A Decrease in Serum Aldosterone Level is Associated with Maintenance of Sinus Rhythm after Successful Cardioversion of Atrial Fibrillation

Background: The activation of the renin–angiotensin–aldosterone system has been implicated in the progression of atrial structural remodeling during atrial fibrillation (AF). However, consequences of the changes of aldosterone in AF have not been evaluated. Objectives: This study's aim was to evaluate changes of serum aldosterone concentration after successful cardioversion of persistent AF and to determine the prognostic value of these changes. Methods: The prospective, single center study included 45 consecutive patients with nonvalvular persistent AF and preserved left ventricular systolic function, referred for cardioversion. None of the patients were taking aldosterone antagonists. Blood samples for aldosterone measurement were collected twice: 24 hours before and 24 hours after cardioversion. Results: Forty‐three patients were successfully converted to sinus rhythm. On the 30th day following cardioversion, 24 patients maintained sinus rhythm (group A), 19 patients relapsed to AF (group B). Serum aldosterone concentration before cardioversion did not differ significantly between both groups (175.6 ± 112.82 pg/mL vs 125.8 ± 51.2 pg/mL; P = 0.25). However, in group A serum aldosterone level decreased significantly within 24 hours after cardioversion, from 175.6 ± 112.8 pg/mL to 101.4 ± 44.2 pg/mL (P = 0.0034). In group B, the aldosterone level before and after cardioversion did not differ significantly (125.8 ± 51.2 pg/mL vs 118.2 ± 59.6 pg/mL; P = 0.68). Logistic regression analysis revealed that a decrease in plasma aldosterone concentration after direct current cardioversion more than 13.2 pg/mL predicted sinus rhythm maintenance in a 30‐day follow‐up, with 87% sensitivity and 64% specificity. Conclusions: There is a positive correlation between the fall in aldosterone concentration 24 hours after cardioversion and maintenance of sinus rhythm during 30 days of observation. (PACE 2010; 561–565)     

Exercise‐Induced Natriuretic Peptide Secretion Predicts Cardioversion Outcome in Patients with Persistent Atrial Fibrillation: Discordant ANP and B‐Type Natriuretic Peptide Response to Exercise Testing

Background: Measurement of natriuretic peptide's (NP) release in response to hemodynamic stress may be complementary to its baseline assessment in individuals. Atrial natriuretic peptide (ANP) and B‐type natriuretic peptide (BNP) increase in patients with atrial fibrillation (AF) and decrease after successful cardioversion, suggesting that AF may stimulate secretion of NPs. However, there are conflicting data on the predictive value of NPs on the cardioversion outcome. Objectives: The purpose of this study was to investigate whether baseline and exercise‐induced NP plasma levels can be useful in predicting successful cardioversion of persistent AF and maintenance of sinus rhythm during 6‐month follow‐up. Methods: A prospective study enrolled 77 consecutive subjects with persistent AF with normal left ventricular function, referred for elective cardioversion. Patients underwent a modified Bruce protocol treadmill exercise test 24 hours before cardioversion. Blood samples for ANP and BNP analyses were obtained at rest and 5 minutes after exercise peak. Results: The group of successful cardioversion and stable sinus rhythm presented higher exercise ANP (110.6 ± 41.2 pg/mL vs 43.8 ± 36.1; pg/mL, P < 0.0001) and lower BNP increase (5.2 ± 5.2 pg/mL vs 40.5 ± 34.2 pg/mL, P < 0.0001) than the group of unsuccessful cardioversion or AF recurrence. Using an optimized cutoff level of ≤12% of relative exercise‐induced increase in BNP concentration, and of >50 pg/mL of ANP increase, successful cardioversion can be predicted with high accuracy. Conclusions: An increase in ANP and stability of BNP plasma concentration during exercise testing are independently associated with successful cardioversion and maintenance of sinus rhythm during 6‐month follow‐up. (PACE 2010; 33:1203–1209)     

Poster Session 2-1: Pharmacological and Cellular Therapy Monday, April 3, 2006, 4:00–5:30pm

