Smartphones Can Interfere with Implanted Cardiac Devices

St Jude Medical pacemaker with ruler , Credit: Steven Fruitsmaak

Cardiac device wearers should keep a safe distance from smartphones to avoid unwanted painful shocks or pauses in function, reveals research presented today at EHRA EUROPACE -- CARDIOSTIM 2015 by Dr. Carsten Lennerz, first author and cardiology resident in the Clinic for Heart and Circulatory Diseases, German Heart Centre, Munich, Germany. The joint meeting of the European Heart Rhythm Association (EHRA) of the European Society of Cardiology (ESC) and Cardiostim is being held in Milan, Italy. The scientific programme is here:http://www.flipsnack.com/Escardio/ehra-europace-cardiostim-2015-advance-programme.html. Lennerz said: 'Pacemakers can mistakenly detect electromagnetic interference (EMI) from smartphones as a cardiac signal, causing them to briefly stop working. This leads to a pause in the cardiac rhythm of the pacing dependent patient and may result in syncope. For implantable cardioverter defibrillators (ICDs) the external signal mimics a life threatening ventricular tachyarrhythmia, leading the ICD to deliver a painful shock.' Device manufacturers and regulatory institutions including the US Food and Drug Administration (FDA) recommend a safety distance of 15 to 20 cm between pacemakers or ICDs and mobile phones. The advice is based on studies performed primarily in pacemakers 10 years ago. Since then smartphones have been introduced and mobile network standards have changed from GSM to UMTS and LTE. New cardiac devices are now in use including ICDs, cardiac resynchronisation therapy (CRT) and MRI compatible devices. The current study evaluated whether the recommended safety distance was still relevant with the new smartphones, networks and cardiac devices. A total of 308 patients (147 pacemakers and 161 ICDs, including 65 CRTs) were exposed to the electromagnetic field of three common smartphones (Samsung Galaxy 3, Nokia Lumia, HTC One XL) which were placed on the skin directly above the cardiac device. The smartphones were connected to a radio communication tester, which works like a mobile network station. The investigators put the smartphones through a standardised protocol of the calling process which included connecting, ringing, talking and disconnecting. The actions were performed in GSM, LTE and UMTS at the maximum transmission power and at 50 Hz, a frequency known to influence cardiac implantable electronic devices. Electrocardiograms (ECGs) were recorded continuously and checked for interference. Lennerz said: 'From earlier studies we know that the most vulnerable phases of a call are ringing and connecting to the network, not talking, so it was important to analyse these separately.' More than 3,400 tests on EMI were performed. One out of 308 patients (0.3 percent) was affected by EMI caused by smartphones. This patient's MRI compatible ICD misdetected electromagnetic waves from the Nokia and HTC smartphones operating on GSM or UMTS as intracardiac signals. Lennerz said: 'Interference between smartphones and cardiac devices is uncommon but can occur so the current recommendations on keeping a safe distance should be upheld. Interestingly, the device influenced by EMI in our study was MRI compatible which shows that these devices are also susceptible.' Professor Christof Kolb, last author and head of the Department of Electrophysiology at the German Heart Centre, said: 'Nearly everyone uses smartphones and there is the possibility of interference with a cardiac device if you come too close. Patients with a cardiac device can use a smartphone but they should not place it directly over the cardiac device. That means not storing it in a pocket above the cardiac device. They should also hold their smartphone to the ear opposite to the side of the device implant.' In a second study on EMI, researchers advise limiting exposure to high voltage power lines.2 The study was conducted in response to public concerns about bicycle routes and walking paths under high voltage power lines (230 kV and more) and whether these are safe for patients with cardiac devices. These high electric fields are also encountered in utility substations where employees who bring up power lines, conduct maintenance or work within the buildings (cleaners, for example) may be exposed. Dr. Katia Dyrda, a cardiologist at Montreal Heart Institute, University of Montreal, said: 'High electric fields may interfere with the normal functioning of cardiac devices, leading to the withholding of appropriate therapy (anti-bradycardia pacing, for example) or to the delivery of inappropriate shocks. The International Organization for Standardization says pacemakers and ICDs should give resistance up to 5.4 kV/m (for 60 Hz electric fields) but electric fields can reach 8.5 kV/m under high voltage power lines and 15 kV/m in utility substations.' She added: 'There is a lot of interest in using the areas under power lines as bicycle paths or hiking trails because it's essentially free space. But patients and the medical community want to understand the risks. There are no recommendations from device manufacturers about power lines or higher electric fields.' The study exposed 40 cardiac devices (21 pacemakers and 19 ICDs) from five manufacturers to electric fields up to 20 kV/m in a high voltage laboratory. The devices were mounted in a saline tank at human torso height. Devices were set up as both left and right sided pectoral implants. The researchers found that when pacemakers were programmed to nominal parameters and in bipolar mode they were immune to EMI up to 8.6 kV/m. But when programmed to higher sensitivity levels or in unipolar mode, the EMI threshold decreased to as low as 1.5 kV/m in some devices. When programmed to nominal parameters, all ICDs were immune to EMI up to 2.9 kV/m . There was no difference in EMI thresholds between left and right sided implants. Dyrda said: 'There is no significant concern for patients with pacemakers programmed in the usual configuration (nominal settings, in bipolar mode). For the minority of patients with devices in unipolar mode or with very sensitive settings, counselling should be given at implantation or at medical follow-up.' She added: 'There is no need for patients with a pacemaker or ICD to avoid crossing under high voltage power lines (> 230 kV) but patients should avoid staying in a stationary position underneath them. Passing near pylons rather than between two pylons mitigates exposure to the electric field because the wires sag in the middle and the field is higher at this location.' Dyrda emphasised that this advice does not concern distribution lines (lines delivering electricity to homes), as the 60 Hz electric field that they generate is very low. She added: 'Patients ask us if they should avoid driving on roads that cross under high voltage power lines. The answer is no. If you're in a vehicle you are always protected because your car acts as a Faraday cage and shields you automatically.' Employees with a pacemaker or defibrillator should tell their employer so that their safety at work can be carefully evaluated, urged Dyrda. She said: 'Our study tested the effect of electric fields up to 20 kV/m and the results can be used to assess individual risks depending on exposure levels during specific tasks and the type and model of cardiac device. This may lead to job adjustments or, more rarely, to a job change.' Contacts and sources: European Society of Cardiology, Source: Article

