ACC/AHA/ESC Guidelines for the Management of Patients With Supraventricular Arrhythmias—Executive Summary

Remote Magnetic Catheter Navigation for Cavotricuspid Isthmus Ablation in Patients With Common-Type Atrial Flutter

Background— Conventional catheter ablation of cavotricuspid isthmus (CTI)-dependent atrial flutter is a widely applied standard therapy. Remote magnetic catheter navigation (RMN) may provide benefits for different ablation procedures, but its efficacy for CTI ablation has not been evaluated in a randomized, controlled trial.

Methods and Results— Ninety patients undergoing de novo ablation of atrial flutter were randomly assigned to conventional manual (n=45) or RMN-guided (n=45) CTI ablation with an 8-mm-tip catheter. Complete bidirectional isthmus block was achieved in 84% (RMN) and 91% (conventional catheter ablation) of the cases ( P =0.52). RMN was associated with shorter fluoroscopy time (median, 10.6 minutes; interquartile range [IQR], 7.6 to 19.9, versus 15.0 minutes; IQR, 11.5 to 23.1; P =0.043) but longer total radiofrequency application (17.1 minutes; IQR, 8.6 to 25, versus 7.5 minutes; IQR, 3.6 to 10.9; P <0.0001), ablation time (55 minutes; IQR, 28 to 76, versus 17 minutes; IQR, 7 to 31; P <0.0001), and procedure duration (114�35 versus 77�24 minutes, P <0.0001). Procedure duration in the RMN group did not decrease significantly with case experience. Long-term procedure success, defined as achievement of complete CTI block and freedom from atrial flutter recurrence during 6 months of follow-up, was lower in the RMN group (73% versus 89%, P =0.063). Right atrial angiography after ablation revealed no significant differences between groups in terms of right atrial diameter or CTI length, morphology, and angulation. Furthermore, none of these parameters was predictive for difficult (ablation time >20 minutes) or unsuccessful ablation.

Conclusions— RMN-guided CTI ablation is associated with reduced radiation exposure but prolonged ablation and procedure times as compared with conventional catheter navigation. Our findings suggest that ablation lesions produced with an RMN-guided 8-mm catheter are less effective irrespective of CTI anatomy.

Trial Registration— clinicaltrials.gov Identifier: NCT00560872

Patient perception of symptoms and quality of life following ablation in patients with supraventricular tachycardia

OBJECTIVES

It remains unclear which symptom experiences and aspects of quality of life (QOL) change after ablation in patients with supraventricular tachycardia (SVT). To determine how patient perceptions of symptoms and QOL change after ablation, we used a single group pretest-posttest design.

METHODS

Patients with SVT (n=52; mean age 41+/-17 years; 65% female) completed generic and disease-specific measures at baseline and 1 month after ablation.

RESULTS

Significant improvement after ablation was noted on virtually all measures (P <.05). Patients reported decreases from baseline regarding frequency and duration of episodes, number of symptoms, and impact of SVT on routine activities. All symptoms decreased in prevalence; however, no symptoms were completely eliminated at 1-month follow-up. Women, more so than men, reported larger changes in symptom and QOL scores after ablation.

CONCLUSIONS

Despite the small sample, statistically significant improvement was found after ablation in a variety of patients with different symptoms and QOL indices.

Development and initial psychometric evaluation of the Patient Perspective of Arrhythmia Questionnaire

There are no disease-specific questionnaires to measure patient sensitive outcomes in arrhythmia patients. We report the development and preliminary psychometric testing of the Patient Perception of Arrhythmia Questionnaire (PPAQ). The PPAQ was developed using formative research, exploratory factor analysis, expert review, pilot study, and regression. The PPAQ measures frequency and duration of episodes, symptoms, impact on daily activities, and restricted activity days. After preliminary content validation, the sensitivity of the PPAQ was tested in 103 arrhythmia patients. The measures showed good sensitivity and reliability. Preliminary construct validation was supported by significant differences (p < .001) among groups of arrhythmia patients consistent with clinical patterns. Preliminary evidence from patients with supraventricular arrhythmias suggests that the questionnaire has acceptable psychometrics and could be useful in future studies of arrhythmia patients.

