Genetic Characterization of Extensively Drug-Resistant Shigella sonnei Infections, Spain, 2021-2022.

In 2022, the United Kingdom reported an increase in drug resistance in Shigella sonnei isolates. We report 33 cases in Spain genetically related to the UK cases and 4 cases with similar antimicrobial resistance profiles infected with genetically distant strains. Our results suggest circulation of multiple genetic clusters of multidrug-resistant S. sonnei in Spain.

High-power and short-duration ablation for pulmonary vein isolation: Safety, efficacy, and long-term durability.

INTRODUCTION: PV reconnection is often the result of catheter instability and tissue edema. High-power short-duration (HP-SD) ablation strategies have been shown to improve atrial linear continuity in acute pre-clinical models. This study compares the safety, efficacy, and long-term durability of HP-SD ablation with conventional ablation. METHODS AND RESULTS: In 6 swine, 2 ablation lines were performed anterior and posterior to the crista terminalis, in the smooth and trabeculated right atrium, respectively; and the right superior PV was isolated. In 3 swine, ablation was performed using conventional parameters (Thermocool-Smarttouch® SF; 30 W/30 seconds) and in 3 other swine using HP-SD parameters (QDOT-MICRO™, 90 W/4 seconds). After 30 days, linear integrity was examined by voltage mapping and pacing, and the heart and surrounding tissues were examined by histopathology. Acute line integrity was achieved with both ablation strategies; however, HP-SD ablation required 80% less RF time compared with conventional ablation (P ≤ 0.01 for all lines). Chronic line integrity was higher with HP-SD ablation: all 3 posterior lines were continuous and transmural compared to only 1 line created by conventional ablation. In the trabeculated tissue, HP-SD ablation lesions were wider and of similar depth with 1 of 3 lines being continuous compared to 0 of 3 using conventional ablation. Chronic PVI without stenosis was evident in both groups. There were no steam-pops. Pleural markings were present in both strategies, but parenchymal lung injury was only evident with conventional ablation. CONCLUSIONS: HP-SD ablation strategy results in improved linear continuity, shorter ablation time, and a safety profile comparable to conventional ablation.

Incidence and risk factors for symptomatic heart failure after catheter ablation of atrial fibrillation and atrial flutter.

AIMS: To determine the incidence and risk factors for development of symptomatic heart failure (HF) following catheter ablation for atrial fibrillation (AF) and atrial flutter. METHODS AND RESULTS: We prospectively enrolled consecutive patients undergoing pulmonary vein isolation (PVI) or cavotricuspid isthmus (CTI) ablation between November 2013 and June 2014. Post-discharge symptoms were assessed via telephone follow-up and clinic visits. The primary outcome was symptomatic HF requiring treatment with new/increased diuretic dosing. Secondary outcomes were prolonged index hospitalization and readmission for HF ≤30 days. Univariate and multivariable logistic regressions were used to assess the relationship between patient/procedural characteristic and post-ablation HF. Among 111 PVI patients [median age 62.0 years; left ventricular ejection fraction (LVEF) 55%], 29 patients (26.1%) developed symptomatic HF, 6 patients (5.4%) required prolonged index hospitalization, and 8 patients (7.2%) were readmitted for HF. In univariate analyses, persistent AF [odds ratio (OR) 2.97, P = 0.02], AF at start of the procedure (OR 2.99, P = 0.01), additional ablation lines (OR 11.07, P < 0.0001), and final left atrial pressure (OR 1.10 per 1 mmHg increase, P = 0.02) were associated with HF development. Peri-procedural diuresis, net fluid balance, and LVEF were not correlated. In multivariable analyses, only additional ablation lines (ORadj 9.17, P = 0.007) were independently associated with post-ablation HF. Six patients (16.7%) developed HF after CTI ablation. CONCLUSION: A 26.1% of patients undergoing PVI and 16.7% of patients undergoing CTI ablation developed symptomatic HF when prospectively and uniformly assessed. 12.6% of patients experienced prolonged index hospitalizations or readmission for management of HF within 1 week after PVI. Improved understanding of risk factors for post-ablation HF may be critical in developing strategies to address during AF ablation.

