Post-operative arrhythmias

Post-operative arrhythmias

Aug 23, 2015 0
cardiology,general surgery,intensive care,onthepods

James talks to Dr Sean Lal about the management of post-operative arrhythmias on the wards, common causes and an approach to atrial fibrillation as well as bradycardias in this podcast.

Summary Writer:  Angeli Thakkar

Editor:  James Edwards

Interviewee: Sean Lal

About Dr Sean Lal

Dr Sean Lal is a consultant cardiologist who completed his undergraduate and graduate medical studies at the University of Sydney. He undertook general and specialty clinical training at Royal Prince Alfred Hospital.

Sean has a clinical and research interest in heart failure, specifically advanced techniques in cardiac regeneration. He is currently pursuing post-graduate studies in this field through the University of Sydney and Harvard Medical School.

Sean is a Clinical Senior Lecturer at the Sydney Medical School, in addition to being a Lecturer in Anatomy and Head of the Cardiac Research Laboratory in the School of Medical Sciences at The University of Sydney.

 

Post-Operative Arrhythmias 

With Dr Sean Lal, Cardiology Advanced Trainee* at Royal Prince Alfred Hospital, New South Wales, Australia

Case 1

You are asked to see a post-operative patient on the ward with new onset atrial fibrillation. What would be your approach to assessing and managing this patient?

  • Tachyarrhythmia (HR >100) e.g. atrial fibrillation, atrial flutter
    • can be precipitated by hypovolaemia, anaemia or electrolyte imbalances in the post-operative setting
    • exclude infection/sepsis and coronary ischaemia as underlying causes
    • another cause is thyrotoxicosis
  • Sinus Tachycardia
    • can reflect dehydration, however in someone 3-4 days post-op, you need to consider pulmonary embolism
  • What are the vitals? Is the patient symptomatic?
  • What/when was the operation done?
  • Please do a 12-lead ECG and I will come and review the patient
  • 12 Lead ECG
    • Confirm atrial fibrillation or atrial flutter
      • Fibrillation – irregularly irregular tachycardia
      • Flutter – regular; HR approx. 150
  • Ensure the patient is haemodynamically stable
    • Go through ABCDEF and ensure blood pressure is stable
      • It is rare for atrial fibrillation/flutter to cause haemodynamic compromise
      • Normally secondary to an underlying cause e.g. infection that may be causing the patients instability
      • The only situation where atrial fibrillation would cause haemodynamic instability is if Ejection Fraction<20%
  • Is the patient symptomatic? e.g. chest pain/angina; shortness of breath; pre-syncope; palpitations
  • Review the notes
    • Is there a history of arrhythmias or coronary disease
  • If the patient is asymptomatic and haemodynamically stable -> rarely need immediate management apart from correcting the reversible factors
    • 60% of first onset atrial fibrillation will revert overnight with no management
    • Attempt to try correcting reversible factors
      e.g. UEC – K/Mg replacement
      IVF – can raise BP and reduce heart rate
      Give antibiotics if suspecting an infective process
    • Only then consider antiarrhythmic agents:
      • First Line
        • Metoprolol then consider digoxin/amiodarone
          • Metoprolol 25mg BD PO is a good starting point – can wait a few hours after the first dose and give a further 25mg if there is still no/minimal effect
          • **unsafe to give IV metoprolol on the wards
          • Digoxin requires a loading dose of 500mcg PO/IV and then 250mcg 6hrs later and a further 250mcg 6hrs after that
          • **consider IV digoxin if concerned about patients inability to absorb tablets or if patient is NBM
          • Amiodarone bolus of 300mg IV over 45minutes (in HDU/CCU); continuous infusion requires a PICC line as peripheral cannulas can thrombose
  • If it is the first presentation of atrial fibrillation and the patient is symptomatic or tachycardic (HR >150) then they should go to a monitored bed
    • If paroxysmal atrial fibrillation and the patient is asymptomatic there is no need for a monitored bed and they can be managed on the ward
  • If they have not reverted by 24hrs despite correcting reversible factors, consider anticoagulation:
    • Contact surgeons in this setting as anticoagulation depends on their concern regards bleeding risk
      • They may want full anticoagulation – IV heparin +/- bolus dose or clexane at 1mg/kg BD or they may just want aspirin

Case 2

You are asked to see a patient with a HR of 40 whilst sleeping, what is your approach to management?

  • Sinus bradycardia – usually present in young people when asleep
  • Ventricular bigeminy/ectopic beats
  • What are the vitals? Is the patient symptomatic?
  • What/when was the operation done?
  • Please do a 12-lead ECG and I will come and review the patient
  • 12 lead ECG
    • Determine what type of bradycardia the patient is in
      • Sinus bradycardia
      • 1st degree heart block – prolongation PR interval; generally asymptomatic unless very prolonged (in which case most likely some conduction disease)
      • 2nd degree heart block
        • Mobitz T1 – Wenkebach; prolongation of PR interval followed by a blocked P wave (dropped QRS complex)
          • Generally does not require further intervention unless symptomatic
        • Mobitz T2 – intermittent non-conducted P waves not preceded by PR shortening
          • every second P wave may not be conducted to ventricles; can have higher degrees of AV block where more than one or two P waves are not conducted – escape rhythm is coming further down from ventricles
          • needs a monitored bed as can be unstable
      • Complete heart block – atria and ventricles doing two separate things
        • P waves come through; QRS widened suggesting rhythm coming from ventricles
        • Can be quite unstable
        • If narrow complex – suggests junctional escape
        • If wide complex/bundle branch pattern – can be unstable; occasionally need temporary pacing wire even if patient is not unstable
  • Isthe patient symptomatic?
    • g. dizzy/syncope
  • Look for low output states
    • Reduced urine output or rising creatinine
    • Altered mental status or frank acidosis
  • Look at medication chart
    • Is the patient on B-blockers or Ca-channel blockers
    • If the patient is on digoxin ?toxicity
  • Contact cardiology – at any time if concerned
    • If patient symptomatic i.e. chest pain/pre-syncope
    • If clinical evidence of heart failure or compromise
      • What would they expect to be done?
        • 12 lead ECG
        • history and clinical exam ?haemodynamic compromise/murmur; symptomatic – palpitations/syncope/chest pain
      • Who goes to a monitored bed
        • secondary heart failure;
        • Symptomatic or if haemodynamically compromised (consider CCU vs. ICU)
        • asymptomatic HR >150/<40

*This podcast was recorded in 2013 at which time Dr Sean Lal, who is now a consultant Cardiologist, was an Advanced Trainee

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Tags: #Post-operative arrhythmias

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