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Aim: It is not well known how comorbidities may change the prognosis of atrial fibrillation (AF) patients. This study was aimed to analyze the impact of cardiovascular disease on this population. Materials & methods: EMIR was a multicenter, prospective study, including 1433 AF patients taking rivaroxaban for ≥6 months. Data were analyzed according to the presence of vascular disease. Results: Coronary artery disease was detected in 16.4%, peripheral artery disease/aortic plaque in 6.7%, vascular disease in 28.3%. Patients with coronary artery disease had higher rates (per 100 patient-years) of major adverse cardiovascular events (2.98 vs 0.71; p < 0.001) and cardiovascular death (1.79 vs 0.41; p = 0.004). Those with vascular disease had higher rates of thromboembolic events (1.47 vs 0.44; p = 0.007), major adverse cardiovascular events (2.03 vs 0.70; p = 0.004), and cardiovascular death (1.24 vs 0.39; p = 0.025). Patients with peripheral artery disease/aortic plaque had similar rates. Conclusion: AF patients with vascular disease have a higher risk of non-embolic outcomes.

Background: Assessing bleeding risk during the decision-making process of starting oral anticoagulation (OAC) therapy in atrial fibrillation (AF) patients is essential. Several bleeding risk scores have been proposed for vitamin K antagonist users but, few studies have focused on validation of these bleeding risk scores in patients taking direct oral anticoagulants (DOACs). The aim was to compare the predictive ability of HAS-BLED and ORBIT bleeding risk scores in AF patients taking rivaroxaban in the EMIR ('Estudio observacional para la identificación de los factores de riesgo asociados a eventos cardiovasculares mayores en pacientes con fibrilación auricular no valvular tratados con un anticoagulante oral directo [Rivaroxaban]) Study., Methods and Results: EMIR Study was an observational, multicenter, post-authorization, and prospective study that involved AF patients under OAC with rivaroxaban at least 6 months before enrolment. We analysed baseline clinical characteristics and adverse events after 2.5 years of follow-up and validated the predictive ability of HAS-BLED and ORBIT scores for major bleeding (MB) events.We analysed 1433 patients with mean age of 74.2 ± 9.7 (44.5% female). Mean HAS-BLED score was 1.6 ± 1.0 and ORBIT score was 1.1 ± 1.2. The ORBIT score categorised a higher proportion of patients as 'low-risk' (87.1%) compared with 53.5% using the HAS-BLED score. There were 33 MB events (1.04%/year) and 87 patients died (2.73%/year). Both HAS-BLED and ORBIT had a good predictive ability for MB{Area under the curve (AUC) 0.770, [95% confidence interval (CI) 0.693-0.847; P <0.001] and AUC 0.765 (95% CI 0.672-0.858; P <0.001), respectively}. There was a non-significant difference for discriminative ability of the two tested scores (P = 0.930) and risk reclassification in terms of net reclassification improvement (NRI) -5.7 (95% CI -42.4-31.1; P = 0.762). HAS-BLED score showed the best calibration and ORBIT score showed the largest mismatch in calibration, particularly in higher predicted risk patients., Conclusion: In a prospective real-world AF population under rivaroxaban from EMIR registry, the HAS-BLED score had good predictive performance and calibration compared with ORBIT score for MB events. ORBIT score presented worse calibration than HAS-BLED in this DOAC treated population., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Objective: To analyze the effectiveness and safety of rivaroxaban in patients with atrial fibrillation (AF). Methods: The clinical profile and outcomes of the EMIR study were indirectly compared with those of ROCKET-AF, eight other Spanish observational studies and XANTUS. Results: In EMIR, mean age was 74.2 years and CHA 2 DS 2 -VASc was 3.5. In the rivaroxaban arm of the ROCKET-AF trial, mean age was 73 years and CHADS 2 was 3.5, whereas in the Spanish studies mean age ranged from 74.9 years to 78.4 years and CHA 2 DS 2 -VASc from 3.5 to 4.3. In EMIR, rates of stroke/systemic embolism, major adverse cardiovascular events, cardiovascular death and major bleeding were 0.57, 1.07, 0.63 and 1.04 events/100 patient-years, respectively. In ROCKET-AF, these numbers were 1.7, 3.91, 1.53 and 3.6 events/100 patient-years, respectively. In the Spanish studies, rates of stroke and major bleeding were 0-1.8 and 0.22-4.2 events/100 patient-years, respectively. In XANTUS, rates of stroke, major adverse cardiovascular events and major bleeding were 0.7, 1.8 and 2.1 events/100 patient-years, respectively. Conclusion: Despite the fact that rivaroxaban is prescribed for elderly patients with a high thromboembolic risk, rates of outcomes remain low.