Read More........→June 24, 2015

The Blind Can Read With New Finger Mounted Device That Converts Text to Audio in Real Time

Courtesy of the researchers

Researchers at the MIT Media Laboratory have built a prototype of a finger-mounted device with a built-in camera that converts written text into audio for visually impaired users. The device provides feedback — either tactile or audible — that guides the user’s finger along a line of text, and the system generates the corresponding audio in real time. Researchers at the MIT Media Lab have created a finger-worn device with a built-in camera that can convert text to speech for the visually impaired. “You really need to have a tight coupling between what the person hears and where the fingertip is,” says Roy Shilkrot, an MIT graduate student in media arts and sciences and, together with Media Lab postdoc Jochen Huber, lead author on a new paper describing the device. “For visually impaired users, this is a translation. It’s something that translates whatever the finger is ‘seeing’ to audio. They really need a fast, real-time feedback to maintain this connection. If it’s broken, it breaks the illusion.” Huber will present the paper at the Association for Computing Machinery’s Computer-Human Interface conference in April. His and Shilkrot’s co-authors are Pattie Maes, the Alexander W. Dreyfoos Professor in Media Arts and Sciences at MIT; Suranga Nanayakkara, an assistant professor of engineering product development at the Singapore University of Technology and Design, who was a postdoc and later a visiting professor in Maes’ lab; and Meng Ee Wong of Nanyang Technological University in Singapore. The paper also reports the results of a usability study conducted with vision-impaired volunteers, in which the researchers tested several variations of their device. One included two haptic motors, one on top of the finger and the other beneath it. The vibration of the motors indicated whether the subject should raise or lower the tracking finger. Researchers at the MIT Media Lab have created a finger-worn device with a built-in camera that can convert text to speech for the visually impaired. Another version, without the motors, instead used audio feedback: a musical tone that increased in volume if the user’s finger began to drift away from the line of text. The researchers also tested the motors and musical tone in conjunction. There was no consensus among the subjects, however, on which types of feedback were most useful. So in ongoing work, the researchers are concentrating on audio feedback, since it allows for a smaller, lighter-weight sensor. Bottom line: The key to the system’s real-time performance is an algorithm for processing the camera’s video feed, which Shilkrot and his colleagues developed. Each time the user positions his or her finger at the start of a new line, the algorithm makes a host of guesses about the baseline of the letters. Since most lines of text include letters whose bottoms descend below the baseline, and because skewed orientations of the finger can cause the system to confuse nearby lines, those guesses will differ. But most of them tend to cluster together, and the algorithm selects the median value of the densest cluster. That value, in turn, constrains the guesses that the system makes with each new frame of video, as the user’s finger moves to the right, which reduces the algorithm’s computational burden. Given its estimate of the baseline of the text, the algorithm also tracks each individual word as it slides past the camera. When it recognizes that a word is positioned near the center of the camera’s field of view — which reduces distortion — it crops just that word out of the image. The baseline estimate also allows the algorithm to realign the word, compensating for distortion caused by oddball camera angles, before passing it to open-source software that recognizes the characters and translates recognized words into synthesized speech. In the work reported in the new paper, the algorithms were executed on a laptop connected to the finger-mounted devices. But in ongoing work, Marcel Polanco, a master’s student in computer science and engineering, and Michael Chang, an undergraduate computer science major participating in the project through MIT’s Undergraduate Research Opportunities Program, are developing a version of the software that runs on an Android phone, to make the system more portable. The researchers have also discovered that their device may have broader applications than they’d initially realized. “Since we started working on that, it really became obvious to us that anyone who needs help with reading can benefit from this,” Shilkrot says. “We got many emails and requests from organizations, but also just parents of children with dyslexia, for instance.” “It’s a good idea to use the finger in place of eye motion, because fingers are, like the eye, capable of quickly moving with intention in x and y and can scan things quickly,” says George Stetten, a physician and engineer with joint appointments at Carnegie Mellon’s Robotics Institute and the University of Pittsburgh’s Bioengineering Department, who is developing a finger-mounted device that gives visually impaired users information about distant objects. “I am very impressed with what they do.” Contacts and sources: Larry Hardesty, MIT News Office, Source: Inffableisland.com

Read More........→March 11, 2015