Left atrial conduction times and regional velocities in persistent atrial fibrillation patients with and without fibrotic atrial cardiomyopathy.

Despite the progress in understanding left atrial substrate and arrhythmogenesis, only little is known about conduction characteristics in atrial fibrillation patients with various stages of fibrotic atrial cardiomyopathy (FACM). This study evaluates left atrial conduction times and conduction velocities based on high-density voltage and activation maps in sinus rhythm (CARTO®3 V7) of 53 patients with persistent atrial fibrillation (LVEF 60% (55-60 IQR), LAVI 39 ml/m2 (31-47 IQR), LApa 24 ± 6 cm2). Measurements were made in low voltage areas (LVA ≤ 0.5 mV) and normal voltage areas (NVA ≥ 1.5 mV) at the left atrial anterior and posterior walls. Maps of 28 FACM and 25 no FACM patients were analyzed (19 FACM I/II, 9 FACM III/IV, LVA 14 ± 11 cm2). Left atrial conduction time averaged to 110 ± 24 ms but was shown to be prolonged in FACM (119 ms, + 17%) when compared to no FACM patients (101 ms, p = 0.005). This finding was pronounced in high-grade FACM (III/IV) (133 ms, + 31.2%, p = 0.001). In addition, the LVA extension correlated significantly with the left atrial conduction time (r = 0.56, p = 0.002). Conduction velocities were overall slower in LVA than in NVA (0.6 ± 0.3 vs. 1.3 ± 0.5 m/s, -51%, p < 0.001). Anterior conduction appeared slower than posterior, which was significant in NVA (1 vs. 1.4 m/s, -29%, p < 0.001) but not in LVA (0.6 vs. 0.8 m/s, p = 0.096). FACM has a significant influence on left atrial conduction characteristics in patients with persistent atrial fibrillation. Left atrial conduction time prolongs with the grade of FACM and the quantitative expanse of LVA up to 31%. LVAs show a 51% conduction velocity reduction compared to NVA. Moreover, regional conduction velocity differences are present in the left atrium when comparing anterior to posterior walls. Our data may influence individualized ablation strategies.

Mechanistic assessment and ablation of left ventricular assist device related ventricular tachycardia in patients with severe heart failure.

Aims: Left-ventricular-assist-devices (lvad) are an established treatment for patients with severe heart failure with reduced ejection fraction (HF) and reduce mortality. However, HF patients have significant substrate for ventricular tachycardia (VT) and the lvad itself might be pro-arrhythmogenic. We investigated the mechanism of VT in lvad-patients in relation to the underlying etiology and provide in silico and ex-vivo data for ablation in these HF patients. Methods and Results: We retrospectively analyzed invasive electrophysiological (EP) studies of 17 patients with VT and lvad. The mechanism of VT was determined using electroanatomical, entrainment and activation time mapping. Ischemic cardiomyopathy was present in 70% of patients. VT originated from the lvad region in >30%. 1/6 patients with VT originating from the lvad region had episodes before lvad implantation, while 7/11 patients with VT originating from other regions had episodes before implantation. Number and time of radiofrequency (RF)-ablation lesions were not different between VTs originating from the lvad or other regions. Long-term freedom from VT was 50% upon ablation in patients with VT originating from the lvad region and 64% if ablation was conducted in other regions. To potentially preemptively mitigate lvad related VT in patients undergoing lvad implantation, we obtained in silico derived data and performed ex-vivo experiments targeting ventricular myocardium. Of the tested settings, application of 25 W for 30 s was safe and associated with optimal lesion characteristics. Conclusion: A significant percentage of patients with lvad undergoing VT ablation exhibit arrhythmia originating in close vicinity to the device and recurrence rates are high. Based on in silico and ex-vivo data, we propose individualized RF-ablation in selected patients at risk for/with lvad related VT.

Cardiac radioablation of incessant ventricular tachycardia in patients with terminal heart failure under permanent left ventricular assist device therapy-description of two cases.

