Catheter Ablation of Atypical Atrioventricular Nodal Reentrant Tachycardia.

BACKGROUND: Because of its low prevalence, data on atypical atrioventricular nodal reentrant tachycardia (AVNRT) are scarce, and the optimal ablation method has not been established. Our study aimed at assessing the efficacy and safety of conventional slow pathway ablation, as applied for typical cases, in atypical AVNRT. METHODS: We studied 2079 patients with AVNRT subjected to slow pathway ablation. In 113 patients, mean age 48.5±18.1 years, 68 female, atypical AVNRT or coexistent atypical and typical AVNRT without other concomitant arrhythmia was diagnosed. Ablation data and outcomes were compared with a group of age- and sex-matched control patients with typical AVNRT. RESULTS: Fluoroscopy and radiofrequency current delivery times were not different in the atypical and typical groups, 20.3±12.2 versus 20.8±12.9 minutes (P=0.730) and 5.9±5.0 versus 5.5±4.5 minutes (P=0.650), respectively. Slow pathway ablation was accomplished from the right septum in 110 patients, and from the left septum in 3 patients, in the atypical group. There was no need for additional ablation lesions at other anatomic sites, and no cases of atrioventricular block were encountered. Recurrence rates of the arrhythmia were 5.6% in the atypical (6/108 patients) and 1.8% in the typical (2/111 patients) groups in the next 3 months following ablation (P=0.167). CONCLUSIONS: Conventional ablation at the anatomic area of the slow pathway is the therapy of choice for symptomatic AVNRT, regardless of whether the typical or atypical form is present.

Catheter ablation vs. antiarrhythmic drug therapy in patients with symptomatic atrioventricular nodal re-entrant tachycardia: a randomized, controlled trial.

AIMS: To conduct a randomized trial in order to guide the optimum therapy of symptomatic atrioventricular nodal re-entrant tachycardia (AVNRT). METHODS AND RESULTS: Patients with at least one symptomatic episode of tachycardia per month and an electrophysiologic diagnosis of AVNRT were randomly assigned to catheter ablation or chronic antiarrhythmic drug (AAD) therapy with bisoprolol (5 mg od) and/or diltiazem (120-300 mg od). All patients were properly educated to treat subsequent tachycardia episodes with autonomic manoeuvres or a 'pill in the pocket' approach. The primary endpoint of the study was hospital admission for persistent tachycardia cardioversion, during a follow-up period of 5 years. Sixty-one patients were included in the study. In the ablation group, 1 patient was lost to follow-up, and 29 were free of arrhythmia or conduction disturbances at a 5-year follow-up. In the AAD group, three patients were lost to follow-up. Of the remainder, 10 patients (35.7%) continued with initial therapy, 11 patients (39.2%) remained on diltiazem alone, and 7 patients (25%) interrupted their therapy within the first 3 months following randomization, and subsequently developed an episode requiring cardioversion. During a follow-up of 5 years, 21 patients in the AAD group required hospital admission for cardioversion. Survival free from the study endpoint was significantly higher in the ablation group compared with the AAD group (log-rank test, P < 0.001). CONCLUSIONS: Catheter ablation is the therapy of choice for symptomatic AVNRT. Antiarrhythmic drug therapy is ineffective and not well tolerated.

Atypical atrioventricular nodal reentrant tachycardia: prevalence, electrophysiologic characteristics, and tachycardia circuit.

AIMS: This study aimed at assessing the prevalence, electrophysiologic characteristics, and mechanism of atypical atrioventricular nodal reentrant tachycardia (AVNRT). METHODS AND RESULTS: We studied 925 consecutive patients with AVNRT. Atrial-His (AH) and His-atrial (HA) intervals were measured during atypical AVNRT (HA > 70 ms), and compared with measurements in 34 patients with typical (slow-fast) AVNRT. Assuming that conduction velocity over the fast pathway is similar in the anterograde and retrograde directions, the AH interval during the fast-slow form should be smaller than the HA during slow-fast. Atypical AVNRT was diagnosed in 59 patients (6.4%), median age 50 years (range 19-79 years), and 37 (59.7%) of them female. Fast-slow AVNRT was diagnosed in 44 patients (74.5%), and slow-slow AVNRT in 9 patients (15.2%). The remaining six patients (10.2%) could not be reliably classified due to inconsistent AH, and HA/AH patterns or variable intervals. Tachycardia induction with anterograde conduction jumps was seen in two patients with the fast-slow, and in three patients with slow-slow or intermediate forms. Atrial-His in the fast-slow group was significantly longer than HA in the slow-fast group, 99.7 ± 40.5 ms vs. 45.8 ± 7.7 ms, P < 0.001. Tachycardia cycle length was longer in fast-slow compared with slow-fast, 379.1 ± 68.5 ms vs. 317.1 ± 42.8 ms, P < 0.001. CONCLUSION: Of AVNRT cases, 6.4% are atypical and may display patterns that do not necessarily correspond to the fast-slow or slow-slow conventional types. Atypical fast-slow and typical AVNRT do not appear to utilize the same limb for fast conduction.