Background: The aim of the study was to evaluate the performance of the 2MACE in patients with atrial fibrillation (AF) treated with rivaroxaban and to improve the accuracy of 2MACE., Methods: This was a post-authorization and observational study of AF adults treated with rivaroxaban for ≥ 6 months. The primary endpoint was any of the major adverse cardiac events (MACE), namely, cardiovascular death, non-fatal myocardial infarction, and myocardial revascularization. The area under the curve (AUC) was calculated to evaluate the performance of 2MACE, and a new score, 2MACER to predict MACE., Results: A total of 1433 patients were included (74.2 ± 9.7 years, CHA₂DS₂-VASc 3.5 ± 1.5, 26.9% 2MACE ≥ 3). The annual event rates (follow-up 2.5 years) were 1.07% for MACE, 0.66% for thromboembolic events and 1.04% for major bleeding. Patients with 2MACE ≥ 3 (vs. < 3) had higher risk of stroke/systemic embolism/transient ischemic attack (odds ratio [OR] 5.270; 95% CI 2.216-12.532), major bleeding (OR 4.624; 95% CI 2.163-9.882), MACE (OR 3.202; 95% CI 1.548-6.626) and cardiovascular death (OR 3.395; 95% CI 1.396-8.259). 2MACE was recalculated giving 1 more point to patients with baseline a glomerular filtration rate < 50 mL/min/1.73 m² (2MACER); 2MACER vs. 2MACE: IDI 0.1%, p = 0.126; NRI 23.9%, p = 0.125; AUC: 0.651 (95% CI 0.547-0.755) vs. 0.638 (95% CI 0.534-0.742), respectively; p = 0.361., Conclusions: In clinical practice, AF patients anticoagulated with rivaroxaban exhibit a low risk of events. 2MACE score acts as a modest predictor of a higher risk of adverse outcomes in this population. 2MACER did not significantly increase the ability of 2MACE to predict MACE.

Aim: To analyze the frequency and variables related to inappropriate rivaroxaban dosage in clinical practice and its impact on outcomes after 2 years. Materials & methods: Postauthorization, observational, multicenter study, in which atrial fibrillation patients, treated with rivaroxaban ≥6 months were included. Results:  A total of 1421 patients (74.2 ± 9.7 years, CHA 2 DS 2 -VASc 3.5 ± 1.6) were included. Overall, 22.9% received rivaroxaban 15 mg. The proper dose of rivaroxaban was taken by 83.3% (9.7% underdosed, 7.0% overdosed). Older age and renal insufficiency were associated with inadequate rivaroxaban dosage. There was a trend toward higher all-cause mortality among underdosed patients (adjusted hazard ratio 1.39; 95% CI 0.75-2.58), and more bleedings in overdosed patients (2.29 vs 0.80 events/100 patient-years; p = 0.14). Conclusion: In clinical practice, rivaroxaban is properly dosed in most patients.