How we implemented a resident-led medical simulation curriculum in a large internal medicine residency program.

Mannequin-based simulation in graduate medical education has gained widespread acceptance. Its use in non-procedural training within internal medicine (IM) remains scant, possibly due to the logistical barriers to implementation of simulation curricula in large residency programs. We report the Massachusetts General Hospital Department of Medicine's scale-up of a voluntary pilot program to a mandatory longitudinal simulation curriculum in a large IM residency program (n = 54). We utilized an eight-case curriculum implemented over the first four months of the academic year. An intensive care unit curriculum was piloted in the spring. In order to administer a comprehensive curriculum in a large residency program where faculty resources are limited, thirty second-year and third-year residents served as session facilitators and two senior residents served as chairpersons of the program. Post-session anonymous survey revealed high learner satisfaction scores for the mandatory program, similar to those of the voluntary pilot program. Most interns believed the sessions should continue to be mandatory. Utilizing residents as volunteer facilitators and program leaders allowed the implementation of a well-received mandatory simulation program in a large IM residency program and facilitated program sustainability.

Multi-sensor esophageal temperature probe used during radiofrequency ablation for atrial fibrillation is associated with increased intraluminal temperature detection and increased risk of esophageal injury compared to single-sensor probe.

BACKGROUND: Radiofrequency (RF) ablation in the posterior left atrium has risk of thermal injury to the adjacent esophagus. Increased intraluminal esophageal temperature has been correlated with risk of esophageal injury. The objective of this study was to compare esophageal temperature monitoring (ETM) using a multi-sensor temperature probe with 12 sensors to a single-sensor probe during catheter ablation for atrial fibrillation (AF). METHODS AND RESULTS: We compared the detection of intraluminal esophageal temperature rises in 543 patients undergoing RF ablation for AF with ETM. Esophageal endoscopy (EGD) was performed on all patients with maximum esophageal temperature ≥ 39°C. Esophageal lesions were classified by severity as mild or severe ulcerations. Four hundred fifty-five patients underwent RF ablation with single-sensor ETM and 88 patients with multi-sensor ETM. Thirty-nine percent of patients with single-sensor versus 75% with multi-sensor ETM reached a maximum detected esophageal temperature ≥ 39°C (P < 0.0001). Esophageal injury was detected by EGD in 29% of patients with maximum temperature ≥ 39°C by single-sensor versus 46% of patients with multi-sensor ETM (P = 0.021). Thirty-nine percent of patients with lesions in the single-sensor probe group had severe ulcerations compared to 33% of patients in the multi-sensor probe group (P = 0.641). CONCLUSIONS: Intraluminal esophageal temperature ≥ 39°C is detected more frequently by the multi-sensor temperature probe versus the single-sensor probe, with more frequent esophageal injury and with comparable severity of injury. Despite detecting esophageal temperature rises in more patients, the multi-sensor probe may not have any measurable benefit compared to a single-sensor probe.

Post-COVID-19 syndrome: Descriptive analysis based on a survivors' cohort in Colombia.

Background: The prevalence of post-COVID-19 Syndrome (PCS) is estimated to be between 10% and 20%. The main reported symptoms are fatigue, memory alterations, dyspnea, sleep disorders, arthralgia, anxiety, taste alterations, coughing and depression. This study aims to determine the prevalence of post-COVID-19 symptoms in a group of Colombian patients who were recruited during their outpatient appointments. Methodology: This cross-sectional study was conducted between December 2021 to May 2022. It included patients from outpatient facilities located in five main cities in Colombia who were positive for SARS-CoV-2 infection detected by reverse transcription-polymerase chain reaction (RT-PCR) testing and reported PCS in the following 12 weeks after their COVID-19 diagnosis. Results: A total of 1047 individuals >18 years old met the inclusion criteria and were included in the study. The median age was 46 years old. 68.2% of the participants were female, 41.5% of the patients reported having a pre-existent condition (hypertension, anxiety disorder, diabetes, hyperthyroidism, obesity and asthma). Only 22% had received at least one dose of COVID-19 vaccine prior to the COVID-19 episode registered. The more prevalent symptoms within our group are described as follows: fatigue (53.3%), dyspnea (40.3%), arthralgia and/or myalgia (43%), cephalea (40.5%), sleep disorders (35.7%) and coughing (31.3%). 72% of the patients presented four or more post-COVID 19 symptoms, 9% two symptoms, and 10% only one symptom. Conclusion: The findings of this study are consistent with international literature publicly available. The distribution and prevalence of post-COVID symptoms highlight the importance of further research to improve understanding and its potential consequences and implications in terms of quality of life and health care planning services.