Meta-analysis of ablation of atrial flutter and supraventricular tachycardia

The purpose of this study was to perform a systematic review and meta-analysis to evaluate the safety and efficacy of radiofrequency ablation (RFA) of typical atrial flutter (AFL) and atrioventricular node-dependent supraventricular tachycardia (SVT) in adult patients. Medline and EMBASE were searched (1990 to 2007) for all study design trials of RFA. Data relating to single- and multiple-procedure success, arrhythmia recurrence, repeat ablation, adverse events, and death were extracted. For RFA in AFL, 18 primary studies with 22 treatment arms and 1,323 patients were identified. Single-procedure success for AFL was 91.7% (95% confidence interval [CI] 88.4% to 94.9%). Multiple-procedure success was 97.0% (95% CI 94.7% to 99.4%). Postablation arrhythmia was noted in 13.2% of patients (95% CI 7.5% to 18.9%), while repeat ablation was reported in 8% (95% CI 4.5% to 11.4%). For RFA of SVT, 39 primary studies with 49 treatment arms in 7,693 patients with accessory pathways and atrioventricular nodal reentrant tachycardia were identified. Single-procedure success for SVT was 93.2% (95% CI 90.8% to 95.5%). Multiple-procedure success was 94.6% (95% CI 92.4% to 96.9). Postablation arrhythmia was noted in 5.6% patients (95% CI 4.1% to 7.2%). Repeat ablation occurred in 6.5% (95% CI 4.7% to 8.3%). For AFL studies, all-cause mortality was 0.6%, and adverse events were reported in 0.5% of patients. For SVT studies, all-cause mortality was 0.1%, and adverse events were reported in 2.9% of patients. In conclusion, studies of RFA for the treatment of patients with AFL and SVT report high efficacy rates and low rates of complications.

[Atrial fibrillation ablation: who comes into consideration?]

Atrial fibrillation ablation is, since the introduction of the guidelines in 2006 and which were updated in 2007, now a standard procedure in many electrophysiological centers. Pulmonary vein isolation has proven itself as a way to eliminate focal triggers. From pathophysiological studies of atrial fibrillation development, it is known that ablation performed early in paroxysmal atrial fibrillation has the highest chance for success. In patients with persistent or permanent atrial fibrillation, success rates are lower and repeat interventions are needed more often. Therefore, continuation of antiarrhythmic drug therapy is often necessary in these patient groups. Thus, the curative use of ablation for atrial fibrillation is only possible with the current techniques for patients with paroxysmal atrial fibrillation.

Adenosine-induced ventricular arrhythmias in patients with supraventricular tachycardias

BACKGROUND

Adenosine is widely used for the diagnosis and the termination of supraventricular arrhythmias. There are many case reports and few series about the proarrhythmic potential of adenosine. We sought to evaluate the proarrhythmic potential of adenosine used to terminate the supraventricular arrhythmias.

METHODS

The records of all patients that received adenosine for the termination of supraventricular tachycardia were reviewed retrospectively and those with a continuous electrocardiographic (ECG) recording during adenosine administration were included to the study.

RESULTS

Our search identified 52 supraventricular episodes of 46 patients with a continuous ECG recording during adenosine administration. Following adenosine administration, premature ventricular contraction (PVC) or ventricular tachycardia (VT) developed in 22 (47.8%) patients and in 26 (50%) tachycardia episodes. No patient had a sustained VT. Nonsustained VT developed in eight (17.4%) patients. All VT episodes were polymorphic, short, and self-terminating. When the basal and demographic properties of patients with PVC or VT and those without PVT or VT were compared, there was no significant difference.

CONCLUSIONS

Adenosine is a quite safe and effective drug for the termination of narrow QRS complex tachycardia but it often induces nonsustained VT or PVC that are clinically insignificant in the absence of other accompanying heart disease.

Clinical characteristics, treatment, and outcome of tachycardia induced cardiomyopathy

Tachycardia-induced cardiomyopathy is characterized by ventricular systolic dysfunction and congestive heart failure resulting from persistent or highly frequent tachyarrhythmias with uncontrolled heart rate. While reversible and often considered benign, few studies have examined the outcome of the disorder. The clinical characteristics, treatment, and long-term outcomes of 12 consecutive patients with tachycardia-induced cardiomyopathy (9 men, age, 51.9 +/- 17.6 years) were studied. The mean period between the occurrence of tachyarrhythmias and the development of congestive heart failure was 26.0 +/- 34.3 days. The mean heart rate on admission was 156.3 +/- 28.7 beats/min. All patients had severe heart failure with a NYHA functional class of 2.3 +/- 0.5, left ventricular ejection fraction of 0.32 +/- 0.10, and brain natriuretic peptide level of 505.7 +/- 449.1 pg/mL. In all patients, cardiac dysfunction recovered after 53.5 +/- 61.3 days. During the follow-up of 53 +/- 24 months, 2 patients had a recurrence of heart failure with uncontrolled tachyarrhythmia and 1 patient died suddenly. In tachycardia-induced cardiomyopathy, recurrent heart failure with uncontrollable tachyarrhythmia and sudden death were observed after recovery from cardiac dysfunction. A substrate for heart failure and/or life-threatening arrhythmia might persist, and careful, long-term follow-up seems required.