Aims: The GOLD AF Registry has been designed to prospectively assess the population, indications, and outcomes using second-generation phased radiofrequency (RF) ablation (pulmonary vein ablation catheter GOLD) in a global examination of standard-of-care use for the treatment of paroxysmal and persistent atrial fibrillation (AF)., Methods and Results: GOLD AF (NCT02433613) is a prospective, observational, multi-centre registry designed to characterize efficacy and safety of phased RF ablation in patients with AF. The primary endpoint was freedom from AF recurrence at 12-month follow-up after a 90-day blanking period. Ancillary objectives include safety, procedural efficiency, and quality of life (QoL). The QoL assessment using the Atrial Fibrillation Effect on QualiTy-of-Life (AFEQT) and the European Heart Rhythm Association (EHRA) Score of AF-related symptoms was collected at baseline and 12 months. In total, 1054 patients were included in this analysis (age 60.6, 67.6% male, 26.5% PersAF). Kaplan-Meier estimate of freedom from AF recurrence was 77.7% at 12 months. Peri-procedural device or procedure-related complications were observed in 26 (2.5%) patients, with a low stroke rate of 0.3%. One-year post-ablation, the EHRA AF Symptom score decreased in 68% of patients. The AFEQT score improvement was observed in 88.4% and 90.4% of patients who completed the questionnaire in-person or interviewed by phone at 12 month follow-up, respectively., Conclusion: Phased RF ablation for the treatment of paroxysmal and persistent AF demonstrated a 77.7% freedom from AF recurrence at 12 months in addition to a significant reduction in arrhythmia symptoms and clinically meaningful improved QoL. Low peri-procedural complication rate of <3% was reported., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction and Objectives: Ivabradine is an inhibitor of the If channel, the main determinant of the pacemaker function of the sinus node. The drug has been approved for the treatment of angina and heart failure. There is some evidence of its role as an inhibitor of atrial-ventricular node (AVN) conduction. The aim of the BRAKE-AF project is to assess ivabradine use for rate control in atrial fibrillation (AF)., Methods: A multicenter, randomized, parallel, open-label, noninferiority phase III clinical trial will be conducted to compare ivabradine vs digoxin in 232 patients with uncontrolled permanent AF despite beta-blockers or calcium channel blockers. The primary efficacy endpoint is the reduction in daytime heart rate measured by 24-hour Holter monitoring at 3 months. This clinical trial will be supported by an electrophysiological study of the effect of ivabradine on the action potential of the human AVN. To do this, an experimental model will be used with Chinese hamster ovarium cells transfected with the DNA encoding the expression of the t channels involved in this action potential and recording of the ionic currents with patch clamp techniques., Results: New data will be obtained on the effect of ivabradine on the human AVN and its safety and efficacy in patients with permanent AF., Conclusions: The results of the BRAKE-AF project might allow inclusion of ivabradine within the limited arsenal of drugs currently available for rate control in AF., Clinical Trial Registration: http://www.clinicaltrials.gov. Identifier: NCT03718273., (Copyright © 2019 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.)

We report the entrapment of Pulmonary Vein Ablation Catheter (Medtronic, Minneapolis, MN, USA) and its guidewire within the right pulmonary veins in two patients. The catheters could be retrieved without complications but they were disabled in both cases. This nondescribed incident should be recognized by PVAC users since it may be a source of potential severe complications during pulmonary vein isolation procedures., (© 2018 Wiley Periodicals, Inc.)

Background: Hypertension is an important, modifiable risk factor for the development of atrial fibrillation (AF). Even after pulmonary vein isolation (PVI), 20-40% experience recurrent AF. Animal studies have shown that renal denervation (RDN) reduces AF inducibility. One clinical study with important limitations suggested that RDN additional to PVI could reduce recurrent AF., Objective: The goal of this multicenter randomized controlled study is to investigate whether RDN added to PVI reduces AF recurrence., Methods: The main end point is the time until first AF recurrence according to EHRA guidelines after a blanking period of 3 months. Assuming a 12-month accrual period and 12 months of follow-up, a power of 0.80, a two-sided alpha of 0.05 and an expected drop-out of 10% per group, 69 patients per group are required. We plan to randomize a total of 138 hypertensive patients with AF and signs of sympathetic overdrive in a 1:1 fashion. Patients should use at least two antihypertensive drugs. Sympathetic overdrive includes obesity, exercise-induced excessive blood pressure (BP) increase, significant white coat hypertension, hospital admission or fever induced AF, tachycardia induced AF and diabetes mellitus. The interventional group will undergo PVI + RDN and the control group will undergo PVI., Results: Patients will have follow-up for 1 year, and continuous loop monitoring is advocated., Conclusion: This randomized, controlled study will elucidate if RDN on top of PVI reduces AF recurrence.