COVID-19 Associated Pulmonary Aspergillosis (CAPA): Hospital or Home Environment as a Source of Life-Threatening Aspergillus fumigatus Infection?

Most cases of invasive aspergillosis are caused by Aspergillus fumigatus, whose conidia are ubiquitous in the environment. Additionally, in indoor environments, such as houses or hospitals, conidia are frequently detected too. Hospital-acquired aspergillosis is usually associated with airborne fungal contamination of the hospital air, especially after building construction events. A. fumigatus strain typing can fulfill many needs both in clinical settings and otherwise. The high incidence of aspergillosis in COVID patients from our hospital, made us wonder if they were hospital-acquired aspergillosis. The purpose of this study was to evaluate whether the hospital environment was the source of aspergillosis infection in CAPA patients, admitted to the Hospital Universitario Central de Asturias, during the first and second wave of the COVID-19 pandemic, or whether it was community-acquired aspergillosis before admission. During 2020, sixty-nine A. fumigatus strains were collected for this study: 59 were clinical isolates from 28 COVID-19 patients, and 10 strains were environmentally isolated from seven hospital rooms and intensive care units. A diagnosis of pulmonary aspergillosis was based on the ECCM/ISHAM criteria. Strains were genotyped by PCR amplification and sequencing of a panel of four hypervariable tandem repeats within exons of surface protein coding genes (TRESPERG). A total of seven genotypes among the 10 environmental strains and 28 genotypes among the 59 clinical strains were identified. Genotyping revealed that only one environmental A. fumigatus from UCI 5 (box 54) isolated in October (30 October 2020) and one A. fumigatus isolated from a COVID-19 patient admitted in Pneumology (Room 532-B) in November (24 November 2020) had the same genotype, but there was a significant difference in time and location. There was also no relationship in time and location between similar A. fumigatus genotypes of patients. The global A. fumigatus, environmental and clinical isolates, showed a wide diversity of genotypes. To our knowledge, this is the first study monitoring and genotyping A. fumigatus isolates obtained from hospital air and COVID-19 patients, admitted with aspergillosis, during one year. Our work shows that patients do not acquire A. fumigatus in the hospital. This proves that COVID-associated aspergillosis in our hospital is not a nosocomial infection, but supports the hypothesis of "community aspergillosis" acquisition outside the hospital, having the home environment (pandemic period at home) as the main suspected focus of infection.

Odometry and laser scanner fusion based on a discrete extended Kalman Filter for robotic platooning guidance.

This paper describes a relative localization system used to achieve the navigation of a convoy of robotic units in indoor environments. This positioning system is carried out fusing two sensorial sources: (a) an odometric system and (b) a laser scanner together with artificial landmarks located on top of the units. The laser source allows one to compensate the cumulative error inherent to dead-reckoning; whereas the odometry source provides less pose uncertainty in short trajectories. A discrete Extended Kalman Filter, customized for this application, is used in order to accomplish this aim under real time constraints. Different experimental results with a convoy of Pioneer P3-DX units tracking non-linear trajectories are shown. The paper shows that a simple setup based on low cost laser range systems and robot built-in odometry sensors is able to give a high degree of robustness and accuracy to the relative localization problem of convoy units for indoor applications.

Elevated temperature and browning increase dietary methylmercury, but decrease essential fatty acids at the base of lake food webs.

