What Causes Sleep Apnea

What Causes Sleep Apnea

What causes sleep apnea?

Any factor can cause the narrowing of the airway, and the upper airway obstruction may cause nocturnal hypoxia during sleep, leading to sleep apnea syndrome. The main common causes are:

  • Aging:

The prevalence of OSA (obstructive sleep apnea) increases with age from young adulthood through the age of 60s and 70s, then appears to plateau.

  • Gender:

The OSA is two to three times more common in men than in women. But between men and the peri- and post-menopausal women, the gender difference in prevalence is not as great.

  • Obesity:

For both men and women, the prevalence of OSA increases with increasing BMI and some weight-related indicators such as neck circumference, waist-to-hip ratio. Studies have found that a 10% weight gain can increase the risk of developing OSA by 6 times.

  • Upper airway structure abnormalities:

The obstruction of the upper airway (oral cavity, nasal cavity, and pharynx) caused by various reasons, including nasal diseases/nasal congestion such as deviated or crooked nasal septum, turbinate hypertrophy, sinus polyps, etc., oral and pharyngeal factors such as tonsil and adenoid hypertrophy, an overly long or floppy soft palate, elongated uvula, swollen tongue, the back of the tongue base, etc., craniofacial abnormalities such as the smaller-than-normal lower jaw, and upper airway narrowing caused by other reasons such as infection, trauma or surgery, etc.

  • Drinking alcohol or using sedative-hypnotic drugs:

These substances can make the soft tissues of the upper airway more flaccid, which will obstruct the airflow, make breathing more difficult, cause sleep apnea, and prolong the duration of apnea.

  • Smoking:

Smoking may increase the risk of developing OSA, or at least worsen existing symptoms. In one study, current smokers were three times more likely to have OSA than those who had smoked in the past (but had quit) or who had never smoked.

  • Other diseases causing sleep apnea syndrome:

cerebrovascular disease, congestive heart failure, hypothyroidism, acromegaly, vocal fold paralysis, brain tumors, neuromuscular disorders, laryngopharyngeal reflux, gastroesophageal reflux, and airway compression due to mediastinal mass. These diseases mentioned above can cause or aggravate airway resistance, thus causing sleep apnea.

Other medical conditions that may have an increased association with OSA include obesity hypoventilation syndrome, hypertension (particularly resistant hypertension), cardiovascular disease, atrial fibrillation, pulmonary hypertension, end-stage kidney disease, chronic lung disease, including asthma, chronic obstructive pulmonary disease (COPD), and idiopathic, pulmonary fibrosis; stroke and transient ischemic attacks, pregnancy ( gestational diabetes, pregnancy-induced hypertension), acromegaly, hypothyroidism, polycystic ovary syndrome, Parkinson’s disease, floppy eyelid syndrome.

Who is most affected by sleep apnea?

  • Sleep apnea syndrome is most common in people who are obese, especially those who are centripetally obese with thicker necks and larger hips.
  • Men are more likely to develop OSA than women.
  • People who are older are also more likely to have OSA.
  • In terms of facial appearance, people with small mouths and small lower jaws are more likely to develop OSA.
  • People who smoke or drink alcohol for a long time or take sedative drugs before bedtime are also at high risk for OSA.
  • In addition, there is a certain degree of familial aggregation of OSA, which may be related to genetic factors and common lifestyle habits. For example, genetic factors may make most of the family have small mouths and jaws, or common lifestyle habits make more overweight people in the family, etc.
  • Furthermore, the development of OSA is associated with the onset of certain specific medical conditions, such as women who are pregnant are more likely to develop OSA than women who are not pregnant; and menopausal women are at greater risk of developing OSA compared to premenopausal women.

What are the conditions that predispose to sleep apnea syndrome?

Sleeping in the supine position, drinking alcohol, or using sedative-hypnotic drugs before bedtime can significantly increase the risk of apnea during sleep that night, and worsen existing OSA symptoms.

Review: Guard your heart with Wellue Heart Health Monitor

Review: Guard your heart with Wellue Heart Health Monitor

From: https://gadgetsandwearables.com/

Monitoring ECG with smartwatches is becoming increasingly common. Apple, Fitbit, and a number of other brands have come out with solutions. What these have in common is that they are on-demand, work from the wrist and typically capture a reading lasting around 30 seconds. Wellue Heart Health Monitor is something much more sophisticated.

