The impact of catheter ablation in the interpulmonary isthmus on atrial fibrillation ablation outcomes: a randomized study.

INTRODUCTION: Previous studies have underscored the importance of the interpulmonary isthmus in the initiation and maintenance of atrial fibrillation (AF). The efficacy of additional radiofrequency energy delivery in the interpulmonary isthmus following pulmonary vein antral isolation (PVAI) was investigated. METHODS AND RESULTS: A total of 76 patients (49 males, mean age 56.8 ± 10.3) with drug-resistant paroxysmal (n = 64) and short-lasting persistent AF (n = 12) underwent PVAI. Patients were then randomly assigned to receive either "no further ablation" (group I, n = 38) or additional lesions in the interpulmonary isthmus of both ipsilateral pulmonary veins (group II, n = 38). There were no significant differences between study groups regarding the clinical and echocardiographic data. A trend towards a longer fluoroscopy time was observed in group II (P = 0.076). After a mean follow-up period of 11.1 ± 2.6 months, 22 patients in group I (57.9%) and 25 patients in group II (65.8%) were free from arrhythmia recurrence without any antiarrhythmic drug treatment after a single ablation procedure. The Kaplan-Meier arrhythmia-free survival curves showed no significant differences between study groups (P = 0.460). CONCLUSIONS: Additional lesions in the interpulmonary isthmus following PVAI do not have incremental value in preventing AF recurrence.

Electrocardiographic differentiation of common type atrioventricular nodal reentrant tachycardia from atrioventricular reciprocating tachycardia via a concealed accessory pathway.

OBJECTIVE: The present study aimed to evaluate the diagnostic value of specific ECG markers in the differentiation of common type atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) via a concealed accessory pathway. METHODS: One hundred and ten ECGs with paroxysmal narrow QRS complex, short RP tachycardia were evaluated. Subjects with overt ventricular pre-excitation during sinus rhythm were excluded from the study. The mechanism of arrhythmia was established during the electrophysiological study and confirmed by the efficacy of radiofrequency ablation. RESULTS: Of the 110 patients, 74 displayed common type AVNRT and 36 AVRT. Predictors of AVNRT were the presence of pseudo r'-waves in lead V1 [sensitivity 39.19%; specificity 97.14%; positive predictive value (PPV) 96.67%; negative predictive value (NPV) 43.04%] and pseudo S-waves in inferior leads (sensitivity 28.38%; specificity 94.29%; PPV 91.30%; NPV 38.37%). In the setting of visible P-waves, an RP interval < or =90 ms favoured the diagnosis of AVNRT (sensitivity 57.14%; specificity 80.65%). Predictors of AVRT were QRS alternans (sensitivity 50%; specificity 89.19%; PPV 69.23%; NPV 78.57%) as well as ST-segment alterations during tachycardia. The overall sensitivity, specificity, PPV and NPV of ST-segment depression for discriminating AVRT from AVNRT were 97.22%, 58.11%, 53.03%, 97.73%, respectively. Similarly, the sensitivity, specificity, PPV and NPV of ST-segment elevation in lead aVR were 94.44%, 58.11%, 52.31%, and 95.56%, respectively. Multiple logistic regression analysis showed that ST-segment depression [(odds ratio (OR): 12.67, 95% confidence interval (CI): 1.77-90.81, P = 0.011)] and QRS alternans (OR: 9.43, 95% CI: 1.38-64.37, P = 0.022) displayed the highest predictive ability favouring the diagnosis of AVRT. CONCLUSIONS: Twelve-lead ECG parameters may help to differentiate the mechanism of supraventricular tachycardia prior to the ablation procedure.

Pre-ablative predictors of atrial fibrillation recurrence following pulmonary vein isolation: the potential role of inflammation.