PURPOSE: Cardiac radioablation (cRA) using a stereotactic single-session radioablative approach has recently been described as a possible treatment option for patients with otherwise untreatable recurrent ventricular tachycardia (VT). There is very limited experience in cRA for patients undergoing left ventricular assist device (LVAD) therapy. We present clinical experiences of two patients treated with cRA for incessant VT under long-term LVAD therapy. METHODS: Two male patients (54 and 61 years old) with terminal heart failure under LVAD therapy (both patients for 8 years) showed incessant VT despite extensive antiarrhythmic drug therapy and repeated catheter ablation. cRA with a single dose of 25 Gy was applied as a last resort strategy under compassionate use in both patients following an electroanatomical mapping procedure. RESULTS: Both patients displayed ongoing VT during and after the cRA procedure. Repeated attempts at post-procedural rhythm conversion failed in both patients; however, one patient was hemodynamically stabilized and could be discharged home for several months before falling prey to a fatal bleeding complication. The second patient initially stabilized for a few days following cRA before renewed acceleration of running VT required bilateral ablation of the stellate ganglion; the patient died 50 days later. No immediate side effects of cRA were detected in either patient. CONCLUSION: cRA might serve as a last resort strategy for patients with terminal heart failure undergoing LVAD therapy and displaying incessant VT. Intermediate- and long-term outcomes of these seriously ill patients often remain poor; therefore, best supportive care strategies should also be evaluated as long as no clear beneficial effects of cRA procedures can be shown. For patients treated with cRA under running ventricular rhythm abnormality, strategies for post-procedural generation of stabilized rhythm have to be established.

Cardiac radiotherapy transiently alters left ventricular electrical properties and induces cardiomyocyte-specific ventricular substrate changes in heart failure.

AIMS: Ongoing clinical trials investigate the therapeutic value of stereotactic cardiac radioablation (cRA) in heart failure patients with ventricular tachycardia. Animal data indicate an effect on local cardiac conduction properties. However, the exact mechanism of cRA in patients remains elusive. Aim of the current study was to investigate in vivo and in vitro myocardial properties in heart failure and ventricular tachycardia upon cRA. METHODS AND RESULTS: High-density 3D electroanatomic mapping in sinus rhythm was performed in a patient with a left ventricular assist device and repeated ventricular tachycardia episodes upon several catheter-based endocardial radio-frequency ablation attempts. Subsequent to electroanatomic mapping and cRA of the left ventricular septum, two additional high-density electroanatomic maps were obtained at 2- and 4-month post-cRA. Myocardial tissue samples were collected from the left ventricular septum during 4-month post-cRA from the irradiated and borderzone regions. In addition, we performed molecular biology and mitochondrial density measurements of tissue and isolated cardiomyocytes. Local voltage was altered in the irradiated region of the left ventricular septum during follow-up. No change of local voltage was observed in the control (i.e. borderzone) region upon irradiation. Interestingly, local activation time was significantly shortened upon irradiation (2-month post-cRA), a process that was reversible (4-month post-cRA). Molecular biology unveiled an increased expression of voltage-dependent sodium channels in the irradiated region as compared with the borderzone, while Connexin43 and transforming growth factor beta were unchanged (4-month post-cRA). Moreover, mitochondrial density was decreased in the irradiated region as compared with the borderzone. CONCLUSION: Our study supports the notion of transiently altered cardiac conduction potentially related to structural and functional cellular changes as an underlying mechanism of cRA in patients with ventricular tachycardia.

Minimally invasive approach to the treatment of atrial fibrillation: Concomitant Convergent and LARIAT procedure.

The Convergent procedure comprises epi- and endocardial ablation of the left atrium and represents an effective alternative to conventional endocardial ablation in patients with therapy-resistant atrial fibrillation. The LARIAT approach allows the epi- and endocardial closure of the left atrial appendage and effectively reduces the risk of stroke in patients with atrial fibrillation. In this video tutorial, we provide step-by-step guidance through the concomitant Convergent and LARIAT procedures.

Clinical outcomes of cryoballoon ablation for pulmonary vein isolation: Impact of intraprocedural heart rhythm.