This is the type of device that was previously only available in hospital settings. It offers 24-hour monitoring of ECG and provides analysis of up to 14 different kinds of abnormal heart events. The device is non-invasive and completely safe to use.

The procedure is simple and consists of sticking two electrodes onto the skin on your chest. You can do this with a chest strap or patches.

In private hospital settings, a single session with a 24-hour ECG monitor can set you back upwards of between $150 and $200. Wellue’s device comes with a one-off $299 price tag. There are no subscription fees or other expenses and more than one person can use it. You can check it out on getwellue.com .

The company sells a range of other products. Our review of its O2Ring can be found on this link. That one is primarily designed for people who need to track their oxygen levels in detail, especially those who have or suspect they have sleep apnea or another medical problem. Wellue even sells a couple of wireless portable ultrasound devices allowing you to image a full human body!

Over the past few weeks, I’ve tested the Heart Health Monitor in a number of different use scenarios and with different people. Here’s what I made of it.

Wellue Heart Health Monitor review: Design & hardware

  • Single-lead ECG monitor
  • Looks and feels like a standard heart chest strap
  • Records for up to 24 hours
  • Three-day battery life on a single charge

Look & feel

In the box, the Heart Health Monitor comes with the main unit, a power/data cable for charging and uploading data, a little USB drive with the analysis software, a pack of disposable electrode patches, and a chest strap. As far as the USB drive, you don’t really need it. It contains the PC version of the software, but you can also download this from Wellue’s website along with the Mac equivalent. Also, downloading directly from the website will ensure you have the latest version which is better.

The EKG monitor looks well made. it has a rubbery feel to it and the middle part bends. This is so that it contours better against your chest. The size of the main unit is 100 x 23 x 8.3mm and it is extremely lightweight (1.23 oz with the battery). Once positioned on your chest, you really don’t feel like you are wearing it. If you’re a runner and have worn a heart rate chest strap – this is exactly the same.

There is no display or “On” button. When you attach the main unit to the electrodes it will automatically start recording and end when you remove it. Rather annoyingly, there is also no “Off” switch. So it is a bit like a television set that is on standby – a little LED light will flash every few seconds even when the device is not used. Which to me seems like a waste of battery life. Surely it would not have been that difficult adding a little “Off” button.

Moving quickly on to water resistance which comes in at a rating of IP22. Meaning, the Heart Health Monitor is “protected against insertion of fingers” and can withstand “vertically or nearly vertically dripping water”. So it is not water-proof.

Not surprising as I cannot really see a scenario when you would need to wear it in water. This is a general health monitor, not a sports tracking device. Having said that, you can wear it while exercising.

All in all, the design gets a thumbs up from me. The monitor is comfortable to wear, feels quality made and is small enough to carry around with you with ease. Plus there’s no power-hungry display.

The device is much more convenient that a hospital ECG Holter monitor which is bulky, with wires and 5-7 electrodes that need to be attached to the chest. My only wish would be for a way to entirely switch the thing off.

Under the hood

Wellue Heart Health Monitor is a single lead ECG reader. It can record up to 360,000 ECG/EKG signals in a day, intelligently identifying a bunch of different heart arrhythmia risks. According to the company’s website, its analysis system is based on 300,000 patients and 50 million learning data points.

As far as memory, you can store 10 individual ECG sessions on it or 30 hours of data. The maximum session you can record is 24 hours. To make space, once the memory is full it will start overwriting the old data. But because you are meant to use PC or Mac software, your historical data sits on your computer’s hard disk. Which makes your session logs limitless.

Fully charged, the Heart Health Monitor can keep going for 72 hours. Wellue says you can refuel it up 300 times before performance will start to become degraded. A battery replacement possibility would be a plus. Having said that, with normal use the Heart Health Monitor should be good for a few years before it starts to see battery degradation.

To refuel simply plug one end of the proprietary cable into the monitor and the other end into any standard USB outlet. When the LED light turns from reddish to green, you’ll know the battery is on max capacity. This does not take long.

