Substitutional photoluminescence modulation in adducts of a europium chelate with a range of alkali metal cations: a gas-phase study.

We present gas-phase dispersed photoluminescence spectra of europium(III) 9-hydroxyphenalen-1-one (HPLN) complexes forming adducts with alkali metal ions ([Eu(PLN)3M](+) with M = Li, Na, K, Rb, and Cs) confined in a quadrupole ion trap for study. The mass selected alkali metal cation adducts display a split hypersensitive (5)D0 → (7)F2 Eu(3+) emission band. One of the two emission components shows a linear dependence on the radius of the alkali metal cation whereas the other component displays a quadratic dependence thereon. In addition, the relative intensities of both components invert in the same order. The experimental results are interpreted with the support of density functional calculations and Judd-Ofelt theory, yielding also structural information on the isolated [Eu(PLN)3M](+) chromophores.

Success of Radiofrequency Catheter Ablation of Atrial Fibrillation: Does Obesity Influence the Outcomes?

Background: Catheter ablation of atrial fibrillation (AF) is an increasingly popular therapeutic option for symptomatic patients who have failed multiple antiarrhythmic drugs (AADs). Patients of higher body mass index often fail direct current cardioversion. The role of body mass index (BMI) on the success of AF ablation is not well understood. Methods: We prospectively studied 511 patients who underwent AF ablation at the Cleveland Clinic Foundation between 2002 and 2005. Patients were divided into four classes based on their BMI: Class I ( 25); Class II (25.1-30); Class III (30.1-35) and Class IV (>35). These groups were compared for baseline demographic and clinical characteristics. Any recurrence of AF after 3 months of ablation was considered as failure. All classes were followed for at least 12 months and rates of failure were compared. Results: Based on their BMI, 25% of patients were assigned to class I, 37% in class II, 21% in class III and 16% in class IV. Patients of higher classification (class III or IV) were more likely to be male (p<0.001), diabetic (p<0.001), smokers (p=0.002), with coronary artery disease (=0.018), left atrial enlargement (p=0.015) and longstanding AF (p=0.007). Severity of obesity as measured by BMI had a direct correlation to early (p=0.05) and late (p=0.01) recurrence of AF. Conclusion: Obesity is significantly associated with long-term AF recurrence after catheter ablation. Higher incidence of smoking & left atrial enlargement may possibly contribute to higher failure rates in this sub-group of patients.

Impact of varying ablation patterns in a simulation model of persistent atrial fibrillation.

BACKGROUND: Several strategies of endovascular ablation with varying success rates and proarrhythmic effects have been proposed to treat persistent atrial fibrillation (AF). Evaluation of ablation patterns by computer simulation provides a tool for examination of its effectiveness and side effects. METHODS AND RESULTS: A biophysical model of the human atria based on magnetic resonance imaging derived geometry and a membrane kinetics model was used. Uniform conduction properties were assigned to the monolayer surface representing the atria. After induction of AF by burst pacing, progressively broader ablation patterns were applied: (A) individual pulmonary vein isolation (PVI); (B) double ipsilateral PVI; (C) double PVI with a roofline; (D) double PVI with a lateral mitral isthmus line, and (E) double PVI with both linear lesions. In addition, the influence of incomplete linear lesions and dilated atria were simulated. The incidence of AF termination was found to increase from pattern (A) to (E). Atrial flutter rate increased with incomplete ablations and in dilated atria. CONCLUSION: Computer simulation of various ablation patterns in persistent AF is feasible and can reproduce clinical results of catheter ablation. This model can be used to develop and simulate new ablation patterns and anticipate success rates and potential adverse effects.

Dual-loop circuits in postoperative atrial macro re-entrant tachycardias.

BACKGROUND: Patients may develop dual-loop re-entrant atrial arrhythmias late after open-heart surgery, and mapping and catheter ablation remain challenging despite computer-assisted mapping techniques. OBJECTIVES: The purpose of the study was to demonstrate the prevalence and characteristics of dual-loop re-entrant arrhythmias, and to define the optimal mapping and ablation strategy. METHODS: 40 consecutive patients (mean (SD) age 52 (12) years) with intra-atrial re-entrant tachycardia (IART) after open-heart surgery (with an incision of the right atrial free wall) were studied. Dual-loop IART was defined as the presence of two simultaneous atrial circuits. After an abrupt tachycardia change during radiofrequency ablation, electrical disconnection of the targeted re-entry isthmus from the remaining circuit was demonstrated by entrainment mapping. Furthermore, the second circuit loop was localised using electroanatomical mapping and/or entrainment mapping. RESULTS: Dual-loop IART was demonstrated in eight (20%, 5 patients with congenital heart disease, 3 with acquired heart disease) patients. Dual-loop IART included an isthmus-dependant atrial flutter combined with a re-entry related to the atriotomy scar. The diagnosis of dual-loop IART required the comparison of entrainment mapping before and after tachycardia modification. Overall, 35 patients had successful radiofrequency ablation (88%). Success rates were lower in patients with dual-loop IART than in patients without dual-loop IART. Ablation failures in three patients with dual-loop IART were related to the inability to properly transect the second tachycardia isthmus in the right atrial free wall. CONCLUSIONS: Dual-loop IART is relatively common after heart surgery involving a right atriotomy. Abrupt tachycardia change and specific entrainment mapping manoeuvres demonstrate these circuits. Electroanatomical mapping appears to be important to assist catheter ablation of periatriotomy circuits.