BACKGROUND: The current study sought to assess the impact of the intraprocedural heart rhythm (sinus rhythm [SR] vs. atrial fibrillation [AF]) on acute procedural characteristics, durability of pulmonary vein isolation (PVI) and long-term clinical outcomes of cryoballoon (CB) ablation. METHODS: A total of 195 patients with symptomatic paroxysmal (n = 136) or persistent AF (n = 59) underwent CB-based PVI. Ablation procedures were either performed in SR (SR group; n = 147) or during AF (AF group; n = 48). Persistent AF was more frequent in the AF group than in the SR group (62% vs. 20%). All other patient baseline characteristics did not differ between the two groups. RESULTS: The nadir temperature during the CB applications was significantly lower in the AF group than in patients in the SR group (-49 [interquartile range, -44; -54]°C vs. -47 [-42; -52]°C, p = 0.002). Median procedure and fluoroscopy times as well as the rate of real-time recordings were not different between the two groups. Repeat ablation for the treatment of atrial arrhythmia recurrence was performed in 60 patients (SR: 44 [30%] patients; AF: 16 [33%] patients), with a trend towards a lower rate of pulmonary vein reconnections in the AF group (p = 0.07). There was no difference in 3-year arrhythmia-free survival (p = 0.8). CONCLUSIONS: Cryoballoon-based PVI during AF results in lower nadir balloon temperatures and a trend towards a higher durability of PVI as compared to procedures performed in SR. The rate of real-time PVI recordings was not affected by the intraprocedural heart rhythm.

Isolated atrial amyloidosis suspected by electrophysiological voltage mapping and diagnosed by 99m Tc-DPD scintigraphy.

We present not-yet-seen multimodal images of a 55-year-old female patient with isolated atrial amyloidosis (IAA) who clinically suffered from multiple atrial arrhythmias and heart failure symptoms with preserved left ventricular ejection fraction. We aim to show structural and functional abnormalities detected by electrophysiological voltage mapping, cardiac magnetic resonance imaging (MRI) [cMRI; atrial strain measurements, late gadolinium enhancement (LGE) visualization], and 99m Tc-DPD scintigraphy. Bipolar voltage mapping performed during two electrophysiological procedures showed diffuse left atrial low-voltage areas (bipolar < 0.5 mV) and also a moderately diseased right atrium suspected of infiltrative cardiomyopathy. Catheter ablation did successfully treat a left atrial and two right atrial focal tachycardias. For further diagnostics, a 3T cMRI was performed, revealing a subendocardial circumferential left atrial LGE and pathological atrial strain measurements, especially during conduit and reservoir phase. Afterwards, nuclear imaging with 559 MBq of 99m Tc-DPD was performed. The scan revealed amyloid infiltration of the left atrium. Neither an uptake in the ventricular myocardium nor an extra-cardiac uptake of DPD was seen. Genetic testing for transthyretin amyloidosis mutations in this patient was negative, and peripheral neuropathy was ruled out by electromyogram analysis. The synopsis of these findings reveals IAA as the most possible diagnosis and showed isolated atrial nuclear tracer uptake with 99m Tc-DPD scintigraphy for the first time. Non-invasive imaging techniques might help in suggesting IAA but need further investigation.

Long-term left atrial remodeling after ablation of persistent atrial fibrillation: 7-year follow-up by cardiovascular magnetic resonance imaging.

PURPOSE: Restoration of sinus rhythm in patients with persistent atrial fibrillation (ps. AF) induces reverse atrial remodeling and improvement of left ventricular function. We evaluated the effect of ablative treatment on cardiac remodeling after a long follow-up period of 7 years by cardiovascular magnetic resonance (CMR). METHODS: Patients with symptomatic ps. AF underwent CMR within 7 days prior to the ablation procedure. Left atrial and ventricular volumes were measured. All patients underwent circumferential pulmonary vein isolation. At the end of follow-up (FU), a CMR and 7-day ECG registration were performed. RESULTS: Forty-two patients (67 ± 9 years) were included. After a FU of 86 ± 13 months, 23 patients had a successful outcome. In these patients, LVEF improved from 56 ± 5 to 62 ± 4% (p = 0.02), but left atrial volume and ejection fraction (LAV, LAEF) remained unchanged (105 ± 25 to 98 ± 34, p = 0.44; 34 ± 10 to 36 ± 11, p = 0.6, respectively). In 14 patients with a BMI < 30 and no left ventricular hypertrophy (LVH), LAV decreased (104 ± 30 to 82 ± 26 ml, p = 0.01) and LAEF improved (33 ± 12 to 40 ± 11%, p = 0.03). In 9 patients with successful outcome and either BMI ≥ 30 or LVH, LAV increased (110 ± 26 to 125 ± 30 ml, p = 0.03) and LAEF deteriorated (35 ± 11 to 31 ± 10%, p = 0.04). CONCLUSIONS: Successful ablative treatment of atrial fibrillation is associated with reverse left atrial remodeling and improvement of left atrial and ventricular function. In patients with a BMI ≥ 30 or left ventricular hypertrophy, further left atrial enlargement occurs despite successful outcome.