AIMS: An increasing body of evidence has demonstrated the essential role of inflammation in the genesis and maintenance of atrial fibrillation (AF). The aim of the present study was to investigate whether success or failure of electrical pulmonary vein isolation (PVI) in patients with AF is related with the presence of a pre-ablative inflammatory state as determined by known clinical parameters and conventional markers of inflammation including high-sensitivity C-reactive protein, white blood cell (WBC) count, and fibrinogen. METHODS AND RESULTS: Seventy-two patients with paroxysmal (64%) or persistent AF (36%) underwent successful electrical PVI. The mean duration of arrhythmia was 5.5 +/- 2.9 years. After a mean follow-up period of 12.5 +/- 5.7 months, 44 patients (61%) were in sinus rhythm. In univariate Cox proportional hazard regression analysis, hypertension, body mass index (BMI), left ventricular ejection fraction, left ventricular end-diastolic diameter, left atrial diameter (LAD), WBC count, and high-sensitivity C-reactive protein were significantly associated with AF recurrence (P < 0.05). In multivariate Cox proportional hazard regression analysis, hypertension [hazard ratio (HR) 3.127; 95% confidence interval (CI) 1.269-7.706, P = 0.013], LAD (HR 1.077; 95% CI 1.014-1.144, P = 0.015), and WBC count (HR 1.423; 95% CI 1.067-1.897, P = 0.016) were independent pre-ablative predictors of AF recurrence following PVI. CONCLUSION: Conventional markers of the inflammatory cascade such as WBC count and high-sensitivity C-reactive protein as well as elements of the metabolic syndrome such as hypertension and increased BMI were significantly associated with AF recurrence. The impact of a pre-ablative inflammatory state in the overall success rate of PVI needs further elucidation.

Predictors of atrial tachyarrhythmias in subjects with type 1 ECG pattern of Brugada syndrome.

BACKGROUND: Previous studies have demonstrated a high incidence of atrial tachyarrhythmias (ATs) in patients with Brugada syndrome (BS). The present study aimed to investigate whether various 12-lead electrocardiogram (ECG) and electrophysiological parameters may help to differentiate subjects with a high probability to develop ATs. METHODS AND RESULTS: The clinical records of 38 individuals (31 males, age 44.4 +/- 13.9) with spontaneous (n = 15) or ajmaline-induced (n = 23) type 1 ECG pattern of BS were analyzed. During a mean follow-up period of 4.6 +/- 2.2 years, nine subjects suffered ATs (24%). Six subjects displayed paroxysmal atrial fibrillation and three typical atrial flutter. Among the studied 12-lead ECG parameters, subjects with ATs exhibited increased values of P-wave duration in lead II, P-wave dispersion, PR interval in leads II, QRS duration in leads II and V(2), Tpeak-end interval in lead II, and Tpeak-end dispersion of the 12 leads in relation to those without ATs (P < 0.05). Among the assessed electrophysiological parameters, atrial-His (AH) and His-ventricular (HV) intervals were significantly prolonged in subjects with ATs (P < 0.05). Multiple Cox proportional hazards analysis revealed that P-wave duration in lead II, P-wave dispersion, Tpeak-end in lead II, Tpeak-end dispersion of the 12 leads, as well as AH and HV intervals are independent predictors of ATs in subjects with BS (P < 0.05). Cut-off point analysis showed that an HV interval>or=56 ms displayed the highest predictive ability (P < 0.01). CONCLUSION: Our findings demonstrate that simple 12-lead ECG and electrophysiological parameters may easily be applied to identify high-risk subjects with BS ECG phenotype to develop ATs.

Potential-guided versus anatomic-guided approach for slow pathway ablation of the common type atrioventricular nodal reentry tachycardia: a randomized study.