Left Septal Slow Pathway Ablation for Atrioventricular Nodal Reentrant Tachycardia.

BACKGROUND: Immunohistochemistry studies suggest that the anatomic substrate of the slow pathway in atrioventricular nodal reentrant tachycardia (AVNRT) is the left inferior nodal extension. We hypothesized that slow pathway ablation from the left septum is an effective alternative to right-sided ablation. METHODS AND RESULTS: We analyzed our databases of AVNRT in search of cases that had used slow pathway ablation from the left septum because of failure of right septal ablation, and then prospectively subjected consenting patients to a left septal-only procedure. Of 1342 patients subjected to right septal slow pathway ablation for AVNRT, 15 patients, 11 with typical and 4 with atypical AVNRT, had a left septal approach after unsuccessful right-sided ablation (R+L group). Eleven patients were subjected to a left septal-only approach for slow pathway ablation without a previous right septal attempt (L group). Fluoroscopy times in the R+L and L groups were 30.5 (21.0-44.0) and 20.0 (17.0-25.0) minutes, respectively (P=0.061), and radiofrequency current delivery times were 11.3 (5.0-19.1) and 10.0 (7.0-12.0) minutes, respectively (P=0.897). There was no need for additional ablation lesions at other anatomic sites in either group, and no cases of atrioventricular block were encountered. Recurrence rates of the arrhythmia for the R+L and L groups were 6.7% and 0%, respectively, in the 3 months after ablation (P=1.000). CONCLUSIONS: Left septal ablation at the anatomic site of the left inferior nodal extension is an alternative for ablation of both typical and atypical AVNRT when ablation at the right posterior septum is ineffective.

Management of Complications in Anticoagulated Patients with Atrial Fibrillation.

Oral anticoagulation is mandatory for patients at high risk of thromboembolism, but the risk of bleeding should also be taken into account. Direct oral anticoagulants are now recommended for non-valvular AF as a potential alternative to warfarin. In this article we discuss methods to assess the anticoagulant effect of these agents, specific and general antidotes, and management of complications such as embolic and haemorrhagic stroke, and significant bleeding.

Radiofrequency Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation: Meta-Analysis of Quality of Life, Morbidity, and Mortality.

OBJECTIVES: The aim of this study was to perform a collaborative meta-analysis of published and unpublished quality-of-life, morbidity, and mortality data from randomized controlled trial comparisons of radiofrequency ablation (RFA) and antiarrhythmic drug therapy (AAD) in symptomatic atrial fibrillation. BACKGROUND: RFA is superior to AAD in decreasing recurrences of atrial fibrillation, but the effects on other clinical outcomes are not well established. METHODS: The primary investigators of eligible randomized controlled trials were invited to contribute standardized outcome data. Random-effects summary estimates were calculated as standardized mean differences and risk ratios with 95% confidence intervals for continuous and binary outcomes, respectively. Fixed effects were used in subgroup analyses. RESULTS: Twelve randomized controlled trials (n = 1,707 patients) were included. RFA led to greater improvements in 4 36-Item Short Form Health Survey areas and the symptom frequency score from baseline to 3 months. In all quality-of-life metrics, there was a trend toward diminution of the differences between the 2 approaches with follow-up. There were 7 of 866 (5 in a study using phased RFA) and 0 of 704 strokes in the RFA and AAD arms, respectively (p = 0.02, Fisher exact test). Bleeding and mortality events were not significantly different between the 2 arms. There was high heterogeneity for hospitalizations, with decreased hospitalization risk with RFA when it was not first-line therapy (risk ratio: 0.34; 95% confidence interval: 0.24 to 0.46) and increased risk as first-line therapy (risk ratio: 1.22; 95% confidence interval: 1.03 to 1.45). CONCLUSIONS: RFA demonstrates an early but nonsustained superiority over AAD for the improvement of quality of life. There are no obvious differences in other clinical outcomes, and the periprocedural stroke risk is non-negligible.