Atrial fibrillation ablation strategies and outcome in patients with heart failure: insights from the German ablation registry.

BACKGROUND: Heart failure (HF) and atrial fibrillation (AF) often coexist, but data on the prognostic value of differing ablation strategies according to left ventricular ejection fraction (LVEF) are rare. METHODS AND RESULTS: From January 2007 until January 2010, 728 patients with HF were enrolled in the multi-center German ablation registry prior to AF catheter ablation. Patients were divided into three groups according to LVEF: HF with preserved LVEF (≥ 50%, HFpEF, n = 333), mid-range LVEF (40-49%, HFmrEF, n = 207), and reduced LVEF (< 40%, HFrEF, n = 188). Ablation strategies differed significantly between the three groups with the majority of patients with HFpEF (83.4%) and HFmrEF (78.4%) undergoing circumferential pulmonary vein isolation vs. 48.9% of patients with HFrEF. The latter underwent ablation of the atrioventricular (AV) node in 47.3%. Major complications did not differ between the groups. Kaplan-Meier survival analysis demonstrated a significant mortality increase in patients with HFrEF (6.1% in HFrEF vs. 1.5% in HFmrEF vs. 1.9% in HFpEF, p = 0.009) that was limited to patients undergoing ablation of the AV node. CONCLUSIONS: Catheter ablation strategies differ significantly in patients with HFpEF, HFmrEF, and HFrEF. In almost 50% of patients with HFrEF AV-node ablation was performed, going along with a significant increase in mortality rate. These results should raise efforts to further evaluate the prognostic effect of ablation strategies in HF patients.

Clinical impact of repolarization changes in supine versus upright body position.

BACKGROUND: The impact of postural changes on various electrocardiography (ECG) characteristics has only been assessed in a few small studies. This large prospective trial was conducted to confirm or refute preliminary data and add important results with immediate impact on daily clinical practice. METHODS: ECGs in supine and upright position from 1028 patients were analyzed. Evaluation was made according to changes in T-wave vector and direction, ST-segment deviation, heart rate, QT interval and QTc interval was performed. Findings were correlated with the medical history of patients. RESULTS: Positional change from supine to upright resulted in a significantly increased heart rate (8.05 ± 7.71 bpm) and a significantly increased QTc interval after Bazetts (18 ± 23.45 ms) and Fridericas (8.84 ± 17.30) formula. In the upright position significantly more T-waves turned negative (14.7%) than positive (5.7%). ST elevation was recorded in only 0.4% and ST depression in not more than 0.2% of all patients. CONCLUSIONS: The majority of the patients do not show significant morphological changes in their ECG by changing the body position from supine to upright. Changes of QTc time instead, are significant and the interval might be overestimated in upright. Therefore assessment of the QTc interval should strictly be done in a supine position.

German ablation registry: Cryoballoon vs. radiofrequency ablation in paroxysmal atrial fibrillation--One-year outcome data.

