episodes 15-60 seconds, the Apple, Fitbit, Garmin, and Polar devices registered an increase in 67.6%, 42.4%, 24.3%, and 65.5% of episodes, respectively. For episodes ≥60 seconds, the Apple and Polar devices had 23 of 23 and 19 of 21 episodes with at least 90% agreement between device-measured and ECG-measured HR, whereas the Fitbit and Garmin devices had 7 of 20 and 8 of 22 episodes with at least 90% agreement. CONCLUSION: All wearable devices are inaccurate for short-duration SVT. Some devices are accurate for longer duration SVT.

Early clinical experience of radiofrequency catheter ablation using an audiovisual telesupport system.

BACKGROUND: An audiovisual telesupport system that enables real-time audiovisual communications between 2 long-distance hospitals is one method of telemedicine. The usefulness and safety of radiofrequency catheter ablation (RFCA) using an audiovisual telesupport system has not been well established. OBJECTIVE: The purpose of this study was to evaluate the effectiveness and safety of RFCA using an audiovisual telesupport system. METHODS: An audiovisual telesupport system using a strictly secured virtual network was established between Kamisu Saiseikai Hospital (operator with 10 years' experience and 800 procedures) and the University of Tsukuba (advisor with >20 years' experience and 8000 procedures). We evaluated 19 initial consecutive patients who underwent RFCA using this system for tachyarrhythmia: 10 with atrial fibrillation (AF), 5 with paroxysmal supraventricular tachycardia (PSVT), 3 with premature ventricular contraction (PVC), and 1 with atrial flutter. Electrophysiological and procedural characteristics were retrospectively assessed. RESULTS: Acute success was achieved in all 19 patients without any major complications, with the advisor's audiovisual assistance. Mean procedure time and fluoroscopic time were 161 ± 44 minutes and 24 ± 14 minutes for AF, 110 ± 17 minutes and 28 ± 8 minutes for PVC, and 132 ± 19 minutes and 32 ± 2 minutes for PSVT, respectively. There was no recurrence of clinical arrhythmia in 17 of the 19 patients (89%) during 13 ± 9 month follow-up. CONCLUSION: An audiovisual telesupport system for RFCA is a useful and safe method that enabled the electrophysiologist with limited human resources to make an optimal decision regarding procedural strategy and endpoint with the remote advisor's audiovisual assistance.

Sustained quality-of-life improvement post-cryoballoon ablation in patients with paroxysmal atrial fibrillation: Results from the STOP-AF Post-Approval Study.

BACKGROUND: Pulmonary vein isolation by catheter ablation is a class IA indication for the treatment of symptomatic, drug-refractory, paroxysmal atrial fibrillation (PAF). Quality of life (QoL) has been identified as a clinically meaningful endpoint but has not been comprehensively evaluated to date. OBJECTIVE: The purpose of this study was to evaluate the effects of cryoballoon ablation on long-term QoL. METHODS: As part of the STOP-AF Post-Approval Study, QoL was assessed using the Short Form-12 Health Survey (SF-12) along with evaluation of arrhythmia-related symptoms through 36 months. A multivariate linear mixed effects regression was used to determine the association between atrial fibrillation symptoms and QoL scores, and univariate linear regressions were used to assess predictors of 36-month change in QoL scores. RESULTS: Three hundred thirty-five subjects fully completed SF-12 forms at baseline, with 319, 308, 291, and 278 subjects completing surveys at the subsequent follow-up visits. Both physical and mental composite scores increased significantly from baseline (P <.001), and all arrhythmia symptoms significantly decreased from baseline (P <.001), with 62.0% of subjects reporting no symptoms at 6 months compared to 5.7% at baseline (P <.001). Presence of dyspnea and fatigue at baseline were univariate predictors of physical QoL improvement (P = .045 and 0.0497, respectively), whereas each year of age and each year of PAF duration were predictors of a decrease in mental QoL (P = .014 and .04, respectively). CONCLUSION: Cryoballoon ablation for treatment of PAF results in a significant, and sustained, QoL improvement. The observed improvement in physical and mental health likely may be mediated by a reduction in symptom and arrhythmia burden.

