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.