Mobile health applications for the detection of atrial fibrillation: a systematic review.

AIMS: Atrial fibrillation (AF) is the most common sustained arrhythmia and an important risk factor for stroke and heart failure. We aimed to conduct a systematic review of the literature and summarize the performance of mobile health (mHealth) devices in diagnosing and screening for AF. METHODS AND RESULTS: We conducted a systematic search of MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials. Forty-three studies met the inclusion criteria and were divided into two groups: 28 studies aimed at validating smart devices for AF diagnosis, and 15 studies used smart devices to screen for AF. Evaluated technologies included smartphones, with photoplethysmographic (PPG) pulse waveform measurement or accelerometer sensors, smartbands, external electrodes that can provide a smartphone single-lead electrocardiogram (iECG), such as AliveCor, Zenicor and MyDiagnostick, and earlobe monitor. The accuracy of these devices depended on the technology and the population, AliveCor and smartphone PPG sensors being the most frequent systems analysed. The iECG provided by AliveCor demonstrated a sensitivity and specificity between 66.7% and 98.5% and 99.4% and 99.0%, respectively. The PPG sensors detected AF with a sensitivity of 85.0-100% and a specificity of 93.5-99.0%. The incidence of newly diagnosed arrhythmia ranged from 0.12% in a healthy population to 8% among hospitalized patients. CONCLUSION: Although the evidence for clinical effectiveness is limited, these devices may be useful in detecting AF. While mHealth is growing in popularity, its clinical, economic, and policy implications merit further investigation. More head-to-head comparisons between mHealth and medical devices are needed to establish their comparative effectiveness.

Ultrasound-guided axillary vein puncture for cardiac devices implantation in patients under antithrombotic therapy.

BACKGROUND: Ultrasound-guided axillary venous puncture (UGAVP) for cardiac devices implantation has been developed because of its rapidity, safety and potential long-term lead protection. Early work excluded defibrillators (ICD), cardiac resynchronization therapy (CRT) and upgrade procedures. Compared to the cephalic approach, in previous studies, there was a greater use of pressure dressings with this technique, suggesting a higher risk of bleeding. AIMS: To assess UGAVP in patients under antithrombotic therapy (ATT) undergoing cardiac devices implantation including CRT/ICD. METHODS: Prospectively, consecutive patients eligible for a pacemaker or ICD implantation were included. All procedures were performed by a single operator, experienced with UGAVP for femoral access, and fluoroscopy-guided axillary vein access. Guidewires insertion time (from lidocaïne administration), and complications were systematically studied. RESULTS: From 457 cardiac device implantations, 200 patients (77.8 ± 10 y, male 58%) 360 leads were implanted by UGAVP including 36 ICD, 54 CRT and 14 upgrade procedures. A majority (90%) was under ATT: Vitamin K Antagonist or Heparin (n = 58, 29%), direct oral anticoagulant (n = 46, 23%), dual antithrombotic therapy (n = 18, 9%) and single antiplatelet drug (n = 82, 41%). UGAVP was successful in 95.78%. Mean insertion time for 1.8 guidewires per patient was 4.68 ± 3.6 min. No complication (no hematoma) was observed during the follow-up (mean of 45 ± 10 months). Guidewires insertion time reached its plateau after 15 patients. CONCLUSION: UGAVP is fast, feasible and safe for patients under ATT undergoing device implantation including CRT/ICD and upgrade procedures, with a short learning curve.

Scar identification, quantification, and characterization in complex atrial tachycardia: a path to targeted ablation?

Successful catheter ablation of scar-related atrial tachycardia depends on correct identification of the critical isthmus. Often, this is a represented by a small bundle of viable conducting tissue within a low-voltage area. It's identification depends on the magnitude of the signal/noise ratio. Ultra-high density mapping, multipolar catheters with small (eventually unidirectional) and closely-spaced electrodes improves low-voltage electrogram detection. Background noise limitation is also of major importance for improving the signal/noise ratio. Electrophysiological properties of the critical isthmus and the characteristics of the local bipolar electrograms have been recently demonstrated as hallmarks of successful ablation sites in the setting of scar-related atrial tachycardia.