Climate change scenarios predict increases in temperature and organic matter supply from land to water, which affect trophic transfer of nutrients and contaminants in aquatic food webs. How essential nutrients, such as polyunsaturated fatty acids (PUFA), and potentially toxic contaminants, such as methylmercury (MeHg), at the base of aquatic food webs will be affected under climate change scenarios, remains unclear. The objective of this outdoor mesocosm study was to examine how increased water temperature and terrestrially-derived dissolved organic matter supply (tDOM; i.e., lake browning), and the interaction of both, will influence MeHg and PUFA in organisms at the base of food webs (i.e. seston; the most edible plankton size for zooplankton) in subalpine lake ecosystems. The interaction of higher temperature and tDOM increased the burden of MeHg in seston (< 40 µm) and larger sized plankton (microplankton; 40-200 µm), while the MeHg content per unit biomass remained stable. However, PUFA decreased in seston, but increased in microplankton, consisting mainly of filamentous algae, which are less readily bioavailable to zooplankton. We revealed elevated dietary exposure to MeHg, yet decreased supply of dietary PUFA to aquatic consumers with increasing temperature and tDOM supply. This experimental study provides evidence that the overall food quality at the base of aquatic food webs deteriorates during ongoing climate change scenarios by increasing the supply of toxic MeHg and lowering the dietary access to essential nutrients of consumers at higher trophic levels.

Molecular diagnostic of syphilis. / Diagnóstico molecular de la sífilis.

Syphilis is a sexually transmitted infection caused by Treponema pallidum subsp. pallidum with an increasing incidence in Spain and in the rest of the world. Diagnosis is based mainly on serology, since direct diagnosis by dark field microscopy presents difficulties that limit its widespread use. Molecular biology techniques can be a useful tool for diagnosis in primary and secondary syphilis, although not all types of samples show the same behaviour. These techniques are also useful for the diagnosis of congenital syphilis. They are not recommended, however, for neurosyphilis, due to the low sensitivity of polymerase chain reaction in cerebrospinal fluid. These techniques have been used to study the controversial origin of syphilis, and, through the enhanced Centers for Disease Control method, to perform typing, which helps to elucidate the epidemiology of this infection. Finally, molecular techniques can detect mutations related to macrolide resistance, which are present in a very high percentage of infections.

Prevalence of Undiagnosed Sleep Apnea in Patients With Atrial Fibrillation and its Impact on Therapy.

OBJECTIVES: This study sought to evaluate the proportion of patients with atrial fibrillation (AF) who also have undiagnosed sleep apnea and examine the impact of its diagnosis on adherence to sleep apnea therapies. BACKGROUND: Sleep apnea is a modifiable risk factor for AF. However, the proportion of patients with AF who also have undiagnosed sleep apnea and the impact of its diagnosis on therapy have not been well studied. METHODS: This prospective study included 188 consecutive patients with AF without a prior diagnosis of sleep apnea who were scheduled to undergo AF ablation. Participants underwent home sleep apnea testing, completed a sleep apnea screening questionnaire (STOP-BANG [Snoring; Tiredness, Fatigue, or Sleepiness During the Daytime; Observation of Apnea and/or Choking During Sleep; Hypertension; Body Mass Index >35 kg/m2; Age >50 Years; Neck Circumference >40 cm; and Male Sex]) and were followed for ≥2 years to evaluate the impact of diagnosis on therapy. RESULTS: Home sleep apnea testing was positive in 155 of 188 patients (82.4%); among those 155, 127 (82%) had a predominant obstructive component and 28 (18%) had mixed sleep apnea with a 15.2 ± 7.4% central component. Sleep apnea severity was mild in 43.8%, moderate in 32.9%, and severe in 23.2%. The sensitivity and specificity of a STOP-BANG questionnaire were 81.2% and 42.4%, respectively. In a multivariate analysis, STOP-BANG was not predictive for sleep apnea (odds ratio: 0.54; 95% confidence interval: 0.17 to 1.76; p = 0.31). Therapy with continuous positive airway pressure ventilators was initiated in 73 of 85 patients (85.9%) with moderate or severe sleep apnea, and 68 of the 73 patients (93.1%) remained complaint after a mean follow-up period of 21 ± 6.2 months. CONCLUSIONS: Sleep apnea is exceedingly prevalent in patients with AF who are referred for ablation, with a large proportion being undiagnosed due the limited predictive value of sleep apnea symptoms in this AF population. Screening for sleep apnea resulted in high rate of long-term continuous positive airway pressure adherence.

