ACC/AHA/ESC Guidelines for the Management of Patients With Supraventricular Arrhythmias—Executive Summary

Non-fluoroscopic navigation systems for radiofrequency catheter ablation for supraventricular tachycardia reduce ionising radiation exposure

INTRODUCTION

The use of non-fluoroscopic systems (NFS) to guide radiofrequency catheter ablation (RFCA) for the treatment of supraventricular tachycardia (SVT) is associated with lower radiation exposure. This study aimed to determine if NFS reduces fluoroscopy time, radiation dose and procedure time.

METHODS

We prospectively enrolled patients undergoing RFCA for SVT. NFS included EnSiteTM NavXTM or CARTO® mapping. We compared procedure and fluoroscopy times, and radiation exposure between NFS and conventional fluoroscopy (CF) cohorts. Procedural success, complications and one-year success rates were reported.

RESULTS

A total of 200 patients over 27 months were included and RFCA was guided by NFS for 79 patients; those with atrioventricular nodal reentrant tachycardia (AVNRT), left-sided atrioventricular reentrant tachycardia (AVRT) and right-sided AVRT were included (n = 101, 63 and 36, respectively). Fluoroscopy times were significantly lower with NFS than with CF (10.8 ± 11.1 minutes vs. 32.0 ± 27.5 minutes; p < 0.001). The mean fluoroscopic dose area product was also significantly reduced with NFS (NSF: 5,382 ± 5,768 mGy*cm2 vs. CF: 21,070 ± 23,311 mGy*cm2; p < 0.001); for all SVT subtypes. There was no significant reduction in procedure time, except for left-sided AVRT ablation (NFS: 79.2 minutes vs. CF: 116.4 minutes; p = 0.001). Procedural success rates were comparable (NFS: 97.5% vs. CF: 98.3%) and at one-year follow-up, there was no significant difference in the recurrence rates (NFS: 5.2% vs. CF: 4.2%). No clinically significant complications were observed in both groups.

CONCLUSION

The use of NFS for RFCA for SVT is safe, with significantly reduced radiation dose and fluoroscopy time.

Executive Summary: European Heart Rhythm Association Consensus Document on the Management of Supraventricular Arrhythmias: Endorsed by Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardiaca y Electrofisiologia (SOLAECE)

This paper is an executive summary of the full European Heart Rhythm Association (EHRA) consensus document on the management of supraventricular arrhythmias, published in Europace. It summarises developments in the field and provides recommendations for patient management, with particular emphasis on new advances since the previous European Society of Cardiology guidelines. The EHRA consensus document is available to read in full at http://europace.oxfordjournals.org.

Better Lesion Creation And Assessment During Catheter Ablation

Permanent destruction of abnormal cardiac tissue responsible for cardiac arrhythmogenesis whilst avoiding collateral tissue injury forms the cornerstone of catheter ablation therapy. As the acceptance and performance of catheter ablation increases worldwide, limitations in current technology are becoming increasingly apparent in the treatment of complex arrhythmias such as atrial fibrillation. This review will discuss the role of new technologies aimed to improve lesion formation with the ultimate goal of improving arrhythmia-free survival of patients undergoing catheter ablation of atrial arrhythmias.

New oral anticoagulants in patients undergoing atrial flutter radiofrequency catheter ablation: an observational study

AIM

Atrial flutter (AFL) ablation requires optimal periprocedural anticoagulation in order to minimize thromboembolic events/bleeding risk. This study describes the characteristics of patients receiving new oral anticoagulants before AFL ablation and assesses complications.

METHODS

This multicenter, retrospective study reports ischemic and hemorrhagic predischarge, postprocedural complications.

RESULTS

We evaluated 60 patients (62.3% male; mean age: 69.2 ± 9.7 years; CHA2DS2-VASc score: 2.44 ± 1.46, HAS-BLED score: 1.14 ± 0.7). Twenty-one (35.0%) and 23 patients (38.3%) received twice-daily dabigatran 110 or 150 mg; 16 patients (26.6%) received once-daily rivaroxaban (15 mg [n = 5] or 20 mg [n = 11]). Four cases of postprocedural minor bleeding were reported.

CONCLUSION

This is the first study assessing new oral anticoagulants for periprocedural anticoagulation, specifically in patients undergoing AFL ablation. No major bleeding was reported. Further prospective investigation is warranted.

