This study aimed to identify whether left atrial (LA) volume assessed by multidetector computed tomography (MDCT) is related to the long-term success of pulmonary vein ablation (PVA). MDCT is used to ...guide PVA for the treatment of atrial fibrillation (AF). MDCT permits accurate sizing of LA dimensions.
We analysed data from 368 ablation procedures of 279 consecutive patients referred for PVA due to drug-refractory symptomatic AF (age 62 ± 10; 58% men; 71% paroxysmal AF). Prior to the procedure, all patients underwent ECG-gated 64-MDCT scan for assessment of LA and PV anatomy, LA thrombus evaluation, LA volume estimation, and electroanatomical mapping integration. Within a mean follow-up of 356 ± 128 days, 64% of the patients maintained sinus rhythm after the initial ablation, and 84% when including repeat PVA. LA diameter (P = 0.004), LA volume (P = 0.002), and type of AF (P = 0.001) were independent predictors of AF recurrence in univariate analysis. There was a relatively low correlation between the echocardiographic LA diameter and LA volume from MDCT (P = 0.01, r = 0.5). In multivariate analysis, paroxysmal AF (P < 0.006) and LA volume below the median value of 106 mL (P = 0.042) were significantly associated with the success of PVA, whereas LA diameter was not (P = 0.245). Analysing receiver-operator characteristics, the area under the curve for LA volume was 0.73 (P = 0.001) compared with 0.60 (P = 0.09) for LA diameter from echocardiography.
LA volume assessed by MDCT is a better predictor of AF recurrence after PVA than echocardiograpic LA diameter and can be derived from the pre-procedural imaging data set.
Multidetector computed tomography (MDCT) is frequently used to guide circumferential pulmonary vein ablation (PVA) for treatment of atrial fibrillation (AF) as it offers accurate visualization of the ...left atrial (LA) and pulmonary vein (PV) anatomy. This study aimed to identify if PV anatomy is associated with outcomes following PVA using remote magnetic navigation (RMN).
We analysed data from 138 consecutive patients and 146 ablation procedures referred for PVA due to drug-refractory symptomatic AF (age 63 ± 11 years; 57% men; 69% paroxysmal AF). The RMN using the stereotaxis system and open-irrigated 3.5 mm ablation catheters was used in all procedures. Prior to PVA, all patients underwent electrocardiogram-gated 64-MDCT for assessment of LA dimensions, PV anatomy, and electro-anatomical image integration during the procedure. Regular PV anatomy was found in 68%, a common left PV ostium was detected in 26%, and variant anatomy of the right PVs was detected in 6%. After a mean follow-up of 337 ± 102 days, 63% of the patients maintained sinus rhythm after the initial ablation, and 83% when including repeat PVA. Although acutely successful PV isolation did not differ between anatomical subgroups (regular 3.5 ± 0.8 vs. variant 3.2 ± 1.3; P = 0.31), AF recurrence was significantly higher in patients with non-regular PV anatomy (P = 0.04, hazard ratio 1.72). Pulmonary vein anatomy did not influence complication rates.
Pulmonary vein anatomy assessed by MDCT is a good predictor of AF recurrence after PVA using RMN.
Aims
A relevant number of patients presenting for electrical cardioversion carry a pacemaker (PM) or ICD. Case reports suggest a potential hazard of external cardioversion/defibrillation. The ...incidence of shock related device complications is unknown. No guidelines or recommendations by international medical societies for a cardioversion protocol of cardiovascular implantable electronic device (CIED) patients exist. We conducted a nationwide survey to gather real-world clinical data on the current clinical approach towards these patients during electrical cardioversion and to estimate the incidence of shock-related complications.
Methods and results
Ninety hospitals with > 380 ECV in 2014 were identified from mandatory hospital quality reports and 60 were randomly selected. All centers were provided with a standardized questionnaire on the general proceedings and complications during electrical cardioversion of pacemaker, ICD and CRT patients (CIED patients). Thirty-two centers (53%) participated in the survey. In total, 16,554 ECV were reported (534 ± 314 per center). Biphasic cardioversion with a first shock energy of ≥ 150 J via adhesive patches in antero-posterior orientation was preferred by most centers (78%). Eleven percent (
n
= 1809) of pts were reported to carry a PM/ICD. The ECV protocol was heterogeneous among centers. Complications associated with electrical cardioversion were reported in 11/1809 patients (0.6%), all were transitory elevations of pacing thresholds.
Conclusions
In this nationwide snapshot survey of cardioversion procedures in Germany, approximately 11% of patients presenting for elective electrical cardioversion were pacemaker or ICD carriers. Cardioversion protocols in these patients are heterogeneous throughout centers and mostly not in accordance with recommendation of the German Cardiac Society. Complications associated with external electrical cardioversion are rare. Controlled trials and large registries are necessary to provide evidence for future recommendations.