[Strongyloides stercoralis infestation in an immunocompetent 82-year-old woman]. / Infestación por Strongyloides stercoralis en una paciente de 82 años inmunocompetente.

A laboratory finding of eosinophilia in patients with gastrointestinal symptoms should prompt the differential diagnosis of a parasitosis. The diagnosis is based on identification of larvae in three different stool samples. We report the case of an 82-year-old woman who was independent for instrumental and advanced activities of daily living and showed no risk factors for strongyloidiasis who was admitted to our service with diarrhoea and abdominal pain. Blood examination showed peripheral eosinophilia of 38%. Stool sample revealed Strongyloides stercoralis. In the patient's case history, we found similar clinical features with fluctuating eosinophilia over the previous 8 years. The patient was treated with albendazole, resulting in clinical improvement and elimination of eosinophilia.

High-Power and Short-Duration Ablation for Pulmonary Vein Isolation: Biophysical Characterization.

OBJECTIVES: This study sought to examine the biophysical properties of high-power and short-duration (HP-SD) radiofrequency ablation for pulmonary vein isolation. BACKGROUND: Pulmonary vein isolation is the cornerstone of atrial fibrillation ablation. However, pulmonary vein reconnection is frequent and is often the result of catheter instability, tissue edema, and a reversible nontransmural injury. We postulated that HP-SD ablation increases lesion-to-lesion uniformity and transmurality. METHODS: This study included 20 swine and a novel open-irrigated ablation catheter with a thermocouple system able to record temperature at the catheter-tissue interface (QDOT Micro Catheter). Step 1 compared 3 HP-SD ablation settings: 90 W/4 s, 90 W/6 s, and 70 W/8 s in a thigh muscle preparation. Ablation at 90 W/4 s was identified as the best compromise between lesion size and safety parameters, with no steam-pop or char. In step 2, a total of 174 single ablation applications were performed in the beating heart and resulted in 3 (1.7%) steam-pops, all occurring at catheter-tissue interface temperature ≥85°C. Additional 233 applications at 90 W/4 s and temperature limit of 65°C were applied without steam-pop. Step 3 compared the presence of gaps and lesion transmurality in atrial lines and pulmonary vein isolation between HP-SD (90 W/4 s, T ≤65°C) and standard (25 W/20 s) ablation. RESULTS: HP-SD ablation resulted in 100% contiguous lines with all transmural lesions, whereas standard ablation had linear gaps in 25% and partial thickness lesions in 29%. Ablation with HP-SD produced wider lesions (6.02 ± 0.2 mm vs. 4.43 ± 1.0 mm; p = 0.003) at similar depth (3.58 ± 0.3 mm vs. 3.53 ± 0.6 mm; p = 0.81) and improved lesion-to-lesion uniformity with comparable safety end points. CONCLUSIONS: In a preclinical model, HP-SD ablation (90 W/4 s, T ≤65°C) produced an improved lesion-to-lesion uniformity, linear contiguity, and transmurality at a similar safety profile of conventional ablation.

Infarct-Related Ventricular Tachycardia: Redefining the Electrophysiological Substrate of the Isthmus During Sinus Rhythm.

OBJECTIVES: In this study, the scientific objective was to characterize the electrophysiological substrate of the ventricular tachycardia (VT) isthmus during sinus rhythm. BACKGROUND: The authors have recently described the electrophysiological characteristics of the VT isthmus using a novel in vivo high-resolution mapping technology. METHODS: Sixteen swine with healed infarction were studied using high-resolution mapping technology (Rhythmia, Boston Scientific, Cambridge, Massachusetts) in a closed-chest model. The left ventricle was mapped during sinus rhythm and analyzed for activation, conduction velocity, electrogram shape, and amplitude. Twenty-four VTs allowed detailed mapping of the common-channel "isthmus," including the "critical zone." This was defined as the zone of maximal conduction velocity slowing in the circuit, often occurring at entrance and exit from the isthmus caused by rapid angular change in activation vectors. RESULTS: The VT isthmus corresponded to sites displaying steep activation gradient (SAG) during sinus rhythm with conduction velocity slowing of 58.5 ± 22.4% (positive predictive value [PPV] 60%). The VT critical zone displayed SAG with greater conduction velocity slowing of 68.6 ± 18.2% (PPV 70%). Critical-zone sites were consistently localized in areas with bipolar voltage ≤0.55 mV, whereas isthmus sites were localized in areas with variable voltage amplitude (1.05 ± 0.80 mV [0.03 to 2.88 mV]). Importantly, critical zones served as common-site "anchors" for multiple VT configurations and cycle lengths. Isthmus and critical-zone sites occupied only 18.0 ± 7.0% of the low-voltage area (≤1.50 mV). Isolated late potentials were present in both isthmus and nonisthmus sites, including dead-end pathways (PPV 36%; 95% confidence interval: 34.2% to 39.6%). CONCLUSIONS: The VT critical zone corresponds to a location characterized by SAG and very low voltage amplitude during sinus rhythm. Thus, it allows identification of a re-entry anchor with high sensitivity and specificity. By contrast, voltage and electrogram characteristics during sinus rhythm have limited specificity for identifying the VT isthmus.

