AF & COPD Flashcards
what is atrial fibrillation
A type of supraventricular tachyarrhythmia. Characterized by uncoordinated atrial activity on the surface ECG with fibrillatory waves of varying shape, amplitude, and timing associated with irregularly irregular ventricular response when atrioventricular conduction is intact
pathophysiology of atrial fibrillation
- Rapidly firing ectopic foci located inside 1 or more pulmonary veins
- Abnormal atrial tissue substrate - ↑ atrial pressure, ↑ atrial muscle mass, atrial fibrosis, inflammation and infiltration of the atrium
- Only a proportion of electrical impulses in the atria reach the ventricles electrical re-entry which then results in atrial fibrillation
what are the different types of atrial fibrillation
initial episode - AF > 30 second diagnosed by ECG
paroxysmal - recurrent 2 or more episodes that terminate within 7 days
peristent - continuous > 7 days or AF > 48 in which a decision is made to perfrom CV
long standing - continuous AF for > 12 months
permanent - joint decision by patient and clinician to cease further attempts to restore or maintain sinus rhythm
aetiology of AF?
- in developed country most common HTN, coronary artery disease and MI
- in developing country most common congestive heart failure, HTN and rheumatic valvular disease
- Cardiac conditions Sinus sick syndrome (electrophysiological abnormalities), Wolff-Parkinson-White syndrome, Cardiac surgery, congenital heart disease, tumour near heart
- Infections pericarditis, amyloidosis, myocarditis
- Alcohol intoxication/Caffeine/Drugs
- Hyperthyroidism/thyrotoxicosis
- Lung cancer/PE
- Diabetes
- Obesity
- Idiopathic – 11%
clinical features of AF
palpitations tachycardia irregularly irregular pulse SOB chest pain dec exercise capacity/fatigue stroke as 1st presentation elevated JVP hypotension - AF induced haemodynamic instability
investigation for AF
feels for irregularly irregular pulse
ECG - if AF, will show fibrillation, irregular ventricular rate (RR intervals), no clear P waves, QRS rhythm is rapid and irregular
if paroxysmal AF is suspected and no AF recorded in initial ECG –> 24 hour ambulatory ECG
FBC, U&E, TFTs
CXR to exclude HF or resp. causes
Transthoracic echocardiography in those confirmed with AF - find any structural heart causes and baseline for long-term management
when will you admit a person with AF to hospital
if severe symptoms/serious complication
- pulse > 150
- BP < 90
- LOC / severe dizziness/ongoing chest pain/inc SOB
mx of acute AF
cardiovesion - electrical DC shock/IV drugs if - new-onset AF (<48 hours) - AF with a reversible cause - heart failure a cause \+ atrial flutter
- If unstable electrical DC shock + IV amiodarone after
- If stable either DC shock of IV amiodarone at a later stage
- A transesophageal echo is done to look for clots in heart before cardioversion otherwise it can dislodge and case a stroke or anti-coag for 4 weeks before cardioversion
Rate control - B-blocker, CCB or digoxin
Rhythm control - amiodarone
Anti-coag - after CHA2DS2-VASc and HAS-BLED
- DOAC as 1st line
- warfarin if mechanical valve, aortic stenosis or rheumatic fever
mx of chronic AF
- Rate controlling drugs – beta blockers, Ca channel blockers
- Antiarrhythmic drug – Quinidine, Beta blockers, amiodarone
- CHA2DS2-VASc for stroke assessment + HAS-BLED for bleeding risks
- Oral anticoagulant e.g. warfarin, NOACs – need to be calculated by the CHA2DS2-VASc scoring system
what is discussed in AF annual review
- Follow up 1 week after starting rate control treatment
- Check symptoms at rest and during exercise/assess HR
- If not controlled consider increasing dose/combining any 2 of beta blockers/digoxin/diltiazem (check this + beta blocker with specialist)
- If still not controlled refer within 4 weeks to cardiologist
- Side effects
- HR/BP
- Calculate TTR to ensure an INR of between 2 and 3 with warfarin
- Exclude measurements taken within the 1st 6 weeks of treatment
- Calculate over a maintenance period of at least 6 months
- If poor control then attempt to correct contributing factors/switch to NOACs
pathophysiology of COPD
poorly reversible airflow limitation that is usually progressive
associated with persistent inflammatory response of the lungs
chronic bronchitis
- airway narrowing
- hypertrophy and hyperplasia of mucus secreting glands
- bronchial wall inflammation
- mucosal oedema
- epithelial cell later may ulcerate
squmaous epithelium may replace columnar epithelium when ulcers heal –> squamour metaplasia
emphysema
- dilatation and destruction of the lung tissue distil to the terminal bronchioles
- loss of the elastic coil
- expiratory airflow limitation and air trapping
- smoking > 20 years
what scale is used to classify COPD
Medical Research Council Dyspnoea Scale
Grade 1 - breathless on strenuous exercise
Grade 2 - breathless on walking up hil
Grade 3 - breathless that slows walking on the flat
Grade 4 - stop to catch their breath after walking 100 meters on the flat
Grade 5 - unable to leave the house due to SOB
investigation of COPD?
MRC Dyspnoea Scale
spirometry - PEV1/FVC ratio < 0.7
CXR - hyperinflation and to exclude other diagnosis
FBC - anaemia, inc haematrocrit, polycythaemia, eosinophil count, sputum culture BMI ECG ECHO BNP Alpha 1 antitrypsin
what is used to assess the severity of COPD?
GOLD framework
what is the single most important diagnostic test for COPD
spirometry with bronchodilator reversibility test
- FEV1/FVC < 0.7
what are the different stages of COPD?
Stage 1, mild — FEV1 80% of predicted value or higher. With these values, a diagnosis of COPD can only be made on the basis of respiratory symptoms.
Stage 2, moderate — FEV1 50–79% of predicted value.
Stage 3, severe — FEV1 30–49% of predicted value.
Stage 4, very severe — FEV1 less than 30% of predicted value.
what is considered to be asthma features
previous diagnosis of asthma or of atopy, a higher blood eosinophil count, substantial variation in FEV1 over time (at least 400ml) or substantial diurnal variation in peak flow (at least 20%)
management of COPD without asthma features
1) SABA or SAMA PRN
2) LABA + LAMA