Extracorporeal life support for cardiac arrest in a 13-year-old girl caused by Wolff-Parkinson-White syndrome

Generally, Wolff-Parkinson-White (WPW) syndrome presents good prognosis. However, several case reports demonstrated malignant arrhythmia or sudden cardiac death as WPW syndrome's first presentation. Cardiopulmonary resuscitation using extracorporeal life support is a therapeutic option in refractory cardiac arrest. We present a WPW syndrome patient who had sudden cardiac arrest as the first presentation of the disease and treated it using extracorporeal life support with good neurologic outcome.

Electrophysiology testing and catheter ablation are helpful when evaluating asymptomatic patients with Wolff-Parkinson-White pattern: the pro perspective

Important advances in the natural history and diagnosis of, and therapy for, asymptomatic Wolff-Parkinson-White (WPW) syndrome have been made in the last decade by our group. These data have necessitated revisiting current practice guidelines to decide on the optimal management of the asymptomatic WPW population. There has also been an emphasis on identifying initially asymptomatic individuals who are at risk by nationwide screening programs using the electrocardiogram for prophylactic catheter ablation to prevent the lifetime risk of sudden cardiac death, particularly in young asymptomatic people, because only a subgroup of them is at high risk, requiring early catheter ablation.

[Differential diagnosis of a narrow QRS tachycardia]

The differential diagnosis of a narrow QRS tachycardia requires on the one hand knowledge about the clinical data of the tachycardia patient but on the other hand a systematic step by step analysis of the electrocardiogram (ECG) is the most successful approach. Apart from the question of regularity or irregularity of the QRS complexes, the presence and detection of P waves is also of importance. The P wave timing in relation to the preceding and the following QRS complexes as well as the numerical relationship of P waves and QRS complexes allow a well-founded suspected diagnosis to be achieved in most cases. Even the differentiation between atrioventricular (AV) nodal reentrant tachycardia (AVNRT) versus orthodromic AV reentrant tachycardia (AVRT), e.g. by accessory leads, is in most cases possible in a surface ECG. Obviously, there are constellations which need an invasive electrophysiological procedure for a definitive diagnosis.

Radiofrequency ablation changes the quality of life of children with supraventricular tachycardias

OBJECTIVE

Radiofrequency ablation (RFA) has rapidly become the first-line therapy for children with supraventricular tachycardia (SVT). Recently, more attention has been given to the measurement of health-related quality of life (QoL) in children. The primary aim of this study was to determine if there is a change in the QoL in children with SVT pre and post RFA procedure using the Pediatric Quality of Life Inventory (PedsQL) cardiac inventory. In addition, the study discusses the impact of age, gender and variety of SVT mechanisms on the QoL.

DESIGN, SETTING AND PATIENTS

All consecutive children with SVT referred for RFA at Mansoura University Children's Hospital were enrolled in this study. The PedsQL cardiac module questionnaire was given to the children/parents to be filled out before and 1 month following RFA procedure. Evaluated areas were physical, emotional, social, school and psychosocial function. The paired t test was used to test the difference between pre-time and post-time points for the study groups. Demographic and clinical data were collected.

RESULTS

The study sample consisted of 38 patients who underwent a successful ablation. The mean age of the patients at the time of RFA procedure was 12.4±5.3 years. There was a statistically significant improvement in all measured areas 1 month post successful RFA as compared with pre ablation. Post ablation, the greatest score improvement was in physical functioning. Older children (>12 years) showed the greatest benefit, but gender and type of SVT did not influence outcome.

CONCLUSIONS

RFA therapy is useful in improving QoL and perceptions in children with recurrent SVT.

Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis

We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: −2.83; P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: −2.36; P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time.

Anaesthetic and sedative agents used for electrical cardioversion

BACKGROUND

Electrical cardioversion is an effective procedure for restoring normal sinus rhythm in the hearts of patients with irregular heart rhythms. It is important that the patient is not fully conscious during the procedure, as it can be painful and distressing. The drug used to make patients unaware of the procedure should rapidly achieve the desired level of sedation, should wear off quickly and should not cause cardiovascular or respiratory side effects.

