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Conference season

So it’s March and conference season has begun.

In the world of cardiology there is a rhythm to the year with major announcements being made at the large American and European conferences, and smaller trials being flagged at the subspecialty conferences.

The American College of Cardiology meeting was earlier this month, with major news about the PCSK inhibitors (new fangled drugs for cholesterol) and news regarding His bundle pacing (see separate post).  I didn’t get to go, but kept up to date by the bloggers at the conference in particular Dr John Mandrola from the heart.org, as well as the ACC and ESC video coverage.

I did get to go the European Heart Rhythm Association meeting in Barcelona.  I was pleased to win a grant from the European Society of Cardiology to fund attendance.

It was a small meeting which meant is was easy to get around and go to interesting sessions by the greats in Electrophysiology.  Particularly good were the prize lectures by Dr Johnathan Kalman on atrial arrhythmias and Dr Josep Brugada of the eponymous Brugada syndrome about the genetic basis of rhythm disorders.

It’s a fantastic way of keeping uptodate with the latest developments in the specialty, and to network with colleagues across Europe – I met co-investigators for some of my research studies from Poland and the Czech republic as well as the UK.

Fitbit – curse or cure?

I’ve seen a few patient now because they’ve been worried about their Fitbit heart rate reports.

The Fitbit is an amazing bit of kit that can constantly monitor your heart rate. It’s worn on the wrist and is a step up from the older chest strap monitors that are widely used in sport, mainly because their convenience means they can be worn all the time.

This means the Fitbit is generating huge amounts of data on heart rate that we simply have never seen before as doctors. We’ve had the ability to accurately record continuous heart rate and ECG monitors for some years but these are complex devices put on by medical professionals and simply aren’t as widely used as a Fitbit. They are also mostly used in people with a high probability of heart rhythm problems rather than the healthy fitness focussed population.

Some people who feel well otherwise may see their heart rate is outside the normal range and unsurprisingly worry about it.

Most people who see me are worried that their heart rate is too slow at times. They can google it and find lots of information about fast heart rates but not necessarily slow heart rates.

Most people will have nothing to worry about, especially if they have no symptoms like feeling faint or fatigued; and if their heart rate goes up normally with exercise.

There are diseases such as sick sinus syndrome or heart block that can cause slow heart rates – these usually are picked up because of fainting or a constant very slow heart rate in the 30-40’s. This can be successfully treated with a pacemaker. More difficult is people who have a generally slow rate even on exercise – something known as chronotropic incompetence which can also be treated with a pacemaker.

Constantly rapid heart rates are worth investigating – some rhythms such as atrial fibrillation or slow atrial tachycardia can occur without symptoms and cause impaired heart function simply as a function of a rapid rate (over 100beats per minute) for weeks on end.

So the Fitbit is a helpful piece of technology which can certainly help to motivate and inform exercise programs. I’m sure it will pick up people who do have concerning heart rhythm problems but this will be a rare event!

Radiotherapy for Ventricular tachycardia

An amazing article in the New England Journal of Medicine this week.

This is the preeminent medical journal across the world. They’ve just published the experience of 5 patients who had radiotherapy to treat ventricular tachycardia.

Ventricular tachycardia is a dangerous heart rhythm disturbance that is most frequently caused by electrical short circuits around scar tissue in the heart. The heart can go very fast and not beat efficiently.

Most patients get a defibrillator to prevent sudden death, but this doesn’t prevent the tachycardia from happening – it just deals with the consequences.

Usual treatment is medications – where this fails ablation can be used. This involves putting wires into the heart to deliver microwave energy to burn tissue around the scar that is not working properly but can conduct electricity. This (hopefully) prevents the short circuit in the heart.

Problem is we can get to the muscle on the inside the heart and outside the heart but can’t easily deal with the muscle in-between.

These procedures take 4-8 hours under a general anaesthetic and can be very risky – my last patient we thought had a 20% risk of death from the procedure (he did ok and got home!)

This new method is completely different. An electrical map of the heart is created using an ECG vest and a CT scan that locates the scar. Radiotherapy is delivered around the scar and the procedure takes minutes. It takes time for the cells to react and the procedure to work but these patients had their ventricular tachycardia practically disappear.

Now there are lots of questions to answer about this – larger trials are needed to see if it really does work so well, how long it lasts, if there is collateral damage to the rest of the heart or organs but this is potentially a game changer in the field. You can see why it got published in the top journal. Here’s hoping it develops well and works out because it could transform our care of these patients.

High blood pressure – just got higher?

So the big news this week is that the American Heart Association has just released new guidelines.

What does that have to do with us? Well the UK and European guidelines all look at the same research studies and no doubt they will be updated soon.

The new guidelines define high blood pressure as greater than 130mmHg systolic and 80mmHg diastolic.

This is lower than before but the guidance on labelling and treatment is a little more complicated. Essentially if there are any risk factors such as being older or having diabetes then we should aim to get down into the normal range.

This is supported by the Sprint trial which was published in 2015, which actually suggested lower pressures of down to 120mmHg were better still, but given the fact that trial populations are quite tightly controlled he guideline committee went for a higher target for the general population.