BACKGROUND: Although radiofrequency (RF) ablation has long been the standard of care for atrial fibrillation (AF) ablation, cryoballoon technology has emerged as a feasible approach with promising results. Prospective multicenter registry data referring to both ablation technologies in AF ablation are lacking so far. OBJECTIVE: The purpose of this study was to report data from the German ablation registry with respect to efficacy and safety in pulmonary vein ablation with different energy sources for paroxysmal AF after 1-year follow-up. METHODS: A total of 2306 patients with symptomatic paroxysmal AF from the German ablation registry were included in this analysis. The cohort was divided into two groups according to the ablation energy source used: cryoballoon and RF ablation. MACCE was defined as a combination of death, myocardial infarction, or stroke. RESULTS: AF recurrence rate after a single ablation procedure at 1 year follow-up was not significantly different between the two groups (45.8% after cryoablation and 45.4% after RF ablation, P = .87). Also, the rate of patients without AF recurrence and free of antiarrhythmic drug at 12-month follow-up was similar (cryoablation 44.2% and RF 41.4%, P = .25). MACCE occurred with an incidence of 0.7% within 500 days after cryoablation and 1.4% after RF ablation (P = .30). Persistent phrenic nerve palsy was more common after cryoablation compared to RF ablation (1.1% vs. 0.3%, P <.05). CONCLUSION: AF recurrence rate at 1-year follow-up was similar in RF ablation compared to cryoablation, whereas the spectrum and relevance of complications were significantly different between the two ablation methods. This finding might influence the choice of ablation method offered to the individual paroxysmal AF patient.

Fast atrial activity predicts recurrence of atrial fibrillation after pulmonary vein isolation: results from a prospective randomized study.

BACKGROUND: Recurrence of atrial fibrillation (AF) after ablative treatment is common. We hypothesized that AF recurrence is heralded by fast ectopic atrial activity occurring after electrical reconnection of previously isolated pulmonary veins. METHODS: Patients with paroxysmal or persistent AF undergoing pulmonary vein isolation (PVI) were followed up by 24-h Holter monitoring every 3 months for the first year and every 6 months thereafter. Antiarrhythmic drugs were withdrawn after a blanking period of 4 weeks for paroxysmal and 3 months for persistent AF. Ectopic atrial activity was defined as a burden of atrial extrasystoles >5% of the total QRS number. Fast atrial activity was present if mean cycle length of ectopic atrial activity was shorter than 50% of the mean cycle length of sinus rhythm in the last ten heartbeats. Patients with symptomatic fast atrial activity but without AF recurrence were randomized to undergo a second PVI procedure or resume antiarrhythmic medication. During follow-up, a 24-h Holter recording was performed every 3 months. Additionally, a 7-day external loop recording was performed in every pt with palpitations and no AF or ectopic atrial activity in the 24-h Holter. RESULTS: One hundred twenty-four pts with AF (88 paroxysmal, 36 persistent) developed fast atrial activity 6 ± 3 months after PVI. Twenty-two pts were asymptomatic and eight pts refused randomization. Ninety-four pts (61 men, age 57 ± 12 years) were randomized to either receive a second PVI procedure (group I, 48 pts) or antiarrhythmic medication (group II, 46 pts). Re-PVI in group I was performed 10 ± 8 months after the first PVI. During a follow-up of 20 ± 6 months, 11 pts of group I (23%) and 43 pts of group II (93%) had recurrence of AF. The mean time of AF recurrence after appearance of fast atrial activity was 4 ± 2 in group I and 5 ± 3 months in group II. CONCLUSIONS: In patients with atrial fibrillation and after the first PVI procedure, appearance of symptomatic fast atrial activity is associated with a high risk of AF recurrence. Re-isolation of reconnected pulmonary veins in these pts significantly reduces the risk of AF recurrence.

Three-dimensional rotational venography of the coronary sinus tree facilitates left ventricular lead implantation for CRT.

BACKGROUND: Precise knowledge of the coronary sinus (CS) tree anatomy facilitates catheter-based intubation of the CS, target vein and lead selection and reduces the need for fluoroscopy, contrast medium and overall procedure time in cardiac resynchronization therapy (CRT). Three-dimensional rotational angiography (3DRA) provides a new means of multiangle imaging of the CS tree that can be applied preoperatively. PURPOSE AND METHODS: Our study aims to investigate the feasibility of preoperative rotational CS venography and its implications for CRT device implantation procedures. For this purpose, CS visualization was done either conventionally with retrograde CS venography and standard fluoroscopic views (SFV, n = 30), or with antegrade CS imaging via contrast medium injection into the left coronary artery using 3DRA in the venous phase of contrast flow (3DRA, n = 30). RESULTS: 3DRA successfully identified the posterior and left marginal veins in 92% of patients and allowed target vein visualization in 86%. Additional retrograde venography was necessary in four patients (14%). Fluoroscopy time and contrast medium administration for stable CS intubation were lower in the group with 3DRA than in those with SFV (all p < 0.05). The time for CS lead placement after guiding catheter intubation was 8.9 ± 5.5 min in the 3DRA group versus 14.7 ± 7.4 min in SFV patients (p < 0.05). Consequently, total fluoroscopy time (-12.1 min), volume of contrast medium (-29.5 ml) and overall procedure time (-32.8 min) were significantly lower in 3DRA than in SFV patients (p < 0.05). CONCLUSION: 3DRA offers reliable multiangle visualization of the CS anatomy and facilitates successful CRT lead implantation.