A new algorithm for concealed accessory pathway localization using T-wave-subtracted retrograde P-wave polarity during orthodromic atrioventricular reentrant tachycardia

INTRODUCTION

AP localization can be predicted by analyzing the polarity of the delta wave, QRS polarity, and R/S ratio in patients with Wolff-Parkinson-White syndrome. However, the estimation of AP location is limited in patients with concealed pathways during atrioventricular reentrant tachycardias (AVRT). Thus, we analyzed retrograde P-wave polarity during orthodromic AVRT and developed an algorithm to predict the localization of concealed accessory pathways (AP).

METHODS AND RESULTS

A total number of 131 patients with a single AP and inducible orthodromic AVRT were included. The initial 61 patients were analyzed retrospectively for algorithm development, whereas 70 patients were evaluated prospectively. The retrograde P-wave polarity was analyzed by subtracting the superimposing T-wave during orthodromic AVRT using custom-designed software. Four leads of the surface electrocardiogram (ECG) were identified to accurately distinguish AP locations assigned to four different regions around each AV annulus: I, aVR, aVL, and V(1). Lead V(1) was used to differentiate right (negative or isoelectric) from left (solely positive) APs. Retrograde P-wave in lead I was negative in left posterior APs exclusively and became more positive with an AP location shifting towards right anterior. P-wave polarity in lead aVR demonstrated a shift from a positive polarity from left APs to isoelectric in right APs. The opposite direction (shift from positive to isoelectric) was observed for lead aVL. The subsequently developed algorithm for concealed AP localization using these surface ECG leads demonstrated a high sensitivity, specificity, and positive predictive value particularly for common AP localizations (left posterior and inferior, and right septal) when applied in a prospective fashion.

CONCLUSION

Concealed AP localization can be accurately predicted by the analysis of retrograde P-wave polarity during orthodromic AVRT using the algorithm derived from the presented study.

A prognostic index for the successful use of adenosine in patients with paroxysmal supraventricular tachycardia in emergency settings: a retrospective study

STUDY OBJECTIVES

The use of adenosine on failure of vagal maneuvers in patients with paroxysmal supraventricular tachycardia (PSVT) is recommended. The aim of the present study was to identify a possible prognostic index for the efficacy of adenosine in PSVT.

METHODS

This retrospective study included 321 patients with PSVT, in whom vagal maneuvers failed to restore normal sinus rhythm and who received 6 mg adenosine, followed by 12 mg adenosine (repeated if necessary). A 2-step clustering algorithm was used to reveal nonapparent groupings. Various patients' characteristics were inserted into the model.

RESULTS

A straightforward index has been chosen that would aid the distinction of patients failing to respond to adenosine. The formula, (age / heart rate at admission) + number of past PSVT episodes, was chosen as the one that combined the highest sensitivity (96.2%) and specificity (71.2%).

CONCLUSIONS

This prognostic index constitutes a useful and reliable bedside diagnostic tool to identify patients with PSVT who were less likely to respond to adenosine administration in the emergency setting.

A prospective, randomized trial of an emergency department observation unit for acute onset atrial fibrillation

STUDY OBJECTIVE

An emergency department (ED) observation unit protocol for the management of acute onset atrial fibrillation is compared with routine hospital admission and management.

METHODS

Adult patients presenting to the ED with atrial fibrillation of less than 48 hours' duration without hemodynamic instability or other comorbid conditions requiring hospitalization were enrolled. Participants were randomized to either ED observation unit care or routine inpatient care. The ED observation unit protocol included pulse rate control, cardiac monitoring, reassessment, and electrical cardioversion if atrial fibrillation persisted. Patients who reverted to sinus rhythm were discharged with a cardiology follow-up within 3 days, whereas those still in atrial fibrillation were admitted. All cases were followed up for 6 months and adverse events recorded.

RESULTS

Of the 153 patients, 75 were randomized to the ED observation unit and 78 to routine inhospital care. Eighty-five percent of ED observation unit patients converted to sinus rhythm versus 73% in the routine care group (difference 12%; 95% confidence interval [CI] -1% to 25%]; P=.06). The median length of stay was 10.1 versus 25.2 hours (difference 15.1 hours; 95% CI 11.2 to 19.6; P<.001) for ED observation unit and inhospital care respectively. Nine ED observation unit patients required inpatient admission. Eleven percent of the ED observation unit group had recurrence of atrial fibrillation during follow-up versus 10% of the routine inpatient care group (difference 1%; 95% CI -9% to 11%; P=.93). There was no significant difference between the groups in the frequency of hospitalization or the number of tests, and the number of adverse events during follow-up was similar in the 2 groups.