Safety and long-term effectiveness of paroxysmal atrial fibrillation ablation with a contact force-sensing catheter: real-world experience from a prospective, multicentre observational cohort registry.

Aims: Real-time contact force (CF)-sensing radiofrequency ablation catheter for treatment of paroxysmal atrial fibrillation (PAF) allows optimization of electrode-tissue contact, which correlates with long-term success. This prospective, multicentre observational registry assessed the real-world clinical effectiveness of a CF-sensing catheter for ablation of drug-refractory PAF. Methods and results: Patients were followed-up at 3, 6, and 12 months after ablation. Outcome measures included isolation of targeted pulmonary veins (PVs) confirmed by entrance block (acute success), patient-reported freedom from symptomatic atrial fibrillation (AF) at 12 months (long-term effectiveness), Atrial Fibrillation Effect on Quality-of-life scores at 6 and 12 months, and incidence of predefined procedural complications. The registry enrolled 261 PAF patients (mean age 58.8 ± 11.3 years; 70.7% men; 91.7% Caucasian). Acute PV isolation was reported in 98.8% of patients [95% confidence interval (CI): 96.4-99.7%], and 12-month success for freedom from symptomatic AF was 75.7% (95% CI: 69.7-80.7%). Average CF for the evaluable cohort was 16.4 ± 3.9 g. There was a significant correlation between long-term effectiveness and stability of CF use [percentage of time CF was within investigator-selected working range; odds ratio (95% Wald CI), 1.0 (1.00-1.1); P = 0.030]. Average CF did not correlate with 12-month success. Clinically meaningful quality of life (QoL) improvements were observed at 6 and 12 months. Primary adverse events occurred in 2.7% patients. Conclusion: This observational registry showed that PAF ablation with a CF-sensing catheter had high acute success rates, favourable 12-month outcomes, and a good safety profile. Patients' QoL improved significantly. Long-term effectiveness significantly correlated with stable CF with adequate catheter-tissue contact (NCT01677052).

Radiofrequency catheter ablation of atrial fibrillation: Electrical modification suggesting transmurality is faster achieved with remote magnetic catheter in comparison with contact force use.

BACKGROUND: Remote magnetic navigation (RMN) and contact force (CF) sensing catheters are available technologies for radiofrequency (RF) catheter ablation of atrial fibrillation (AF). Our purpose was to compare time to electrogram (EGM) modification suggesting transmural lesions between RMN and CF-guided AF ablation. METHODS AND RESULTS: A total of 1,008 RF applications were analyzed in 21 patients undergoing RMN (n = 11) or CF-guided ablation (n = 10) for paroxysmal AF. All procedures were performed in sinus rhythm during general anesthesia. Time to EGM modification was measured until transmurality criteria were fulfilled: (1) complete disappearance of R if initial QR morphology; (2) diminution > 75% of R if initial QRS morphology; (3) complete disappearance of R' of initial RSR' morphology. Impedance drop as well as force time integral (FTI) were also assessed for each application. Mean CF at the beginning of each RF application in the CF group was 11 ± 2 g and mean FTI per application was 488 ± 163 gs. Time to EGM modification was significantly shorter in the RMN group (4.52 ± 0.1 seconds vs. 5.6 ± 0.09 seconds; P < 0.00001). There was no significant difference between other procedural parameters. CONCLUSION: Remote magnetic AF ablation is associated with faster EGM modification suggesting transmurality than optimized CF and FTI-guided catheter ablation.

Electroanatomic characteristics of the mitral isthmus associated with successful mitral isthmus ablation.

