zimmie

MacBook Air: 9 Watts
Two TB3 MBP: 15 Watts
Four TB3 MBP: 28 Watts

The two TB3 MBP will get better sustained processor performance than the MacBook Air.

The two TB3 MBP also has a faster SSD with four chips rather than the MacBook Air's two.

Also, while the MacBook Air's GPU is listed as "Iris Plus", its processor options do not appear to have the on-package DRAM (called eDRAM; works as VRAM and L4 cache) all the Pro models have. This shouldn't have a huge effect on performance, but it should mean the integrated GPU digs a little less into main memory.

Edited to add: I just noticed the new two TB3 MBP can't drive a 6K display. The MBA and the four TB4 MBP both can. Weird!

svanstrom said:

zimmie said:

This is a segment of a pathological ECG recorded using an Apple Watch Series 4:
You can clearly see

• The arhythmic QRS complex.
• The missing P wave.
• The overall character of the QRS complex, and how it's the same beat-to-beat (always a qRs).
• The shape of the T wave. Absolute and relative refractory.
• The QT interval

This is diagnostic-quality, without a doubt. I particularly like how you can tell the patient's heart was expecting to have longer for the T at 13.16 seconds, but it was abruptly shortened for the qRs at 13.32 seconds. The Q to T-peak interval on the subsequent beats is noticeably shorter.

I really wish there was an "ECG for Apple Watch dummies"-book.

Playing around with the watch I've seen all kinds of "irregularities" when I one way or another have felt off; but I haven't got a clue if any of them are signs of a five minutes life expectancy, or not.

And since I'm not about to become that guy that runs to the emergency room every few days I feel like there's a gap here; a gap between the capabilities of my watch to potentially save my life, and me being able to understand the data that I'm given.

Wikipedia has decent articles on the characteristics of an ECG.

The important starting point is the down-UP-down. Each feature of an ECG recording has a letter designation. The quick dip down is the Q, the big spike up is the R, and the small dip down afterwards is the S. Taken together, they make up the QRS complex. When talking about the complex in the abstract, the letters are always uppercase. When talking about the specifics, case can vary. For example, qRs indicates a small Q, big R, small S, which is normal. More Q or S amplitude or less R amplitude can indicate certain problems. Some can be missing entirely. There can even be an extra R (called R prime, written R') in some situations.

Each of these features marks the heart doing something. Together, the QRS is the ventricular beat.

Q is the plane between the ventricles contracting in preparation for a ventricular beat.
R is the ventricles beginning their inward contraction.
S is when the contraction ends.

In a normal ECG, there is a bump up a bit before the QRS called the P wave. This wave is from the atria contracting. It is absent in the recording above, indicating the atria were not contracting. That is almost always caused by atrial fibrillation (kind of a quivering twitch rather than a rhythmic beat).

Then after the ventricular beat, the T wave shows the ventricles relaxing.



ECGs are sensitive to movement. When recording one, you should try to be as still as possible. The R is generally visible, even during movement, but the other features may be overwhelmed entirely.

Everybody with an Apple Watch Series 4 or above should collect a baseline ECG, just to have around in case they need it for comparison later.



To be clear about this next part, I have had medical training, but not in a long time. I haven't practiced any form of medicine in years, and this is NOT MEDICAL ADVICE. It is generic.

It is important to note ECGs can be ambiguous and hard to read, even for professionals. If your ECG looks weird, but you feel fine, maybe schedule a low-priority appointment with your doctor to check it out and learn more. If you feel weird, but your ECG looks fine, it's probably not your heart (most urgent heart problems show up on even single-lead ECGs). If you feel weird, but in a way you have felt before, and your ECG looks weird (missing parts like the one above, different shape from beat-to-beat), call your doctor and see what they recommend.

If you feel weird in a new way and your ECG looks weird, think seriously about going to an ER or urgent care clinic.

Edited to add: Somehow I didn't finish the sentence mentioning R' above. Fixed that.

digitol said:

Caution! Apple watch and it’s measurements/monitoring is often inaccurate. This should not substitute for a Doctor. In fact, it’s almost criminal how horrible these devices are. Many things to account for, that isn’t taken into consideration for health, which may hurt certain individuals with underlying health issues or other circumstances. Apple watch is more of a toy. 

This is a segment of a pathological ECG recorded using an Apple Watch Series 4:
You can clearly see

• The arhythmic QRS complex.
• The missing P wave.
• The overall character of the QRS complex, and how it's the same beat-to-beat (always a qRs).
• The shape of the T wave. Absolute and relative refractory.
• The QT interval

This is diagnostic-quality, without a doubt. I particularly like how you can tell the patient's heart was expecting to have longer for the T at 13.16 seconds, but it was abruptly shortened for the qRs at 13.32 seconds. The Q to T-peak interval on the subsequent beats is noticeably shorter.

Rayz2016 said:

svanstrom said:

Isn’t that like saying that the iPhone gps caught a car speeding while the more advanced police radar couldn’t do that when the car later on was parked…?

Yes, I think “seemingly missed” might not be how I would’ve phrased it.  Sometimes you have to monitor someone over a period of time before the condition presents itself. The point being made here is that doctors were willing to base a course of action on the info they’re getting from an Apple Watch, when they had no data from their own equipment. That is quite significant. 

Exactly. A lot of heart issues only present relatively briefly. The situation above disappeared after about an hour, which is not generally enough time to get into an emergency room (without also being grievously injured, anyway), let alone to a cardiologist. The options are either monitoring over a really long period of time (certainly longer than anyone would want to be hooked up to a 12-lead), or using a personal ECG. A lot of doctors definitely realize this, and realize any hard data showing an issue is better than no data.

I seriously doubt Apple wants to get into rings. Sizing is unbelievably fiddly.

Covering 90% of the population takes about 20 fixed ring sizes. This number goes down somewhat if people are willing to wear it on any finger, but lots of people have a preferred finger for rings, and others feel wrong. Can you imagine Apple stocking 20 different SKUs per finish just for different sizes?

Now imagine a ring with segments for the electronics and an adjustable sizing segment. Would anybody want that? Sliding parts pinch, and the skin on your fingers is among the most vulnerable to pinches.

Some kind of elastic could work, but can you see Apple ever making anything with elastic?

Edited to add: Just seems like folding displays. They look cool in demos which can ignore the practical considerations, but those practical considerations are killer.

CarPlay has actually supported this for a few years.

When a connection is established, the car sends data about its displays and controls to the phone. This data includes how many displays and their size, and as of iOS 13 a "safe" area for each display and optionally display area and safe area resize notifications. Check out the WWDC 2019 videos. There's a really cool session (Advances in CarPlay Systems) discussing this.

Once the phone knows how many displays and what size and type they are, it generates one or more MPEG-4 AVC video streams which it sends to the car. The car sends a stream of control data back to the phone (touchscreen events, "Hey Siri", dial/button events, and the aforementioned display area resize notifications). It's a pretty simple protocol overall.