Background: Atrial rate-responsive pacing (RRP) has proved to be safe in pacemaker recipients with chronotropic incompetence. Although RRP is available in all current implantable cardioverter defibrillators (ICDs), the outcomes of this pacing mode in ICD patients are unknown. The aim is to evaluate the relationship between atrial RRP and atrial arrhythmias in ICD recipients., Methods: Dual-chamber and triple-chamber ICD patients were included in this multicenter cohort study. Patients with permanent atrial fibrillation (AF) or VVI pacing mode were excluded. The number and duration of atrial tachycardia (AT)/AF episodes were assessed., Results: Data from 415 patients and 80,707 AT/AF episodes (median duration: 0.4 hours) were collected after a 21.3 ± 14.1-month follow-up. Atrial RRP was programmed in 90 (21.7%) patients and was associated with a higher atrial pacing percentage in the overall study population (51.2 ± 33.8% vs 18.4 ± 25.7%, P < 0.001) and to a higher ventricular pacing percentage among dual-chamber devices (22.3 ± 37.6% vs 9.3 ± 25%, P < 0.001). Independent factors associated with sustained AT/AF episodes (>23 hours) were previous AF (odds ratio [OR]: 7.98; 95% confidence interval [CI]: 4.11-15.47; P < 0.001) and atrial RRP (OR: 3.58; 95% CI: 1.82-7.03; P < 0.001). RRP was related to a lower sustained AT/AF episodes-free survival both in patients with a history of AF (43% vs 70%, P = 0.035) and without a history of AF (82% vs 97%, P = 0.004) at 2 years., Conclusions: Atrial RRP in ICD patients was related to a higher incidence of sustained atrial arrhythmias. This pacing mode may have an atrial proarrhythmic effect on ICD patients, especially among those with a history of AF., (©2016 Wiley Periodicals, Inc.)

Background: Empiric circumferential pulmonary vein isolation (CPVI) has become the therapy of choice for drug-refractory atrial fibrillation (AF). Although results are suboptimal, it is unknown whether mechanistically-based strategies targeting AF drivers are superior., Objectives: This study sought to determine the efficacy and safety of localized high-frequency source ablation (HFSA) compared with CPVI in patients with drug-refractory AF., Methods: This prospective, multicenter, single-blinded study of 232 patients (age 53 ± 10 years, 186 males) randomized those with paroxysmal AF (n = 115) to CPVI or HFSA-only (noninferiority design) and those with persistent AF (n = 117) to CPVI or a combined ablation approach (CPVI + HFSA, superiority design). The primary endpoint was freedom from AF at 6 months post-first ablation procedure. Secondary endpoints included freedom from atrial tachyarrhythmias (AT) at 6 and 12 months, periprocedural complications, overall adverse events, and quality of life., Results: In paroxysmal AF, HFSA failed to achieve noninferiority at 6 months after a single procedure but, after redo procedures, was noninferior to CPVI at 12 months for freedom from AF and AF/AT. Serious adverse events were significantly reduced in the HFSA group versus CPVI patients (p = 0.02). In persistent AF, there were no significant differences between treatment groups for primary and secondary endpoints, but CPVI + HFSA trended toward more serious adverse events., Conclusions: In paroxysmal AF, HFSA failed to achieve noninferiority at 6 months but was noninferior to CPVI at 1 year in achieving freedom of AF/AT and a lower incidence of severe adverse events. In persistent AF, CPVI + HFSA offered no incremental value. (Radiofrequency Ablation of Drivers of Atrial Fibrillation [RADAR-AF]; NCT00674401)., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Catheter ablation (CA) is a highly effective therapy for the treatment of paroxysmal atrial fibrillation (AF) when compared with antiarrhythmic drug therapy (ADT). No randomized studies have compared the two strategies in persistent AF. The present randomized trial aimed to compare the effectiveness of CA vs. ADT in treating persistent AF., Methods and Results: Patients with persistent AF were randomly assigned to CA or ADT (excluding patients with long-standing persistent AF). Primary endpoint at 12-month follow-up was defined as any episode of AF or atrial flutter lasting >24 h that occurred after a 3-month blanking period. Secondary endpoints were any atrial tachyarrhythmia lasting >30 s, hospitalization, and electrical cardioversion. In total, 146 patients were included (aged 55 ± 9 years, 77% male). The ADT group received class Ic (43.8%) or class III drugs (56.3%). In an intention-to-treat analysis, 69 of 98 patients (70.4%) in the CA group and 21 of 48 patients (43.7%) in the ADT group were free of the primary endpoint (P = 0.002), implying an absolute risk difference of 26.6% (95% CI 10.0-43.3) in favour of CA. The proportion of patients free of any recurrence (>30 s) was higher in the CA group than in the ADT group (60.2 vs. 29.2%; P < 0.001) and cardioversion was less frequent (34.7 vs. 50%, respectively; P = 0.018)., Conclusion: Catheter ablation is superior to medical therapy for the maintenance of sinus rhythm in patients with persistent AF at 12-month follow-up., Clinical Trial Registration Information: NCT00863213 (http://clinicaltrials.gov/ct2/show/NCT00863213).