OBJECTIVES

We aimed to compare the safety, effectiveness and adverse events associated with various anaesthetic or sedative agents used in direct current cardioversion for cardiac arrhythmia in both elective and emergency settings.We sought answers to the following specific questions.• Which drugs deliver the best outcomes for patients undergoing electrical cardioversion?• Does using a particular agent confer advantages or disadvantages?• Is additional analgesic necessary to prevent pain?

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) on 27 March 2014. Our search terms were relevant to the review question and were not limited by outcomes. We also carried out searches of clinical trials registers and forward and backward citation tracking.

SELECTION CRITERIA

We considered all randomized controlled trials and quasi-randomized and cluster-randomized studies with adult participants undergoing electrical cardioversion procedures in the elective or emergency setting.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data, consulting with a third review author for disagreements. We used standard Cochrane methodological procedures, including assessment of risk of bias for all studies.

MAIN RESULTS

We included 23 studies with 1250 participants that compared one drug with one or more other drugs. Of these comparisons, 19 studies compared propofol with another drug. Seven of these compared propofol with etomidate (four of which combined the drugs with remifentanil or fentanyl), five midazolam, six thiopentone and two sevoflurane. Three studies compared etomidate with thiopentone, and three etomidate with midazolam. Two studies compared thiopentone with midazolam, one thiopentone with diazepam and one midazolam with diazepam. Drug doses and the time over which the drugs were given varied between studies. Although all studies were described as randomized, limited information was provided about the methods used for selection and group allocation. A high level of performance bias was observed across studies, as study authors had not attempted to blind the anaesthetist to group allocation. Similarly, study authors had rarely provided sufficient information on whether outcome assessors had been blinded.Included studies presented outcome data for hypotension, apnoea, participant recall, success of cardioversion, minor adverse events of nausea and vomiting, pain at injection site and myoclonus, additional analgesia and participant satisfaction. We did not pool the data from different studies in view of the multiple drug comparisons, differences in definitions and reporting of outcomes, variability of endpoints and high or unclear risk of bias across studies.

AUTHORS' CONCLUSIONS

Few studies reported statistically significant results for our relevant outcomes, and most study authors concluded that both, or all, agents compared in individual studies were adequate for cardioversion procedures. It is our opinion that at present, there is no evidence to suggest that current anaesthetic practice for cardioversion should change.

Noninvasive pacing study via pacemakers and implantable cardioverter-defibrillators for differentiating right from left atrial flutter

BACKGROUND

Patients with atrial flutter who are implanted with a pacemaker (PM) or implantable cardioverter-defibrillator (ICD) present with the opportunity to perform a noninvasive pacing study (NIPS) using the right atrial pacing lead to differentiate right from left atrial flutter.

OBJECTIVES

The purpose of this study was to study the feasibility and accuracy of NIPS to distinguish right from left atrial flutter.

METHODS

We enrolled consecutive patients scheduled for an electrophysiological study or ablation procedure who were in atrial flutter and who were implanted with a PM or ICD with a functional atrial lead in the right atrial appendage. Flutter tachycardia cycle lengths (TCLs) and postpacing intervals (PPIs) were measured noninvasively via the device during the procedure.

RESULTS

A total of 48 (67%) patients were studied. Right atrial flutter was present in 32 patients (of whom 29 had typical cavotricuspid isthmus-dependent flutter) and 16 (33%) patients had left atrial flutter. A PPI-TCL interval of >100 ms was 100% specific and 81% sensitive to identify left atrial flutter, with an overall accuracy of 94% and a c statistic of 0.94 (95% confidence interval 0.87-1.00). A PPI-TCL interval of ≤100 ms had a positive predictive value of 86% for diagnosing typical flutter.

CONCLUSION

NIPS via PMs and ICDs with a PPI-TCL interval of >100 ms can reliably identify left atrial flutter (although we have only validated this cutoff for leads implanted in the right atrial appendage). This simple maneuver may allow planning for left-sided access and may avoid an unnecessary invasive electrophysiological study if left atrial flutter ablation is not to be considered.

Clinical and electrophysiological characteristics of typical atrioventricular nodal reentrant tachycardia in the elderly - changing of slow pathway location with aging

BACKGROUND

The aim of this study was to retrospectively evaluate the clinical and electrophysiological characteristics of elderly patients with typical atrioventricular nodal reentrant tachycardia (AVNRT), and to assess the acute safety and efficacy of slow-pathway radiofrequency (RF) ablation in this specific group of patients.

