09: Cardiac Investigations: Other monitoring
Person with palpitations/syncope
Which test would you recommend and why?
Which test interactive
Case study 1: Patient presenting with palpitations
George Brown, age 68, presented to his GP, with a 3-4 week history of palpitations – he describes episodes where he feels his heart is “racing” and “jumping about all over the place.”
On taking a full clinical history, the GP learns that:
- The palpitations usually occur when George is lying in bed at night and can waken him up from sleep
- An episode usually lasts for a few minutes but on one occasion, lasted about 15mins and made him feel sweaty and short of breath - he was going to call for help but then it settled
- It appears to be after spending the evening in the pub having a few drinks
Past medical history - High blood pressure, has been prescribed Lisinopril
Other cardiovascular risk factors - Smoker of 20 cigarettes per day
Clinical examination - Normal
Blood tests are sent off to the lab - to check U&Es, LFTs and Thyroid function
12-lead ECG – Normal sinus rhythm
Q1: What do you think is the most likely cause of the palpitations?
- VT – No, the patient would likely feel more unwell with this and may experience syncope
- Heart block – No, this is unlikely if the patient feels his heart is racing
- AF – Yes this arrhythmia is commonly triggered by alcohol or caffeine
Q2: Which test do you think the GP should order in the first instance?
- Admit to hospital for continuous monitoring – Not necessary since the patient is currently stable and in SR
- 48 hour Holter monitor – Yes, the GP asks the patient to wear this over the weekend, continue his normal activities and note in the diary the time of any symptoms
- Event monitor – Not in the 1st instance but may be required if symptoms are not experienced whilst wearing the Holter
What happens next to George?
The GP receives the result of the Holter monitor, which confirms his suspicion that George is experiencing paroxysmal atrial fibrillation (PAF). The tape shows mainly sinus rhythm, with 1 supraventricular ectopic and 2 episodes of AF. One of these lasted only about 10 seconds, at a ventricular rate of 84bpm, and was not associated with any symptoms. The other episode lasted about 10 minutes, at a ventricular rate of 147bmp, and occured about 4am on Sunday morning. George noted in his diary that he felt "chest discomfort, sweaty, short of breath and heart racing".
The GP refers George to the nurse led AF clinic for a full risk assessment and to commence treatment. (NB not all health board areas offer a nurse led clinic. Where this is not available, the GP would most likely refer George to a cardiology clinic or manage George in primary care. George will be seen at the clinic within 2 weeks, for a full risk assessment and to start treatment.
To learn more about risk assessment and treatment of AF, see the Atrial Fibrillation module.
Case study 2: Patient presenting with syncope
Mary Smith, age 72, presented to the GP, with a history of 2 episodes of “fainting” in the last 3 months; the last time was about 2 weeks ago.
On taking a detailed clinical history, the GP learns that:
- Each episode of fainting happened suddenly, without any warning signs
- There did not appear to be any triggers such as a hot environment, undue exertion or standing still for a long period etc; Mary was out doing some shopping
- Her husband thought she was probably unconscious for about a minute or two, although it felt like much longer
- Mary felt completely fine when she came around again
Past medical history:
- Previous MI and LAD angioplasty 2 years ago
- Evidence of LV dysfunction and LVH on echo about 6 months ago
- No previous history of fainting
Cardiovascular risk factors:
- Essentially normal
- No evidence of postural hypotension
Blood tests are sent off to the lab - to check U&Es, LFTs, FBC
12-lead ECG – Nil acute but Q-waves anteriorly.
The GP suspects cardiac syncope and makes a referral to Cardiology.
He advises Mary that if this occurs again, that she or her husband should immediately call 999 so that she can be checked out more fully at that time.
Q1: What do you think may be the arrhythmia causing the syncope?
- Complete heart block: Yes, this is possible.
- 1st degree heart block: No, this is very unlikely unless the heart rate is also very low.
- Asystole: Yes, a very brief period of asystole is possible.
- Sinus tachycardia: No, this is unlikely.
- VT: Yes, this is possible.
- SVT: Yes, this is possible.
Q2. Which test/s do you think the GP should order in the first instance?
- 24 hour Holter monitor: Yes, the GP will likely order this in the first instance as it can be done right away.
- External loop recorder: Yes, the GP can arrange for this to be fitted as soon as possible, if the Holter does not show anything.
- Implantable loop recorder: Yes, this is more likely to pick something abnormal up but there may be a slight delay organising this so the Holter and external loop recorder can be done in the meantime.
- Event monitor: No, this would not be appropriate as Mary does not experience any warning signs.
- Exercise tolerance test: No, there is no indication that Mary’s symptoms are related to exertion/exercise.
What happens next to Mary?
As the GP expected, the Holter monitor does not show up anything and neither does the external loop recorder. However, a few months after Mary's implantable loop recorder is fittted, she experiences another syncopal episode. There is evidence that she had an episode of asystole at this time, lasting about 8 seconds.
Mary had been given a future appointment to be seen at a cardiology clinic but, because her husband calls 999 at the time of her collapse, she is admitted to hospital and transferred to the coronary care unit for full assessment and treatment. She has a permanent pacemaker fitted before discharge.
“Syncope is a transient loss of consciousness due to transient global cerebral hypoperfusion, characterised by rapid onset, short duration and spontaneous complete recovery.” (Moya A, Sutton R, Ammirati F, et al. 2009. Guidelines for the diagnosis and management of syncope. Eur Heart J. 30(21):2631-2671)