CONCLUSION

An ED observation unit protocol that includes electrical cardioversion is a feasible alternative to routine hospital admission for acute onset of atrial fibrillation and results in a shorter initial length of stay.

When should we recommend catheter ablation for patients with the Wolff-Parkinson-White syndrome?

PURPOSE OF REVIEW

Catheter ablation has been proven as very effective and safe therapy for patients with symptomatic Wolff-Parkinson-White (WPW) syndrome. Its application in asymptomatic individuals with WPW pattern remains controversial. This review will elaborate on the role of catheter ablation in symptomatic and asymptomatic patients with WPW pattern on ECG.

RECENT FINDINGS

Several recent prospective studies evaluated invasive risk stratification followed by prophylactic catheter ablation in asymptomatic patients with WPW pattern. Inducibility of arrhythmias in these patients during invasive electrophysiological study was shown to predict the development of future symptomatic arrhythmias. Although ablation of accessory pathways performed in 'inducible' patients decreased the incidence of subsequent symptomatic arrhythmias, the studies were not powered to detect a reduction in life-threatening arrhythmias.

SUMMARY

Radiofrequency catheter ablation remains the first-line therapy for patients with symptomatic WPW syndrome. Invasive electrophysiological study and possible ablation of accessory pathway may be offered to well informed asymptomatic individuals with WPW if they are willing to trade the very small risk of subsequent sudden death or incapacity for a small immediate procedural risk of serious complications or death. Asymptomatic patients may require invasive risk stratification and possible catheter ablation for important social or professional reasons.

Long term outcome of cavotricuspid isthmus cryoablation for the treatment of common atrial flutter in 180 patients: a single center experience

OBJECTIVE

Recent literature has shown that common type atrial flutter (AFL) can recur late after cavotricuspid isthmus (CTI) catheter ablation using radiofrequency energy (RF). We report the long term outcome of a large group of patients undergoing CTI ablation using cryothermy for AFL in a single center.

METHODS

Patients with AFL referred for CTI ablation were recruited prospectively from July 2001 to July 2006. Cryoablation was performed using a deflectable, 10.5 F, 6.5 mm tip catheter. CTI block was reassessed 30 min after the last application during isoproterenol infusion. Recurrences were evaluated by 12-lead ECG and 24 h Holter recording every clinic visit (1/3/6/9 and 12 months after the procedure and yearly thereafter) or if symptoms developed.

RESULTS

The 180 enrolled patients had the following characteristics: 39 women (22%), mean age 58 years, no structural heart disease in 86 patients (48%), mean left atrium diameter 44+/-7 mm and mean left ventricular ejection fraction 57+/-7%. The average number of applications per patient was 7 (3 to 20) with a mean temperature and duration of -88 degrees C and 3 min, respectively. Acute success was achieved in 95% (171) of the patients. There were no complications. After a mean follow-up of 27+/-17 (from 12 to 60) months, the chronic success rate was 91%. The majority of the recurrences occurred within the first year post ablation. One hundred and twenty three patients had a history of atrial fibrillation (AF) prior to CTI ablation and 85 (69%) of those remained having AF after cryoablation. In 20 of 57 (35%) patients without a history of AF prior to CTI ablation, AF occurred during follow-up.

CONCLUSIONS

This prospective study showed a 91% chronic success rate (range 12 to 60 months) for cryoablation of the CTI in patients with common type AFL and ratified the frequent association of AF with AFL.

A randomized comparison of amiodarone and class IC antiarrhythmic drugs to treat atrial fibrillation in patients paced for sinus node disease: the Prevention Investigation and Treatment: A Group for Observation and Research on Atrial arrhythmias (PITAGORA) trial

BACKGROUND

Rhythm control is an important goal in the treatment of recurrent atrial tachyarrhythmias (AT). The PITAGORA study was a randomized trial in patients paced for sinus node disease (SND), designed to test the noninferiority of class IC antiarrhythmic drugs (AADs) to amiodarone in terms of a primary end point composed of death, permanent AT, cardiovascular hospitalization, atrial cardioversion, or AAD change.

METHODS

Randomization was stratified to assign 2 patients to amiodarone and 2 patients to class IC AADs: propafenone or flecainide. One hundred seventy-six patients (46% men, 72 +/- 8 years) were enrolled. Device diagnostics continuously monitored AT recurrences and duration.