Flutter localized to the anterior left atrium after catheter ablation of atrial fibrillation.

INTRODUCTION: Organized atrial arrhythmias following atrial fibrillation (AF) ablation are typically due to recovered pulmonary vein (PV) conduction or reentry at incomplete ablation lines. We describe the role of nonablated anterior left atrium (LA) in arrhythmias observed after AF ablation. METHODS: A total of 275 consecutive patients with paroxysmal (n = 200) or chronic (n = 75) AF had PV isolation with/without additional linear ablation at the mitral isthmus (n = 106), LA roof (n = 23), or both (n = 88). Organized arrhythmias occurring after ablation were evaluated utilizing activation and entrainment mapping. RESULTS: Fourteen patients (11 female, 65 +/- 13 years, 10 chronic AF, 10 structural heart disease) demonstrated tachycardia localized to the anterior LA, an area not targeted by prior ablation. Eight had ECG features during sinus rhythm suggestive of impaired anterior LA conduction at baseline. These arrhythmias demonstrated a distinctive ECG flutter morphology in 7 of 10 (70%) with discrete -/+ or +/-/+ aspect in inferior leads. Mapping the anterior LA revealed electrograms spanning the entire tachycardia cycle length (325 +/- 125 msec). Entrainment was possible in all with a postpacing interval exceeding the tachycardia cycle length by 9 +/- 10 msec. Electroanatomic mapping in 6 demonstrated small reentrant circuits rotating clockwise in 4 and counterclockwise in 2. Low-amplitude, fractionated mid-diastolic potentials with long duration (200 +/- 80 msec) occupying 63 +/- 22% of the cycle length were targeted for ablation resulting in termination and subsequent noninducibility. CONCLUSION: Organized arrhythmias occurring after AF ablation can be due to reentrant circuits localized to the anterior LA, predominantly in females with chronic AF, structural heart disease, and abnormal atrial conduction. They are characterized by a distinctive surface ECG and highly responsive to RF ablation at the slow conduction area.

Long-term evaluation of atrial fibrillation ablation guided by noninducibility.

BACKGROUND: Pulmonary vein (PV) isolation and linear lesions are effective in eliminating paroxysmal atrial fibrillation (AF), but linear lesions probably are not required in all patients. Noninducibility of AF has been shown to be associated with freedom from arrhythmia in 87% of patients. OBJECTIVES: The purpose of this study was to prospectively evaluate the role of noninducibility in guiding a stepwise approach tailored to the patient. METHODS: In 74 patients (age 53 +/- 8 years) with paroxysmal AF, PV isolation was performed during induced or spontaneous AF. If AF was inducible after PV isolation, one to two additional linear lesions were placed at the mitral isthmus and/or left atrial roof, with the endpoint of noninducibility of AF or atrial flutter. Inducibility (AF/atrial flutter, lasting > or = 10 minutes) was assessed using burst pacing at an output of 20 mA down to refractoriness from the coronary sinus and both atrial appendages. RESULTS: In 42 patients (57%), PV isolation restored sinus rhythm and rendered AF noninducible. In the 32 patients with persistent or inducible AF after PV isolation, a single linear lesion achieved noninducibility in 20, whereas two linear lesions were required in 12 and resulted in conversion to sinus rhythm and noninducibility in 10. Using this stepwise approach, a total of 69 patients (93%) were rendered noninducible. During follow-up of 18 +/- 4 months, 67 patients (91%) were free from arrhythmia without antiarrhythmic drugs. Repeat procedures were performed in 23 patients: repeat ablation was required to consolidate prior targets in 15 patients (20%), and "new" linear lesions, which were not predicted by inducibility during the index procedure, were required in 8 (11%). CONCLUSION: Noninducibility can be used as an endpoint for determining the subset of patients with paroxysmal AF who require additional linear lesions after PV isolation. This tailored approach is effective in 91% of patients while preventing delivery of unnecessary linear lesions.

Reduction of fluoroscopy exposure and procedure duration during ablation of atrial fibrillation using a novel anatomical navigation system.