Activation Mapping With Integration of Vector and Velocity Information Improves the Ability to Identify the Mechanism and Location of Complex Scar-Related Atrial Tachycardias.

BACKGROUND: Activation mapping of scar-related atrial tachycardias (ATs) can be difficult to interpret because of inaccurate time annotation of complex electrograms and passive diastolic activity. We examined whether integration of a vector map can help to describe patterns of propagation to better explain the mechanism and location of ATs. METHODS: The investigational mapping algorithm calculates vectors and applies physiological constraints of electrical excitation in human atrial tissue to determine the arrhythmia source and circuit. Phase I consisted of retrospective evaluation in 35 patients with ATs. Phase II consisted of prospective validation in 20 patients with ATs. Macroreentry was defined as a continuous propagation in a circular path >30 mm; localized reentry was defined as a circular path ≤30 mm; a focal source had a centrifugal spread from a point source. RESULTS: In phase I, standard activation mapping identified 28 of 40 ATs (70%): 25 macroreentry and 3 focal tachycardias. In the remaining 12 ATs, the mechanism and location could not be identified by activation and required entrainment or empirical ablation for termination (radiofrequency time, 17.3±6.6 minutes). In comparison, the investigational algorithm identified 37 of 40 (92.5%) ATs, including 5 macroreentry, 3 localized reentry, and 1 focal AT not identified by standard mapping. It also predicted the successful termination site of all 37 of 40 ATs. In phase II, the investigational algorithm identified 12 macroreentry, 6 localized reentry, and 2 focal tachycardias that all terminated with limited ablation (3.2±1.7 minutes). It identified 3 macroreentry, 3 localized reentry, and 1 focal AT not well characterized by standard mapping. The diagnosis of localized reentry was supported by highly curved vectors, resetting with increasing curve and termination with limited ablation (22±6 s). CONCLUSIONS: Activation mapping integrating vectors can help determine the arrhythmia mechanism and identify its critical components. It has particular value for identifying complex macroreentrant circuits and for differentiating a focal source from a localized reentry.

Evaluation of ablation catheter technology: Comparison between thigh preparation model and an in vivo beating heart.

BACKGROUND: An in vivo animal thigh model is the standard technique for evaluation of ablation catheter technologies, including efficacy and safety of ablation. However, the biophysics of ablation in a thigh model may not be similar to a beating heart. OBJECTIVE: The purpose of this study was to compare efficacy and safety of ablation between a thigh preparation model and a beating heart. METHODS: In 7 swine, radiofrequency ablation using a 3.5-mm open irrigated catheter (ThermoCool Smart Touch) was performed sequentially in a thigh muscle and in vivo beating ventricles. Ablation was performed at low (30 W for 40 s) and high (40 W for 60 s) energy settings and at similar contact force. Ablation lesions were scanned in high resolution and measured using electronic calipers. RESULTS: A total of 152 radiofrequency ablation lesions were measured (86 thigh and 66 heart). At low energy, lesion width was greater in the thigh model (12.19 ± 1.8 mm vs 8.99 ± 2.1 mm; P <.001), whereas lesion depth was similar between the thigh and heart (5.71 ± 0.8 mm vs 5.95 ± 1.3 mm, respectively; P = .18). The planar cross-sectional lesion area was greater in the thigh model (thigh 54.8 ± 10.8 mm2 vs heart 43.1 ± 16.1 mm2; P <.001). At the high-energy setting, lesion depth, width, and area were all greater in the thigh model (thigh 91.5 ± 16.8 mm2 vs heart 56.0 ± 15.5 mm2; P <.001). The incidence of steam pop and char formation was similar between the models. CONCLUSION: The thigh preparation model is a reasonable technique for evaluation of ablation catheter technology; however it often results in overestimation of lesion size, especially at higher energy settings.