AIMS: The success of mitral isthmus (MI) ablation has been related to CT scan defined MI anatomy. We sought to correlate electroanatomical MI characteristics with MI ablation success in patients with perimitral flutter (PMF). METHODS AND RESULTS: In 53 consecutive patients (46 males, 61 ± 10 years) with PMF, MI was ablated with endocardial ± coronary sinus (CS) linear radiofrequency (RF) ablation lesion. Acute (termination of PMF during ablation) and long-term procedural success were studied. Mitral isthmus characteristics (thickness--minimal endocardial to CS distance, length, maximal MI bipolar voltage), as well as MI ablation line length and width, RF duration, and delivered energy were analysed. In 43 of the 53 patients (81%), acute success was observed. This was more frequently achieved in patients with thinner MI (2.4 ± 3.1 vs. 7 ± 3.2 mm; P = 0.0009). Mitral isthmus thickness predicted ablation failure with a ROC area of 0.84. The best threshold to predict MI ablation failure was 8.3 mm with a sensitivity of 67% and a specificity of 97%. Left atrial size was of greater importance in failed cases (2D echo surface: 24.1 ± 2.5 vs. 32.5 ± 6.9 cm2, P = 0.005; electroanatomic volume: 124 ± 32 vs. 165 ± 23 mL, P = 0.02). None of the other electroanatomical characteristics were associated with outcome. After a mean follow-up of 28 ± 15 months, 21 patients (39%) had atrial fibrillation (AF) or atypical flutter (PMF recurrence in four). CONCLUSION: Smaller MI thickness is associated with acute success in PMF ablation. Mitral isthmus electroanatomical characteristics might be used for decision-making on strategy during persistent AF ablation and for selecting the best location for interrupting PMF.

Pacemakers implantation and radiofrequency catheter ablation procedures during medical missions in Morocco: an 8-year experience.

AIMS: Radiofrequency catheter ablation (RFCA) for arrhythmias in the context of short-term medical missions (MM) in a developing country has not been reported so far. We describe here our experience with RFCA and pacemaker implantation in Morocco with a fully portable electrophysiological (EP) system under the auspice of the Monaco-Morocco Cardiology Association. METHODS AND RESULTS: Since November 2007, two to three MM (mean duration 4 days including transportation) per year were conducted (including two physicians and one nurse from Monaco) and were alternately located in Marrakech, Fes, Agadir, Casablanca, Rabat, Essaouira, and Oujda. All patients' files were sent by local teams and/or referring Moroccan cardiologists before MM. Each case was discussed with the Monaco EP team before the MM. Pacemakers and leads were donated by companies (Sorin Group, Medtronic, Saint-Jude Medical). The EP system (EP Tracer, CardioTek) as well as diagnostic/ablation catheters were brought for RFCA procedures. After the procedures, follow-up was performed by local teams. Procedures took place in gynaecological or orthopaedic operating room, or, when available, in the interventional cardiology cathlab. Thirty-one RFCA were performed during 11 MM (atrioventricular node re-entrant tachycardia = 12; atrioventricular re-entrant tachycardia/Mahaïm fibre = 15; typical atrial flutter = 3; ventricular ectopy = 1). Acute success was 93.5% for RFCA. Two major RFCA-related complications occurred (air embolism and complete atrioventricular block). No complication was related to pacemaker implantations (n = 44; mean 4 pacemakers per mission). CONCLUSION: Radiofrequency catheter ablation for arrhythmias in developing countries is technically challenging but feasible, despite technical and cultural difficulties.

Ultra-High-Definition Mapping of Atrial Arrhythmias.

The advantages of ultra-high-definition (UHD) mapping are presented in the context of different atrial arrhythmias, whether focal or macroreentrant. Not only are these sophisticated systems time-saving, but they also allow accurate identification of the substrate (scar quantification), as well as a more precise characterization of the critical isthmuses or focal sources of the atrial circuits. UHD mapping may become a standard approach for their curative treatment. This new technology allows automatic acquisition and accurate annotation of the electrograms, without the need for manual correction. Owing to better resolution, critical isthmuses and low-voltage regions of interest may now be successfully targeted without the need for entrainment maneuvers. Finally, the system also allows rapid assessment of the completeness of the lesions once delivered. (Circ J 2016; 80: 579-586).

Atrial flutter: more than just one of a kind.