Prof. Yuji Nakazato ¹ , Masayuki Yasuda ¹ , Hiroto Tsuchiya ¹ , Akitoshi Sasaki ¹ , Takashi Tokano ¹ , Hiroyuki Daida ^{1   1} Cardiology, Juntendo University, Tokyo, Japan
The purpose of this study is to clarify the efficacy and safety of bepridil for persistent atrial fibrillation (AF). Method: Bepridil (100-200mg/day) was administered to 159 patients (141 males, mean age 58 years) with persistent AF. The effects of conversion and maintenance of sinus rhythm were evaluated. If sinus restoration was not obtained until 3 months observation, DC cardioversion was performed. Results: In 87 of 159 patients (55%), sinus rhythm was restored within an average 2.1 months following administration of bepridil. 74 of those 87 patients (85%) have been maintained in sinus rhythm for the average follow-up of 16 months. The 31 out of remaining 72 patients failed pharmacological conversion and performed DC cardioversion. All of the patients restored sinus rhythm, and 18 of them (58%) maintained sinus rhythm for an average of 20 months. Although ECG revealed significant prolongation of QT interval from 0.38/0.03 to 0.42/0.06 sec, QTc was unchanged and no serious adverse complications including torsade de pointes were recognized. Conclusion: Bepridil is clinically safe and useful with favorable efficacy for conversion and maintenance of sinus rhythm in patients with persistent AF.     

Ventricular Pauses during Atrial Fibrillation Predict Relapse after Electrical Cardioversion: A Prospective Study

Aims: To investigate the use of ambulatory electrocardiogram (ECG) monitoring in atrial fibrillation (AF) to predict recurrence after electrical cardioversion (ECV). Methods: RR interval variables were obtained from 24 hours ECGs recorded before ECV in 119 patients (85 men, age 66 ± 10 years) with persistent AF. Patients were followed for 1 month. Results: Of the 119 patients, 16 (13%) failed ECV and 65 (55%) were in AF at 1 week and 81 (68%) at 1 month after ECV. The maximum RR interval (RR‐max) and the minimum RR interval (RR‐min) during AF were found to be reproducible. The RR‐max was longer in those who had AF 1 week (2.55 ± 0.49 vs 2.01 ± 0.52 seconds, P = 0.005) and 1 month (2.56 ± 0.50 vs 1.89 ± 0.43 ms; P < 0.001) after ECV than in those who maintained sinus rhythm. Those in AF at 1 month included more patients with RR‐max ≥ 2.8 seconds (31% vs 11% P = 0.021). The average heart rate was lower in patients with RR‐max ≥ 2.8 seconds, but the average rate was not predictive of AF recurrence. Conclusion: Ventricular pauses during AF predict relapse after ECV. (PACE 2010; 934–938)     

The use of ranolazine to facilitate electrical cardioversion in cardioversion-resistant patients: a case series

Background: Occasionally atrial fibrillation (AF) is resistant to electrical cardioversion (EC). Ranolazine (RZ) is an antianginal agent, which inhibits abnormal late Na⁺ channel currents in cardiomyocytes and decreases Na⁺/Ca⁺⁺ overload. RZ is a potent inhibitor of after‐depolarizations and triggered activity and prolongs atrial refractory periods. We postulated RZ could facilitate EC in patients resistant to EC. Methods: Over a 3‐year period, we identified 25 EC‐resistant patients who had been administered oral RZ shortly after failing attempted EC. The anterior‐posterior cardioversion approach was used and each patient had failed to be restored to sinus rhythm despite using up to the maximum output of a biphasic cardioversion device. Repeat EC was performed 3.5–4 hours after administration of 2 g of oral RZ using the same device, sedation, and lead placement. Results: Sinus rhythm was successfully restored in 19 (76%) of 25 EC‐resistant patients. Three patients spontaneously converted before the second attempt at EC within 4 hours of the RZ dose. Of the 22 patients undergoing another attempt at EC, 16 were successfully converted to sinus rhythm. Five of the six patients who were refractory to repeat EC despite RZ had AF of unknown duration and each is now in permanent AF. No adverse effects were noted. Conclusion: RZ shows promise as a safe and convenient agent to facilitate EC in EC‐resistant patients. It appears to be most effective in patients whose AF duration is known to be less than 3 months. (PACE 2011;1–6)     

The relation between ejection fraction and mitral annulus motion before and after direct‐current electrical cardioversion