OBJECTIVE: The present study aimed to compare the effectiveness and safety of the potential- and the anatomic-guided approach for slow pathway ablation in patients with recurrent episodes of symptomatic common type atrioventricular (AV) nodal reentrant tachycardia. METHODS: Two hundred and twenty-eight patients were randomly assigned to undergo either a potential- (n=114, 47% men, mean age 52.85 +/- 14.04 years) or an anatomic-guided approach (n=114, 50% men, mean age 52.45 +/- 14.46 years) for radiofrequency ablation of the slow pathway.The mean duration of the follow-up period was 26.7 +/- 7.9 and 24.8 +/- 7.6 months in the potential- and anatomic- guided approach, respectively (P > 0.05). RESULTS: The success rate for slow pathway ablation was 100% in both ablative methods.The mean duration of atrial electrograms at the successful ablation sites of the potential- and the anatomic-guided approaches was 69 +/- 14 msec and 57 +/- 10 msec, respectively (P = 0.001).There were no significant differences between the potential- and the anatomic-guided approach regarding the duration of the procedure (121.13 +/- 56.83 vs. 109.93 +/- 57.12 min, P = 0.139), the duration of fluoroscopic exposure (6.12 +/- 3.32 vs. 6.64 +/- 3.33 min, P = 0.239) or the mean number of radiofrequency applications delivered (3.96 +/- 2.77 vs. 4.33 +/- 2.73, P = 0.311). Residual dual AV nodal pathway following successful ablation was observed in 9.6% of patients who underwent the potential-guided approach and in 23.7% of patients who underwent the anatomic method (P = 0.004). During followup, arrhythmia recurrence was observed in four patients (1.8%), two in each group (P > 0.05). CONCLUSIONS: The efficacy and safety of the slow pathway ablation is very high using either the potential- or the anatomic-guided approach.

Dietary intake in immigrant Arabian pregnant women.

OBJECTIVE: We examined the intake of dietary micronutrients of immigrant Arabian pregnant women in Greece, in order to investigate the possible factors influencing food intake and affecting the overall nutritional profile. METHODS: A dietary assessment of 497 immigrant Arabian pregnant women, admitted to the Obstetrics and Gynecology Department, Outpatient Clinic, Tzaneion General Hospital, Piraeus city, Vyronas Health Center, and Alexandras General Hospital, Athens, Greece was performed between August 2002 and August 2005, along with a comparison of micronutrient intake with the latest dietary recommendations. We carried out blood analysis, and measurements of serum micronutrients in all participants. RESULTS: Four hundred and sixty-seven out of 497 (94%) women followed the traditional Arabian diet, and did not use drug medication or supplements during gestation. The mean dietary intakes of vitamin E, vitamin B12, vitamin C, zinc, calcium and phosphorus in the 2nd and 3rd trimesters were similar to the respective values of the Dietary Reference Intake, while the mean dietary intake of vitamin D was relatively low. The mean intakes of folic acid and iron were lower than the respective values, while the mean intakes of vitamin A and magnesium was slightly higher. The results of the laboratory tests were normal in 470 women (94.5%) except those regarding iron deficiency anemia, which was relatively common. CONCLUSION: Our findings suggest that apart from iron and folic acid supplementation, no further changes would be necessary in the dietary patterns of immigrant Arabian pregnant women, since their traditional nutritional habits seem to provide all micronutrients in sufficient quantities.

The impact of body mass index on the efficacy and safety of catheter ablation of atrial fibrillation.

BACKGROUND: Obesity is a well established risk factor for atrial fibrillation (AF) development. Our purpose was to determine the impact of body mass index (BMI) on the safety and efficacy of radiofrequency catheter ablation of AF. METHODS: Two hundred and twenty-six consecutive patients with symptomatic, drug-refractory paroxysmal (59.3%) and persistent (40.7%) AF underwent wide circumferential electrical pulmonary vein isolation. Patients were classified according to BMI as normal (<25kg/m(2)); overweight (25 to 29.9kg/m(2)); and obese (≥30kg/m(2)). RESULTS: Patients with high BMI were younger and displayed a higher rate of hypertension, increased left atrial diameter, increased left ventricular end-diastolic and end-systolic diameters, and increased levels of several conventional markers of inflammation and oxidative stress including white blood cell count, fibrinogen, uric acid, alanine aminotransferase, and gamma-glutamyltransferase (p<0.05). After a mean follow-up period of 432.32±306.09days from the index procedure, AF recurrence rate was 34.9% for normal weight, 46.2% for overweight, and 46.2% for obese patients (p: 0.258). Subjects classified above the 50th percentile for BMI displayed a trend toward a higher AF recurrence rate (p: 0.08). In univariate Cox regression survival analysis, BMI was not predictive of AF recurrence. Radiation exposure was significantly higher in overweight and obese patients in relation to normal weight patients (p: 0.003). No significant differences regarding major complications were observed among BMI groups. CONCLUSIONS: In this study population, BMI was not an independent predictor of AF recurrence following left atrial catheter ablation.