Introduction and Objectives: Atrial fibrillation (AF) is one of the most common arrhythmias. It is classified according to its presentation as either paroxysmal, persistent or permanent. The presence of this arrhythmia has been associated with a decrease in patients' health-related quality of life (HRQoL). The Atrial Fibrillation-Quality of Life (AF-QoL) questionnaire, which is specifically for use in patients with AF, has recently been developed and validated. The aim of this study was to use this questionnaire to investigate differences in HRQoL associated with different types of AF., Methods: This prospective observational multicenter study was performed in a regular clinical context in Spain. The AF-QoL questionnaire was administered to study patients, who were diagnosed as having one of the three types of AF., Results: The study involved 341 patients with AF, 43% of whom had persistent AF, while 37% had paroxysmal AF, and 20% had permanent AF. Although the type of AF had no significant effect on the overall AF-QoL score, patients with permanent AF had the highest scores on the psychological dimension (i.e. better HRQoL). In addition, an increased frequency of symptoms, more emergency department visits, and poorer functioning were also associated with significant differences in HRQoL in AF patients., Conclusions: Use of the AF-QoL questionnaire showed that the HRQoL of AF patients was influenced by the clinical characteristics of the disease but not, except on the psychological dimension, by the type of AF.

Aims: To assess the performance of AF-QoL, a quality of life questionnaire for patients with atrial fibrillation (AF)., Methods and Results: Observational, prospective, multicentre study in 29 Spanish centres. Three patients' groups were identified at baseline visit: AF patients receiving a new therapeutic intervention according to physician criteria (intervention group); AF clinically stable patients according to physician evaluation (clinically stable group); and patients in a stable condition for more than 1 year after a myocardial infarction (control group). All patients were > or = 18 years. Follow-up visit was at 1 month (clinically stable group) and 3 +/- 1 months (intervention group). Sociodemographic and clinical information was gathered. AF-QoL, SF-36, and patient self-perception of general health status were administered. A total of 417 patients was included. Mean (SD) age was 61.2 (12.4), 31.4% women. AF-QoL mean overall score in AF patients (43.6) was lower (worse health-related quality of life, HRQoL) than in the control group (51.7) (P < 0.05). At baseline, patients with higher frequency of symptoms (P < 0.05) and worse NYHA functional class (P < 0.01) reported lower AF-QoL scores. AF-QoL and SF-36 correlated in all of their domains (r = 0.14-0.8, P < 0.01). AF-QoL showed good internal consistency (0.92) and test-retest reliability (0.86)., Conclusion: AF-QoL is a valid and reliable HRQoL measure. Further investigation is recommended before using it in clinical practice.