METHODS AND RESULTS

The present study retrospectively included a total of 1,290 patients receiving successful slow-pathway RF ablation for typical slow-fast AVNRT. Patients were divided into 2 groups: group I included 1,148 patients aged <65 years and group II included 142 patients aged >65 years. The required total procedure duration and total fluoroscopy exposure time were significantly higher in group II vs. group I (P=0.005 and P=0.0001, respectively). The number of RF pulses needed for a successful procedural end-point was significantly higher in group II than in group I (4.4 vs. 7.2, P=0.005). While the ratio of the anterior location near to the His-bundle region was significantly higher in group II, the ratio of posterior and midseptal locations were significantly higher in group I (P=0.0001). The overall procedure success rates were similar. There was no significant difference between the 2 groups in respect of the complications rates.

CONCLUSIONS

This experience demonstrates that RF catheter ablation, targeting the slow pathway, could be considered as first-line therapy for typical AVNRT patients older than 65 years as well as younger patients, as it is very safe and effective in the acute period of treatment.

Ablation of typical atrial flutter using a non-fluoroscopic catheter tracking system vs. conventional fluoroscopy--results from a prospective randomized study

AIMS

Reduction of radiation exposure using a sensor-based non-fluoroscopic catheter tracking (NFCT) system (MediGuide™, St Jude Medical, Inc.) was recently demonstrated by retrospective comparisons. We aimed to prospectively compare the effects of using NFCT vs. standard fluoroscopy on procedural parameters in patients undergoing radiofrequency ablation of typical atrial flutter.

METHODS AND RESULTS

We prospectively randomized 40 patients undergoing cavotricuspid isthmus ablation for typical atrial flutter to either NFCT (n = 20) or conventional fluoroscopy (CONV, n = 20). Procedural parameters such as fluoroscopy time, radiation dose, and procedure duration, as well as periprocedural complications were compared. There were no statistically significant differences in baseline characteristics between the two groups. Bidirectional isthmus block was achieved in all patients. Fluoroscopy time was significantly reduced in the NFCT group {0.3 [inter-quartile range (IQR) 0.2; 0.48] min} when compared with CONV [5.7 (IQR 4.2; 11.5) min] (P < 0.001). This resulted in a significant reduction in radiation dose in patients randomized to NFCT [17.4 (IQR 11; 206.6) cGy cm(2)] vs. the CONV group [418.4 (IQR 277; 812.2) cGy cm(2)] (P < 0.001). There were no significant differences in procedure duration between the NFCT group [49.5 (IQR 37; 65) min] when compared with the CONV group [33.5 (IQR 26.3; 55.5) min] (P = 0.053). No adverse events were recorded. Freedom from atrial flutter at 6 months of follow-up was 19/20 (95%) in the NFCT and 18/20 (90%) in the CONV group (n.s.).

CONCLUSION

In this first prospective randomized study, by comparing NFCT with standard fluoroscopy in patients undergoing radiofrequency ablation of typical atrial flutter, NFCT significantly reduced both radiation dose and fluoroscopy time with no effects on procedural duration. These findings support the incorporation of NFCT in routine clinical use.

Remote magnetic navigation for ablation of typical atrial flutter: Long-term results

INTRODUCTION AND AIM

Remote magnetic navigation has proved to be effective in the ablation of most supraventricular and ventricular arrhythmias. Initial studies reported worse results with this system compared to conventional ablation for atrial flutter. The aim of this study was to assess the acute and long-term success of atrial flutter ablation with remote magnetic navigation and to retrospectively compare the results obtained with an 8-mm tip catheter versus an irrigated catheter.

METHODS

We studied 38 consecutive patients, mean age 61 ± 15 years, 28 male, who underwent ablation of typical atrial flutter with the Niobe II remote magnetic navigation system (Stereotaxis). Ablation was performed with an 8-mm tip catheter in 17 patients and with an irrigated-tip catheter in 21 patients. Acute success was defined as the presence of bidirectional isthmus block, and long-term success as absence of symptoms and atrial flutter during Holter monitoring.