Uric acid elevation in atrial fibrillation.

INTRODUCTION: Uric acid is a cardiovascular risk marker associated with oxidative stress and inflammation. Recently, atrial fibrillation (AF) has been associated with inflammation and oxidative stress. We therefore investigated the association between AF and uric acid levels. METHODS: Consecutive patients with AF and healthy control subjects were screened. Demographic, clinical, and echocardiographic characteristics were carefully recorded. In each participant, uric acid levels and conventional inflammatory markers were determined. The final study population consisted of 45 patients with paroxysmal AF, 41 patients with permanent AF, and 48 control subjects. RESULTS: A significant variance in uric acid levels was evident between patients with paroxysmal AF (5.7 +/- 1.1 mg/dl), permanent AF (6.7 +/- 1.4 mg/dl), and control subjects (5.1 +/- 1.3 mg/dl) (p<0.001). After univariate analysis considering 2 groups (control, AF patients), the following variables were significantly associated with the presence of AF: age, hypertension, -blocker use, low left ventricular ejection fraction (LVEF), increased left atrial diameter, uric acid levels, and C-reactive protein (CRP) levels. After multivariate logistic regression analysis, only CRP was an independent predictor for AF (odds ratio, OR: 2.172). In a subgroup analysis, CRP (OR: 1.434) and LVEF (OR: 0.361) were independent predictors of paroxysmal AF, while CRP (OR: 3.048), uric acid (OR: 2.172), and LVEF (OR: 0.34) were predictors of permanent AF. CONCLUSIONS: There is an association between increased levels of uric acid and permanent AF. Also, uric acid elevation may be related to the burden of AF. Undoubtedly, larger studies should further examine this potential association.

Predictors of atrial fibrillation recurrence in patients with long-lasting atrial fibrillation.

BACKGROUND: Limited data are available on the predictors of atrial fibrillation (AF) recurrence in patients with chronic AF. OBJECTIVES: To evaluate potential clinical, echocardiographic and electrophysiological predictors of AF recurrence, after internal cardioversion for long-lasting AF. METHODS: A total of 99 consecutive patients (63 men and 36 women, mean age 63.33+/-9.27 years) with long-standing AF (52.42+/-72.02 months) underwent internal cardioversion with a catheter that consisted of two defibrillating coils. Shocks were delivered according to a step-up protocol. Clinical follow-up and electrocardiographic recordings were performed on a monthly basis for a 12-month period or whenever patients experienced symptoms suggestive of recurrent AF. RESULTS: Ninety-three patients (93.94%) underwent a successful uncomplicated cardioversion, with a mean atrial defibrillation threshold of 10.69+/-6.76 J. Immediate reinitiation of AF was observed in 15 patients (15.78%) of whom a repeated cardioversion restored sinus rhythm in 13 cases. Early recurrence of AF (within one week) was observed in 12 of 93 patients (12.90%). At the end of the 12-month follow-up period, during which seven patients were lost, 42 of the 86 remaining patients (48.84%) were still in sinus rhythm. Multivariate regression analysis showed that left atrial diameter (OR 1.126, 95% CI 1.015 to 1.249; P=0.025) and mitral A wave velocity (OR 0.972, 95% CI 0.945 to 0.999; P=0.044) were significant and independent predictors of AF recurrence, whereas age, left ventricular ejection fraction and AF cycle length were not predictive of arrhythmia recurrence. CONCLUSION: The present study showed that the left atrial diameter and mitral A wave velocity are the only variables associated with AF recurrence after successful cardioversion.

