New medical device, ECG on IPhone

Would you as a heart patient consider this device? One of the issues to understand is how a 12 lead ECG works vs. a single lead ECG. To understand this, pick up a piece of paper, look at it from every conceivable angle…front, back, top, bottom, side views. This gives a one directional view of the heart, so it really depends on where the issue lies if you are trying to pick up ischemia…lack of blood flow to heart muscle. An ECG has limited ability to diagnose heart attacks, that is why we use serial blood tests to measure enzyme troponin release to diagnose. Now don’t get me wrong, in many heart attacks there are EKG changes, but they don’t always show in a single lead ECG.

I think this tool is beneficial, especially for capturing arrhythmias or irregular heart rhythms. The second issue is if you use this device, who will read the data and what action will they take? Do you download and send to your cardiologist, your primary care physician, or the ER. Then who is responsible, and from their perspective who gets paid for reviewing. Many physicians are overworked and to add interpreting medical device data to their day won’t go over well in today’s environment. I perceive the future will have more devices like this, but the medical community needs to change current practices, and change is slow.

A new device and app is taking the mhealth capabilities of the iPhone to a whole new level.

San Francisco-based AliveCor announced Monday that it has received clearance from the U.S. Food and Drug Administration to market its heart monitor. Now, U.S. users of the iPhone 4 and iPhone 4S can shell out $199 (taxes and shipping are extra) to preorder the device, which begins shipping in January. Oh, and in case anyone was wondering, the iPhone does not come included, the company’s website notes handily. (Looks the like final device ended up costing more than the $100 that founder and physician David Albert at one time envisioned.)

So how does it work? The small wireless device comprising two electrodes can snap on to the back of an iPhone and then the souped-up iPhone can be placed next to the heart, against the skin to deliver clinical quality electrocardiograms. It functions like any iPhone cover intended to protect the smartphone.

Before the FDA clearance, prominent cardiologist Eric Topol used the device on an air plane to determine that a fellow traveler was having a heart attack, ordering the plane to land.

While interest in mhealth is exploding, this device appears to be mhealth on steroids, given that it is actually a physical device aiming to give medical data. The device has been eagerly anticipated by mhealth watchers and it will be interesting to see how well the product is adopted.

Perhaps this is the beginning of what Silicon Valley VC and provocateur Vinod Khosla proclaimed when he said that machines will one day replace 80 percent of middling doctors. No surprises that Khosla Venture, his VC firm, is an investor in AliveCor.

In June, the company raised $10.5 million in a series B round from Khosla Ventures as well as existing series A investors like Burrill & Company, Qualcomm Ventures and Oklahoma Life Sciences fund.

Read more:

The Heart: An Incredible Electric Machine

A quick primer on the electrical system of the heart followed by two major breakthroughs in pacemaker technology this year.

What makes the heart beat? Learn about the conduction system, an incredible machine.

A leadless, subcutaneous defibrillator makes the list of 5 biggest medical breakthroughs of the year.

Boston Scientific has begun marketing a FIRST-OF-ITS-KIND DEFIBRILLATOR after receiving FDA approval in September. The implantable device, which protects against sudden cardiac arrest, was developed by a California firm purchased by Boston Scientific and is expected to be a financial win for the Natick-based company. Unlike others on the market, the S-ICD does not touch the heart, instead sending electrical pulses to correct abnormal rhythms through wires implanted just beneath the skin.

No More Batteries: Piezoelectric Pacemaker Powered By The Heart

An experimental device converts kinetic energy from beating hearts into electricitythan can power a pacemaker, meaning the chance for no more batteries in the future, according to a talk at the American Heart Association’s Scientific Sessions 2012.

The study is preliminary but a piezoelectric approach is promising for pacemakers because they require only small amounts of power to operate. Batteries must be replaced every five to seven years, which is costly and inconvenient.  Piezoelectricity might also power other implantable cardiac devices like defibrillators, which also have minimal energy needs.

“Many of the patients are children who live with pacemakers for many years,” said M. Amin Karami, Ph.D., lead author of the study and research fellow in the Department of Aerospace Engineering at the University of Michigan in Ann Arbor. “You can imagine how many operations they are spared if this new technology is implemented.”

Researchers measured heartbeat-induced vibrations in the chest. Then, they used a “shaker” to reproduce the vibrations in the laboratory and connected it to a prototype cardiac energy harvester they developed. Measurements of the prototype’s performance, based on sets of 100 simulated heartbeats at various heart rates, showed the energy harvester performed as the scientists had predicted — generating more than 10 times the power than modern pacemakers require. The next step will be implanting the energy harvester, which is about half the size of batteries now used in pacemakers, Karami said. Researchers hope to integrate their technology into commercial pacemakers.

Two types of energy harvesters can power a typical pacemaker: linear and nonlinear. Linear harvesters work well only at a specific heart rate, so heart rate changes prevent them from harvesting enough power.

In contrast, a nonlinear harvester, the type used in the study, uses magnets to enhance power production and make the harvester less sensitive to heart rate changes. The nonlinear harvester generated enough power from heartbeats ranging from 20 to 600 beats per minute to continuously power a pacemaker. Devices such as cell phones or microwave ovens would not affect the nonlinear device, Karami said.


What is a Heart Attack?

Figure A shows a heart with dead heart muscle caused by a heart attack. Figure B is a cross-section of a coronary artery with plaque buildup and a blood clot.  

A nice image from the National Heart Lung and Blood Institute of what a heart attack  is.  This represents a rather large heart  attack because of insufficient blood from the LAD or the widow maker. This type of a heart attack would  typically cause changes in the EKG. This would create a STEMI or ST segment Elevated Myocardial Infarction. This means likelyhood is a heart attack involving the full thickness of the heart wall. When this occurs we usually note changes in the EKG.

See   Medical terms you should know for a description of the EKG changes that occur with this type of a heart attack.  


Heart Rhythm Monitors

One of the benefits of attending a formal hospital based cardiac rehabilitation program is that most of the time your heart rhythm is monitored as you wear a telemetry monitor. With today’s advanced technology you can monitor your own heart rhythm at  home. There are many portable handheld monitors which you can capture a picture of your heart rhythm save it and bring it with you to your followup physician appointment. It is good to record this at rest, with peak exercise and if you are symptomatic. Below is a link to such a device.  Now don’t get sticker shock…this can be the co-pay amount of just one week’s visits to a cardiac rehabilitation program, and you get to keep this!

Omron HCG-801 Portable ECG Handheld Heart Rate Monitor