The bottom line is that we should all look at our blood pressure and try to manage our weight, salt intake and exercise to keep the pressure normal. Many people will need medications also to help keep in a normal range and stay hale and hearty for longer!

What does systolic and diastolic mean?

The heart pumps blood every beat – so the systolic blood pressure is the higher number just after the heart contracts, and the lower number is the diastolic pressure which is what the pressure falls too when the heart is relaxing and the valves are closed to prevent blood rushing back to the heart.

mmHg??

The unit is a millimetre of mercury – that’s right – blood pressure was first measured by connecting a column of mercury to the arterial circulation of dogs and horses to see what height it would rise to (Poiseuille, 1828)! They needed a denser and so heavier fluid than water to fit in a column. We still use the units today – there was a push to change to SI units – kilo pascals but it never took off.

To stent or not to stent? The impact of the ORBITA study

Stents are metal scaffolds, usually coated in drugs, that can be inserted into narrowed coronary arteries to unblock them.

Stents have been around since the end of the last century and have been getting better ever since – more flexible and now have drugs on them.

Initially these were used for stable patients with angina to relieve symptoms.  Over the last couple of decades, we have shown that they are brilliant treatments for heart attacks.

But it’s taken until now to for someone to do a proper randomised, controlled trial to look at their use in stable patients.

Dr Al-Lamee and colleagues from Imperial College and across the UK published the ORBITA study in the Lancet last week.

This is a landmark study which looked at patients with chest pain on exertion, treated them with medicines. and if they still had angina randomised them to either a stent or a sham procedure.

A sham procedure is one where catheters are placed in the heart, but no stents are placed.  The patient stayed on the operating table for some time, the patient had headphones on and didn’t know if they were getting a stent or not, and the doctors in the cath lab doing the procedure weren’t involved in the patient’s care afterwards.  A proper double blind (neither the patient nor the treating doctors) knew which treatment that they had.

6 weeks later they looked at symptoms using questionnaires and exercise capacity.  There was no difference between the groups!

This is a shocking result.

They clearly had enough patients to detect a difference (it was sufficiently powered), they demonstrated significant blockages that were successfully unblocked with stents, but it made no difference to the patients.

The article suggests that worldwide there may be 500,000 stents placed in patients similar to those studied in this paper – this paper may well change guidelines and practice.

Great to see the UK leading the world in doing proper, useful research that changes how we treat patients.  Also there are lessons to be learned in how we improve treatment with medications.

High Cholesterol, now what?

In the last few weeks I’ve been asked about high cholesterol by family and fellow doctors.
Now that cholesterol checks are so easily done, the harder thing is understanding the result and what that means for you.
A bit of background – cholesterol is a fat that is necessary for the walls of all cells.  It is carried around the bloodstream in 2 different types of proteins – Low density (LDL) and High density (HDL).
High LDL levels are associated with a higher risk of heart attacks, strokes and peripheral vascular disease.
Higher HDL levels seem to be protective.
So the first thing to look at when the total cholesterol is high, is to look at the breakdown into HDL and LDL.
What to do about high LDL levels?  It depends on the overall risk of problems.
In the UK the 10 year risk is usually estimated using the Qrisk calculator. The main determinant of risk is age and you can plug your numbers into the online calculator (qrisk.org).
People in their 40’s are likely to be at lower risk, particularly if you don’t smoke, don’t have diabetes and exercise regularly.
There is good evidence that if your risk of running into problems over the next 10 years is high, then using statins can lower that risk by 20-30%.
However most trials have focussed on people with a high risk of problems.  This is obviously because these people have the most to gain, and it’s the easiest to demonstrate a difference with treatment.
For example, the WOSCOPS study in Scotland enrolled patients with an LDL > 4mM (average 5mM) and lowered it to 3.9 with 5 years of pravastatin and demonstrated a significant reduction in cardiovascularly endpoints and a nearly statistically significant reduction in mortality. (P=0.051). Benefits were maintained out to 15 years.
The Jupiter study looked at people with a mean LDL of 2.8mM and an elevated CRP (>2) suggestive of inflammation, and did find a small benefit.
Current recommendations suggest it is not worthwhile treating patients with a patient 10 yr risk <5%(European guideline), and do suggest treating if risk is >7.5% (US guideline) or >10% (NICE UK guideline)
Lowering LDL with lifestyle measures or non-statin drugs has not been proven to reduce risk. The data regarding dietary measures indicates that most people can lower their LDL by ~5%, but if you have a bad diet to start with you can see reductions of up to 30%.
There’s no real data about long term statin therapy to extrapolate results from shorter term trials. It’s also unknown if treating patients earlier is better than leaving treatment until risk increases.
So to sum up I personally wouldn’t panic if my cholesterol were high – I would consider getting a high sensitivity CRP test (one that can detect a level of <5) and check your Qrisk score.  And be sensible about lifestyle – at least half an hour of brisk walking a day, not too much salt or alcohol, and a balanced diet with plenty of vegetables and fish.

Healthy Heart Blog

A start to blogging!

A few posts on the intersection of cardiac research and common questions from patients and colleagues.

Cardiology probably has the biggest evidence base of any specialty – but it makes you realise that there’s even more we don’t yet know!

Hopefully this will prove to be helpful to patients, colleagues, and myself