Mitral annulus motion (MAM) and the relation between left ventricular ejection fraction (EF) and MAM has been shown to differ between patients with sinus rhythm and patients with atrial fibrillation. However, it has not been investigated how the relation between EF and MAM changes on direct‐current (DC) electrical cardioversion to sinus rhythm. Therefore, 31 consecutive patients on the waiting list for DC electrical cardioversion were examined by echocardiography before DC electrical cardioversion, and those who maintained sinus rhythm (13 patients) were examined again 4–8 weeks after cardioversion. The conversion factor (CF) (ratio EF/MAM) decreased from 8·4 ± 1·7 before to 5·8 ± 0·8 SD after cardioversion (P<0·001). The EF increased slightly (P<0·05) but the MAM had a much greater increase (P<0·001), resulting in the decrease in CF. There was no significant difference in CF between patients after cardioversion and age‐ and gender‐matched control patients with sinus rhythm, indicating that CF is normalized or almost normalized 4–8 weeks after cardioversion. This indicates that when MAM is used for investigation of the left ventricular function, and the function is expressed as EF, the same CF as in other patients with sinus rhythm can be used 4–8 weeks after DC electrical cardioversion.     

Reversible Impairment of Left and Right Ventricular Systolic and Diastolic Function During Short-Lasting Atrial Fibrillation in Patients with an Implantable Atrial Defibrillator: A Tissue Doppler Imaging Study

AF with a fast ventricular response may cause ventricular mechanical impairment, though whether short-lasting AF with satisfactory rate control may affect ventricular function is unknown. This study investigated if prompt cardioversion by an implantable atrial defibrillator (IAD) may prevent left (LV) and right ventricular (RV) systolic and diastolic dysfunction. Ten patients (mean age 61 +/- 9 years, 8 men) with paroxysmal AF without structural heart disease who received an IAD were studied by echocardiography and tissue Doppler imaging (TDI) for both ventricles. Measurements were made during baseline sinus rhythm and at 1-minute, 20-minute, 4-hour, and 1-week postcardioversion of an episode of spontaneous AF. The occurrence of AF and the ventricular rate were monitored at 2-hour intervals by the device. There were 50 episodes of AF with a mean duration of 8.8 +/- 8.9 days (2 hours to 37 days). There was no difference in M-mode measured LV fractional shortening and ejection fraction between baseline sinus rhythm and after cardioversion. However, the TDI derived myocardial systolic velocity (TDI-S) was significantly lower at 1-minute postcardioversion and was normalized at 1 week in both LVs (baseline: 5.7 +/- 1.8, 1 minute: 4.2 +/- 1.0, 20 minutes: 4.3 +/- 0.9, 4 hours: 4.8 +/- 1.0, 1 week: 5.5 +/- 1.8 cm/s; P < 0.005 when comparing 1 minute and 20 minutes to baseline; P < 0.05 when comparing 4 hour to baseline) and RV (baseline: 10.4 +/- 2.1, 1 minute: 7.8 +/- 1.4, 20 minutes: 8.1 +/- 1.2, 4 hours: 9.2 +/- 1.5, 1 week: 10.0 +/- 2.0 cm/s; P < 0.005 when comparing 1 minute, 20 minutes, and 4 hours to baseline). For diastolic function, transmitral Doppler study showed a decrease in early filling velocity at 1 minute (P < 0.05) and 20 minutes (P < 0.005), which was normalized at 4 hours. There was no change in transtricuspid Doppler flow. However, TDI derived myocardial early filling velocity was decreased in the LV (baseline: 6.0 +/- 2.8, 1 minute: 5.4 +/- 2.3, 20 minutes: 5.4 +/- 2.1, 4 hours: 6.1 +/- 2.2, 1 week: 5.8 +/- 1.7 cm/s; P < 0.05 when comparing 1 minute and 20 minutes to baseline) and RV (baseline: 8.9 +/- 3.5, 1 minute: 7.9 +/- 3.3, 20 minutes: 8.1 +/- 3.3, 4 hours: 8.5 +/- 2.9, 1 week: 8.4 +/- 3.5 cm/s; P < 0.05 when comparing 1 minute to baseline). AF of a longer duration (> 48 hours) resulted in a more depressed TDI-S in LV (> 48 hours: 4.2 +/- 1.0, < or = 48 hours: 5.3 +/- 1.3 cm/s; P < 0.01). Shocks in sinus rhythm did not affect any of the above echocardiographic parameters. Therefore, despite adequate rate control, short-lasting AF impairs systolic and diastolic function in both ventricles, which improves gradually after cardioversion. Early restoration of sinus rhythm by an IAD minimizes ventricular dysfunction. TDI is a sensitive tool to assess early systolic and diastolic dysfunction.     