RESULTS

Bidirectional isthmus block was achieved in 37 patients (97%), and the success rate was similar in both groups. Total procedure time was not significantly different between the groups but fluoroscopy time was shorter in the irrigated tip group (13.4 ± 3.7 min vs. 6 ± 4.4 min; p<0.01). The number of applications and total radiofrequency time did not differ. There were no complications. During a follow-up of 32 ± 19 months there were two relapses, one in each group.

CONCLUSIONS

The Niobe II remote control system for ablation of typical atrial flutter is safe and effective in both the short and long term. The 8-mm and irrigated-tip catheters showed similar safety and efficacy.

Successful obstetric management of arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic myocardial disorder characterized by the replacement of myocardium by fibro-adipose tissue. The proper obstetric management of this disease remains unclear due to the lack of an adequate number of cases reported in the literature. We report the successful management of a pregnant patient with ARVC. A female patient with ARVC presented to our hospital at 9 weeks of gestation. Before pregnancy, she was treated with bisoprolol, which resulted in a reduction in extrasystoles and she never developed palpitations. Periodical cardiological examinations showed clinical stability, and the only therapeutic change consisted of an increase in the bisoprolol dosage. She delivered at term by elective cesarean section. We decided that avoiding changes in the chronic therapy of our patient was the best management because she had reached clinical stability before pregnancy and discontinuation of therapy may pose an addition risk. In our opinion, cesarean section was the best mode of delivery in our ARVC patient to avoid the stress of labor, which may raise heart rate and cause arrhythmia. Our experience and the case reports in the literature suggest that pregnancy is tolerated in female patients with ARVC, but they need to be monitored during pregnancy by a multidisciplinary team.

Recurrences of symptoms after AV node re-entrant tachycardia ablation: a clinical arrhythmia risk score to assess putative underlying cause

PURPOSE OF THE RESEARCH

To identify clinical factors associated with the probability for each arrhythmic mechanism causing recurring symptoms after atrioventricular nodal re-entrant tachycardia (AVNRT) ablation. Slow pathway radiofrequency ablation is used to treat AVNRT. After ablation, recurrence of symptoms due to AVNRT or other arrhythmias can occur.

RESULTS

We studied 835 patients successfully treated with AVNRT ablation. Variables associated with each specific arrhythmia underlying symptom recurrence were studied by logistic regression. During a mean follow-up of 2.2 ± 2 years, 136 (16%) patients had a recurrence of symptoms. Following invasive and non-invasive studies, symptoms were mostly attributed to sinus tachycardia, recurrence of AVNRT and atrial arrhythmias (respectively 4.7%, 5.2% and 6.1%). Older age and history of atrial fibrillation were associated with a markedly increased risk of symptom recurrence due to atrial arrhythmias (OR=15.58, 7.09-35.22, p<0.001) whereas younger age was associated with a higher risk of sinus tachycardia. A simple 3-item clinical score based on age categories and atrial fibrillation history efficiently predicted atrial arrhythmia (C-Index=0.82, 0.75-0.89) and sinus tachycardia (C-Index=0.83, 0.75-0.90). 8.3% of patients with scores=0 had atrial arrhythmias whereas 100% of patients with scores ≥4 had atrial arrhythmias.

CONCLUSIONS

While recurrence of symptoms after successful AVNRT ablation is relatively frequent (16%), true AVNRT recurrence accounts for only 1/3 of these recurrences. A simple clinical score based on age and history of atrial fibrillation enables efficient risk stratification for symptom recurrence attributable to atrial arrhythmias and inappropriate sinus tachycardia.

Frequency of supraventricular arrhythmias in patients with idiopathic pulmonary arterial hypertension