Since its first description about one century ago, our understanding of atrial flutter (AFL) circuits has considerably evolved. One AFL circuit can have variable electrocardiographic (ECG) manifestations depending on the presence of pre-existing atrial lesions, or impaired atrial substrate. Conversely, different (right sided or even left sided) atrial circuits including different mechanisms (macroreentrant, microreentrant, or focal) can present with a very similar surface ECG manifestation. The development of efficient high-resolution electroanatomical mapping systems has improved our knowledge about AFL mechanisms, as well as facilitated their curative treatment with radiofrequency catheter ablation. This article will review ECG features for typical and atypical flutters, and emphasize the limitations for circuit location from the surface ECG.

Remotely controlled steerable sheath improves result and procedural parameters of atrial fibrillation ablation with magnetic navigation.

AIMS: The magnetic navigation (MN) system may be coupled with a new advancement system that fully controls both the catheter and a robotic deflectable sheath (RSh) or with a fixed-curve sheath and a catheter-only advancement system (CAS). We aimed to compare these approaches for atrial fibrillation (AF) ablation. METHODS AND RESULTS: Atrial fibrillation ablation patients (45, 23 paroxysmal and 22 persistent) performed with MN-RSh (RSh group) were compared with a control group (37, 18 paroxysmal and19 persistent) performed with MN-CAS (CAS group). Setup duration was measured from the procedure's start to operator transfer to control room. Ablation step duration was defined as the time from the beginning of the first radiofrequency (RF) pulse to the end of the last one and was separately acquired for the left and the right pulmonary vein (PV) pairs. Clinical characteristics, left atrial size, and AF-type distribution were similar between the groups. Setup duration as well as mapping times was also similar. Ablation step duration for the left PVs was similar, but was shorter for the right PVs in RSh group (46 ± 9 vs. 63 ± 12 min, P < 0.0001). Radiofrequency delivery time (34 ± 9 vs. 40 ± 11 min, P = 0.007) and procedure duration (227 ± 36 vs. 254 ± 62 min, P = 0.01) were shorter in RSh group. No complication occurred in RSh group. During follow-up, there were five recurrences (11%) in RSh group and 11 (29%) in CAS group (P = 0.027). CONCLUSION: The use of the RSh for AF ablation with MN is safe and improves outcome. Right PV isolation is faster, RF delivery time and procedure time are reduced.

Comparison between radiofrequency with contact force-sensing and second-generation cryoballoon for paroxysmal atrial fibrillation catheter ablation: a multicentre European evaluation.

AIMS: Whether pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) using contact force (CF)-guided radiofrequency (RF) or second-generation cryoballoon (CB) present similar efficacy and safety remains uncertain. METHODS AND RESULTS: We performed a multicentre study comparing procedural safety and arrhythmia recurrence after standardized PVI catheter ablation for PAF using CF-guided RF ablation (Thermocool(®) SmartTouch™, Biosense Webster; or Tacticath™, St Jude Medical) (CF group) with second-generation CB ablation (Arctic Front Advance™, Medtronic) (CB group). Overall, 376 patients (mean age 59.8 ± 10.4 years, 280 males) were enrolled in 4 centres: 198 in CF group and 178 in CB group. Procedure was shorter for CB group than for CF group (109.6 ± 40 vs. 122.5 ± 40.7 min, P = 0.003), but fluoroscopy duration and X-ray exposure were not statistically different (P = 0.1 and P = 0.22, respectively). Overall complication rate was similar in both groups: 14 (7.1%) in the CF group vs. 13 (7.3%) in the CB group (P = 0.93). However, transient right phrenic nerve palsy occurred only in CB group (10 patients, 5.6%; P = 0.001 vs. CF group) and severe non-lethal complications (embolic event, tamponade, or oesophageal injury) occurred only in CF group (5 patients, 2.5%; P = 0.03 vs. CB group). No periprocedural death occurred in either group. Single-procedure freedom from any atrial arrhythmias at 18 months post-ablation was comparable in CF group and CB group (76 vs. 73.3%, respectively, log rank P = 0.63). CONCLUSION: Pulmonary vein isolation using CF-guided RF and second-generation CB leads to comparable single-procedure arrhythmia-free survival at up to 18 months with similar overall complication rate.

General anesthesia is not superior to local anesthesia for remote magnetic ablation of atrial fibrillation.