Ventricular oversensing remains a significant problem in modern implantable cardioverter-defibrillator (ICD) systems. The role of manufacturer-related differences in device-based signal processing on ...the one hand and sensing lead properties on the other is largely unknown. This retrospective study aimed to evaluate and compare the incidence and mechanisms of ventricular oversensing in single- or dual-chamber ICD systems from Biotronik (BTK), Guidant (GDT), and Medtronic (MDT).
In 245 consecutive patients, device function, stored episodes, and lead parameters were evaluated at implant and during 243 ± 18 days of follow-up. Oversensing occurred in 3.3% of the patients four T-wave oversensing (TWO), three R-wave double-sensing, and one diaphragmatic myopotentials. The incidence of ventricular oversensing was generally low if an ICD device and an ICD lead were from one identical manufacturer (BTK: 2/68, GDT: 1/80, and MDT: 1/69; P = 0.67). In the subgroup of ICDs connected to leads from other manufacturers, however, ventricular oversensing was observed in none of 19 GDT and MDT ICDs but in 4 of 9 BTK devices (44.4%, P = 0.012). These four cases of oversensing (three R-wave double-sensing and one TWO) all occurred in BTK ICDs connected to integrated bipolar ICD leads from other manufacturers.
Significant manufacturer-related differences exist in the incidence of ventricular oversensing in single- and dual-chamber ICD systems. Biotronik devices connected to integrated bipolar ICD leads from other manufacturers have an increased risk for R-wave double-sensing.
Atrial fibrillation is the most common clinically relevant heart rhythm disorder and is associated with increased morbidity and mortality. Most important risk factors for atrial fibrillation are high ...age, arterial hypertension, diabetes mellitus, heart failure and rheumatic heart disease. Chronic atrial fibrillation is classified as paroxysmal, persistent, long-standing persistent and permanent atrial fibrillation. Spontaneous conversion to sinus rhythm is observed in paroxysmal atrial fibrillation, whereas in persistent atrial fibrillation, pharmacological or electrical cardioversion is required in order to restore sinus rhythm. In permanent atrial fibrillation, the arrythmia is accepted by patient and physician and cardioversion is not attempted. Rate control only is thus applied in permanent atrial fibrillation, whereas in paroxysmal and persistent atrial fibrillation, addition rhythm control with anti-arrhythmic drugs and/or ablation is attempted if symptoms persist and age and co-morbidities do not pose contra-indications. Besides rhythm management, oral anticoagulation is the mainstay of therapy for most patients with atrial fibrillation. Risk scores such as the CHA2DS2-VASc score help to identify patients with a high risk of stroke and need for oral anticoagulation. The underuse of vitamin K antagonists in clinical practise is partly due to considerable disadvantages: an increased bleeding risk, a narrow therapeutic window and multiple drug interactions prompting frequent laboratory controls to assess an individual dosage. New oral anticoagulants targeting thrombin (dabigatran) or factor Xa (rivaroxaban, apixaban and edoxaban) may replace warfarin in many patients with atrial fibrillation due to convincing data both on efficacy and safety as well as convenience. However, challenges remain with respect to lack of specific antidotes and high costs.
Evaluation of a new cardiac MDCT protocol using a split-bolus contrast injection protocol and single MDCT scan for reliable diagnosis of LA/LAA thrombi in comparison to TEE, optimizing radiation ...exposure and use of contrast agent.
A total of 182 consecutive patients with drug refractory AF scheduled for PVI (62.6 % male, mean age: 64.1 ± 10.2 years) underwent routine diagnostic work including TEE and cardiac MDCT for the evaluation of LA/LAA anatomy and thrombus formation between November 2010 and March 2012. Contrast media injection was split into a pre-bolus of 30 ml and main bolus of 70 ml iodinated contrast agent separated by a short time delay.
In this study, split-bolus cardiac MDCT identified 14 of 182 patients with filling defects of the LA/LAA. In all of these 14 patients, abnormalities were found in TEE. All 5 of the 14 patients with thrombus formation in cardiac MDCT were confirmed by TEE.
MDCT was 100 % accurate for thrombus, with strong but not perfect overall results for SEC equivalent on MDCT.
• Patients with no filling defect or thrombus in MDCT in the LA/LAA region are unlikely to have thrombus and may undergo PVI without TEE.• Here, the role of an additional TEE in pre-procedural management prior to PVI in patients with AF has to be redefined.• Using a split-bolus injection protocol increases the diagnostic accuracy of thrombus in the LA/LAA region.