Determinants of plasma NT-pro-BNP levels in patients with atrial fibrillation and preserved left ventricular ejection fraction.

OBJECTIVES: The present study aimed to investigate the clinical and echocardiographic determinants of plasma NT-pro-BNP levels in patients with atrial fibrillation (AF) and preserved left ventricular ejection fraction (LVEF). METHODS: NT-pro-BNP levels were measured in 45 patients with paroxysmal AF, 41 patients with permanent AF and 48 controls. RESULTS: NT-pro-BNP levels were found significantly elevated in patients with paroxysmal (215+/-815 pg/ml) and permanent AF (1,086+/-835 pg/ml) in relation to control population (86.3+/-77.9 pg/ml) (P<0.001). According to the univariate linear regression analysis, age, hypertension, beta-blocker use, left atrial diameter (LAD), LVEF and AF status (paroxysmal or permanent or both) were significantly associated with NT-pro-BNP levels (P<0.05). In multiple linear regression analysis, LVEF (B coefficient: -53.030; CI: -95.738 to -10.322; P: 0.015) and LAD (B coefficient: 285.858; CI: 23.731-547.986; P: 0.033) were significant and independent determinants of NT-pro-BNP levels. CONCLUSIONS: Plasma NT-pro-BNP levels were significantly higher in patients with paroxysmal and permanent AF compared to those with sinus rhythm in the setting of preserved left ventricular systolic function. LVEF and LAD were independent predictors of NT-pro-BNP levels.

Ablation of atrial fibrillation in patients with heart failure: reversal of atrial and ventricular remodelling.

INTRODUCTION: The management of patients with heart failure and atrial fibrillation (AF) is a medical challenge, especially in the case of patients in whom sinus rhythm or rate control cannot be achieved with optimal pharmaceutical treatment. METHODS: Thirteen consecutive patients (11 men and 2 women, 35-70 years old, median age 55 +/- 23 years) with heart failure (NYHA I-IV, median ejection fraction 35 +/- 5%, range 25-40%) and symptomatic persistent (10 patients, 76.9%) or permanent (3 patients, 23.1%) AF, underwent circumferential ablation using a system of electroanatomic mapping with contact. Circumferential ablation, encircling the pulmonary veins in pairs, and linear ablation between the left and right superior pulmonary vein and along the mitral isthmus were performed. Follow up included 24-hour Holter monitoring and transthoracic echocardiogram at 1, 3, 6, 9 and 12 months. RESULTS: Eight patients (62%) remained in sinus rhythm at the end of the follow up and had achieved a statistically significant improvement in ejection fraction (from 37.5 8.75% to 60.0 +/- 3.75%, p = 0.011), reduction of left ventricular end-diastolic diameter (from 63.0 +/- 3.25 mm to 56.5 +/- 1.75 mm, p = 0.011) and reduction of left atrial diameter (from 49.0 +/- 5.5 mm to 44.5 +/- 4.25 mm, p = 0.011). In contrast, patients with relapse of AF had none of the above changes (p > 0.05). Prognostic indexes of AF recurrence appeared to be the failure to improve ejection fraction (p = 0.003), non-reversal of left ventricular (p = 0.002) and left atrial (p = 0.006) remodelling, a shorter energy application time (p = 0.030) and the presence of coronary artery disease (p = 0.035). None of the patients suffered any complication from the procedure. CONCLUSION: AF ablation in selected patients with heart failure and low ejection fraction is a relatively effective method of maintaining sinus rhythm, improving left ventricular systolic function and reversing atrial and ventricular remodelling.