BACKGROUND: Remote magnetic navigation is an emerging technology for atrial fibrillation (AF) ablation. General anesthesia (GA) has shown to be superior to local anesthesia (LA) for manual AF ablation in terms of catheter stability and lesion formation. We aimed at comparing GA with LA for remote magnetic AF ablation procedures. METHODS: All patients eligible for a remote magnetic ablation of AF were included in this study. Ninety patients (70% of the patients were male; age: 60 ± 10 years; CHA2 DS2 -VASC : 1.6 ± 1.2; paroxysmal AF: 60%, persistent AF: 40%), including 45 patients with GA, and 45 patients with LA were enrolled consecutively. RESULTS: There was no significant difference in total procedure time between the two groups (237 ± 50 minutes in the GA group vs 240 ± 61 minutes in the LA group; P = 0.84). Fluoroscopy time was significantly increased in the GA group (14.6 ± 6 minutes vs 11.6 ± 6 minutes, P = 0.018). Ablation time was not different between the two groups (2,320 ± 984 seconds in the GA group vs 2,055 ± 1,023 seconds in the LA group; P = 0.25). After a mean follow-up of 1 year (including repeat procedures), 39/45 patients (86.6%) within the GA group were free from recurrences versus 40/45 patients (88.8%) in the LA group (P = 0.74) without antiarrhythmic drugs. CONCLUSION: For remote magnetic AF ablation, procedures under LA have similar results to GA in terms of efficacy and safety after 1-year follow-up.

Contact force and force-time integral in atrial radiofrequency ablation predict transmurality of lesions.

AIMS: During radiofrequency (RF) delivery, lesion volume is highly dependent on contact force (CF). It has recently been shown that changes of bipolar electrogram (EGM) predict transmurality. We hypothesized that there is a correlation between CF and EGM criteria of transmural lesion (TL) during RF. METHODS AND RESULTS: We prospectively studied consecutive 512 RF applications from atrial fibrillation ablation procedures. A force-sensing ablation catheter (Tacticath(®), Endosense) was used to continuously measure CF and force-time integral (FTI) during each RF application. Distal bipolar EGM was analysed before, during, and after each RF application. Depending on initial EGM morphology, transmurality of lesions was defined by: (i) disappearance of the positivity after RF when there was QR morphology, (ii) diminution >75% of the positivity when there was QRS morphology, or (iii) disappearance of the R' positivity when there was RSR' morphology. Electrogram criteria were validated by electrophysiologists blinded to force measurements. Force-time integral was higher in TL than in non-transmural lesions (NTLs): 652 ± 248 vs. 212 ± 140 gs (P < 0.001). Mean CF per RF pulse was higher in TL than in NTL: 26.3 ± 12.5 vs. 11.3 ± 10.3 g (P < 0.001). The best cut-off to predict TL was an FTI ≥ 392 gs [sensitivity 0.89, specificity (Sp) 0.93, positive predictive value (PPV) 0.98, and negative predictive value 0.67] and a higher FTI (>700 gs) warrants transmurality of RF atrial lesions (100% Sp and PPV). CONCLUSION: Contact force and FTI during RF are correlated with TL. During RF delivery, a target FTI > 392 gs can be used as an endpoint.

Ultrasound-guided venous puncture in electrophysiological procedures: a safe method, rapidly learned.

BACKGROUND: We sought to determine the feasibility and learning curve associated with systematic use of real-time ultrasound-guided venous puncture (UGVP) in patients undergoing electrophysiological (EP) procedures. METHODS: Four operators performed UGVP in consecutive patients undergoing EP procedures (group I). Puncture time was defined as the time from ultrasound (US) visualization of the femoral vein to the insertion of all sheaths. A learning curve as defined by UGVP evolution over the time was established for each operator. This population was compared to an historical group of patients in whom venous puncture was performed without US (group II). RESULTS: A total of 150 patients per group were included. UGVP was successfully achieved in all patients. Mean time for 2.8 ± 0.7 sheaths per patient insertion was 280 ± 151 seconds in group I. There was one minor vascular complication (VC) out of 150 patients (0.66%) without major VC in group I as compared with group II (2% major VC and 4.6% minor VC; P < 0.05). UGVP time reached a plateau at the sixth patient-case for each operator; thus, learning curve was estimated to six patients. CONCLUSION: UGVP is a short learning curve technique, significantly associated with a low incidence of minor VCs. This study supports wide use of UGVP in patients undergoing EP procedures.

