Structured versus free block play: the impact on arithmetic processing.

BACKGROUND: Block play is one type of intervention that improves visuospatial skills. There are multiple forms of block play and it is unclear whether they have differential cognitive effects. METHOD: Given the importance of visuospatial skills for mathematical performance, we studied the differential impact of two types of block playstructured (copying a block design) and free (building from imagination) on arithmetic processing, using behavioral and fMRI methods. Forty-three children aged 8.3±0.8 years participated (21 free play and 22 structured block play). RESULTS: Results showed that while both groups showed behavioral improvements, only the structured block play group showed significant improvements in both addition and subtraction performance. Additionally, the structured block play group showed increased activation in several regions linked to memory, motor, and arithmetic processing after training. CONCLUSION: The results inform choices for activities used in the classroom to improve visuospatial skills and suggest structured block play may be beneficial for arithmetic processing.

Left Atrial Strain Impairment Precedes Geometric Remodeling as a Marker of Post-Myocardial Infarction Diastolic Dysfunction.

OBJECTIVES: The aims of this study were to test the magnitude of agreement between echocardiography (echo)- and cardiac magnetic resonance (CMR)-derived left atrial (LA) strain and to study their relative diagnostic performance in discriminating diastolic dysfunction (DD) and predicting atrial fibrillation (AF). BACKGROUNDS: Peak atrial longitudinal strain (PALS) is a novel performance index. Utility of echo-quantified LA strain has yet to be prospectively tested in relation to current DD guidelines or compared to CMR. METHODS: The study population comprised 257 post-myocardial infarction (MI) patients undergoing echo and CMR, including prospective derivation (n = 157) and clinical validation (n = 100) cohorts. DD was graded on echo using established consensus guidelines blinded to strain results. RESULTS: PALS on both echo and CMR was nearly 2-fold lower among patients with versus no DD (p < 0.001) and was significantly different in those with mild versus no DD (p < 0.01). In contrast, LA geometric parameters including echo- and CMR-derived volumes were significantly different between advanced versus no DD groups (p < 0.001) but not between groups with mild versus no DD (all p > 0.05). Echo and CMR PALS yielded small differences irrespective of orientation and similar diagnostic performance for DD in the derivation (area under the curve [AUC]: 0.70 to 0.78) and validation (AUC: 0.75 to 0.78) cohorts. Impaired PALS on both modalities was independently associated with MI size (p < 0.001). During 4.4 ± 3.8 years of follow-up in the derivation cohort, 8% developed AF. Both 2-chamber echo- and CMR-derived PALS stratified arrhythmic risk (p = 0.004 and p = 0.02, respectively), including a 4-fold difference among patients in the lowest versus remainder of quartiles of echo-derived PALS (24% vs. 6%). Similarly, echo and CMR PALS were lower (both p < 0.05) among patients with subsequent heart failure hospitalizations. CONCLUSIONS: Echo-derived PALS parallels results of CMR, yields incremental diagnostic utility versus LA geometry for stratifying presence and severity of DD, and improves prediction of AF and congestive heart failure after MI.

Premature Ventricular Contractions and Cardiomyopathy.

Premature ventricular contractions (PVCs) are a common arrhythmia that may cause symptoms of variable severity. PVCs have recently garnered interest in their ability to induce adverse structural heart remodeling in an entity known as PVC-induced cardiomyopathy. This entity is a retrospective diagnosis that likely remains under-recognized and may occur concurrently with other forms of cardiomyopathy. The appropriate identification and management of PVCs in the setting of associated cardiomyopathy may have a significant impact on cardiac function and the clinical course, including recovery of left ventricular ejection fraction and improvement in patient functional status. Treatment consists of catheter ablation and/or antiarrhythmic drug therapy, but continued monitoring and follow-up are required, as the recurrence of high PVC burden may lead to redevelopment of cardiomyopathy.

Smartwatch Performance for the Detection and Quantification of Atrial Fibrillation.

Background Atrial fibrillation (AF) burden and duration appear to be related to stroke risk. A wearable consumer electronic device could provide long-term assessment of these measures inexpensively and noninvasively. This study compares the accuracy of an AF-sensing watch (AFSW; Apple Watch with KardiaBand) with simultaneous recordings from an insertable cardiac monitor (ICM; Reveal LINQ). Methods SmartRhythm 2.0, a convolutional neural network, was trained on anonymized data of heart rate, activity level, and ECGs from 7500 AliveCor users. The network was validated on data collected in 24 patients with ICMs and a history of paroxysmal AF who simultaneously wore the AFSW with SmartRhythm 0.1 software. The primary outcome was sensitivity of the AFSW for AF episodes ≥1 hour. Secondary end points included sensitivity of the AFSW for detection of AF by subject and sensitivity for total AF duration across all subjects. Subjects with >50% false-positive AF episodes on ICM were excluded. Results We analyzed 31 348.9 hours (mean (SD), 11.3 (4.4) hours/day) of simultaneous AFSW and ICM recordings in 24 patients. The ICM detected 82 episodes of AF ≥1 hour while the AFSW was worn, with a total duration of 1127.1 hours. Of these, the SmartRhythm 2.0 neural network detected 80 episodes (episode sensitivity, 97.5%) with a total duration of 1101.1 hours (duration sensitivity, 97.7%). Three of the 18 subjects with AF ≥1 hour had AF only when the watch was not being worn (patient sensitivity, 83.3%; or 100% during time worn). Positive predictive value for AF episodes was 39.9%. Conclusions An AFSW is highly sensitive for detection of AF and assessment of AF duration in an ambulatory population when compared with an ICM. Such devices may represent an inexpensive, noninvasive approach to long-term AF surveillance and management.