Efficacy of Dronedarone Versus Propafenone in the Maintenance of Sinus Rhythm in Patients With Atrial Fibrillation After Electrical Cardioversion

Purpose

Our objective was to compare the efficacy of dronedarone and propafenone in maintaining sinus rhythm in patients with atrial fibrillation (AF) after electrical cardioversion.

Methods

In this single-center, open-label, randomized trial, we randomly assigned patients with AF after electrical cardioversion to receive dronedarone 400 mg BID or propafenone 150 mg TID.Follow-up clinical evaluations were conducted at 1, 2, 3, and 6 months of treatment. The primary end point was the time to the first recurrence of AF.

Findings

A total of 98 patients were enrolled (79 men; mean age, 59.2 years; n = 49 per group). The median times to first recurrence of AF were 31 days in the dronedarone group and 32 days in the propafenone group (P = 0.715). The median (interquartile range) ventricular rates at first recurrence of AF were 76.5 (67.3–86.5) beats/min in the dronedarone group and 83.0 (71.0–96.0) beats/min in the propafenone group (P = 0.059).

Implications

Dronedarone and propafenone had similar efficacies in maintaining sinus rhythm in patients with AF after electrical cardioversion. The ventricular rate at the first recurrence of AF was numerically but not statistically significantly lower in the dronedarone group than in the propafenone group. ClinicalTrials.gov identifier: NCT01991119.     

Prediction of Maintenance of Sinus Rhythm after Cardioversion of Atrial Fibrillation by Analysis of Serial Signal-Averaged P Waves

After cardioversion from atrial fibrillation (AF) many patients develop early recurrence of the arrhythmia. While these patients may be appropriate for immediate prophylaxis against AF recurrence their identification at the time of cardioversion is not possible. Since the signal-averaged P wave (SAPW) is abnormal in individuals with atrial arrhythmia, we assessed its utility for predicting early AF recurrence after cardioversion. Seventy-five cardioversions in 31 patients were evaluated. The mean age was 59 (range 28–79) years; 26 were male. Fifty-eight cardioversions were internal using low energy biphasic DC shocks delivered via electrodes placed in the right atrial appendage and coronary sinus. P wave specific signal averaging was performed at 3 and 24 hours after each cardioversion to estimate filtered P wave duration and energy from 20, 40, and 60 to 150 Hz. Follow-up was by regular clinic visits and transtelephonic ECG monitoring. Early recurrence of AF (prospectively defined as sinus rhythm duration < 1 week) occurred after 30 cardioversions. No differences were found in any P wave variable measured at 3 hours between these cardioversions and those that resulted in a longer duration of sinus rhythm. Paired 3- and 24-hour signal-averaged data were available in 47 cardioversions. There were significant falls in P wave energy from 3 to 24 hours after 31 cardioversions that resulted in sinus rhythm for > 1 week, (P40: 3 hours 11.2 [±1.5] μV²· s, 24 hours 8.6 [±1.2] μV²· s, P < 0.001), but not following the 16 after which AF returned within 1 week (P40: 3 hours 9.0 [±1.2] μV²· s, 24 hours 8.5 [±1.2] μV²· s, P = NS). A fall in P40 of > 25% had a positive predictive accuracy for maintenance of sinus rhythm of 87%; negative predictive accuracy was only 37%. Similar falls in P wave energy occurred after cardioversions that resulted in longer term (> 4 weeks) sinus rhythm, but not in those that did not. However, the predictive accuracy of a fall in P40 was less (positive predictive accuracy 38%, negative predictive accuracy 62%). Patients with relapsing permanent AF who remain in sinus rhythm for at least 1 week after cardioversion show a fall in P wave energy within the first 24 hours. However, in these patients the technique does not predict recurrent AF within 1 week nor sinus rhythm > 4 weeks. These observations suggest persistent disordered atrial activation as a mechanism for early recurrence of AF after cardioversion.     