Background: Inappropriate ICD therapy for supraventricular tachycardia (SVT) remains a significant problem. A morphology‐based algorithm (Wavelet™) compares baseline and tachycardia electrograms ...(EGM). For this analysis different EGM sources can be programmed. This study evaluates the performance of Wavelet using two different EGM configurations (SVC‐Can and RV‐Can) for the detection of exercise‐induced SVT.
Methods: Patients with a Medtronic model 7230 single chamber ICD and a dual coil lead were included. For each EGM source (SVC‐Can or RV‐Can), a baseline EGM template was acquired and the morphology similarity to this template (match percentage) was evaluated for 10–15 beats at different heart rates during exercise testing. The lower VT detection limit was programmed to 600 ms (therapies off).
Results: A total of 28 patients (66.9 ± 4.7 years, 93% men) and 5,824 intracardiac QRS complexes were analyzed. With the RV‐Can source, a consistently high similarity to the baseline EGM template was observed (≤100 bpm: 90.90 ± 0.56%; >100 bpm: 90.24 ± 0.55%, P > 0.05). In contrast, SVC‐Can was associated with a lower match percentage at baseline and a significant decrease at higher heart rates (≤100 bpm: 77.91 ± 2.65%; >100 bpm: 59.05 ± 5.65%, P < 0.005). Accordingly, the specificity for appropriate detection of exercise‐induced SVT was higher with RV‐Can (21/21 episodes) than with SVC‐Can (8/18 episodes, specificity 100% vs 44%; P < 0.0001).
Conclusion: The RV‐Can configuration appears to be superior to SVC‐Can as EGM source for appropriate SVT detection with the Wavelet algorithm.
Implantable cardioverter defibrillators (ICD) are used as standard therapy to prevent sudden cardiac death in heart failure patients. Today, physicians in emergency and intensive care medicine are ...often confronted with problems of ICD therapy in these patients. We report a case of a patient suffering from recurrent ventricular tachycardia (VT) requiring antiarrhythmia treatment with amiodarone. With an increasing drug loading, the VT cycle length was progressively prolonged resulting in a slow VT undetectable for the ICD. Subsequently, the patient was scheduled for VT ablation after which the patient became free of arrhythmia recurrences.
Chronic Atrial Dilation, Electrical Remodeling, and Atrial Fibrillation in the Goat
Hans-Ruprecht Neuberger, Ulrich Schotten, Yuri Blaauw, Dirk Vollmann, Sabine Eijsbouts, Arne van Hunnik, Maurits ...Allessie
Both electrical remodeling and dilation of the atria are known to promote atrial fibrillation (AF). However, little is known about the interaction between the two processes. In seven goats, complete atrioventricular block was made to induce chronic atrial dilation. In dilated atria, two days of AF still shortened the atrial refractory period (AERP) (electrical remodeling) and stabilized the arrhythmia. However, the median AF cycle length no longer followed the shortening in AERP, resulting in widening of the temporal excitable gap during AF. Mapping revealed a higher amount of intra-atrial conduction disturbances in dilated atria. These observations suggest a shift from functional to anatomic circuits during AF.
This study was designed to investigate the mutual effects of chronic atrial dilation and electrical remodeling on the characteristics of atrial fibrillation (AF).
Both electrical remodeling and atrial dilation promote the inducibility and perpetuation of AF.
In seven goats AF was induced during 48 h by burst pacing, both at baseline and after four weeks of slow idioventricular rhythm (total AV block). Atrial size and refractory period (AERP) were monitored together with the duration and cycle length of AF paroxysms (AFCL). After four weeks of total atrioventricular (AV) block, the conduction in both atria was mapped during AF. Six non-instrumented goats served as controls.
At baseline, AF-induced electrical remodeling shortened AERP and AFCL to the same extent (from 185 ± 9 ms to 149 ± 14 ms p < 0.05 and from 154 ± 11 ms to 121 ± 5 ms p < 0.05, respectively). After four weeks of AV block the right atrial diameter had increased by 13.2 ± 3.0% (p < 0.01). Surprisingly, in dilated atria electrical remodeling still shortened the AERP (from 165 ± 9 ms to 132 ± 15 ms p < 0.05) but failed to shorten the AFCL (140 ± 19 ms vs. 139 ± 11 ms p = 0.98). Mapping revealed a higher incidence of intra-atrial conduction delays during AF. Histologic analysis showed no atrial fibrosis but did reveal a positive correlation between the size of atrial myocytes and the incidence of intra-atrial conduction block (r = 0.60, p = 0.03).
In a goat model of chronic atrial dilation, AF-induced electrical remodeling was unchanged. However, AFCL no longer shortened during electrical remodeling. Thus, in dilated atria a wider excitable gap exists during AF, probably caused by intra-atrial conduction defects and a higher contribution of anatomically defined re-entrant circuits.
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