Distinct Substrates of Idiopathic Ventricular Fibrillation Revealed by Arrhythmia Characteristics on Implantable Cardioverter-Defibrillator.

BACKGROUND: Idiopathic ventricular fibrillation (IVF) can be associated with undetected distinct conditions such as microstructural cardiomyopathic alterations (MiCM) or Purkinje (Purk) activities with structurally normal hearts. OBJECTIVE: This study sought to evaluate the characteristics of recurrent VF recorded on implantable defibrillator electrograms, associated with these substrates. METHODS: This was a multicenter collaboration study. At 32 centers, we selected patients with an initial diagnosis of IVF and recurrent arrhythmia at follow-up without antiarrhythmic drugs, in whom mapping demonstrated Purk or MiCM substrate. We analyzed variables related to previous ectopy, sinus rate preceding VF, trigger, and initial VF cycle lengths. Logistic regression with cross validation was used to evaluate the performance of criteria to discriminate Purk or MiCM substrates. RESULTS: Among 95 patients (35 women, age 35 ± 11 years) meeting the inclusion criteria, IVF was associated with MiCM in 41 and Purk in 54 patients. A total of 117 arrhythmia recurrences including 91% VF were recorded on defibrillator. Three variables were mostly discriminant. Sinus tachycardia (≤570 ms) was more frequent in MiCM (35.9% vs 13.4%, P = 0.014) whereas short-coupled (<350 ms) triggers were most frequent in Purk-related VF (95.5% vs 23.1%, P = 0.001), which also had shorter VFCLs (182 ± 15 ms vs 215 ± 24 ms, P < 0.001).The multivariable combination provided the highest prediction (accuracy = 0.93 ± 0.05, range 0.833-1.000), discriminating 81% of IVF substrates with a high probability (>80%). Ectopy were inconsistently present before VF. CONCLUSIONS: Characteristics of arrhythmia recurrences on implantable cardioverter- defibrillator provide phenotypic markers of the distinct and hidden substrates underlying IVF. These findings have significant clinical and genetic implications.

Characteristics of recurrent clockwise atrial flutter after previous radiofrequency catheter ablation for counterclockwise isthmus-dependent atrial flutter.

AIMS: Isthmus-dependent (ID) clockwise (CW) atrial flutters (AFl) are rare in comparison with counterclockwise (CCW) AFl. Little is known about clinical and electrophysiological characteristics of CW AFl occurring after previous radiofrequency (RF) catheter ablation of CCW AFl. We sought to compare CW AFl de novo vs. CW AFl occurring after previous CCW AFl RF ablation. METHODS AND RESULTS: A total of 246 procedures of RF catheter ablation for AFl from January 2009 to January 2011 were reviewed. Clinical and electrophysiological data were analysed. Patients were excluded if they were in sinus rhythm at the beginning of the procedure, if they had concomitant/previous atrial fibrillation ablation, or if AFl was not ID. Twenty-seven patients presented CW AFl (10.9% of all ID AFl), including 10 CW AFl occurring after a previous RF catheter ablation for CCW AFl. Mean time for recurrence after the previous procedure of CCW AFl RF ablation was 3.5 years. They were younger (61.6 ± 11 years) than patients with CW AFl de novo (74.0 ± 7.2 years; P = 0.005). Bidirectional isthmus block was obtained in all patients. There was a significant difference in terms of double potential separation after ablation (155 ± 31 ms for CW AFl de novo vs. 111 ± 7 ms for recurrent CW AFl; P = 0.028). No differences were observed concerning CHADS score, AFl cycle length, and electrocardiogram typical pattern for CW AFl between the two groups. CONCLUSION: Patients with CW AFl occurrence after CCW AFl RF catheter ablation are younger than patients with CW AFl de novo. They also have a smaller interspike interval after block completion.