Temporary disturbances of the QT interval precede the onset of ventricular tachyarrhythmias in patients with structural heart diseases

An increase in sinus rate prior to ventricular tachyarrhythmias has been demonstrated in previous studies. There is no clear data available concerning changes in ventricular de- and repolarization prior to ventricular tachyarrhythmias, especially in patients with structural heart disease. Therefore, the aim of this study was to analyze the QT and QTc interval (Bazett's formula immediately before the onset of ventricular tachyarrhythmias in stored electrograms of patients with ICDs. The study analyzed 228 spontaneous ventricular tachyarrhythmia episodes in 52 patients (mean age 64 +/- 10 years, 49 men, 3 women) and compared them with 146 electrograms of baseline rhythm recorded during regular ICD follow-up. Mean ventricular cycle length (CL), QT interval, and QTc were measured before the onset of ventricular tachyarrhythmia and during baseline rhythm. Prior to ventricular tachyarrhythmias onset, CL was significantly shorter than during baseline rhythm (714 +/- 139 vs 828 +/- 149 ms, P < 0.0001). By contrast, the QT interval (430 +/- 67 ms) and QTc interval (518 +/- 67 ms) were significantly prolonged before the onset of ventricular tachyarrhythmias as compared to baseline rhythm (QT 406 +/- 67 ms, QTc 450 +/- 61 ms; P < 0.0001). CL, QT, and QTc changes were independent of concomitant treatment with antiarrhythmic drugs. Ventricular tachyarrhythmias are preceded by a significant prolongation of the QT and QTc intervals. This phenomenon may represent a greater than normal disparity of repolarization recovery times possibly facilitating the development of ventricular tachyarrhythmias.     

Impact of serum flecainide level on control of atrial fibrillation in a case treated with cardiac resynchronization therapy

A 72-year-old male patient with dilated cardiomyopathy was treated with oral flecainide (100 mg/day) for persistent atrial fibrillation (AF) that could not be converted to sinus rhythm by electrical cardioversion. Initiation of flecainide treatment provided sinus rhythm without prolongation of QRS and QTc, bradycardia and first-degree atrioventricular block at a serum flecainide level of 438 ng/mL. Then, he received cardiac resynchronization therapy (CRT). Dose reduction to 50 mg/day because of stabilization of heart rate after CRT produced AF at a serum flecainide level of 270 ng/mL. Electrical cardioversion did not restore the AF to a sinus or pacing rhythm. Dose escalation of flecainide (to 100 mg/day) restored the pacing rhythm at a serum flecainide level of 401 ng/mL. This case suggests that in the Japanese population, serum flecainide level should be maintained at >300 ng/mL to control AF even after effective CRT.     

The Influence of Left Ventricle Diastolic Function on Natriuretic Peptides Levels in Patients with Atrial Fibrillation

Background: The diagnosis of the impaired left ventricle (LV) diastolic function during atrial fibrillation (AF) using traditional methods is very difficult. Natriuretic peptides seem to be useful for assessment of diastolic function in patients with AF. Aim: To evaluate the influence of LV diastolic dysfunction on natriuretic peptides concentrations and to assess the diagnostic value of atrial natriuretic peptide (ANP) and B‐type natriuretic peptide (BNP) in patients with AF and impaired LV diastolic function. Methods: The study included 42 patients (23 males, 19 females), aged 58.6 ± 8.2 years with nonvalvular persistent AF with preserved LV systolic function who were converted into sinus rhythm by DC cardioversion (CV) and maintained sinus rhythm for at least 30 days. Echocardiography (ECG), ANP, and BNP level measurements were taken at baseline 24 hours before CV and 24 hours and 30 days after CV. On the 30th day following CV in patients with sinus rhythm, Doppler ECG was performed to assess LV diastolic function. Results: Thirty days after CV, normal LV diastolic function in 15 patients and impaired diastolic function in 27 patients was diagnosed: 20 with impaired LV relaxation and seven with impaired LV compliance. During AF and 24 hours, and 30 days after sinus rhythm restoration, significantly higher ANP and BNP levels were observed in patients with LV diastolic dysfunction as compared to the subgroup with normal LV diastolic function. The average values of ANP during AF in patients with normal and impaired diastolic function were 167.3 ± 70.1 pg/mL and 298.7 ± 83.6 pg/mL, respectively (P < 0.001), and the average values of BNP in the above mentioned subgroups were 49.5 ± 14.7 pg/mL and 145.6 ± 49.6 pg/mL respectively (P < 0.001). While comparing the diagnostic value of both natriuretic peptides it was noted that BNP was a more specific and sensitive marker of impaired LV diastolic function. ANP value >220.7 pg/mL measured during AF identified patients with impaired LV diastolic function with 85% sensitivity and 90% specificity. BNP value >74.7 pg/mL proved 95% sensitive and 100% specific in the diagnosing of such a group. Conclusions: The increase of ANP/BNP concentration in patients with AF results not only from the presence of AF, but also reflects the impaired LV diastolic function. Natriuretic peptides, especially BNP, may be useful in diagnosing LV diastolic dysfunction in patients with AF.     