Hardware specs

  • Size (main unit): 100 x 23 x 8.3mm
  • Weight < 1.23 oz (with battery)
  • ECG lead type: Single-lead ECG
  • Input impendence: ≥10MΩ, 10Hz
  • Frequency response: 0/67 – 40 Hz
  • Linearity and dynamic range: 10mV (peak-to-valley)
  • Gain error: Maximum error ±10%
  • Type of battery: rechargeable lithium battery
  • Battery running time: 72 hours (fully charged)
  • Charging time (2 horus (to 90% power)
  • Water-resistance: IP22
  • Storage: 10 individual ECG sessions on it or 30 hours of data

Wellue Heart Health Monitor review: Functionality

  • Use with the chest strap or stick-on patches
  • Picks up on 14 different ECG abnormalities
  • No Bluetooth or WiFi is required
  • Excellent PC and Mac software
  • Smartphone app of limited use

Setup and first use

A highlight of this product for me is the ease of use. Simply tighten the strap around your chest and attach the main unit to the pins – the end with the letter R needs to go on the right side. A little vibration along with the blinking green light will let you know that it has started recording. Prior to that you’ll want to wet the plastic strip on the inside of the strap a little. This is to ensure a good signal is captured right from the outset.

The other option is to use the patches provided to secure the device to your chest. Just ensure that they are positioned at a 45-degree angle. These are single-use, disposable patches and your purchase gets you 10 in a box. You also have the option of obtaining a box of additional patches – a pack of 60 costs $29.

I tried both ways of wearing it and must say that I prefer the chest strap. It is easier to put on and take off. Once it is attached to the chest, you don’t feel anything anymore and it doesn’t bother you at all.

And while it might not feel as secure while you are sleeping, in the end I found it captured uninterrupted sessions most of the time. With typical tossing and turning there’s the potential to bump the main unit. This starts a new session each time. I found that while this typically did not happen to me with the chest strap option, it did at times with the patches. Plus, when you remove the stickers they leave a red mark on your skin and it takes about a day before the rash disappears.

You’ll be happy to know that nothing is transmitted to the outside world, so no Bluetooth or WiFi is required. And the device will keep recording your signal continuously until you remove it.

Another option, which I didn’t really find all that useful, is to rest your fingers on the electrodes. This is meant for a quick check and works with the smartphone app. But the signal quality is not as good so I found that to be of limited use.

The smartphone app shows a live feed of ECG & heart rate

The Heart Health Monitor comes with computer and smartphone software to help you screen for heart problems. Starting off with the weaker part of the system – the iOS and Android smartphone app.

Like some other Wellue products, you are meant to use the ViHealth app. Pair your Heart Health Monitor to the smartphone, attach it to your chest and it will automatically start to stream data to the smartphone display.

Below the real-time data of your heart rate and electrocardiogram session curve, you’ll see a little “Record ECG” button. This allows you to capture and save details of your session. The max recording time is 30 minutes.

You also have the option of going into a history log and reviewing any individual recordings. Plus you can export the ECG readings in PDF format. But this is where the functionality ends. No analysis is provided so you are left on your own to draw conclusions.

The PC, MAC software makes this product what it is

The smartphone app can be useful for a quick checkup but is of limited use as it lacks the deep AI analysis of the PC and Mac software. Which is the part of the system which makes this product what it is. After all, ECG recordings without analysis are of limited use.

The way this works is that you download and install the software on your computer. Then each time you connect the Heart Health Monitor to your computer (via the USB power cable), you’ll have the option to download recently captured ECG data. This is submitted to the cloud for analysis and 20-30 minutes later a report will be ready with your results. Motion artifacts are filtered out in the analysis.

When you think about it, in a full day the device captures hundreds of thousands of data points that would be impossible to evaluate as a whole manually. So the AI part is an absolute necessity.

As mentioned, the device and AI ECG algorithm can pick up on many different events. This includes Sinus Rhythm, Ectopic Rhythm, Sinus Tachycardia, Sinus Bradycardia, PAC (Premature Supraventricular Contraction), PVC (Premature Ventricular Contraction), Couplet of PAC, Couplet of PVC, PAC Bigeminy, PVC Bigeminy, PAC Trigeminy, PVC Trigeminy, Supraventricular Tachycardia, Ventricular Tachycardia, Atrial Flutter, Atrial Fibrillation and heart rate variability (HRV).

