Jari Tapanainen

Interatrial conduction can be accurately determined using standard 12-lead electrocardiography: validation of P-wave morphology using electroanatomic mapping in man.

BACKGROUND Different P-wave morphologies during sinus rhythm as displayed on standard ECGs have been postulated to correspond to differences in interatrial conduction. OBJECTIVE The purpose of this study was to evaluate the hypothesis by comparing P-wave morphologies using left atrial activation maps. METHODS Twenty-eight patients (mean age 49 +/- 9 years) admitted for ablation of paroxysmal atrial fibrillation were studied. Electroanatomic mapping of left atrial activation was performed at baseline during sinus rhythm with simultaneous recording of standard 12-lead ECG. Unfiltered signal-averaged P waves were analyzed to determine orthogonal P-wave morphology. The morphology was subsequently classified into one of three predefined types. All analyses were blinded. RESULTS The primary left atrial breakthrough site was the fossa ovalis in 8 patients, Bachmann bundle in 18, and coronary sinus in 2. Type 1 P-wave morphology was observed in 9 patients, type 2 in 17, and type 3 in 2. Seven of eight patients with fossa ovalis breakthrough had type 1 P-wave morphology, 16 of 18 patients with Bachmann bundle breakthrough had type 2 morphology, and both patients with coronary sinus breakthrough had type 3 P-wave morphology. Overall, P-wave morphology criteria correctly identified the site of left atrial breakthrough in 25 (89%) of 28 patients. CONCLUSION In the vast majority of patients, P-wave morphology derived from standard 12-lead ECG can be used to correctly identify the left atrial breakthrough site and the corresponding route of interatrial conduction.

Interatrial right-to-left conduction in patients with paroxysmal atrial fibrillation

PurposeWe wanted to illustrate the right-to-left impulse propagation routes during sinus in patients with paroxysmal atrial fibrillation (PAF), as alterations in conduction patterns have been linked to the pathogenesis of PAF, and as no large patient materials have been published.MethodsPatients underwent 3-D electroanatomical contact mapping prior to catheter ablation. The site of the earliest left atrial (LA) activation was determined.ResultsThree different interatrial routes were identified, either as solitary pathways (36/50 patients, 72%) or in their combinations (14/50). Bachmann’s bundle (BB) was involved in the majority of the cases with solitary routes (25/36). More seldom, impulse propagation occurred near the oval fossa (FO) (7/36) or the coronary sinus ostium (4/36). In patients with combined routes, both the BB (10/14) and FO routes (11/14) were included in most cases.ConclusionsIn PAF patients, LA can be activated during sinus rhythm through three distinct connections, either encompassing a single route or via any combination of these connections. In one third, the earliest LA activation occurs outside BB. The knowledge of the propagation patterns may give insight into the pathophysiology of PAF and into refining ablation therapy.

Cryoablation of substrates adjacent to the atrioventricular node: acute and long-term safety of 1303 ablation procedures

AIMS Radiofrequency (RF) ablation is effective for ablation of atrial arrhythmias. However, RF ablation in the vicinity of the atrioventricular (AV) node is associated with a risk of inadvertent, irreversible high-grade AV block, depending on the type of substrate. Cryoablation is an alternative method. The objective was to investigate the acute and long-term risks of AV block during cryoablation. METHODS AND RESULTS We studied 1303 consecutive cryoablations of substrates in the vicinity of the AV node in 1201 patients (median age 51 years, range 6-89 years) on acute and long-term impairment to the AV nodal conduction system. The arrhythmias treated were AV nodal reentrant tachycardias (n=1116), paraseptal and superoparaseptal accessory pathways (n=100), and focal atrial tachycardias (n=87). In 158 (12%) procedures, cryomapping (38 cases) or cryoablation (120 cases) were stopped due to transient AV block (first-degree AV block 74 cases, second-degree AV block 67 cases, and third-degree AV block 17 cases) after which another site was tested. Transient AV block occurred within seconds of mapping up to 3 min of ablation. The incidence of AV block was similar for different substrates. In most cases, AV nodal conduction was restored within seconds but in two cases transient AV block lasted 21 and 45 min, respectively. There were no cases of acute permanent AV blocks. No late AV blocks occurred during follow-up (mean 24 months, range 6-96 months). CONCLUSION Cryoablation adjacent to the AV node carries a negligible risk of permanent AV block. Transient AV block during ablation is a benign finding.