Effects of pretreatment with intravenous flecainide on efficacy of external cardioversion of persistent atrial fibrillation

Electrical cardioversion is the most effective and safe method to restore sinus rhythm in patients with persistent AF. However, at least 25% of electrical cardioversions are unsuccessful. The aim of the present study was to evaluate, in a prospective, randomized and double-blind study, the efficacy of a pretreatment with intravenous flecainide in patients who underwent electrical cardioversion. Fifty-four consecutive patients with persistent AF, mean arrhythmia duration 8 (mean 3-18) weeks, were randomized in two groups. In the first group (n = 26), patients received flecainide (2 mg/kg as a 30-minute IV infusion) before electrical cardioversion. In the second group (n = 28), 100 mL IV infusion of 5% glucose was administered 30 minutes before electrical cardioversion. The study evaluated the (1). acute efficacy of electrical cardioversion, (2). mean and maximal energy required, (3). mean number of shocks needed, and (4). incidence of complications. The two groups were similar in terms of age, sex, mean AF duration, left ventricular systolic function, atrial dimension, and cardiovascular risk factors. Seventy-seven percent of patients recovered sinus rhythm with electrical cardioversion. No statistical difference was noted between the two groups: flecainide 19/26 (73%) versus placebo 23/28 (82%). No significant differences were found concerning mean or maximal energy and number of shocks required. No major complications were observed. After a 30-day follow-up, 54% of patients maintained sinus rhythm with no difference between the two groups. Pretreatment with intravenous flecainide before electrical cardioversion is not useful in reducing technical failure of cardioversion, however, flecainide does not diminish the effectiveness of electrical cardioversion.     

Effect of sinus rhythm restoration on markers of thrombin generation in atrial fibrillation

Background

Atrial fibrillation (AF) confers a hypercoagulable state; however, it is not clear whether restoration of sinus rhythm is associated with normalisation of markers of thrombogenesis. We studied the impact of sustained sinus rhythm on prothrombotic markers, and their predictive abilities in foreseeing rhythm outcome after cardioversion.

Methods

In a double blind, placebo-controlled study, 171 patients referred for electrical cardioversion of persistent AF were randomised to receive candesartan or placebo for 3-6 weeks before and 6 months after cardioversion. Endogenous thrombin potential (ETP), prothrombin fragment 1?+?2 (F1?+?2) and D-dimer were measured before cardioversion and at end of study. These markers were also measured in a reference group comprising 49 subjects without AF.

Results

The markers remained unchanged in those 28 patients who maintained sinus rhythm. Discontinuation of warfarin treatment in a subset of 13 low-risk patients in sinus rhythm was associated with significantly higher levels of D-dimer and F1?+?2 compared to the reference group; D-dimer (456 ng/mL (276, 763) vs. 279 ng/mL (192, 348), p?=?0.002) and F1?+?2 (700 pmol/L (345, 845) vs. 232 pmol/L (190, 281), p?<?0.001). None of the markers were associated with rhythm outcome after electrical cardioversion.

Conclusions

Sustained sinus rhythm for 6 months after cardioversion for AF had no impact on ETP, F1?+?2 or D-dimer levels. Discontinuation of warfarin in low-risk patients with sustained sinus rhythm was associated with significantly higher levels of D-dimer and F1?+?2 compared to the reference group. Our results suggest persistent hypercoagulability in AF patients despite long-term maintenance of sinus rhythm.

Trial registration

The CAPRAF study was registered at clinicaltrials.gov (NCT00130975) in August 2005.

