24 hr ECG Interpretation 17 th September 2015

24 hr ECG Interpretation 17 th September 2015 Trinity Park, Ipswich Andrew Chalk, Chief Cardiac Physiologist Jamie Williams, Senior Cardiac Physiologist

Learning objectives • • • Ambulatory monitoring: a brief introduction The “standard” 24 hr ECG report ECG rhythm interpretation Cardiologist support Summary Questions

Indications for ambulatory monitoring • Syncope “People with a suspected cardiac arrhythmic cause of syncope are offered an ambulatory electrocardiogram (ECG) as a first‑line specialist cardiovascular investigation” (NICE Quality Statement, 2014). • Palpitations • Presyncope • Rate control in AF patients

Ambulatory Monitors Holter monitors (spacelabs) • 3 electrodes, usually 24 hrs (48 -72 hr) External event recorders (R test, Novacor) • 2 electrodes, loop recorder, patient activated and also device will record “important” events, 1 -4 weeks Implantable loop recorder (Reveal, Medtronic) • Surgical implant, regular follow ups in CRM clinic, patient activated and also device will record “important” events, 2 -3 yrs

So what happens when the patient returns the monitor…? • Analysed by the Physiologist Team • Report generated • D/w Cardiologist if any concerns

The standard report • Predominant rhythm (? normal intervals and rates) • Important observations (e. g. pauses, sustained tachycardias) • Ventricular ectopics • Supraventricular ectopics • Bradycardias • Any other arrhythmias • Patient diary events

Predominant rhythm • Are there P waves present? Are they normal? • Is the PR interval prolonged? (120 -200 ms) • Is the QRS complex normal duration? (<120 ms) • Is there a sufficient HR variability? - HR range - Mean HR • Are they any paroxysmal rhythms (? PAF)

Normal sinus rhythm

1 st degree AV block (prolonged PR interval >200 ms) Junctional rhythm (inverted P wave)

Atrial fibrillation Atrial flutter Paroxysmal atrial fibrillation

Important observations • Pauses – type, duration, diurnal/nocturnal - Sinus pauses/arrest - 2 nd degree AV block (Mobitz type 1 & II) - 3 rd degree AV block Sinus Arrest

Advanced AV block 2 nd degree AV block (Mobitz type I, Wenckebach) 2 nd degree AV block (Mobitz type II)

Advanced AV block 3 rd degree AV block Ventricular standstill

• Sustained arrhythmias - Broad complex tachycardias (Sustained/Nonsustained ventricular tachycardia) - Supraventricular tachycardias (SVT)

Ventricular ectopics • How many? Alternative focus? Runs of VE’s? Salvos, bigeminy, trigeminy?

Ventricular bigeminy Ventricular trigeminy

Supraventricular rhythms Supraventricular/atrial ectopics (SVE’s)

Supraventricular tachycardia (SVT)

Quantifying arrhythmias • • • Very occasional: ≤ 10 Occasional: 11 – 1499 Moderate: 1500 – 2499 Frequent: >2500 Very frequent: > 25% of total beats • 60 bpm x 60 minutes x 24 hrs = 86400 beats per day

Sinus bradycardia Chronotropic incompetence • Inability for heart to > rate in relation to > physical demand • Fatigue/SOB • SSS

Patient diary • Very important each patient has one • We check 5 minutes pre and post documented time • Confirm/rule out cardiac cause of symptoms • Noctural/diurnal bradycardia • Patient exercising or cardiac arrhythmia? ?

Cardiologist Support for Physiologists Urgent discussion if… • Sinus pauses >3 seconds • Ventricular pauses >3 seconds • Mobitz type II, 3 rd degree AV block • Diurnal heart rates <40 bpm • Sustained (>30 secs) atrial fibrillation/flutter/ SVT >120 bpm • Recurrent (>1 episode) ventricular tachycardia • Prolonged (≥ 5 beats) ventricular tachycardia

Summary • • Examples of available ambulatory monitors Explanation of physiologist reports ECG interpretation Cardiologist support

References • Houghton, A and Gray, D. (2015). Making Sense of the ECG: A hands on guide, 4 th Edition. Taylor & Francis Group, UK • Thaler, M. (2015). The Only EKG Book You’ll Ever Need, 8 th Edition. Wolters Kluwer, USA • Hampton, J. (2013). The ECG in Practice, 6 th Edition. Churchill Livingstone Elsevier, UK • Nice (2015). Quality statement 6: Specialist cardiovascular investigation – ambulatory electrocardiogram (ECG). www. nice. org. uk/guidance/qs 71 • American Heart Association Journal – Circulation • BMJ Journal – Heart

Any questions? andrew. chalk@ipswichhospital. nhs. uk andrew. chalk@nhs. net