The report is in an easy-to-digest format. It flags up irregularities in the ECG in a summary format along with conclusions. You can jump to the exact spot in the ECG where a disordered heartbeat occurred via the navigation panel on the left.

The software also lists hourly data in table format quantifying when and where something was found along with the number of events. Of course, you also get the actual ECG waveform. All of this can be exported in PDF format and shared with the doctor or loved ones.

There really is lots of info to sink your teeth into. However, something on my wish list would be more detailed explanations. We are not all qualified doctors so you end up Googling to understand some of the terms. But don’t be surprised if you do find some sort of abnormality. A prolonged test is bound to pick up on at least something minor. That’s normal.

Routine ECG/EKG checkups at your doctors typically take a few minutes. This can make it difficult to pick up on heart problems. After all, ECG events can be of sporadic and transient in nature. Hence the benefit of longer readings and the usefulness of this device.

Quality of data

As far as the quality of data, I can vouch that the heart rate information is accurate and that the device delivers a stable quality the recordings. The accuracy of ECG and analysis by AI, on other hand, you have to trust. There’s no way for me to perfectly assess this accuracy.

In my case, I tried it out in various use scenarios. For the most part, it found nothing wrong, only picking up on minor issues. Which is what I’d expect. Here’s an example of my results from a 9-hour monitoring session.

This is the detailed five-page report. Click on the thumb to open.

I also lent the device to a person with a known ECG abnormality – Afib, taking medication for the condition. And during five and a half-hour recording sessions, the Heart Health Monitor identified, logged, and charted a total of 632 instances of Afib. That’s how detailed the data gets!

Here’s the full report.

Also worth a mention are studies on Wellue’s website illustrating the suitability of using a single-lead ECG recorder for detecting cardiac arrhythmias in patients referred for dynamic ECG monitoring. You can read more on this link.

Wellue Heart Health Monitor review: The bottom line, is it worth it?

Wellue Heart Health Monitor is a clever little device that provides similar information to a traditional Holter Monitor. But it is easier to use and less costly. It allows you to do tests at your convenience without having to schedule doctor appointments. A way to conduct a preliminary analysis of arrhythmia and other heart abnormalities from the comfort of your home.

The device itself is very lightweight and offers a couple of ways of attaching to your chest. Once positioned, you really don’t feel like you are wearing it.

A highlight of this product is the PC and Mac software. The AI ECG analysis provides a wealth of info on your heart health including cardiac activity (heart rate, rhythm disturbances, HRV parameters), along with details of all individual irregularities. The signal form of a single-channel ECG is recorded in full. Of course, the accuracy is never going to be as high as a clinical-grade device but suffices for the purpose. Wellue also sells a 12-Lead Holter Monitor (use coupon GW10 for a 10% discount), which has medical-grade accuracy and works with the AI Analysis.

And while the PC and Mac software is quite good, the smartphone app is pretty barebones. Perhaps something that will be upgraded with future software updates.

Is Wellue Heart Health Monitor really something a person with no known heart issues needs? Perhaps not. But I would recommend it to those that have pre-existing conditions or those that want an additional way to keep tabs on their family’s health.

Finally, it is worth pointing out that this is not a medical device and is not meant to replace clinical Holter monitoring. Look at it as a convenient way to record your heart rhythm for prolonged periods and identify potential conditions – any time you feel the need to.

Does Poor Sleep Cause High Blood Pressure

Does Poor Sleep Cause High Blood Pressure

Poor sleep may cause high blood pressure? Some researchers report that poor sleep has become a risk factor for hypertension in the group of young and middled-aged people.

1. Insufficient sleep or excessive sleep

There is a U-shape curve relationship between sleep duration and high blooe pressure, which means sleeping for not-enough time or too much will increase the risk of developing hypertension. It is suggested to sleep for 7 or 8 hours for adults.

Previous studies have showed that people aged 32 to 59 who averaged less than 6 hours of sleep were more than twice as likely to develop hypertension as those who have enough sleep time. Those who sleep less than 4.9 hours have 3.15 times of the risk of developing hypertension.

Why does lack of sleep affect our blood pressure?

