45% of those with heart disease have OSA

OSA has long been known to increase your Cardiovascular (heart attack) and Cerebrovascular (stroke) risk. The constant drops in your oxygen levels known as desaturations, cortical arousals, and cardiovascular responses can have significant detrimental effects on your cardiac state, and predispose to heart disease.

We’ve known about this link for a long time, and we’ve advocated screening for OSA in all people with heart disease.

A recent multicentre observational study by Furlan et al (1) has confirmed the extremely high prevalence of OSA in those with known Coronary Artery Disease.

The study looked at over 1300 adults over the age of 18 from another multicentre study (Sleep and Stent Study), across multiple countries. These adults underwent percutaneous coronary intervention (PCI) for known coronary artery disease – ie. atherosclerosis, blockages inside their coronary arteries, angina, and heart attacks.

OSA was found in 45% of individuals with Coronary Artery Disease!

Given this extremely high prevalance of OSA, we highly recommend you have an in-hospital Sleep Study if you have Coronary Artery Disease, including:

•  Atherosclerosis
•  A history of angina or heart attacks
•  Coronary blockages needing ballon / stent insertion
•  Coronary bypass surgery

 Your heart health is important to us. Contact us now for an appointment.


1. Furlan et al. Am J Respir Crit Care Med. 2015.

© APSS 2015

OSA and Congenital long QT syndrome

We’ve long known OSA has been associated with a higher prevalence of AF, and worsening AF control. We now know it’s also associated with many Cardiac Arrhythmias, including deadly Congenital long QT syndrome (LQTS).

LQTS is characterised by prolonged ventricular repolarization and increased risk of torsades de pointes. Those with LQTS usually present with seizures, syncope, even sudden cardiac death (SCD).

Shamsuzzaman (1) looked at patients with LQTS and performed sleep studies in them, and (not un-expectedly) they concluded that OSA in these patients were asscoiated with a worsening of their LQTS.

•  OSA worsens QTc
•  Worsening QTc is a biomarker for sudden cardiac death
•  This worsening in their QTc was during wake, as well as sleep!

OSA has a profound impact on your Cardiac burden.

Adelaide’s resident Specialist Cardiologists at the Centre for Heart Rhythm Disorders (2) agree that it’s time we all acknowledged OSA’s impact on Cardiac Arrhythmias.

If you have a cardiac problem, whether it be a rhythm problem or otherwise, see us now.

1. Shamsuzzaman et al. Sleep 2015.
2. Dr Rajeev Pathak, Dr Rajiv Mahajan, Dr Dennis Lau, Prof Prashanthan Sanders. Sleep 2015

© APSS 2015

Urgent recall : Resmed ASV machines could increase mortality risk in heart failure

Central Sleep Apnoea (CSA) in the setting of Heart Failure usually presents as Cheyne Stokes Respiration (CSR) on a sleep study. One of the ways to attempt to correct CSR is with a particular kind of PAP machine called “ASV”… Auto Servo Ventilation.

ASV machines map your breathing, and apply particular pressures on a breath-to-breath basis.

Today, Resmed released an Urgent Recall of their ASV machines because of an apparent safety concern.

Preliminary analysis of their data suggests an exceedingly high risk of cardiovascular death (33.5% higher) in those with Heart Failure using ASV, compared to those not on ASV.

At Adelaide Sleep, we keep abreast of all new Sleep Developments. All of our patients are consulted before and after their sleep studies, and before and after their treatment commencement, as per the current recommendations by the Australasian Sleep Association (ASA). We do not believe in direct-CPAP-outlet sales, nor do we believe in direct-to-consumer-sleep-study services. By seeing a Medical Specialist, you would’ve had a face-to-face medical consultation regarding your ASV machine.

If you believe that you are on an ASV machine, and would like to speak to a Medical Specialist regarding this, contact us now.

Addit : Philips Respironics have also released a statement echoing that of Resmed – caution in prescribing and using their BiPAP autoSV / BiPAP autoSV Advanced therapy machines and algorithm, in the at-risk group.

