| 1. |
- Gold, Michael R, et al.
(författare)
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Impact of atrial prevention pacing on atrial fibrillation burden: primary results of the Study of Atrial Fibrillation Reduction (SAFARI) trial.
- 2009
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - : Elsevier BV. - 1556-3871. ; 6:3, s. 295-301
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The role of atrial-based pacing algorithms in preventing atrial fibrillation (AF) remains controversial. The inconsistent results noted in previous trials may be due in part to differences in endpoints, pacing algorithms, and study design. SAFARI, a worldwide, prospective, randomized clinical trial, was designed to address these issues and to evaluate the safety and efficacy of a suite of prevention pacing therapies (PPTs) among patients with paroxysmal AF. METHODS AND RESULTS: Patients who met standard pacemaker indications and documented symptomatic AF were implanted with a pacemaker (Vitatron Selection 9000). At 4 months, only patients with documented AF despite dual-chamber pacing were randomized to PPTs ON or PPTs OFF and followed for 6 months. Incidence of permanent AF and change in AF burden were compared between the two groups. Among the 555 patients enrolled, 240 had AF burden at 4 months and were randomized. The risk of developing permanent AF was similar in both groups (0 in the PPTs ON group vs. 3 in the OFF group). However, there was a significant reduction in AF burden between baseline and 10-month follow-up in the ON group compared with the OFF group (median decrease of 0.08 hours/day vs no change, P = .03). CONCLUSION: Among patients with paroxysmal AF and standard bradycardia indications, PPTs are safe and associated with less AF burden compared with conventional pacing.
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| 2. |
- Sahlén, Anders, et al.
(författare)
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Cardiac fatigue in long-distance runners is associated with ventricular repolarization abnormalities.
- 2009
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - : Elsevier BV. - 1556-3871 .- 1547-5271. ; 6:4, s. 512-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Prolonged exercise can induce cardiac fatigue, which is characterized by biomarker release and impaired myocardial function. The impact on ventricular electrophysiology is largely unknown. OBJECTIVE: The objective of this study was to examine changes in ventricular repolarization after a 30-km cross-country race in runners aged >or=55 years. METHODS: Fifteen healthy participants (62 +/- 5 years) were assessed using biomarkers (N-terminal pro-brain natriuretic peptide [NT-proBNP], troponin T [TnT]), tissue Doppler echocardiography, and vectorcardiography at baseline, within 1 hour postrace and on days 1 and 6 postrace. RESULTS: During the race, NT-proBNP increased from 42 ng/L (interquartile range 25-117) to 187 ng/L (113-464), and TnT increased from undetectable levels to 0.03 microg/L (0.015-0.05). Global strain (19.1% +/- 2.2%) decreased on day 1 (17.2% +/- 1.8%) and day 6 (17.9% +/- 1.5%; P <.01). QT(c) increased from 431 +/- 15 ms prerace to 445 +/- 22 ms postrace and 445 +/- 15 ms on day 1 (P <.05), mainly because of an increased T(peak-end) interval (prerace 108 +/- 13 ms, postrace 127 +/- 43 ms, day 1 127 +/- 43 ms; P <.05). Postrace, T(area) (baseline 75 +/- 26 microVs) peaked on day 1 (105 +/- 42 microVs) and remained high on day 6 (89 +/- 37 microVs; P <.05). Runners with higher baseline NT-proBNP developed greater impairment of myocardial velocities (rho = -0.68 to -0.54; P <.05) and a larger increase in T(area) (rho = 0.73; P <.01). CONCLUSION: Cardiac fatigue induced by prolonged exertion is associated with sustained abnormalities in ventricular repolarization. Runners with higher baseline NT-proBNP are especially liable to such alterations of cardiac function.
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| 3. |
- Schwieler, J H, et al.
(författare)
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Reentry in an accessory atrioventricular pathway as a trigger for atrial fibrillation initiation in manifest Wolff-Parkinson-White syndrome: A matter of reflection?