When our sleep time is reduced, the waking time is relatively prolonged, the excitability on the heart influenced by the sympathetic nerve system is strengthened, which will activate the hypothalamic-pituitary-adrenal axis, promoting a series of hormones secretion, then resulting in increased blood pressure.

In addition, hypertension can also affect sleep, causing autonomic dysfunction, resulting in a significant decline in sleep quality. Eventually, there is a vicious cycle between sleep deprivation and high blood pressure.

2. Snoring

Mild snoring has little impact on health, but severe snoring with apnea, known medically as obstructive sleep apnea (OSA), is a cause for alarm.

Studies have shown that about 50% – 92% of OSA patients have hypertension, and 30% – 50% of hypertension patients have OSA. Excluding the influence of obesity and age, OSA has become an independent risk factor for hypertension.

Why does snoring affect our hypertension?

OSA patients are prone to apnea during sleep, which leads to intermittent hypoxia. The transition from hypoxia to resuming breathing increases the activity of sympathetic nerves, causing peripheral vascular contraction.

In addition, the impaired endothelial function of resistence vessels will affect their diastolic function, resulting in vasoconstriction and increased blood pressure. Studies have shown that endothelium – dependent dilation of resistance vessels is impaired in OSA patients compared with healthy people.

Wellue’s Solution & Recommended Products

1. WiFi BP Monitor with ECG to meansure blood pressure and track ECG in daily life

The American Heart Association BP measurement guideline stated that 3 readings should be taken in succession, separated by at least 1 min. The average value of 3 bp measurements should be used as the more accurate and reliable blood pressure readings.

This wifi blood pressure monitor is perfect for you to continuously measure 3 times of blood pressure to prevent from giving you a false sense of security about your health.

In addition, this monitor can track ECG for 30s and the connected APP will offer AI Analysis to detect some ECG events. Data can be conveniently synced through both of Wi-Fi and Bluetooth.

wifi bp monitor with ecg function

2. Checkme O2 Max Wrist Oxygen Monitor to check sleep apnea or to ensure the effect of the treatment

According to the American Sleep Association, the repetitive breathing pauses caused by sleep apnea during the nights can occur several times per hour and last for over 10 seconds. Continuous trackers like Checkme™ O2 Max supports long hours monitoring during your sleep, can help detecting all the Apneic events and Hypopenic events in every 2 seconds.

checkme o2 max oxygen monitor

3. iBreeze APAP Machine

The iBreeze makes it easier than ever for new CPAP patients to adjust to therapy. The smart technology of the iBreeze also helps make humidification more dynamic, helps prevent leaks, and also captures critical sleep data for you and your doctor to have and review anytime.

This machine is the ideal choice for patients who have difficulty adjusting to CPAP machines.

apap machine
How to Do an ECG at Home?

How to Do an ECG at Home?

From: https://www.interactive-biology.com/

An ECG or an EKG – it’s an electrocardiogram. It shows you the electrical activity of the heart. But how do you do one at home? I’m going to show you how to do a 24-hour EKG at home using this little device, the Wellue 24 Hour ECG Recorder.

About the ECG

As the electrical signal travels through the heart, that signal can be recorded using an ECG – an electrocardiogram. An ECG has different parts:

  • The P wave – this shows the depolarization of the atria
  • The QRS complex/interval – this shows the depolarization of the ventricles
  • The T wave – This shows the repolarization of the ventricles. 
ECG waveform labeled
ECG waveform labeled

The ECG gives you an idea of how well the heart is functioning and can cue you in when there are issues like atrial fibrillation, heart defects, abnormal heart rhythms or arrhythmias, and a bunch of other cardiovascular issues.

For a more in-depth explanation, see our post that gives goes into more details about the ECG.

Holter Monitors

There are all kinds of devices that can be used to take an ECG at home. In fact, my watch even does an ECG. But in order to get a full picture of your heart function, a doctor might order you to wear a Holter monitor

A traditional Holter monitor is a device that you might put in your pocket or attach to your belt. It usually has 5 leads that attach to sticky pads that are attached to your thoracic region in different places. But the folks over at Wellue have sent me over a different kind of 24-hour ECG monitor that has some really cool features.

Man wearing traditional Holter monitor.
Man wearing traditional Holter monitor

The Wellue 24 Hour ECG Recorder

This 24-hour ECG recorder is a relatively small device. There are two ways to wear it and get recordings.