Second generation of cryoballoons can improve efficiency of cryoablation for atrial fibrillation.

BACKGROUND: We investigated whether the new second generation of cryoballoons can improve the efficiency and safety of cryoablation for atrial fibrillation (AF) during ablation and in terms of outcome. METHODS: Data of AF patients consecutively treated with a single 28-mm cryoballoon were analyzed. Patients were divided into two groups: the G1 group was treated with the first-generation cryoballoons (ArcticFront) and G2 with the second generation (ArcticFront Advance). Failure of cryoablation treatment was defined as detection of an episode of AF, atrial flutter, or atrial tachycardia lasting ≥ 30 seconds during 3-month follow-up. Left atrial diameter (LAD) was measured by transthoracic echocardiography before cryoablation. RESULTS: One hundred twenty-five patients (group G1/G2: 57/68) were enrolled. Mean total time of the whole procedure, cryomapping, and cryoablation was shorter with G2 than with G1 (P < 0.05). No complication occurred with G1 whereas with G2 the complication rate was 8.8%. During mean 12 ± 4 months follow-up, the overall success rate of cryoablation was 76.0% (95/125); it was higher with G2 (89.7% [61/68] vs 59.7% [34/57], P < 0.001). Patients in whom treatment failed had larger LAD (48 ± 8 mm vs 44 ± 6 mm, P = 0.002) than those in whom it succeeded. Type of cryoballoon (relative risk [RR] = 5.75 [2.16, 15.27], P < 0.0001) and LAD (RR = 0.90 [0.83, 0.97], P = 0.0043) were shown in multivariable analysis to be individually related to the difference in success rate. CONCLUSION: Ablation for AF with the new generation of cryoballoons is associated with higher success rate of pulmonary vein isolation and better outcome. However, more complications occurred during the early stage of application of the G2 cryoballoon.

Prolonged ablation on critical segments of pulmonary vein ostia in paroxysmal atrial fibrillation: a prospective randomized controlled study.

INTRODUCTION: Electrical reconnection of the pulmonary veins (PVs) plays a key role in the recurrence of atrial fibrillation (AF) after ablative treatment. This randomized controlled study tested the hypothesis that prolonged ablations, on areas that may be critical for left atrial (LA)-PV conduction, can significantly reduce the rate of acute PV reconnection and AF recurrence. METHODS: Patients with paroxysmal AF were randomly assigned to either a control or an add-on group.Ostial PV isolation (PVI) was performed by point-to-point RF ablation (irrigated tip, 30 Watts, 30 seconds).An ostial segment was assumed to be critical for LA-PV connection if any of the following reactions occurred during RF application: (1) sudden delay of LA-PV conduction, (2) change of activation sequence,and (3) PVI. In this case, RF application was prolonged from 30 seconds to 90 seconds in the add-on group only. RESULTS: A total of 131 patients (58 ± 11 years, 47 female) were assigned to a control (n = 64) and an add-on (n = 67) group. Ablation time was longer in the add-on (48 ± 16 minutes vs 37 ± 15 minutes, P = 0.03). Acute PV reconnection was observed in 20 of 64 controls and in eight of 66 add-on patients (31% vs 12%, P < 0.001). During a follow-up of 26 months, AF recurred in 33 of 64 controls and in 16 of 66 add-on patients (52% vs 24%, P = 0.001) after a single ablation procedure. CONCLUSIONS: Prolonged radiofrequency application on critical segments of LA-PV connection is a safe and effective ablative strategy that significantly reduces acute PV reconnection and AF recurrence rates after a single ablation procedure for paroxysmal AF.