Supraventricular arrhythmias (SVA) may be risk factors of prognosis in patients with pulmonary arterial hypertension. SVA are increasingly reported in patients with pulmonary hypertension, but little is known about their incidence and outcomes for patients with idiopathic pulmonary arterial hypertension (IPAH) in a large cohort. In this 6-year prospective multicenter study, 280 patients with IPAH were enrolled to investigate the incidence of SVA and assess risk factors, clinical manifestation, management, and impact on survival. The cumulative 6-year incidence of SVA was 15.8%. The most common types of SVA were atrial fibrillation (n = 16) and atrial flutter (n = 13), followed by atrial tachycardia (n = 11). Most episodes of SVA were associated with significant clinical deterioration and right-sided cardiac failure. Sinus rhythm was successfully restored in most patients, resulting in clinical recovery. Increased right ventricular diameter, left atrial area, and higher right atrial pressure and pulmonary vascular resistance were associated with increased risk for experiencing SVA. SVA predicted a greater risk for mortality in a stepwise forward Cox analysis (hazard ratio 4.757, 95% confidence interval 2.695 to 8.397, p <0.001). Kaplan-Meier survival curves showed that patients with SVA, mainly permanent SVA, had a lower survival rate than those who did not develop SVA (p = 0.008). In conclusion, SVA often lead to clinical deterioration and may be associated with an increased risk for death in a large cohort of patients with IPAH. Restoration and maintenance of sinus rhythm are important treatment goals in patients with IPAH.

Feasibility of AmbulanCe-Based Telemedicine (FACT) study: safety, feasibility and reliability of third generation in-ambulance telemedicine

Background

Telemedicine is currently mainly applied as an in-hospital service, but this technology also holds potential to improve emergency care in the prehospital arena. We report on the safety, feasibility and reliability of in-ambulance teleconsultation using a telemedicine system of the third generation.

Methods

A routine ambulance was equipped with a system for real-time bidirectional audio-video communication, automated transmission of vital parameters, glycemia and electronic patient identification. All patients ( ≥18 years) transported during emergency missions by a Prehospital Intervention Team of the Universitair Ziekenhuis Brussel were eligible for inclusion. To guarantee mobility and to facilitate 24/7 availability, the teleconsultants used lightweight laptop computers to access a dedicated telemedicine platform, which also provided functionalities for neurological assessment, electronic reporting and prehospital notification of the in-hospital team. Key registrations included any safety issue, mobile connectivity, communication of patient information, audiovisual quality, user-friendliness and accuracy of the prehospital diagnosis.

Results

Prehospital teleconsultation was obtained in 41 out of 43 cases (95.3%). The success rates for communication of blood pressure, heart rate, blood oxygen saturation, glycemia, and electronic patient identification were 78.7%, 84.8%, 80.6%, 64.0%, and 84.2%. A preliminary prehospital diagnosis was formulated in 90.2%, with satisfactory agreement with final in-hospital diagnoses. Communication of a prehospital report to the in-hospital team was successful in 94.7% and prenotification of the in-hospital team via SMS in 90.2%. Failures resulted mainly from limited mobile connectivity and to a lesser extent from software, hardware or human error. The user acceptance was high.

Conclusions

Ambulance-based telemedicine of the third generation is safe, feasible and reliable but further research and development, especially with regard to high speed broadband access, is needed before this approach can be implemented in daily practice.

Oral verapamil in paroxysmal supraventricular tachycardia recurrence control: a randomized clinical trial

BACKGROUND

Adenosine is the first-line medication in patients with paroxysmal supraventricular tachycardia. Because it is cleared so rapidly from the circulation, recurrence of paroxysmal supraventricular tachycardia after initial successful conversion may occur.

OBJECTIVE

This study was conducted to evaluate the role of oral verapamil administration to control early recurrences of paroxysmal supraventricular tachycardia after adenosine infusion.

METHODS

Patients with acute paroxysmal supraventricular tachycardia and no contraindications for adenosine or verapamil treatment were included in study. All patients received an adenosine protocol (6 mg rapid bolus intravenous injection followed by two repeated doses of 12 mg if necessary). Patients in the adenosine-only group did not received any other medications but patients in the adenosine/verapamil group received 40 mg verapamil orally immediately after converting the rhythm to sinus rhythm. All patients were followed up for 6 h in the acute care area of the emergency department under continuous cardiac monitoring.

RESULTS

A total of 113 patients were assessed for eligibility and 92 patients were randomized into two groups (adenosine only versus adenosine/verapamil). There was no statistically significant difference in paroxysmal supraventricular tachycardia recurrence rate between the two groups in the first 30 min after treatment. Recurrence rate was statistically significantly lower in the adenosine/verapamil group than in the adenosine-only group between 30 and 120 min after treatment and thereafter. Two patients in the adenosine-only group experienced flushing and one patient in the adenosine/verapamil group experienced decreased systolic blood pressure.

CONCLUSION

Oral verapamil can decrease paroxysmal supraventricular tachycardia recurrence after successful control with intravenous adenosine.