Using a Chest Strap

It comes with a detachable strap that you can use to strap it around your chest. This method is the easiest. However, when I did it this way, it didn’t work very well for me. Evidently, I move around during my sleep and when I looked at the ECG report that I got after using it that first night, there was a lot of crazy stuff going on. There were times when I was moving around like crazy and it messed up the signal.

Using Disposable Electrodes

It comes with disposable electrodes that you can use to stick the device directly onto your chest. They are VERY sticky and once you put them on and won’t move. Personally, this is the method I recommend because you get more reliable results. Once you attach it to your chest, it’ll just start monitoring your ECG. 

The Wellue 24 Hour ECG Recorder comes with disposable electrodes in addition to the chest strap for attaching the device to the body.

Unique Feature: ECG Recorder with AI Analysis

Once you’ve collected data by wearing the device, you can connect it here to your computer using the provided USB cable and import the results. It then uses AI to analyze your ECG report giving a preliminary diagnosis. It’ll let you know if it detected any atrial fibrillation or abnormal heartbeats. It’ll alert you of any tachycardia or other arrhythmias.

You should still follow up with a medical professional if you’re noticing any potential problems with your ECG, but I love that these devices are getting smarter and in more convenient packages.

Sample ECG Report

Here’s an ECG report I got after wearing the Wellue ECG Monitor.

The Cons about Using the Wellue ECG Device

First off, the chest strap is useless for me. And while I do see that they are trying to make it easy for you to get into monitoring your ECG, I wouldn’t use this unless you’re not going to be doing a lot of movement. So if you’re just doing an ECG for a shorter period of time and you know you’ll be relaxing, maybe that’s a good time to use it.

Secondly, if you do decide to use the electrode patches, know that when you purchase them, it comes with 10 patches. And once you open the packaging, it says that you want to use them within 30 days.

So if you’re going to be using it more long-term or at some later point in the future, you’ll have to purchase additional patches. Fortunately, they aren’t very expensive. 

Besides those few really minor issues, the convenience you get using this as opposed to some of the other more cumbersome Holter monitors is pretty awesome. 


Do I recommend it? Well, if you’re trying to get a detailed view of the electrical activity of your heart, this is a great tool. I’ll be using it at least once a month to get an idea of where I stand. Although knowing myself, it’ll probably be much more than that.

How to do a 12-Lead ECG?

How to do a 12-Lead ECG?

Since the American Heart Association’s recommendation to obtain prehospital 12-lead electrocardiograms on patients with acute coronary syndrome, EMS providers have played an increasingly important role in identifying these patients, beginning the appropriate treatment, and transporting them to appropriate hospitals capable of emergency angioplasty.

The acquisition of the 12-lead ECG in the field is theoretically not different from those obtained inside the emergency department. However, due to the unique prehospital environment, there are several tips and pearls to consider when placing the patient electrodes.

Conditions Requiring an ECG

A 12-lead isn’t just for chest pain. Obtain a 12-lead for possible strokes, altered levels of consciousness, weakness, dizziness, fatigue, palpitations and otherwise vague medical complaints. Remember that diabetic patient, younger women and various ethnicities often have atypical presentations and may have “silent myocardial infarctions.” Be vigilant. You may just save a life.

Proper acquisition of the 12-lead ECG

Proper acquisition of the 12-lead ECG is paramount to getting the most out of this tool. An improperly acquired 12-lead doesn’t provide diagnostic-quality information and can render the tracing mostly useless. Here are a few tips to making sure you get it done right:

Skin Preparation

Skin Preparation

It’s important to prepare the skin by cleaning it with an alcohol prep and by abrading it with a cloth towel to remove dead skin cells. You may need to wash the area with saline and dry it. Remove excess body hair by shaving. For females, place the leads under the breast tissue. You may need to lift and clean the skin underneath the breast to get a clear tracing.

Lead Placement

12-lead ECG placement

Traditionally, the limb leads go on the limbs, and while it’s acceptable to move them closer if you have to, try to avoid placing the leads over bony prominences or overly fatty areas. Look for a generally flat, clean, intact area of skin with muscle generally underneath.