Precordial electrode placement for optimal ECG monitoring: implications for ambulatory monitor devices and event recorders.

INTRODUCTION: Detection of QRS complexes, P-waves and atrial fibrillation f-waves in electrocardiographic (ECG) signals is critical for the correct diagnosis of arrhythmias. We aimed to find the best bipolar lead (BL) with the highest signal amplitude and shortest inter-electrode spacing. METHODS: ECG signals (120 seconds) were recorded in 36 patients with 16 precordial electrodes placed in a standardized pattern. An average signal was analysed for each of 120 possible BLs obtained by calculating the difference between pairs of unipolar leads. Peak-to-peak amplitudes of QRS waves (50ms around R-peak) and P waves (270-70ms before R-peak) were calculated. For patients with atrial fibrillation, power of the fibrillatory (f) wave was used instead. Maximum values at each distance were considered and differentiation analysis was performed based on incremental changes (amplitude to distance). RESULTS: There was a significant correlation between distance and QRS-amplitude (r=0.78, p<0.001), P-wave amplitude (r=0.60, p<0.01) and f-wave power (r=0.79, p<0.001). The range of values was: QRS-amplitude 0.7-2.33mV, P-wave amplitude 0.07-0.18mV, and f-wave power 0.55-2.12mV(2)/s. The maximum value for the shortest distance was on a heart-aligned axis over the left ventricle for the QRS complex (1.9mV at 8.7cm) and over the atria for the P-wave (0.98mV) and f-waves (1.45mV(2)/s at 8cm, respectively). CONCLUSION: There is a strong positive correlation between electrode distance and ECG signal-amplitude. Distance of 8cm on a heart-aligned axis and over the relevant heart-chamber provides the highest signal amplitude for the shortest distance. These findings are essential for the design and use of ambulatory monitoring devices.

Combined use of three-dimensional rotational angiogram of left atrium and circular multi-electrode ablation catheter for pulmonary vein isolation.

BACKGROUND: A novel circular pulmonary vein ablation catheter (PVAC) has been introduced for pulmonary vein isolation (PVI). Accurate delineation of left atrium-pulmonary vein (LA-PV) anatomy is important for this technique. The aim of this study was to test whether the 3-dimensional rotational angiography (3D RTA) of the left atrium can facilitate PVI using PVAC technique. METHODS: Twenty patients with paroxysmal atrial fibrillation (AF) were enrolled in this study. The 3D RTA was reconstructed and registered with live fluoroscopy in all the patients. AF ablation was performed with a PVAC catheter in the navigation of registered 3D RTA. RESULTS: The 3DRTA image was successfully reconstructed and registered with live fluoroscopy in all patients (100%). The LA-PV anatomy was delineated clearly in all patients. Navigation of the PVAC inside the registered 3D RTA, ensured accurate placement within the atrium to perform ablation, and the PVAC was correctly placed inside the PV ostium to verify the PVI. All the PVs were isolated. Total procedural time was (87.5 ± 12.1) minutes, and fluoroscopy time was (20.1 ± 6.3) minutes. Follow-up after (7.1 ± 1.5) months showed freedom from AF in 70% (14/20) patients. No PV stenosis was observed. CONCLUSIONS: Intraprocedure reconstructed and registered 3D RTA can clearly delineate the LA-PV anatomy in real-time. The results demonstrate the feasibility and reliability of combining use of 3DRA and PVAC in AF ablation procedures.

Predictive value of left atrial volume measured by non-invasive cardiac imaging in the treatment of paroxysmal atrial fibrillation.