Atrial electrical activity detection using linear combination of 12-lead ECG signals

ECG analysis is the method for cardiac arrhythmia diagnosis. During the diagnostic process many features should be taken into consideration, such as regularity and atrial activity. Since in some arrhythmias, the atrial electrical activity (AEA) waves are hidden in other waves, and a precise classification from surface ECG is inapplicable, a confirmation diagnosis is usually performed during an invasive procedure. In this paper, we study a "semiautomatic" method for AEA-waves detection using a linear combination of 12-lead ECG signals. This method's objective is to be applicable to a variety of arrhythmias with emphasis given to detect concealed AEA waves. It includes two variations--using maximum energy ratio and a synthetic AEA signal. In the former variation, an energy ratio-based cost function is created and maximized using the gradient ascent method. The latter variation adapted the linear combiner method, when applied on a synthetic signal, combined with surface ECG leads. A study was performed evaluating the AEA-waves detection from 63 patients (nine training, 54 validation) presenting eight arrhythmia types. Averaged sensitivity of 92.21% and averaged precision of 92.08% were achieved compared to the definite diagnosis. In conclusion, the presented method may lead to early and accurate detection of arrhythmias, which will result in a better oriented treatment.

Wolff-Parkinson-White syndrome in the era of catheter ablation: insights from a registry study of 2169 patients

BACKGROUND

The management of Wolff-Parkinson-White is based on the distinction between asymptomatic and symptomatic presentations, but evidence is limited in the asymptomatic population.

METHODS AND RESULTS

The Wolff-Parkinson-White registry was an 8-year prospective study of either symptomatic or asymptomatic Wolff-Parkinson-White patients referred to our Arrhythmology Department for evaluation or ablation. Inclusion criteria were a baseline electrophysiological testing with or without radiofrequency catheter ablation (RFA). Primary end points were the percentage of patients who experienced ventricular fibrillation (VF) or potentially malignant arrhythmias and risk factors. Among 2169 enrolled patients, 1001 (550 asymptomatic) did not undergo RFA (no-RFA group) and 1168 (206 asymptomatic) underwent ablation (RFA group). There were no differences in clinical and electrophysiological characteristics between the 2 groups except for symptoms. In the no-RFA group, VF occurred in 1.5% of patients, virtually exclusively (13 of 15) in children (median age, 11 years), and was associated with a short accessory pathway antegrade refractory period (P<0.001) and atrioventricular reentrant tachycardia initiating atrial fibrillation (P<0.001) but not symptoms. In the RFA group, ablation was successful in 98.5%, and after RFA, no patients developed malignant arrhythmias or VF over the 8-year follow-up. Untreated patients were more likely to experience malignant arrhythmias and VF (log-rank P<0.001). Time-dependent receiver-operating characteristic curves for predicting VF identified an optimal anterograde effective refractory period of the accessory pathway cutoff of 240 milliseconds.

CONCLUSIONS

The prognosis of the Wolff-Parkinson-White syndrome essentially depends on intrinsic electrophysiological properties of AP rather than on symptoms. RFA performed during the same procedure after electrophysiological testing is of benefit in improving the long-term outcomes.

Electrocardiography series. Narrow QRS-complex tachycardia: part 2

We discuss two cases of incessant atrial tachycardia (AT), including the presentation and clinical course. It is important to differentiate AT from other causes of supraventricular tachycardia, such as atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT), as it would have implications on clinical management. Electrocardiographic features of AT, especially the presence of an AV Wenckebach phenomenon with 'grouped beating', are critical for differentiating AT from AVRT and AVNRT. It is also vital to identify the P waves and their relations to QRS on electrocardiography, as this would aid in the differentiation of various supraventricular tachycardias.