Abnormal atrial activation in young patients with lone atrial fibrillation.

AIMS Patients with a history of atrial fibrillation (AF) have previously been shown to have altered atrial conduction, as seen non-invasively using signal-averaged P-wave analysis. However, little is known about the P-wave morphology in patients in the early phases of AF with structurally normal hearts. METHODS AND RESULTS Thirty-six patients with lone AF were included before the age of 40 years (34±4 years, 34 men) and compared with age- and gender-matched control subjects. Standard 12-lead electrocardiogram (ECG) was recorded for at least 10 s. P-wave morphology and duration were estimated using signal-averaged P-wave analysis. Echocardiography was performed in association with the ECG recording. Heart rate (67±13 vs. 65±7 b.p.m., P=0.800) and PQ-interval (163±16 vs. 164±23 ms, P=0.629) were similar in AF cases and controls, as was P-wave duration (136±13 vs. 129±13 ms, P=0.107). The distribution of P-wave morphology differed between the AF cases and controls [33/58/0/8 vs. 75/25/0/0% (Type 1/Type 2/Type 3/atypical), P=0.001], with a larger proportion of patients with AF exhibiting signs of impaired interatrial conduction. CONCLUSION A significant difference in P-wave morphology distribution was seen between patients with early-onset, lone paroxysmal AF and age- and gender-matched healthy control subjects. This finding indicates that alterations in atrial electrophysiology are common in the early stage of the arrhythmia, and since it occurs in young patients without co-morbidity may well be the cause rather than the consequence of AF.

Non-invasive detection of conduction pathways to left atrium using magnetocardiography: validation by intra-cardiac electroanatomic mapping

AIMS Alteration in conduction from right to left atrium (LA) is linked to susceptibility to atrial fibrillation (AF). We examined whether different inter-atrial conduction pathways can be identified non-invasively by magnetocardiographic mapping (MCG). METHODS AND RESULTS In 27 patients undergoing catheter ablation of paroxysmal AF, LA activation sequence was determined during sinus rhythm using invasive electroanatomic mapping. Before this, 99-channel magnetocardiography was recorded over anterior chest. The orientation of the magnetic fields during the early (40-70 ms from P onset) and later part (last 50%) of LA depolarization was determined using pseudocurrent conversion. Breakthrough of electrical activation to LA occurred through Bachmann bundle (BB) in 14, margin of fossa ovalis (FO) in 3, coronary sinus ostial region (CS) in 2, and their combinations in 10 cases by invasive reference in total of 29 different P-waves. Based on the combination of pseudocurrent angles over early and late parts of LA activation, the MCG maps were divided to three types. These types correctly identified the LA breakthrough sites to BB, CS, FO, or their combinations in 27 of 29 (93%) cases. CONCLUSION Magnetocardiographic mapping seems capable of distinguishing inter-atrial conduction pathways. Recognizing the inter-atrial conduction pattern may assist in understanding the pathogenesis of AF and identifying the subgroups for patient-tailored therapy.