     

QT dispersion in children with ventricular arrhythmia and a structurally normal heart

In adults, increased QT dispersion has been shown to predict arrhythmic risk as well as risk of sudden death in several clinical settings. It is not known whether or not QT dispersion is increased in children with idiopathic ventricular arrhythmia. We studied three groups of children: (1) 20 patients with idiopathic VT (aged 3-18 years; mean 11.2 years); (2) 30 patients with benign PVCs (aged 1-20 years; mean 10.5 years); and (3) 30 control subjects (aged 4-17 years; mean 12 years). Standard ECGs were reviewed and the dispersion of both QT and JT intervals was compared. No patient had structural heart disease or long QT syndrome. The QT and QTc dispersion (QT delta, QTc delta) among the three groups did not differ: QTc delta of the VT group was 70 ms +/- 30 ms, QTc delta of PVC patients was 60 ms +/- 30 ms, and the QTc delta of the control group was 65 ms +/- 30 ms. The JTc delta among the three groups did not differ as well: JTc delta of the VT group was 70 ms +/- 30 ms, the JTc delta of the PVC group was 60 msec +/- 25 msec, and the JTc delta of the control group was 70 ms +/- 30 ms. We conclude that QT and JT dispersion are not significantly altered in children with idiopathic VT or benign PVCs when compared to control subjects. QT dispersion is not a reliable marker for arrhythmic risk in children with idiopathic ventricular arrhythmias and structurally normal hearts.     

Electrical cardioversion for persistent atrial fibrillation or atrial flutter in clinical practice: predictors of long-term outcome

Despite the results of Atrial Fibrillation Follow-up Investigation of Rhythm Management and Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation trials, which favour a general shift in atrial fibrillation (AF) therapeutic approach towards control of ventricular rate, a strategy based on restoration of sinus rhythm could still play a role in selected patients at lower risk of AF recurrence. We explored possible predictors of relapses after external electrical cardioversion among patients with persistent AF or atrial flutter (AFL). We analysed the clinical characteristics and conventional echocardiographic parameters of patients with persistent AF/AFL enrolled in an institutional electrical cardioversion programme. Among 242 patients (AF/AFL, 195/47; mean age 62+/-13 years), sinus rhythm was restored in 215 (89%) and maintained in 73 (34%) at a follow-up of 930 days (median). No baseline clinical/echocardiographic variables predicted acute efficacy of cardioversion at logistic regression analysis. However, two variables predicted long-term AF/AFL recurrence among patients with successful cardioversion at multivariate Cox's proportional hazards analysis: (i) duration of arrhythmia>or=1 year (HR, 2.07; 95% CI, 1.29-3.33) and (ii) presence of previous cardioversion (HR, 1.67; 95% CI, 1.17-2.38). These variables also presented high-positive predictive values (72% and 80% respectively). Whereas the high acute efficacy of electrical cardioversion (approximately 90%) does not appear to be predictable, two simple clinical variables could help identify patients at higher risk of long-term AF/AFL recurrence after successful electrical cardioversion. We think there could be a case for initially attempting external electrical cardioversion to patients who have had AF/AFL for <1 year. In such patients, the chance of long-term success appears to be relatively high.     

Classification of atrial fibrillation as a model of decisional analysis for the treatment of patients with current atrial fibrillation observed in the emergency department.

Atrial fibrillation (AF) is the most common cardiac arrhythmia observed in the emergency room (ER). We propose a new classification of AF which is useful for the standardization of terms to be used for future clinical trials and for clinical management of this arrhythmia in the ER. We recognized three categories: (1) atrial fibrillation lasting less than 72 hours (AF < 72 h); (2) persistent atrial fibrillation and (3) permanent atrial fibrillation. Atrial fibrillation lasting less than 72 hours can be reconverted to sinus rhythm spontaneously or with pharmacological or electrical cardioversion. If AF < 72 h is not treated and the arrhythmia persists for more than 72 hours we recognize persistent AF. In persistent AF the systemic thrombo-embolism is a significant risk and therapeutic anticoagulation must be associated to pharmacological or electrical cardioversion even though transoesophageal echocardiography does not visualize thrombi or spontaneous echocontrast in the cardiac chambers. These treatments can reconvert the persistent AF to sinus rhythm, but, in the absence of treatment, or if treatment fails, the arrhythmia goes into the permanent category. In permanent AF ventricular rate control and anticoagulation, if suitable, are the first choice for stroke prevention.     