Cryoballoon Ablation in Patients With Paroxysmal Atrial Fibrillation: An Evaluation of Cohorts With and Without Structural Heart Disease.

BACKGROUND: Pulmonary vein isolation (PVI) is the most widely adopted strategy for paroxysmal atrial fibrillation (PAF) ablation. Limited evidence on acute results and late outcomes of cryoballoon (CB)-PVI in patients with structural heart disease (SHD) exist. The aim of this analysis was to compare acute procedural results and the 1-year recurrence rate of a single CB-PVI procedure in a PAF population with and without SHD. METHOD: From April 2012 to May 2017, a total of 2,031 patients with AF underwent CB-PVI and were followed prospectively in the framework of the One Shot TO Pulmonary vein isolation (1STOP) ClinicalService project, involving 36 Italian cardiology centres. We identified patients with SHD according to criteria proposed by current ESC guidelines: left ventricular (LV) systolic or diastolic dysfunction, long-standing hypertension with LV hypertrophy, and/or other structural heart disease. Data on procedural outcomes and long-term freedom from AF recurrence were evaluated. RESULTS: Our population consisted of 1,452 patients, of whom 282 (19.4%) were classified as having SHD. Compared to non-SHD patients, the SHD cohort was older (mean ± standard deviation, 62.9 ± 9.0 vs 58.2 ± 11.4 years; p < 0.001), was more frequently male (79.1% vs 69.8%; p < 0.002), had a higher thrombo-embolic risk (CHA2DS2VASc ≥2: 63.4% vs 40.2%; p < 0.001), had a higher body mass index (27.7 ± 3.9 vs 26.4 ± 3.9 kg/m2; p < 0.001), had a larger atrial diameter (43.8 ± 7.0 vs 40.2 ± 5.8 mm; p < 0.001), and had a lower LV ejection fraction (57.2 ± 7.7% vs 60.7 ± 6.0%; p < 0.001). At the time of ablation, 73% of patients were on class Ic or III anti-arrhythmic drugs. Procedure time (106.9 ± 41.5 vs 112.1 ± 46.8 min; p = 0.248), fluoroscopic time (28.7 ± 14.7 vs 28.6 ± 15.2 min; p = 0.819), and complication rate (3.9% vs 4.8%; p = 0.525) were not different between the SHD and non-SHD cohorts. However, the acute success rate (98.9% vs 97.7%; p = 0.016) was higher in patients with SHD. After a follow-up of 13.4 ± 12.8 months, freedom from symptomatic recurrence was 78.0% for SHD and 78.4% for non-SHD (p = 0.895). Recurrence rate was not related to either left atrial size or LVEF. In the SHD cohort, Class Ic or III anti-arrhythmic drugs treatment decreased from 70.7% of patients before ablation to 28.7% of patients after CB-PVI (p = 0.001). CONCLUSIONS: CB-PVI was extensively applied to treat patients with PAF. Unlike previous PVI experiences, the acute success and recurrence rate after a single procedure was not related to the presence of SHD or to the degree of cardiac remodelling. Further studies are required to define whether CB-PVI has a useful role in patients with a significantly reduced ejection fraction as those patients were under-represented in the current population.

Effect of remote ischemic preconditioning on electrophysiological parameters in nonvalvular paroxysmal atrial fibrillation: The RIPPAF Randomized Clinical Trial.