RESULTS

In a mean follow-up of 20 +/- 9 months, the primary end point occurred in 23 (30.7%) of 75 class IC patients and in 28 (40.0%) of 70 amiodarone patients. The absolute difference in the end point incidence (-9.3%; 95% CI between 3.7% and -22.3%) confirmed the noninferiority of class IC to amiodarone (P = .007). Kaplan-Meier 1-year freedom from AT episodes >10 minutes, 1 day, and 7 days was 40%, 73%, and 91% for amiodarone and 28%, 78%, and 86% for class IC AADs (P = nonsignificant).

CONCLUSIONS

In patients paced for SND and suffering from AT, class IC AADs proved not to be inferior to amiodarone in terms of the primary composite end point described or end points which were differently composed of mortality, efficacy, or AAD side effects. The AADs studied also showed similar results in terms of symptoms, quality of life, and freedom from AT recurrences.

Markers of inflammation before and after curative ablation of atrial flutter

BACKGROUND

Atrial arrhythmias are associated with inflammation. The cause and effect of the association are unknown.

OBJECTIVE

The purpose of this study was to test the hypothesis that atrial tachyarrhythmias contribute to inflammation.

METHODS

We performed a prospective observational study wherein C-reactive protein (CRP) and interleukin-6 (IL-6) levels from the femoral vein and coronary sinus (CS) were compared before curative ablation for atrial flutter (AFL; n = 59) and paroxysmal supraventricular tachycardia (SVT; n = 110). Follow-up levels were obtained at 1 and 6 months.

RESULTS

Peripheral levels of both biomarkers were significantly higher in the AFL group. After multivariate adjustment, only those in the AFL group who presented in AFL or atrial fibrillation (AF) had significantly elevated CRP levels (odds ratio 1.26; P = .033). Levels of each marker were similar in the CS and peripheral blood in the SVT group; in the AFL group, both CRP and IL-6 were significantly lower in the CS than in the periphery (P = .0076 and P = .0021, respectively). CRP was significantly lower a median of 47 days after AFL ablation (from a median of 6.28 mg/L to a median of 2.92 mg/L; P = .028) and remained reduced at second follow-up. IL-6 decreased across three time points after AFL ablation (P = .002). No reduction in inflammatory biomarkers was observed after SVT ablation.

CONCLUSIONS

CRP and IL-6 levels are elevated in patients presenting in AFL. Given the lower CS values in these patients, their origin appears to be systemic rather than cardiac. Because these levels significantly fall after ablation of AFL, the atrial tachyarrhythmia appears to be the cause (not the effect) of the inflammation.

Emerging adenosine receptor agonists

Adenosine receptors (ARs) are a four-member subfamily of G protein-coupled receptors and are major targets of caffeine and theophylline. There are four subtypes of ARs, designated as A1, A2A, A2B and A3. Selective agonists are now available for all four subtypes. Over a dozen of these selective agonists are now in clinical trials for various conditions, although none has received regulatory approval except for the endogenous AR agonist adenosine itself. A1AR agonists are in clinical trials for cardiac arrhythmias and neuropathic pain. A2AAR agonists are now in trials for myocardial perfusion imaging and as anti-inflammatory agents. A2BAR agonists are under preclinical scrutiny for potential treatment of cardiac ischemia. A3AR agonists are in clinical trials for the treatment of rheumatoid arthritis and colorectal cancer. The present review will mainly cover the agonists that are presently in clinical trials for various conditions and only a brief introduction will be given to major chemical classes of AR agonists presently under investigation.

The Safety and Efficacy of Ibutilide in Children and in Patients with Congenital Heart Disease

BACKGROUND

The safety and efficacy of ibutilide in the cardioversion of atrial flutter and atrial fibrillation in children and in patients with congenital heart disease (CHD) is unknown.

METHODS

Data from 19 patients (age 6 months to 34 years, median 16 years) who received ibutilide for atrial flutter or atrial fibrillation between 1996 and 2005 was retrospectively reviewed. There were 15 patients with CHD (14 had prior heart surgery); four children had normal heart structure.

RESULTS

There were 74 episodes of atrial flutter and four episodes of atrial fibrillation (median episodes per patient was one, range 1-31). Ibutilide converted 55 of all the episodes (71%). Ibutilide was successful during its first-ever administration in 12 of 19 patients (63%). Fourteen episodes in six patients required electrical cardioversion after ibutilide failed. There were no episodes of symptomatic bradycardia. One patient went into torsade de pointes and one patient had nonsustained ventricular tachycardia.

CONCLUSION

With careful monitoring, ibutilide can be an effective tool in selected patients for cardioversion of atrial flutter.