© APSS 2015

CPAP prevents Atrial Fibrillation (AF) in OSA

Previously we described how those with Obstructive Sleep Apnoea (OSA) have a 4-fold increased risk of Atrial Fibrillation (AF)… and how it also significantly increases the risk of recurrence to AF even after procedures such as cardioversion and cardiac ablation.

There is now evidence that treating OSA with CPAP can significantly decrease AF recurrence.

Shukla et al performed a meta-analysis across seven large cardiac studies, totalling over 1000 patients with OSA+AF. If you have OSA+AF, and use CPAP, then your relative risk (RR) is reduced by a tremendous 42%. This was completely independent of whether or not you underwent cardiac ablation!

This confirms our understanding of why OSA is such an important and underestimated condition. CPAP prevents atrial fibrillation recurrence in those with OSA.

We recommend that everyone with AF should consider an in-hospital sleep study.

Contact us now if you’d like to discuss this further.

1.Shukla et al. JACC Electrophysiol. 2015.

© APSS 2015

High blood pressure and Sleep Apnoea : an often overlooked link

There are many reasons why someone’s blood pressure may be high, including genetic reasons, dietary reasons, and cardiac reasons. But did you know that one of the most important (and often missed) contributors is Obstructive Sleep Apnea?

The common link between Obstructive Sleep Apnoea (OSA) and Hypertension (high blood pressure) has been known for a long time, and yet we all still overlook this. There is significant literature regarding the link between the two.

More recently, an analysis of the heartBEAT study by Walia et al(1) showed an association between severe untreated Obstructive Sleep Apnea and resistant Hypertension. This was even whilst on blood pressure medications!

They found those with Severe OSA had a 400% higher risk of resistant hypertension. Medications often did not help, unless the OSA was treated.

The messages from this study are simple : Always think about OSA in those with hypertension, always exclude OSA first…


Key points :

•  OSA is a recognized major contributor to Hypertension
•  On more than 2 antihypertensives… think OSA!
•  Not responding to blood pressure medications… think OSA!
•  OSA increases risk of treatment-resistant hypertension by 4x


Our Adelaide sleep doctors can consult you, perform and report your sleep study, and your Adelaide sleep specialist will commence you on treatment. Give our Adelaide sleep clinic a call now.

1. Walia et al. J Clin Sleep Med. 2014;10:835-843

© APSS 2014

Atrial Fibrillation (AF) and OSA

Obstructive Sleep Apnoea is associated with diabetes, hypertension, erectile dysfunction, glaucoma, and of course heart disease. One of the more exciting and new links is between Atrial Fibrillation (AF) and OSA.

Both conditions are very common. AF is the most common cardiac arrhythmia in Australia, and OSA affects upto 24% of men and 9% of women. OSA combined with sleepiness (OSA Syndrome) occurs in 4% of men and 2% of women (1).

Patients with AF and those with OSA share similar demographic features – they are more likely to be male, hypertensive, of an older age, and have a higher body mass index. However, this link is much more than statistical chance.

Many studies have established that patients with severe OSA are significantly more likely to develop AF, increasing their risk by four times (2).

OSA decreases the likelihood of successful cardioversion (from medications or electrically) and increases the risk of AF returning. The recurrence rate of AF after cardioversion can be as high as 82% (3).

AF also recurs more often in those with OSA after radiofrequency catheter ablation (4).

According to Sleep Disorders Physician Dr Dien Dang, this is unsurprising considering the severe degree of haemodynamic compromise that occurs with OSA.

“OSA causes severe desaturations, cyclical hypoxaemia, and can structurally change your heart over time,” said Dr Dang, “Everyone who has ever had AF should consider a Sleep Study at Burnside Hospital.”

•  The OSA and AF population overlap considerably.
•  OSA can affect AF profoundly
•  Untreated OSA increases AF risk by 4x
•  Untreated OSA increases cardioversion failure by 4x


If you have Atrial Fibrillation, call us now for an in-Hospital Sleep Study.

1.  Young et al. NEJM 1993
2.  The Sleep Heart Health Study. AJRCCM 2006
3.  Kanagala et al. Circulation 2003
4.  Naruse Y et al. Heart Rhythm. 2012

© APSS 2014