Outcomes With Novel Oral Anticoagulants in Obese Patients who Underwent Electrical Cardioversion for Atrial Tachyarrhythmias.

The efficacy of novel oral anticoagulants (NOACs) in severely obese patients is uncertain as volume of distribution is related to weight, and few such patients were enrolled in the pivotal trials. As the month after direct-current cardioversion (DCCV) for atrial fibrillation and atrial flutter is a high-risk period for stroke, we sought to evaluate the safety of performing DCCV in obese patients on NOAC. All patients who underwent DCCV after ≥3 weeks of NOAC or therapeutic warfarin treatment without a previous transesophageal echocardiogram over a 3-year period at a single center were included. Obesity groups were defined as normal (body mass index [BMI] < 25), overweight (BMI 25 to <30), class 1 obesity (BMI 30 to <35), class 2 obesity (BMI 35 to <40), and class 3 or severe obesity (BMI ≥ 40). The primary end point was stroke at 30days. Of 761 patients, 73 were severely obese, 78 class 2 obese, 197 class 1 obese, 254 overweight, and 159 in the normal weight group. Average age 66.4 ± 10.3years and 32.5% women. Mean CHA2DS2-VASc score was 2.6 ± 1.6, and 78.9% were on NOACs with no differences in groups. There were no strokes in the severely obese group, and 1 each in class 2 obesity and normal weight (p = 0.3). In conclusion, there was a low rate of stroke in all weight classes after DCCV in patients taking NOACs and warfarin. NOAC use in severely obese patients who underwent DCCV appears safe even in the absence of transesophageal echocardiogram.

Dialytic interval and the timing of electrocardiographic screening for subcutaneous cardioverter-defibrillator placement in chronic hemodialysis patients.

BACKGROUND: Hemodialysis (HD) patients have a high risk of sudden death but limited vascular access and high complication rates from transvenous implantable cardioverter-defibrillators (ICDs). Subcutaneous ICDs (S-ICD) may be an alternative, but dynamic ECG changes may result in inappropriate shocks. This study aims to define the screen failure rate for S-ICD in patients pre- and post-HD. METHODS: ECG waveforms were obtained using electrodes mimicking the S-ICD sensing vectors in an unselected test group of chronic HD patients and a control group of ICD-eligible non-dialysis patients. Participants passed screening if their QRS and T-waves fit within the screening template in supine and standing positions in any lead. Test group participants were screened before and after HD and control group patients were screened at two separate time points. HD patients were stratified into the four following groups: (A) passed screening before and after HD, (B) failed screening before but passed after HD, (C) passed screening before but failed after HD, and (D) failed screening before and after HD. Patients in group A passed the screening for ICD implantation, and patients in groups B, C, and D failed the screening for ICD implantation. Control patients were similarly classified by pass/fail status at the two assessment points. RESULTS: Of the 76 patients enrolled, 51 were HD patients and 25 were controls. Of the 51 HD patients, 43 (84%) were in group A, four participants (8%) were in group B, one (2%) was in group C, and three participants (6%) were in group D. There were no differences in any of the clinical or demographic variables between the pass and fail test HD groups. None of the 25 controls failed the screening at either time point (p = 0.047 vs HD patients). CONCLUSIONS: Overall, HD patients were more likely to fail S-ICD screening compared to non-HD patients (16 v 0%, p = 0.047) and are more likely to do so prior to HD. Patients on HD should be screened at multiple time points around the dialytic interval to reduce the risk of inappropriate shocks.

Microcomputer-based artificial vision support system for real-time image processing for camera-driven visual prostheses.

It is difficult to predict exactly what blind subjects with camera-driven visual prostheses (e.g., retinal implants) can perceive. Thus, it is prudent to offer them a wide variety of image processing filters and the capability to engage these filters repeatedly in any user-defined order to enhance their visual perception. To attain true portability, we employ a commercial off-the-shelf battery-powered general purpose Linux microprocessor platform to create the microcomputer-based artificial vision support system (microAVS(2)) for real-time image processing. Truly standalone, microAVS(2) is smaller than a deck of playing cards, lightweight, fast, and equipped with USB, RS-232 and Ethernet interfaces. Image processing filters on microAVS(2) operate in a user-defined linear sequential-loop fashion, resulting in vastly reduced memory and CPU requirements during execution. MiccroAVS(2) imports raw video frames from a USB or IP camera, performs image processing, and issues the processed data over an outbound Internet TCP/IP or RS-232 connection to the visual prosthesis system. Hence, microAVS(2) affords users of current and future visual prostheses independent mobility and the capability to customize the visual perception generated. Additionally, microAVS(2) can easily be reconfigured for other prosthetic systems. Testing of microAVS(2) with actual retinal implant carriers is envisioned in the near future.