Cardiovascular protection using beta-blockers: a critical review of the evidence

For more than 3 decades, beta-blockers have been widely used in the treatment of hypertension and are still recommended as first-line agents by national and international guidelines. Recent meta-analyses indicate that, in patients with uncomplicated hypertension, compared with other antihypertensive agents, first-line therapy with beta-blockers was associated with an increased risk of stroke, especially in the elderly cohort with no benefit for the end points of all-cause mortality, cardiovascular morbidity, and mortality. In this review, we critically analyze the evidence supporting the use of beta-blockers in patients with hypertension and evaluate evidence for its role in other indications. The review of the currently available literature shows that in patients with uncomplicated hypertension, there is a paucity of data or absence of evidence to support use of beta-blockers as monotherapy or as first-line agents. Given the increased risk of stroke, their "pseudo-antihypertensive" efficacy (failure to lower central aortic pressure), lack of effect on regression of target end organ effects like left ventricular hypertrophy and endothelial dysfunction, and numerous adverse effects, the risk benefit ratio for beta-blockers is not acceptable for this indication. However, beta-blockers remain very efficacious agents for the treatment of heart failure, certain types of arrhythmia, hypertropic obstructive cardiomyopathy, and in patients with prior myocardial infarction.

Case Studies

Ms A was a 28 year old woman in her second pregnancy (she had one previous termination of pregnancy) who booked-in at 19 weeks’ gestation. She was known to have sickle cell disease (specifically sickle cell anaemia [HbSS]), and her last crisis had occurred 3 years before this pregnancy.

Incidence and clinical relevance of supraventricular tachyarrhythmias in pulmonary hypertension

BACKGROUND

In patients with severe pulmonary hypertension (PH), right ventricular function is a main determinant of clinical stability and outcome. Supraventricular tachyarrhythmias (SVTs) may compromise cardiac function and threaten prognosis in patients with PH, but the incidence and clinical relevance of SVTs in PH and chronic right ventricular failure have not been evaluated.

METHODS

In a 6-year retrospective single-center analysis, 231 consecutive patients followed for pulmonary arterial hypertension, or inoperable chronic thromboembolic PH were studied for SVTs. Analysis included incidence, clinical consequences, treatment, and outcome.

RESULTS

Thirty-one episodes of SVT were observed in 27 of 231 patients (cumulative incidence 11.7%, annual risk 2.8% per patient), including atrial flutter (n = 15), atrial fibrillation (n = 13), and AV nodal reentry tachycardia (n = 3). Supraventricular tachyarrhythmia onset was almost invariably associated with marked clinical deterioration and right ventricular failure (84% of SVT episodes). Outcome was strongly associated with the type of SVT and restoration of sinus rhythm. During follow-up, cumulative mortality was low (6.3%, follow-up 26 +/- 23 months) when sinus rhythm was restored (all cases of AV nodal reentry tachycardia and atrial flutter). In contrast, 9 of 11 patients with sustained atrial fibrillation died from right ventricular failure (cumulative mortality 82%, follow-up 11 +/- 8 months).

CONCLUSIONS

In patients with PH, SVTs constitute a relevant problem, often resulting in clinical deterioration. Sustained atrial fibrillation may be associated with a high risk of death from right ventricular failure.

Results From the Loire-Ardèche-Drôme-Isère-Puy-de-Dôme (LADIP) Trial on Atrial Flutter, a Multicentric Prospective Randomized Study Comparing Amiodarone and Radiofrequency Ablation After the First Episode of Symptomatic Atrial Flutter

Background— There is no published randomized study comparing amiodarone therapy and radiofrequency catheter ablation (RFA) after only 1 episode of symptomatic atrial flutter (AFL). The aim of the Loire-Ardèche-Drôme-Isère-Puy-de-Dôme (LADIP) Trial of Atrial Flutter was 2-fold: (1) to prospectively compare first-line RFA (group I) versus cardioversion and amiodarone therapy (group II) after only 1 AFL episode; and (2) to determine the impact of both treatments on the long-term risk of subsequent atrial fibrillation (AF).

Methods and Results— From October 2002 to February 2006, 104 patients (aged 78±5 years; 20 women) with AFL were included, with 52 patients in group I and 52 patients in group II. The cumulative risk of AFL or AF was interpreted with the use of Kaplan-Meier curves and compared by the log-rank test. Clinical presentation, echocardiographic data, and follow-up were as follows: age (78.5±5 versus 78±5 years), history of AF (27% versus 21.6%); structural heart disease (58% versus 65%), left ventricular ejection fraction (56±14% versus 54.5±14%), left atrial size (43±7 versus 43±6 mm), mean follow-up (13±6 versus 13±6 months; P =NS), recurrence of AFL (3.8% versus 29.5%; P <0.0001), and occurrence of significant AF beyond 10 minutes (25% versus 18%; P =0.3). Five complications (10%) were noted in group II (sick sinus syndrome in 2, hyperthyroidism in 1, and hypothyroidism in 2) and none in group I (0%) ( P =0.03).