- 2008
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - : Elsevier BV. - 1556-3871 .- 1547-5271. ; 5:9, s. 1238-47
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with an accessory pathway (AP) have an increased propensity to develop atrial fibrillation (AF), but the mechanism is unknown. OBJECTIVE: The purpose of this study was to identify crucial risk factors and to test the hypothesis that reflection and/or microreentry of atrial impulses propagating into the AP triggers AF. METHODS: Five hundred thirty-four patients successfully treated with radiofrequency ablation of AP at two university hospitals were evaluated. Patients were separated into those with concealed vs those with manifest AP in terms of their propensity to develop AF. To investigate AF triggering mechanisms, linear and branched two-dimensional models of atrium-to-ventricle propagation across a heterogeneous 1 x 6 AP using human ionic kinetics were simulated. RESULTS: A history of AF was twice as common in patients with manifest AP vs concealed AP irrespective of AP location. AF was more likely to occur in older males and in patients with larger atria. There was no correlation between AF history and AP refractory measures. However, the electrophysiologic properties of APs seemed to fulfill the prerequisites for reflection and/or microreentry of atrially initiated impulses. In the linear AP model, repetitive atrial stimulation resulted in progressively larger delay of atrium-to-ventricle propagation across the passive segment. Eventually, sufficient time for repolarization of the atrial segment allowed for reflection of an impulse that activated the entire atrium and by wavefront-wavetail interaction with a new atrial stimulus AF reentry was initiated. Simulations using the branched model showed that microreentry at the ventricular insertion of the AP could also initiate AF via retrograde atrial activation as a result of unidirectional block at the AP-ventricle junction. CONCLUSION: Propensity for AF in patients with an AP is strongly related to preexcitation, larger atria, male gender, and older age. Reflection and microreentry at the AP may be important for AF initiation in patients with manifest (preexcited) Wolff-Parkinson-White syndrome. Similar mechanisms also may trigger AF in patients without an AP.
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| 4. |
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| 5. |
- Al-Ahmad, A., et al.
(författare)
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Time-resolved three-dimensional imaging of the left atrium and pulmonary veins in the interventional suite-A comparison between multisweep gated rotational three-dimensional reconstructed fluoroscopy and multislice computed tomography
- 2008
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271. ; 5:4, s. 513-519
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cardiac computed tomography (CT) is commonly used to visualize left atrial (LA) anatomy for ablation of atrial fibrillation. We have developed a new imaging technique that allows acquisition and visualization of three-dimensional (3D) cardiac images in the catheter lab. Objective: We sought to compare LA and pulmonary vein (PV) dimensions acquired using gated multisweep rotational fluoroscopy (C-arm CT) system and multislice computed tomography (MSCT) in an in vivo porcine model. Methods: A Siemens AXIOM Artis dTA C-arm system (Siemens AG, Medical Solutions) was modified to allow acquisition of four bidirectional sweeps during synchronized acquisition of the electrocardiogram signal to allow retrospective gating. C-arm CT image volumes were then reconstructed. Gated MSCT (SOMATOM Sensation 16 and 64, Siemens AG, Medical Solutions) and C-arm CT images were acquired in six animals. The two main PV diameters were measured in orthogonal axes. LA volumes were calculated. C-arm CT measurements were compared with the MSCT measurements. Results: The average PV diameters using the C-arm CT were 2.24 × 1.35 cm, versus 2.27 × 1.38 cm for CT. The average difference was 0.034 cm (1.9%) between the C-arm CT and standard CT. The average LA volume using MSCT was 49.1 ± 12.7 cm3, as compared with 51.0 ± 8.7 cm3 obtained by the C-arm CT. The average difference between the C-arm CT and the MSCT was 1.9 cm3 (3.7%). There were no significant differences in either the PV or LA measurements. Conclusions: Visualization of 3D cardiac anatomy during ablation procedures is possible and highly accurate. The 3D cardiac reconstructions acquired during ablation procedures will be valuable for procedural planning and guidance. © 2008 Heart Rhythm Society.
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| 6. |
- Crijns, Harry J., et al.
(författare)
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Safe and effective conversion of persistent atrial fibrillation to sinus rhythm by intravenous AZD7009.
