24hr 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” 24hr 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 24hrs (48-72hr) 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? ( ms) Is the QRS complex normal duration? (<120ms) 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 >200ms) 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/Non- sustained 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 60bpm x 60 minutes x 24hrs = 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 <40bpm Sustained (>30secs) atrial fibrillation/flutter/ SVT >120bpm 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). American Heart Association Journal – Circulation BMJ Journal – Heart

Any questions?