Conclusions— RFA should be considered a first-line therapy even after the first episode of symptomatic AFL. There is a better long-term success rate, the same risk of subsequent AF, and fewer secondary effects.

Optimal target temperature for slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia

OBJECTIVE

To define optimal target temperature for the slow pathway ablation.

MATERIALS AND METHODS

In this study, 268 patients with atrioventricular nodal reentrant tachycardia (190 females; mean age, 49 +/- 14 years) who underwent slow pathway ablation using a combined electroanatomic approach were enrolled. The patients were categorized into Group 1 if target temperature was < 55 degrees C or into Group 2 if target temperature was > or = 55 degrees C. Group 2 was divided into three subgroups of 55 degrees C (Sgp-1), 60 degrees C (Sgp-2), and 65 degrees C (Sgp-3).

RESULTS

Acute success rate was similar in both groups (P = 0.83). The ablation time (26.2 +/- 20 vs. 36.5 +/- 28 min; P = 0.014), fluoroscopy time (11.6 +/- 9.7 vs. 17.8 +/- 16.6 min; P = 0.035), and number of applications (4.1 +/- 3.2 vs. 9.1 +/- 6.5; P = 0.02) were lower for Group 2 than Group 1 patients. The frequency of AV or VA block, impedance rise, and coagulum formation were comparable in two groups (all P > 0.05). During mean follow-up of 14 +/- 3 months, recurrence of the arrhythmia was seen in higher proportion of Group 1 than Group 2 patients (P = 0.036). Among the Group 2 patients, there were no significant differences between the three subgroups in terms of acute success rate, fluoroscopy time, risks of AV and VA block, pericardial effusion, and recurrence (All P > 0.05). Number of applications and RF pulse duration were lower in Sgp-2 and 3 compared to Sgp-1 (All P > 0.05). Impedance rise and coagulum formation were slightly higher in Sgp-3 compared to Sgp-1 and 2 but this difference did not reach statistical significance (All P > 0.05).

CONCLUSIONS

Compared to less than 55 degrees C, target temperatures > or = 55 degrees C during slow pathway ablation significantly reduces fluoroscopy time, RF pulse duration, number of RF applications, and recurrence of AVNRT without increase in risk of AV or VA block or coagulum formation.

Acute anticoagulation adjustment in patients with atrial fibrillation at risk for stroke: approaches, strategies, risks and benefits

The acute management of anticoagulation in patients with atrial fibrillation to prevent stroke and other thromboembolic complications includes the use of individualized strategies tailored to the patient and based on the situation (cardioversion, surgeries, dental procedures, cardiac interventions, other invasive procedures and initiation of, or adjustment to, warfarin dosing). The vast range of choices can cause confusion and few randomized controlled clinical trials in this area provide adequate guidance. Chronic anticoagulation management is more straightforward since clinical evidence is ample, randomized clinical trial data provides cogent informaiton and guidelines have been established. Acute management of anticoagulation in patients with atrial fibrillation to prevent thromboembolic complications is often unrecognized but is emerging as a crucial, but challenging, and increasingly complex aspect of the care of patients with atrial fibrillation. This review addresses issues regarding such patients who may be at risk for stroke and require acute adjustments of anticoagulation (in light of, or in lieu of, chronic anticoagulation). Several promising new strategies are considered in light of established medical care. This analysis provides practical recommendations based on available data and presents results from recent investigations that may provide insight into future strategies.

Incidence of Atrial Fibrillation in Heart Transplant Patients: Long-Term Follow-Up

BACKGROUND

The incidence of atrial fibrillation (AF) in heart transplant patients has not been well documented.

METHODS

To determine the incidence of AF in a cohort of patients undergoing cardiac transplantation, clinical data were obtained from a prospectively collected database for all consecutive orthotopic heart transplantation (OHT) patients and for all consecutive coronary artery bypass graft (CABG) surgery patients between January 1984 and March 2004 at our institution. A cohort of 1,714 OHT patients and low-risk CABG (normal ejection fraction [EF] and no left ventricular hypertrophy [LVH]) patients were age- and sex-matched.