Electrophysiological differences of the spontaneous onset of paroxysmal and persistent atrial fibrillation

BACKGROUND: Information about the spatiotemporal organization of atrial activity at the onset of atrial fibrillation (AF) is still limited. METHODS: AF mapping was performed in 30 patients with AF (mean age 53 +/- 9 years, 26 males) by deploying a noncontact mapping balloon in the left atrium (LA). Twenty-four patients had paroxysmal AF and six patients had persistent AF. Three types of AF episodes were analyzed: nonsustained AF (lasting 30 seconds, with spontaneous conversion or requiring internal cardioversion and subsequent stable sinus rhythm), and persistent AF episodes (stable sinus rhythm lasting 相似文献   

Effect of Ibutilide, a New Class III Agent, On Sustained Atrial Fibrillation in a Canine Model of Acute Ischemia and Myocardial Dysfunction Induced By Microembolization

The effect of ibutiJide, a new Class III antiarrhythmic agent, upon acute onset atriai fibriJIation was investigated in a closed-chest canine model of acute left ventricular fLVj dysfunction. Twenty-four anesthetized mongrel dogs, mean weight 24.9 ± 4 kg were subjected to coronary artery microsphere emboiization and volume Joading, followed by attempted induction of atrial fihrillation (AF) by rapid atrial pacing. Acute ischemic LV dysfunction was successfully induced by emboiization in aii dogs, and caused significant (P < 0.02) decreases in LV systolic pressure, peak + dp/dt (and ? dp/dtj, stroke volume, and RR interval; whereas LV end diastolic pressure and QTc significantiy increased. Sustained AF (≥ 30 min) was successfully induced in 15 of 24 dogs (62%) and unsustained AF (< 30 min) was induced in the remainder (38%). At 30 minutes after induction of sustained AF, 15 dogs were randomized to intravenous ibutiiide (0.15 mg/kg, given as a 0.075 mg/kg bolus, followed by 0.075 mg/kg infusion over 1 hour; n = 7) or placebo (saline; n = 8). There were no statistically significant differences between the ibutilide and the placebo groups with respect to mean LV systolic pressure, LV end diastoJic pressure, LV dp/dt, RR intervaJ, or QTc intervaJ during AF prior to infusion. All seven dogs receiving ibutiJide converted to sinus rhythm after a median of 3 minutes (range 0.5–26 min), whiJe onJy three of eight pJacebo dogs (P < 0.03J converted to sinus rhythm after a median duration of 30 minutes (range 15–60 min) (P < 0.04 for difference in time to conversionj. QTc prolonged by 27 ± 17%, 1 hour after ibutiJide, but was unaJtered after pJacebo (P ≥ 0.02). There were no significant hemodynamic changes after either ibutiJide or pJacebo. We concJude that: (1) sustained AF (> 30 min) can be readily induced in this closed-chest animal model and used t o test antiarrhythmic agents acutely; and (2) intravenous ibutiJide is effective in rapidJy terminating acute onset AF; the drug prolongs the QT_c intervaJ but does not exacerbate preexisting hemodynamic compromise in the acutely ischemic LV.     

Long-term prognostic value of baseline C-reactive protein in predicting recurrence of atrial fibrillation after electrical cardioversion

Background: An increasing body of evidence links atrial fibrillation (AF) to the inflammatory state. It has been suggested that increased C‐reactive protein (CRP) levels are associated with greater risk of AF recurrence at short‐ and mid‐term. Objective: We sought to investigate the association between CRP and long‐term risk of AF recurrence. Methods: This was a prospective observational study. We investigated the association between baseline CRP levels and recurrence of AF over a 3‐year follow‐up period after successful electrical cardioversion (EC). A total of 60 patients were studied (mean age: 68.4 ± 7.2 years, 60% men). All patients were receiving amiodarone for sinus rhythm maintenance. We further divided the study population into three tertiles according to the values of baseline CRP (tertile 1: <0.43 mg/dL; tertile 2: 0.43–0.8 mg/dL; tertile 3: >0.8 mg/dL). Results: Overall, 75% of patients relapsed into AF during the 3‐year study period. AF recurrence was significantly lower in the 1st CRP tertile group (P = 0.039). The Kaplan‐Meier survival analysis showed that the rate of AF recurrence was significantly lower in the lowest CRP tertile (log rank; P < 0.001). In a multivariable Cox regression model adjusted for other potential covariates, only CRP (upper two tertiles) was an independent predictor of AF recurrence (heart rate: 6.3, 95% confidence interval: 3.1–12.7, P < 0.001). Conclusions: Our findings suggest that baseline CRP levels before EC have an independent prognostic value in predicting the long‐term risk of AF recurrence.