Aims: The aim of the present analysis of the DATAS study was to compare the impact of dual- vs. single-chamber defibrillators on atrial fibrillation (AF) occurrence and AF-related clinical events in patients with Class I indication for implantable cardioverter defibrillators (ICDs) and no indication for dual-chamber pacing., Methods and Results: Three hundred and thirty-four patients were randomized, through a centralized assignment, to single-chamber ICDs, dual-chamber ICDs programmed as single-chamber ICDs, and dual ICDs with full diagnostics and AF prevention and therapy capabilities. The latter two groups in the first 8 months of the study, when the study design was that of a randomized parallel trial, were compared in the present analysis. The primary endpoint was composed by the following AF-related clinical events: permanent AF, AF-related hospitalizations, cardiac-embolic events, and inappropriate ICD shocks due to AF misclassification. Two hundred and twenty-three patients were available for this analysis, of whom 111 in the single-chamber-simulated group and 112 in the dual-chamber true group. Atrial fibrillation-related composite endpoint raw incidence was 9 of 111 (8.1%) in the single-chamber group vs. 1 of 112 (0.9%) in the dual-chamber group (P = 0.0098 by Fisher's exact test). Single-chamber ICDs were associated with a significantly higher risk to develop the AF-related composite endpoint by Cox regression analysis (hazard ratio 8.25, 95% CI 1.03-65.96, P = 0.047) and by the Kaplan-Meier survival analysis (log-rank test, P = 0.047)., Conclusion: Dual-chamber ICDs compared with single-chamber ICDs reduced the incidence of an endpoint composed by permanent AF, AF-related hospitalizations, and ICD shocks deemed inappropriate due to AF misclassification.

Background: Radiofrequency catheter ablation is a well-established approach to treating several types of cardiac arrhythmias. The aim of our study was to provide data on the diffusion of catheter ablation procedures in clinical practice through a meta-analysis of National Registries of electrophysiological procedures performed over a 5-year period, from 2000 to 2005., Methods: We found only two national registries of catheter ablation procedures published in the journals indexed in PubMed: The Spanish Catheter Ablation Registry and the Portuguese National Registry on Cardiac Electrophysiology. In addition, we included in our analysis the data from the Italian Registry of Electrophysiological Procedures., Results and Conclusions: This meta-analysis revealed a steady increase in the total number of catheter ablation procedures, particularly for the ablation of atrial flutter, of tachycardia due to double nodal pathways, and of the left atrial substrate in atrial fibrillation. However, the progress of catheter ablation and the impetus for additional research and development of new approaches and technologic advances requires further data on clinical indications, methodologic approach, complications, and long-term success rate in the real world.

Background: The Health-Related Quality of Life (HRQoL) assessment in atrial fibrillation (AF) patients has traditionally been carried out in a poorly standardised fashion, or via the use of non disease-specific HRQoL questionnaires. The development of a HRQoL questionnaire with a good measuring performance will allow for a standardised assessment of the impact of this disease on the patient's daily living., Methods: A bibliography review was conducted to identify the most relevant domains of daily living in AF patients. Subsequently, a focus group was created with the aid of cardiologists, and 17 patients were interviewed to identify the most-affected HRQoL domains. A qualitative analysis of the interview answers was performed, which was used to develop a pilot questionnaire administered to a 112-patient sample. Based on patient responses, an analysis was carried out following the statistical procedures defined by the Classical Test Theory (CTT) and the Item Response Theory (IRT). Reliablility was assessed via Cronbach's coefficient alpha and item-total score correlations. A factorial analysis was performed to determine the number of domains. For each domain, a Rasch analysis was carried out, in order to reduce and stand hierarchically the questionnaire items., Results: By way of the bibliography review and the expert focus group, 10 domains were identified. The patient interviews allowed for the identification of 286 items that later were downsized to 40 items. The resultant preliminary questionnaire was administered to a 112-patient sample (pilot study). The Rasch analysis led to the definition of two domains, comprising 7 and 11 items respectively, which corresponded to the psychological and physical domains (18 items total), thereby giving rise to the initial AF-QoL-18 questionnaire. Cronbach's coefficient alpha was acceptable (0.91)., Conclusion: An initial HRQoL questionnaire, AFQoL-18, has been developed to assess HRQoL in AF patients.