  • The V-Leads go on the chest in a specific pattern. Leads V1 and V2 go in the 4th intercostal spaces (between the ribs) on either side of the sternum. To find these, go about three finger widths up from the xyphoid process, or bottom of the sternum. V1 is on the patient’s right, V2 is on the left.
  • V4 should be placed next; it goes one rib down in the 5th intercostal space, on the midclavicular line. Place V3 in between V2 and V4.
  • V5 goes in the anterior axillary line (front of the armpit) and V6 goes in the mid-axillary line. They go in the same horizontal line as V4.

Electrode Placement for Women

Electrode Placement for Women

Asking a female patient to disrobe can be uncomfortable for the EMS provider, at first. Be professional. Explain to the patient what you plan to do in terms of electrode placement; emphasize that several of the chest leads may need to be placed around and under the left breast.

Have a patient gown available for the patient to use after removing her clothing.

If the patient’s left breast is large enough to cover the V3, V4, or V5 placement area, it will have to be lifted up for proper electrode placement. If possible, you can ask the patient to lift her own breast. Alternatively, use the back of your straightened hand to displace the breast.

Electrode Placement for Bariatric Patients

Electrode Placement for Bariatric Patients

Obese patients may appear to be more difficult at first to accurately place electrodes. The trick is to spend a few extra moments locating the anatomic landmarks. Palpate more deeply to feel the sternal border and Angle of Louie to place leads V1 and V2. V4 is usually located in a straight line below the nipple at the fifth intercostal space. Then, imagine a line track straight down the left lateral side of the chest. Along this line, at the mid-axillary line is the location of lead V6.

Once these leads are placed, then V3 is placed halfway between V2 and V4. Finally, V5 is placed halfway between V4 and V6.

Electrode Placement for Pregnant Patients

Electrode Placement for Pregnant Patients

Despite the appearance of the abdomen during advanced pregnancy, the placement of the electrodes is the same. You can use the technique above if necessary.

Note that left-axis deviation on the ECG may appear in both pregnant and obese patients. This is due to the abnormal position of the heart as the diaphragm pushes high into the thoracic cavity.

Electrode Placement for Pediatric Patients

lectrode Placement for Pediatric Patients

Use smaller electrodes specific to children. Adult electrodes will overlap and potentially cause inaccurate placement. For preschool-age children and older, take time to explain what you are doing. Young children will be fearful of the procedure and may imagine that it will hurt, or that you will shock them. Having a parent close by will help provide reassurance.

Obtaining 12-Lead ECG in Extreme Environments

Extreme heat or cold will affect the integrity of the electrode’s conducting gel. During the cold winter or hot summer months, check to make sure that the electrode bag is kept in a location that minimizes dramatic temperature shifts.

Acquisition Tips to Minimize Artifact

Movement of any sort has the potential to create excessive artifacts in the ECG. Consider these tips:

If your patient is shivering, cover the skin with a light sheet and consider using a small heat pack to provide a sense of comfort. Turn the thermostat in the ambulance up to keep the patient warm.

The patient should be in a semifowler’s position.

Ask the patient to simply breathe normally and keep their hands by their sides. This prevents them from gripping the handrails too tightly, which can cause minute muscle tremors that show up on the ECG as artifacts.

There should be some “slack” in the patient cables. If the cable is taut between the electrode and the monitor, adjust the cable to release the tension.

With practice and preparation, obtaining a clean 12-lead ECG every time will be easier to accomplish. Your confidence in acquiring an accurate tracing will decrease the time it takes to decide how to manage and transport the patient who is experiencing ACS, and increase the chance of survival and recovery.


A quality 12-lead ECG has a smooth, flat baseline (called the isoelectric line). Baseline wander, or the vertical motion of the ECG line, can mask important findings in the ECG tracing and result in a non-diagnostic ECG.

The patient should remain motionless and lay as close to supine as possible for the acquisition of the tracing and the ambulance should be stopped and not move during the process. It sometimes takes a few minutes for the ECG tracing to normalize and you should wait for it to do so. The goal is to be able to see the entire cardiac waveform clearly and be able to measure accurate ST-segment levels. Skin prep is important to reduce artifacts. A tracing with artifact or baseline wander can mask serious ECG findings and may cause a patient to be misdiagnosed.