Atrial Substrate and Triggers of Paroxysmal Atrial Fibrillation in Patients With Obstructive Sleep Apnea.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with atrial remodeling, atrial fibrillation (AF), and increased incidence of arrhythmia recurrence after pulmonary vein (PV) isolation. We aimed to characterize the atrial substrate, including AF triggers in patients with paroxysmal AF and OSA. METHODS AND RESULTS: In 86 patients with paroxysmal AF (43 with ≥moderate OSA [apnea-hypopnea index ≥15] and 43 without OSA [apnea-hypopnea index <5]), right atrial and left atrial voltage distribution, conduction velocities, and electrogram characteristics were analyzed during atrial pacing. AF triggers were examined before and after PV isolation and targeted for ablation. Patients with OSA had lower atrial voltage amplitude (right atrial, P=0.0005; left atrial, P=0.0001), slower conduction velocities (right atrial, P=0.02; left atrial, P=0.0002), and higher prevalence of electrogram fractionation (P=0.0001). The areas of atrial abnormality were consistent among patients, most commonly involving the left atrial septum (32/43; 74.4%). At baseline, the PVs were the most frequent triggers for AF in both groups; however, after PV isolation patients with OSA had increased incidence of additional extra-PV triggers (41.8% versus 11.6%; P=0.003). The 1-year arrhythmia-free survival was similar between patients with and without OSA (83.7% and 81.4%, respectively; P=0.59). In comparison, control patients with paroxysmal AF and OSA who underwent PV isolation alone without ablation on extra-PV triggers had increased risk of arrhythmia recurrence (83.7% versus 64.0%; P=0.003). CONCLUSIONS: OSA is associated with structural and functional atrial remodeling and increased incidence of extra-PV triggers. Elimination of these triggers resulted in improved arrhythmia-free survival.

Evaluation of a novel high-resolution mapping technology for ablation of recurrent scar-related atrial tachycardias.

BACKGROUND: Rhythmia is a new technology capable of rapid and high-resolution mapping. However, its potential advantage over existing technologies in mapping complex scar-related atrial tachycardias (ATs) has not yet been evaluated. OBJECTIVE: The purpose of this study was to examine the utility of Rhythmia for mapping scar-related ATs in patients who had failed previous ablation procedure(s). METHODS: This multicenter study included 20 patients with recurrent ATs within 2 years after a previous ablation procedure (1.8 ± 0.7 per patient). In all cases, the ATs could not be adequately mapped during the index procedure because of scar with fractionated electrograms, precluding accurate time annotation, frequent change in the tachycardia in response to pacing, and/or degeneration into atrial fibrillation. These patients underwent repeat mapping and ablation procedure with Rhythmia. RESULTS: From a total of 28 inducible ATs, 24 were successfully mapped. Eighteen ATs (75%) terminated during radiofrequency ablation and 4 (16.6%) with catheter pressure or entrainment from the site of origin or isthmus. Two ATs that were mapped to the interatrial septum slowed but did not terminate with ablation. In 21 of 24 ATs the mechanism was macroreentry, while in 3 of 24 the mechanism was focal. Interestingly, in 5 patients with previously failed ablation of an allegedly "focal" tachycardia, high-resolution mapping demonstrated macroreentrant arrhythmia. The mean mapping time was 28.6 ± 17 minutes, and the mean radiofrequency ablation time to arrhythmia termination was 3.2 ± 2.6 minutes. During a mean follow-up of 7.5 ± 3.1 months, 15 of 20 patients (75%) were free of AT recurrences. CONCLUSION: The Rhythmia mapping system may be advantageous for mapping complex scar-related ATs.