PURPOSE: We investigate the role of left atrial volume (LAV) as a predictor of outcome following pulmonary vein isolation (PVI) in patients with exclusive paroxysmal atrial fibrillation (AF). METHODS: PVI was performed in 213 patients (80 females, aged 60 ± 10 years) with paroxysmal AF using either the pulmonary vein ablation catheter (PVAC, n = 78) or conventional single-tip ablation (n = 135). LAV was assessed by multi-detector computed tomography (n = 39) or cardiac magnetic resonance imaging (n = 174) prior to ablation. LA diameter (LAD) and LA area were determined by echocardiography. Patients were followed up for 12 months clinically and with 72-h Holter ECG. RESULTS: The mean LAV was 85 ± 28 ml (range, 22-189 ml). Mean LAD and mean LA area were 43 ± 6 mm and 23 ± 6 cm². After a follow-up period of 18 ± 5 months, 202 patients were analyzed. AF recurrence was documented in 50 (23%) patients. Univariate analysis showed age (59 ± 11 vs. 65 ± 6 years, p = 0.049), LA area (23 ± 5 vs. 27 ± 6 cm², p = 0.03), and LAV (80 ± 27 vs. 96 ± 28 ml, p = 0.04) to be significantly associated with the outcome. Multivariate analysis revealed that none of these parameters were statistically significant (hazards ratio LAV, 0.52-1.12, p = 0.058; LA area, 0.63-1.14, p = 0.069; and age, 0.90-1.09, p = 0.41). In the case of AF recurrence, patients with LAV >95 ml showed a significantly higher probability for the occurrence of persistent AF (24% vs. 8%, p = 0.02). CONCLUSIONS: The assessment of LA size should not be incorporated as a main factor with regard to predicted ablation success in patients with paroxysmal AF being considered for PVI, as PVI may be successful even with considerable LA enlargement. Ablation should be performed promptly in patients with LAV ≤ 95 ml to prevent further LA dilatation, as patients with LAV >95 ml have an increased probability to develop persistent AF in the case of ablation failure.

Characteristic changes of volume and three-dimensional structure of the left atrium in different forms of atrial fibrillation: predictive value after ablative treatment.

INTRODUCTION: Atrial fibrillation (AF) is associated with electroanatomical remodelling of the left atrium (LA), especially with LA dilatation. However, little is known about the changes of the three-dimensional structure of the LA, regarding the type of atrial fibrillation and their prognostic value after an ablative treatment. METHODS: One hundred fifteen patients (72 males, 59 ± 11 years) with an indication for AF ablation were prospectively included. Preoperatively, all patients underwent cardiac computed tomography (CCT). A reconstruction of the LA and the pulmonary veins (PV) was made from CCT data using specialized software (EP PreNavigator, Philips, The Netherlands). Left atrial volume (LAV) after exclusion of the atrial appendage (LAA) and the PV was determined. The LA was then arbitrarily divided by a cutting plane, between the anterior segment of the PV ostia and the atrial appendage and parallel to the posterior wall, to anterior-(LA-Ant.) and posterior-LA (LA-Post.). The ratio LA-Ant./LAV was defined as asymmetry index (ASI). The cardiac CT data, of 25 patients (11 women, 47 ± 11 years) without organic heart disease, were similarly studied for the same parameters, as a control group. RESULTS: Patients with paroxysmal AF (n = 63) had significantly higher LAV (131 ± 31 vs. 95 ± 18 ml, p < 0.001) and higher ASI (61 ± 6 % vs. 57 ± 4, p = 0.002) than the control group. Patients with persistent AF (n = 34) in comparison with paroxysmal AF showed significantly larger volumes (154 ± 44 vs. 131 ± 31 ml, p = 0.007) but no difference in the ASI (60 ± 8% vs. 61 ± 6%, p = 0.63). Finally, patients with long-term persistent AF (n = 18) showed a bigger asymmetry index than the patients with persistent AF (64 ± 5% vs. 60 ± 8%, p = 0.06) but no significant difference in volumes (161 ± 21 vs. 154 ± 44 ml, p = 0.49). LAA and partial LA volumes had a dilatation pattern similar to LAV. During a follow-up of over 25 ± 7 months, AF recurred in 31 (27%) patients. Multivariate analysis showed that ASI and LAV were the only two significant predictors of AF recurrence after ablative treatment. Independent of LAV, an ASI over 60% predicted AF recurrence with 74% sensitivity and 73% specificity. CONCLUSION: Characteristic differences of both left atrial volume and geometry exist between the different forms of atrial fibrillation (paroxysmal, persistent and long-term persistent). The asymmetry index is a simple parameter derived by cardiac CT data that reflects these changes of LA geometry and predicts the outcome after the pulmonary vein isolation.