RESULTS

The average age in the two groups was 56 +/- 7 years with 87% male and 81% white race and body mass index (BMI) of 26 +/- 4. There were 3 cases of AF (0.3%) in the OHT group and 757 cases of AF (21%) in the low-risk CABG group. The strongest independent predictor of freedom from postoperative AF was having had a transplant (odds ratio [OR] 96, 95% confidence interval [CI] 13-720). The incidence of AF, atrial flutter (AFL), and supraventricular tachycardia (SVT) in OHT was 0.33, 2.8%, and 1.3%, respectively. Given that incidence of AF, AFL, and SVT in historical post-CABG population is 25%, 17%, and 4.3%, transplanted patients appear to have lower incidence of AF, AFL, and SVT than the reference population. Consistent with this, transplanted patients underwent few ablation procedures for atrial arrhythmias. Additionally, the three patients with AF had bicaval anastomoses suggesting the possibility of PACs originating in the donor superior vena cava (SVC) or IVC (inferior vena cava) initiating AF in these patients.

CONCLUSIONS

In a cohort study of transplant and low-risk CABG patients, the strongest independent predictor of freedom from AF is having undergone transplant surgery. One potential explanation for the markedly lower incidence of AF may be effective isolation of thoracic veins with documented cases retaining the native SVC.

Radiofrequency catheter ablation of supraventricular tachycardia in children and adolescents : feasibility and cost-effectiveness in a low-income country

The objective of this study is to provide results and costs of catheter ablation in children and adolescents in a low-income country. Reports from first-world countries have demonstrated the cost-effectiveness of radiofrequency catheter ablation (RFCA) compared to medical treatment of supraventricular tachycardia (SVT). The study included 28 patients younger than 18 years of age with SVT in a pediatric cardiology unit in Guatemala. All patients underwent RFCA. Clinical outcome and cost-effectiveness of RFCA compared to continued medical treatment were the end points. Twenty-four patients had successful ablation (85.7%). Mean age at RFCA was 11.42 +/- 3.49 years. Three patients underwent a second ablation, increasing the success rate to 96.4%. One remaining patient is awaiting a second procedure. At a mean follow-up of 13.69 +/- 7.16 months, all 27 patients who had a successful ablation remained in sinus rhythm. Mean cost per procedure was 4.9 times higher than that of medical treatment. However, the estimated cost of catheter ablation equal that of medical therapy after 5.1 years and is 3.4 times less after 20 years. Radiofrequency catheter ablation of SVT in children and adolescents is safe and cost-effective compared to medical therapy. Resources must be judiciously allocated, especially in low-income countries, to treat the largest number of pediatric patients.

Current Strategies in the Management of Atrial Fibrillation

Treatment of atrial fibrillation (AF) has been undergoing significant changes recently. This is due partly to different mechanisms proposed for persistent and permanent AF and partly due to the introduction of energy-based techniques, providing less invasive procedures. This article aims to review the mechanisms of AF leading to the changes in clinical practice and to review the results of surgery, energy-based, and percutaneous techniques. It is difficult to compare and contrast the results of reported series in the literature due to different definitions of AF; freedom from and recurrence of it. Furthermore, in most series it is difficult to distinguish results of surgery for lone AF and AF associated with valvular heart disease and coronary artery disease.

[The current evidence of S-1 and irinotecan hydrochloride combination chemotherapy with tri-weekly schedule]

A combination therapy of irinotecan hydrochloride (CPT-11) with continuous intravenous infusions of (infusional) 5-fluorouracil (5-FU) and Leucovorin (LV) is often used to treat advanced colorectal cancer. However, recent concerns on safety and convenience have prompted the development of new oral fluoropyrimidine derivatives which improved regimens. Yamada et al conducted a phase I study to assess the maximum tolerated dose and recommended dose of S-1 combined with CPT-11. The study recommended that 150 mg/m2 of CPT-11 be given on day 1 and 80 mg/m2 of S-1 daily on days 1 to 14 every 3 weeks. Recently, several phase I/II studies assessed the efficacy and safety of the combined therapy with S-1 and CPT-11 in patients with advanced colorectal cancer. Some of the studies which were ongoing assessed a tri-weekly schedule regimen. Our results showed that S-1 plus CPT-11 was very effective, with a response rate of 63% and PFS of 8 months. Toxicity was generally mild and manageable on an outpatient basis. The current evidence showed that a combination of S-1 and CPT-11 was more convenient and easier to administer than a combination of CPT-11 plus infusional 5-FU and LV. It will be essential to prove that the combination of S-1 plus CPT-11 can replace the combination of infusional 5-FU and LV plus CPT-11 without negatively affecting efficacy and toxicity.