AIMS: Catheter ablation of atrial fibrillation (AF) is centred on pulmonary vein (PV) ablation with or without additional atrial substrate modification. These procedures may be prolonged with significant fluoroscopy exposure. This study evaluates a new non-fluoroscopic navigation system during ablation of AF. METHODS AND RESULTS: Seventy-two patients undergoing catheter ablation of symptomatic drug refractory AF were prospectively randomized to ablation with (n=35; study group) or without (n=37; control group) non-fluoroscopic navigation. PV isolation was performed in all patients. In patients with persistent or inducible sustained AF after PV isolation linear ablation was performed by joining the superior PVs. PV isolation was achieved in all patients; fluoroscopy (15.4+/-3.4 vs. 21.3+/-6.4 min; P<0.001) and procedural (52+/-12 vs. 61+/-17 min; P=0.02) durations were significantly reduced in the study group. Linear block was achieved in 37 of the 39 patients; with a significant reduction in fluoroscopy (5.6+/-2.2 vs. 9.9+/-4.8 min; P=0.003) and procedural (14.7+/-5.5 vs. 26.6+/-16.9 min; P=0.007) durations in the study group. After a follow-up of 6.9+/-2.9 months (range 3-10), 26 (74%) patients in the non-fluoroscopic navigation group and 29 (78%) patients in the control group were arrhythmia-free after the first procedure. CONCLUSION: This prospectively randomized study demonstrates significant reduction of fluoroscopy exposure and procedural duration using supplementary non-fluoroscopic imaging system for AF ablation.

Fever as a precipitant of idiopathic ventricular fibrillation in patients with normal hearts.

INTRODUCTION: Ventricular fibrillation (VF) is the main mechanism of sudden cardiac death. The clinical precipitants of sudden cardiac death due to idiopathic VF are poorly characterized. Emerging evidence implicates triggers originating predominantly from the distal Purkinje arborization and the right ventricular outflow tract. METHODS AND RESULTS: We report three patients without structural heart disease or repolarization abnormalities in whom a febrile illness was the only concurrent disease associated with unexpected sudden cardiac death due to VF storm. An automated defibrillator was implanted in all three patients. In one patient with persistent recurrent VF episodes, mapping demonstrated the origin of these triggers was from the Purkinje arborization of the anterior wall of the right ventricle. Ablation at a site of earliest activation during ectopy, where pace mapping was concordant and Purkinje potential preceded the onset of ventriculogram, resulted in suppression of all arrhythmias. After follow-up of 22, 9, and 18 months in the three patients, no ventricular arrhythmias have been recorded. CONCLUSION: We present a series of patients in whom an apparently benign febrile illness was associated with malignant ventricular arrhythmias in the absence of cardiac disease or other factors known to precipitate sudden cardiac death. Physicians should be aware of this possible phenomenon in cases of febrile illness associated with syncope.

Transcatheter left atrial appendage occlusion with Amplatzer devices to obviate anticoagulation in patients with atrial fibrillation.

It is assumed that over 90% of clinically apparent embolisms in atrial fibrillation originate from the left atrial appendage. Recently, a percutaneous method (PLAATO technique) to occlude the left atrial appendage to the end of preventing thromboembolic complications of atrial fibrillation has been introduced into clinical practice. This technique is quite intricate and requires general anesthesia. The Amplatzer atrial septal occluder lends itself for a more simple approach to this intervention. The first 16 patients treated at four centers are described. Their age varied from 58 to 83 years. All suffered from atrial fibrillation but eight of them were in sinus rhythm at the time of implantation. All but two procedures were done under local anesthesia of the groin only. There was one technical failure (device embolization) requiring surgery. All other patients left the hospital a day after the procedure without complications. There were no problems or embolic events during an overall follow-up of 5 patient-years and all left atrial appendages were completely occluded without evidence of thrombosis at the atrial side of the device at the latest follow-up echocardiography. With the Amplatzer technique, the left atrial appendage can be percutaneously occluded with a venous puncture under local anesthesia, without echocardiographic guidance, and at a reasonable risk. It remains to be evaluated in larger series or randomized trials how the simpler Amplatzer technique compares with the complex PLAATO technique, and whether left atrial appendage closure is competitive with oral anticoagulation with warfarin or the novel ximelagatran to prevent thromboembolism in atrial fibrillation.

Interventional cardiology in Europe 1999.

AIMS: The purpose of this registry is to collect data on trends in interventional cardiology within Europe. Special interest focuses on relative increases and ratios in newer revascularization approaches and its distribution in different regions in Europe. METHODS AND RESULTS: Questionnaires distributed to delegates of the national societies of cardiology represented in the European Society of Cardiology to be completed by local institutions and operators yielded that 1,452,751 angiograms and 452,019 PTCAs were performed in 1999. This is an increase of 28% and 16%, respectively, compared with 1998. Most of these increases are due to high relative increases in eastern European countries. The number of PTCAs per 106 inhabitants rose to 714 in 1999. Coronary stenting increased by 31% to about 313,000 stents implanted in 1999. Complication rates remained stable, the need for emergency coronary artery bypass grafting showing a further slight decrease to currently 0.3%. CONCLUSION: Interventional cardiology in Europe is still growing, mainly due to rapid growth in countries with lower socio-economical levels. In some central European countries a saturation seemed to be reached with only minor increases in procedures performed. Coronary stenting remains the only noteworthy and growing complement or alternative to balloon angioplasty.