- 2006
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271. ; 3:11, s. 1321-1331
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Tidskriftsartikel (refereegranskat)abstract
- Background Acute drug conversion of persistent atrial fibrillation usually fails. Objectives The purpose of this study was to test the proarrhythmic potential, safety, and efficacy of the novel antiarrhythmic agent AZD7009 in patients with persistent atrial fibrillation (AF) or atrial flutter (mean duration 43 days) scheduled for direct current (DC) cardioversion. Methods Patients were randomized to AZD7009 (3-hour intravenous infusion; n = 86) or placebo (n = 36). AZD7009 was given in doses intended to produce target pseudo–steady-state plasma levels of 0.25, 0.50, 0.75, 1.0, 1.5, 2.0, or 2.5 μmol/L after 30 minutes of infusion. DC cardioversion was performed if conversion to sinus rhythm (SR) did not occur within 2 hours of infusion. Results AZD7009 in a concentration-dependent manner increased the rate of conversion of AF to SR and shortened the time to conversion. At the three highest target concentrations of AZD7009, 45%, 64%, and 70% of AF patients converted after a mean time of 62, 55, and 26 minutes, respectively, whereas no placebo-treated patients converted. SR was maintained for 24 hours in 21 of 22 patients with drug-associated conversion. AZD7009 treatment was associated with QT-interval prolongation; the increase in QT corrected according to Fridericia typically ranged from 40 to 80 ms at targeted pseudo–steady-state plasma concentrations ≥0.75 μmol/L, but a number of outliers with QT corrected according to Fridericia >550 ms were seen in the higher concentration groups, particularly after conversion to SR and prolonged infusion. None of the patients exhibited torsades de pointes according to predefined criteria; however, one patient exhibited a nonsustained, polymorphic ventricular tachycardia of eight beats with torsades de pointes–like features after AZD7009 infusion (asymptomatic and discovered only upon retrospective Holter tape analysis). Clinical adverse events (primarily dizziness, bradycardia, hypotension, and nausea) were significantly more common in the highest target concentration AZD7009 group vs placebo (P <.001). Conclusion AZD7009 exhibited dose-dependent effects in converting AF to SR in AF patients and appeared to be associated with a low risk of proarrhythmia despite continued administration during a period of heightened vulnerability.
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| 7. |
- Holmqvist, Fredrik, et al.
(författare)
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Interatrial conduction can be accurately determined using standard 12-lead electrocardiography: validation of P-wave morphology using electroanatomic mapping in man.
- 2008
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271. ; 5:3, s. 413-418
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- Kennergren, Charles, 1948
(författare)
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A European perspective on lead extraction: part I.
- 2008
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - : Elsevier BV. - 1547-5271. ; 5:1, s. 160-2
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Tidskriftsartikel (refereegranskat)
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| 9. |
- Kennergren, Charles, 1948
(författare)
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European perspective on lead extraction: part II.
- 2008
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - : Elsevier BV. - 1547-5271. ; 5:2, s. 320-3
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Tidskriftsartikel (refereegranskat)
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| 10. |
- Kesek, Milos, et al.
(författare)
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Entrapment of circular mapping catheter in the mitral valve
- 2007
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Ingår i: Heart rhythm : the official journal of the Heart Rhythm Society. - New York, NY : Elsevier. - 1547-5271. ; 4:1, s. 17-19
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Ablation procedures in the left atrium for treatment of atrial fibrillation are becoming increasingly common. The procedure often involves placing one or two circular mapping catheters in the left atrium. Entrapment of an ablation catheter in the mitral valve during ablations of left-sided accessory pathways by the retrograde approach has been described in two earlier published reports. More recently, several reports describe similar entrapment of a mapping catheter. In a recently published review, however, only one case of unspecified valve damage was registered among 8745 atrial fibrillation procedures. OBJECTIVE: The purpose of this study was to evaluate patients with entrapment. METHODS: Retrospective analysis of electrophysiological results. RESULTS: We describe three patients with entrapment during ablations for atrial fibrillation. The entrapments occurred with three different operators at three different electrophysiological laboratories within 2 years. The complication described here may be more common than is widely appreciated. CONCLUSIONS: From our figures, we estimate the incidence of the complication to 0.9% (95% confidence interval, 0.2-2.5%).
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