Cardiac Autonomic Denervation for Ablation of Atrial Fibrillation.

The influence of the autonomic nervous system (ANS) on triggering and perpetuation of atrial fibrillation (AF) is well established. Ganglionated plexi (GP) ablation achieves autonomic denervation by affecting both the parasympathetic and sympathetic components of the ANS. GP ablation can be accomplished endocardially or epicardially, i.e. during the maze procedure or thoracoscopic approaches. Recent evidence indicates that anatomic GP ablation at relevant atrial sites appears to be safe and improves the results of pulmonary vein isolation in patients with paroxysmal and persistent AF.

Effect of one-cycle remote ischemic preconditioning to reduce myocardial injury during percutaneous coronary intervention.

Up to 1/3 of percutaneous coronary interventions (PCIs) are complicated by troponin release. Remote ischemic preconditioning (IPC) confers effective cardioprotection; however, a 30-minute remote IPC protocol may be difficult to implement during ad hoc PCI. This study was performed to assess the ability of a brief remote IPC protocol to attenuate cardiac troponin I (cTnI) release after ad hoc PCI. Ninety-four patients undergoing ad hoc PCI for stable coronary artery disease, with undetectable preprocedural cTnI, were recruited and randomized to receive remote IPC (induced by one 5-minute inflation of a blood pressure cuff to 200 mm Hg around the upper arm) or control after the decision for PCI was made. The primary outcome was the difference between cTnI levels 24 hours after PCI and cTnI levels before coronary angiography (ΔcTnI). ΔcTnI in the remote IPC group was significantly lower compared with the control group (0.04 ng/ml [interquartile range 0.01 to 0.14] vs 0.19 ng/ml [interquartile range 0.18 to 0.59], p <0.001). The incidence of PCI-related myocardial infarction (MI) was greater in the control group (42.6% vs 19.1%, p = 0.014). In multivariate analysis, remote IPC was independently associated with ΔcTnI and PCI-related MI. In conclusion, our results suggest that even 1 cycle of remote IPC immediately before ad hoc PCI attenuates periprocedural cTnI release and reduces the incidence of type 4a MI.

The Electrocardiogram in Athletes Revisited.

Cardiovascular-related sudden death is the leading cause of mortality in athletes during sport. Thus, it is of clinical importance to identify ECG changes that represent normal adaptation in athletes, and differentiate them from truly pathological findings. However, a distinction between adaptive and pathological ECG changes in athletes is not always easy. This article discusses exercise-induced ECG changes and the differential diagnosis of conditions that present with similar ECG patterns.

Complications of transseptal catheterization for different cardiac procedures.

BACKGROUND: Cardiac tamponade is the main complication of transseptal catheterization that is necessary for a variety of cardiac interventions and electrophysiology procedures. METHODS: A retrospective assessment of all consecutive procedures that required transseptal puncture by the same experienced operator (with already >100 previous trans-septal procedures) during the period 2000-2012 was performed. We recorded any puncture-related complications of pericardial effusion and cardiac tamponade (acute or delayed). RESULTS: A total of 393 procedures were retrieved: Group 1 [ablation of left-sided accessory pathways (n = 77), atrioventricular nodal reentry tachycardia-left septal access (AVNRT) (n = 12), and Inoue balloon mitral valvuloplasty (n = 27)], and Group 2 [atrial fibrillation (AF) ablation procedures: ostial pulmonary vein isolation (PVI) (including RF (n = 76) and cryo-balloon (n = 30)), circumferential PVI (n = 51), and combined procedures (n = 120)]. In total, 5 cases of tamponade were recorded, four of them were acute and one delayed (occurring 1h after the procedure). All tamponade cases occurred only during or after AF ablation procedures (cryo-balloon ablation = 1, circumferential PVI = 2, and combined procedures = 2). In one case emergency atrial repair following median sternotomy was necessary, and in another a surgical drainage through a limited thoracotomy was performed. The other three cases were treated with pericardiocentesis and drainage for 12h. No patient was on uninterrupted oral anticoagulation during the procedure. CONCLUSIONS: AF ablation is associated with a higher incidence of tamponade compared to other procedures that require transseptal access. Such procedures should only be performed in hospitals with access to emergency surgical support.