Assessment of Use vs Discontinuation of Oral Anticoagulation After Pulmonary Vein Isolation in Patients With Atrial Fibrillation

Importance Pulmonary vein isolation (PVI) is a recommended treatment for patients with atrial fibrillation, but it is unclear whether it results in a lower risk of stroke. Objectives To investigate the proportion of patients discontinuing anticoagulation treatment after PVI in association with the CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, stroke [doubled], vascular disease, age 65-74 years, sex category [female]) score, identify factors predicting stroke after PVI, and explore the risk of cardiovascular events after PVI in patients with and without guideline-recommended anticoagulation treatment. Design, Setting, and Participants A retrospective cohort study was conducted using Swedish national health registries from January 1, 2006, to December 31, 2012, with a mean-follow up of 2.6 years. A total of 1585 patients with atrial fibrillation undergoing PVI from the Swedish Catheter Ablation Register were included, with information about exposure to warfarin in the national quality register Auricula. Data analysis was performed from January 1, 2015, to April 30, 2016. Exposures Warfarin treatment. Main Outcomes and Measures Ischemic stroke, intracranial hemorrhage, and death. Results In this cohort of 1585 patients, 73.0% were male, the mean (SD) age was 59.0 (9.4) years, and the mean (SD) CHA2DS2-VASc score was 1.5 (1.4). Of the 1585 patients, 1175 were followed up for more than 1 year after PVI. Of these, 360 (30.6%) discontinued warfarin treatment during the first year. In patients with a CHA2DS2-VASc score of 2 or more, patients discontinuing warfarin treatment had a higher rate of ischemic stroke (5 events in 312 years at risk [1.6% per year]) compared with those continuing warfarin treatment (4 events in 1192 years at risk [0.3% per year]) (P = .046). Patients with a CHA2DS2-VASc score of 2 or more or those who had previously experienced an ischemic stroke displayed a higher risk of stroke if warfarin treatment was discontinued (hazard ratio, 4.6; 95% CI, 1.2-17.2; P = .02 and hazard ratio, 13.7; 95% CI, 2.0-91.9; P = .007, respectively). Conclusions and Relevance These findings indicate that discontinuation of warfarin treatment after PVI is not safe in high-risk patients, especially those who have previously experienced an ischemic stroke.

Continuous warfarin therapy is safe and feasible in catheter ablation of atrial fibrillation.

Abstract Objectives. In the context of catheter ablation of atrial fibrillation, oral anticoagulant therapy has been traditionally replaced by bridging with heparin during the periprocedural period. We wanted to study the feasibility and safety of continuous warfarin therapy compared to traditional bridging therapy. Design. The complication rates were compared retrospectively in a consecutive patient series. In the bridging group, warfarin was discontinued three days and low molecular weight heparin started one day prior to the procedure. Warfarin was reinitiated one day after and low molecular weight heparin was continued until the therapeutic INR target was reached. Patients on continuous therapy received warfarin throughout the periprocedural period. All patients received unfractionated heparin during the procedure. Results. Three thromboembolic cerebrovascular events (1.9%) occurred in the bridging group (n = 157) and seven (0.82%) in the warfarin group (n = 850) (p = 0.142). The number of cardiac tamponades was one (0.64%) and four (0.47%), respectively (p = 0.786). Total number of severe bleeding and thromboembolic complications was more common in the bridging group: 9 (5.7%) versus 22 (2.6%); p = 0.036. In multivariate analysis, female gender, advanced age, and bridging therapy predicted complications. Conclusions. Continuous oral anticoagulant therapy is a safe and feasible alternative for bridging therapy in patients undergoing catheter ablation of atrial fibrillation.

Association of the beta-1 adrenergic receptor carboxyl terminal variants with left ventricular hypertrophy among diabetic and non-diabetic survivors of acute myocardial infarction