BACKGROUND: Atrial fibrillation (AF) remains the most relevant arrhythmia with a prevalence of 2%. The treatment options are either highly invasive and cost-intensive or limited by potential side effects or insufficient efficacy. However, no direct means of prevention that could reduce the burden of AF have been tested. OBJECTIVE: The purpose of this study was to determine whether remote ischemic preconditioning (RIPC) has an impact on inducibility and sustainability of AF. METHODS: A total of 146 patients with paroxysmal AF undergoing electrophysiology study were randomized to receive either RIPC, performed by short episodes of forearm ischemia, or sham intervention (clinicaltrials.gov identifier: NCT02779660). Effective refractory periods, conduction times, velocities, and conduction delays measured were analyzed by pacing from the coronary sinus (CS). End points of the study were the inducibility and sustainability of AF after prespecified rapid pacing sequences. RESULTS: RIPC significantly reduces the inducibility (odds ratio 0.35; 95% confidence interval 0.17-0.71; P = .003) and sustainability (odds ratio 0.36; 95% confidence interval 0.16-0.81; P = .01) of AF. Furthermore, it decreased dispersion of atrial refractory periods (16.0 ± 14.0 ms vs 22.7 ± 19.0 ms; P = .021) as well as atrial conduction delays (49.2 ± 19.6 ms vs 56.2 ± 22.5 ms; P = .049 for proximal CS and 42.4 ± 16.6 ms vs 49.8 ± 22.2 ms; P = .029 for distal CS). In the whole cohort, longer atrial conduction delay (57.6 ± 22.2 ms vs 50.0 ± 20.5 ms; P = .044) and slower conduction velocity (1.74 ± 0.3 mm/ms vs 1.93 ± 0.5 mm/ms; P = .006) were associated with inducibility of AF whereas a wider dispersion of effective refractory periods (25.9 ± 18.3 ms vs 15.7 ± 11.6 ms; P = .028) maintained AF episodes. CONCLUSION: RIPC reduces the inducibility and sustainability of AF, which is possibly mediated by changes in electrophysiological properties of the atria. It may be used as a simple noninvasive procedure to reduce AF burden.

Etripamil nasal spray: an investigational agent for the rapid termination of paroxysmal supraventricular tachycardia (SVT).

Introduction: Paroxysmal supraventricular tachycardia (SVT) can be very bothersome and may potentially lead to considerable health-care utilization. Non-parenteral medication is currently unavailable for the rapid termination of paroxysmal SVT. However, an intranasal spray formulation of etripamil, a short-acting calcium-channel blocker, is under investigation as a convenient, safe, and rapidly efficacious means to terminate paroxysmal SVT.Areas covered: This review summarizes the clinical rationale, potential benefit, and clinical trials safety and efficacy data for the use of etripamil nasal spray to terminate paroxysmal SVT.Expert opinion: Based on the efficacy and tolerability demonstrated in phase 1 and 2 clinical trials, etripamil nasal spray is a potential convenient, safe, and effective means for patients to terminate paroxysmal SVT. It has the potential to improve quality of life, reduce health-care burden, and alter the current management paradigm for many patients with SVT. Further ongoing evaluation in ambulatory patients will help to determine its real-life practicality, safety, and effectiveness.

Management of paroxysmal atrial flutter that occurred in an outpatient prior to dental surgery: a case report.

BACKGROUND: It is essential to accomplish the appropriate emergency care particularly in patients undergoing stressful dento-oral surgical procedures. Atrial flutter may be induced by sympathetic hypertonia due to excessive mental and physical stress. There is no report regarding dental care in patients with atrial flutter. Herein, we describe a rare case of the antiarrhythmic management in an outpatient who presented with an electrocardiographic finding of paroxysmal atrial flutter before the initiation of the dento-oral surgical procedure. CASE PRESENTATION: A 60-year-old male patient was scheduled for a dental extraction. He had a history of angina pectoris, diabetes mellitus, and paroxysmal atrial fibrillation with medication. The preoperative electrocardiogram (ECG) revealed left ventricular hypertrophy and ST-T segment abnormality. Immediately before the dental extraction, II-lead ECG revealed atrial flutter; however, he complained of few subjective symptoms, such as precordial discomfort or palpitation. Observing the vital signs, ECG findings, and the general condition of the patient, low dose diltiazem was immediately administered by continuous infusion in order to control the heart rate and prevent atrial flutter-induced supraventricular tachyarrhythmia. Special attention was paid to prevent any critical cardiovascular condition under a preparation of intravenous disopyramide and verapamil and a defibrillator. The intravenous administration of diltiazem progressively restored the sinus rhythm after converting atrial flutter into atrial fibrillation, resulting in the prevention of tachycardia, and then was found to be appropriate as a prophylactic therapy of tachyarrhythmia. CONCLUSIONS: The present case suggests that it is possible to successfully manage some of such patients using our method during dento-oral surgery which is likely to be associated with mental and physical stress. Therefore, it is essential to accomplish an initial emergency care in parallel to the differential diagnosis of unforeseen serious medical conditions or paroxysmal arrhythmia such as atrial flutter.