Atrial fibrillation (AF) is the most prevalent arrhythmia in hospital emergency departments and is a serious disease associated with a twofold increase in morbidity and a high mortality rate. However, the management of AF in this scenario is variable and frequently inadequate. This is probably a consequence of the diverse clinical aspects and therapeutic options to consider in the management of patients with AF. Therefore, implementation of specific, coordinated management strategies by the different care providers involved is needed to improve the quality of care and optimize the use of human and material resources. This document presents the guidelines recommended by the Spanish Society of Cardiology (SEC) and the Spanish Society of Emergency Medicine (SEMES) for the management of AF in hospital emergency departments. These guidelines are based on published scientific evidence and are applicable to most emergency departments in Spain. Specific management strategies are proposed for the conversion and maintenance of sinus rhythm, heart rate control during AF, prophylaxis for thrombi and emboli, and hospital admission and discharge protocols.

Aims: To describe the mechanisms of induction of ventricular fibrillation (VF) by rapid atrial rates in patients with hypertrophic cardiomyopathy (HCM)., Methods: Electrophysiological studies, management and follow-up in three patients with HCM with VF induced by atrial pacing., Results: In one patient, spontaneous sinus tachycardia triggered VF. In another patient, VF occurred after verapamil infusion during rapid atrial fibrillation, and in the remaining patient there was no clinical VF. In all three patients, short runs of atrial pacing (cycle length 272-380 ms) induced VF, and QRS widening preceded fibrillation in all patients. Marked ventricular electrogram fragmentation was documented in one patient during atrial pacing and in another patient during late ventricular extra-stimuli. Hypotension was associated with sinus tachycardia in one patient. The two patients developing clinical VF underwent atrioventricular (AV) junctional ablation; a ventricular defibrillator was implanted in one, and a mode-switching dual-chamber pacemaker in the other. No arrhythmic events occurred during 34- and 35-month follow-up, respectively. In the other patient, postatrial fibrillation pauses caused syncope, and he is asymptomatic 52 months after implantation of a dual-chamber pacemaker., Conclusions: Rapid atrial rates can trigger VF in some patients with HCM, probably through a combination of electrophysiological and ischaemic mechanisms. AV junctional ablation may prevent VF in selected cases.

Atrial fibrillation is the most common cardiac arrhythmia and is usually responsible for symptoms requiring some treatment. Antiarrhythmic drugs are the first choice therapy, but their potential risks are significant. This together with their limited efficacy restricts their use. Antiarrhythmic drug use should be tailored; mainly according to the underlying heart disease. When reversion to sinus rhythm is not eligible, the adequate control of ventricular rate and the reduction of embolic risk are the therapeutic goals. Atrial flutter shows different behaviour regarding the very limited efficacy of antiarrhythmic drugs for reversion to and maintenance in sinus rhythm.

low conduction of early extrastimuli and short refractory periods are some of the factors underlying atrial fibrillation in man. In order to study the effect of ajmaline, a class I antiarrhythmic agent, on these variables, we have performed electrophysiologic studies in 13 patients with and without atrial arrhythmias, before and after the intravenous administration of 1 mg Kg of ajmaline chlorhydrate. During paced rhythm with a 600 ms cycle length, extrastimuli were applied to the right atrial appendage, and conduction to the low septal right atrium and the coronary sinus were measured. Ajmaline prolonged P wave duration from 111 ± 15 to 140 ± 24 ms (P<0.001), conduction of baseline stimuli to low septal right atrium from 69 ± 14 to 95 ± 21 ms (P<0.001) and to coronary sinus from 127 ± 18 to 165 ± 29 ms (P<0.001). Atrial effective refractory period increased from 207 ± 23 to 255 ± 27 ms (P< 0001). Maximum conduction delay of early extrastimuli decreased at the low septal right atrium from 43 ± 22 to 29 ± 16 ms (P<0.25) and at the coronary sinus from 47 ± 22 to 21 ± 14 ms (P<0.001). These results show interesting electrophysiologic effects of ajmaline on atrial tissue, with reversion of some of the abnormalities underlying atrial fibrillation, and suggest an antiarrhythmic effect. [ABSTRACT FROM PUBLISHER]