BackgroundThe beta-1 adrenergic receptor (β1AR) plays a fundamental role in the regulation of cardiovascular functions. It carries a nonsynonymous single nucleotide polymorphism in its carboxyl terminal tail (Arg389Gly), which has been shown to associate with various echocardiographic parameters linked to left ventricular hypertrophy (LVH). Diabetes mellitus (DM), on the other hand, represents a risk factor for LVH. We investigated the possible association between the Arg389Gly polymorphism and LVH among non-diabetic and diabetic acute myocardial infarction (AMI) survivors.MethodsThe study population consisted of 452 AMI survivors, 20.6% of whom had diagnosed DM. Left ventricular parameters were measured with two-dimensional guided M-mode echocardiography 2-7 days after AMI, and the Arg389Gly polymorphism was determined using a polymerase chain reaction-restriction fragment length polymorphism assay.ResultsThe Arg389 homozygotes in the whole study population had a significantly increased left ventricular mass index (LVMI) when compared to the Gly389 carriers (either Gly389 homozygotes or Arg389/Gly389 heterozygotes) [62.7 vs. 58.4, respectively (p = 0.023)]. In particular, the Arg389 homozygotes displayed thicker diastolic interventricular septal (IVSd) measures when compared to the Gly389 carriers [13.2 vs. 12.3 mm, respectively (p = 0.004)]. When the euglycemic and diabetic patients were analyzed separately, the latter had significantly increased LVMI and diastolic left ventricular posterior wall (LVPWd) values compared to the euglycemic patients [LVMI = 69.1 vs. 58.8 (p = 0.001) and LVPWd = 14.2 vs. 12.3 mm (p < 0.001), respectively]. Furthermore, among the euglycemic patients, the Arg389 homozygotes displayed increased LVMI and IVSd values compared to the Gly389 carriers [LVMI = 60.6 vs. 56.3, respectively (p = 0.028) and IVSd = 13.1 vs. 12.0 mm, respectively (p = 0.001)]. There was no difference in the LVMI and IVSd values between the diabetic Arg389 homozygotes and Gly389 carriers.ConclusionsThe data suggest an association between the β1AR Arg389Gly polymorphism and LVH, particularly the septal hypertrophy. The Arg389 variant appears to confer a higher risk of developing LVH than the corresponding Gly389 variant among patients who have suffered AMI. This association cannot be considered to be universal, however, since it does not appear to exist among diabetic AMI survivors.

Cryoablation of atrioventricular nodal re-entrant tachycardia: 7-year follow-up in 515 patients—confirmed safety but very late recurrences occur

Aims Cryoablation is an alternative method to radiofrequency ablation for treatment of atrioventricular nodal re-entrant tachycardia (AVNRT). This study investigates the long-term safety and efficacy of cryoablation in AVNRT. Methods and results We studied 515 consecutive patients (317 women, mean age 50 years, range 13-89 years) undergoing a first cryoablation for AVNRT between 2003 and 2008. Ablations were performed with a 6-mm Freezor Xtra catheter. Six patients were acute failures; 494 out of 509 (97%) primarily successfully ablated patients were followed up for a mean of 7.1 years (range 2-12 years). About 11% (54/494 patients) of patients had recurrences of the index arrhythmia. Time to recurrence varied from days to 9 years; 14 patients (3%) had recurrences later than 2 years, 8 patients (2%) later than 3 years, and 6 patients (2%) later than 4 years. Recurrence rate was higher in patients with slow-slow or fast-slow AVNRT (n = 24) compared with the common slow-fast variant (25 vs. 10%; P = 0.04). Recurrence rate was not higher in patients with residual slow pathway conduction (jump with or without echo beat, n = 199, 39%). Transient atrioventricular (AV) block of the first-, second-, or third-degree during ablation was observed in 45 patients but had no impact on the risk of AVNRT recurrence. No late AV block occurred. Single vs. multiple applications or total amount of cryoenergy delivered did not differ between patients with and without recurrences. Conclusion Cryoablation in AVNRT is safe with a long-term efficacy of 88%; however, very late recurrences occur.

Paroxysmal Regular Supraventricular Tachycardia: The Diagnostic Accuracy of the Transesophageal Ventriculo‐Atrial Interval

Objective: To establish the diagnostic accuracy of the transesophageal ventriculo‐atrial (VA) interval in patients with paroxysmal supraventricular tachycardia (PSVT) and normal baseline electrocardiogram (ECG).