Healthcare utilization and clinical outcomes after catheter ablation of atrial flutter

Atrial flutter ablation is associated with a high rate of acute procedural success and symptom improvement. The relationship between ablation and other clinical outcomes has been limited to small studies primarily conducted at academic centers. We sought to determine if catheter ablation of atrial flutter is associated with reductions in healthcare utilization, atrial fibrillation, or stroke in a large, real world population. California Healthcare Cost and Utilization Project databases were used to identify patients undergoing atrial flutter ablation between 2005 and 2009. The adjusted association between atrial flutter ablation and healthcare utilization, atrial fibrillation, or stroke was investigated using Cox proportional hazards models. Among 33,004 patients with a diagnosis of atrial flutter observed for a median of 2.1 years, 2,733 (8.2%) underwent catheter ablation. Atrial flutter ablation significantly lowered the adjusted risk of inpatient hospitalization (HR 0.88, 95% CI 0.84-0.92, p<0.001), emergency department visits (HR 0.60, 95% CI 0.54-0.65, p<0.001), and overall hospital-based healthcare utilization (HR 0.94, 95% CI 0.90-0.98, p = 0.001). Atrial flutter ablation was also associated with a statistically significant 11% reduction in the adjusted hazard of atrial fibrillation (HR 0.89, 95% CI 0.81-0.97, p = 0.01). Risk of acute stroke was not significantly reduced after ablation (HR 1.09, 95% CI 0.81-1.45, p = 0.57). In a large, real world population, atrial flutter ablation was associated with significant reductions in hospital-based healthcare utilization and a reduced risk of atrial fibrillation. These findings support the early use of catheter ablation for the treatment of atrial flutter.

Access to cardiac rehabilitation does not equate to attendance

BACKGROUND/AIMS

Timely access to appropriate cardiac care is critical for optimizing positive outcomes after a cardiac event. Attendance at cardiac rehabilitation (CR) remains less than optimal (10%-30%). Our aim was to derive an objective, comparable, geographic measure reflecting access to cardiac services after a cardiac event in Australia.

METHODS

An expert panel defined a single patient care pathway and a hierarchy of the minimum health services for CR and secondary prevention. Using geographic information systems a numeric/alpha index was modelled to describe access before and after a cardiac event. The aftercare phase was modelled into five alphabetical categories: from category A (access to medical service, pharmacy, CR, pathology within 1 h) to category E (no services available within 1 h).

RESULTS

Approximately 96% or 19 million people lived within 1 h of the four basic services to support CR and secondary prevention, including 96% of older Australians and 75% of the indigenous population. Conversely, 14% (64,000) indigenous people resided in population locations that had poor access to health services that support CR after a cardiac event.

CONCLUSION

Results demonstrated that the majority of Australians had excellent 'geographic' access to services to support CR and secondary prevention. Therefore, it appears that it is not the distance to services that affects attendance. Our 'geographic' lens has identified that more research on socioeconomic, sociological or psychological aspects to attendance is needed.

Clinical and electrophysiological characteristics of the patients with relatively slow atrioventricular nodal reentrant tachycardia

OBJECTIVE

The aim of this study is to retrospectively investigate clinical and electrophysiologic characteristics of typical AVNRT with relatively slow tachycardia rates below the average value compared to faster ones, in patients without structural heart disease.

METHODS

The present study retrospectively included a total of 1,150 patients receiving successful slow-pathway radio frequency ablation for typical slow-fast AVNRT. Patients were divided into two groups according to their tachycardia cycle length: group I included 1,018 patients with tachycardia cycle length < 400 msn and group II included 132 patients with cycle length > 400 msn. Patients with another form of arrhythmia other than typical AVNRT, the existence of structural heart disease, preexisting prolonged PR interval, history of clinically documented AF, and reasons capable of causing AF were accepted as exclusion criterias.

RESULTS

The patients in group II were older than those in group 1 (p=0.039), and male ratio was significantly higher in group II compared to group I (p=0.02). Wenckebach cycle length and AV node antegrade effective refractory period values before the RF ablation were significantly higher in group II compared to group I (p=0.0001 and 0.01, respectively). Right atrium effective refractory period values in both pre- and post-ablation period were significantly higher in group I compared to group II (p=0.0001 and 0.004, respectively). The existence of atrial vulnerability before ablation was significantly higher in group II compared to group I (p=0.007); however, there was no difference between the two groups in terms of atrial vulnerability after the ablation. In addition, while the ratio of anterior location as an ablation site near the His-bundle region was significantly higher in group II, the ratio of posterior location was significantly higher in group I (p=0.0001 for both).

CONCLUSION

Our experience demonstrates that clinical and electrophysiologic characteristics of AVNRT patients with relatively slower tachycardia rates were quite different compared to the faster AVNRT cases.