1 ECG RHYTHM ABNORMALITIESDR FRANCIS AGYEKUM PHYSICIAN SPECIALIST/CARDIOLOGIST KBTH/LGH
2 Normal Impulse ConductionSinoatrial node AV node Bundle of His Bundle Branches Purkinje fibers
3 The “PQRST” QRS - Ventricular depolarizationP wave - Atrial depolarization QRS - Ventricular depolarization T wave - Ventricular repolarization
4 Rhythm Analysis Step 1: Calculate rate. Step 2: Determine regularity.Step 3: Assess the P waves. Step 4: Determine PR interval. Step 5: Determine QRS duration.
5 DETERMINE THE RHYTHM
6 Arrhythmia Formation Sinus node Atrial cells AV junctionArrhythmias can arise from problems in the: Sinus node Atrial cells AV junction Ventricular cells
7 SA Node Problems The SA Node can: Sinus Bradycardia Sinus Tachycardia*fire too slow fire too fast Sinus Bradycardia Sinus Tachycardia* *Sinus Tachycardia may be an appropriate response to stress.
8 Atrial Cell Problems Atrial cells can: fire occasionally from a focusfire continuously due to a looping re- entrant circuit Premature Atrial Contractions (PACs) Atrial Flutter
9 Atrial Cell Problems Atrial cells can also:• fire continuously from multiple foci or fire continuously due to multiple micro re-entrant “wavelets” Atrial Fibrillation
10 AV Junctional ProblemsThe AV junction can: fire continuously due to a looping re-entrant circuit block impulses coming from the SA Node Paroxysmal Supraventricular Tachycardia AV Junctional Blocks
11 Ventricular Cell ProblemsVentricular cells can: fire occasionally from 1 or more foci fire continuously from multiple foci fire continuously due to a looping re-entrant circuit Premature Ventricular Contractions (PVCs) Ventricular Fibrillation Ventricular Tachycardia
12 Rhythm #1 Rate? 30 bpm Regularity? regular P waves? normalPR interval? 0.12 s QRS duration? 0.10 s Interpretation? Sinus Bradycardia
13 Sinus Bradycardia Etiology: SA node is depolarizing slower than normal, impulse is conducted normally (i.e. normal PR and QRS interval).
14 Rhythm #2 Rate? 130 bpm Regularity? regular P waves? normalPR interval? 0.16 s QRS duration? 0.08 s Interpretation? Sinus Tachycardia
15 Sinus Tachycardia Etiology: SA node is depolarizing faster than normal, impulse is conducted normally. Remember: sinus tachycardia is a response to physical or psychological stress, not a primary arrhythmia.
16 Sinus arrest is usually a transient pause in sinus node activityEtiology: SA node fails to depolarize and no compensatory mechanisms take over Sinus arrest is usually a transient pause in sinus node activity Sinus arrest may be seen due to increased vagal tone, drug intoxication or sick sinus node syndrome.
17 Rhythm #3
18 Premature Atrial ContractionsEtiology: Excitation of an atrial cell forms an impulse that is then conducted normally through the AV node and ventricles.
19 Rhythm #4 Interpretation? Sinus Rhythm with 1 PVC
20 PVCs Etiology: One or more ventricular cells are depolarizing and the impulses are abnormally conducting through the ventricles. When there are more than 1 premature beats and look alike, they are called “uniform”. When they look different, they are called “multiform”.
21 Ventricular ConductionNormal Signal moves rapidly through the ventricles Abnormal Signal moves slowly through the ventricles
22 Rhythm #5 Rate? 100 bpm Regularity? irregularly irregular P waves?none PR interval? none QRS duration? 0.06 s Interpretation? Atrial Fibrillation
23 Atrial Fibrillation Deviation from NSRNo organized atrial depolarization, so no normal P waves (impulses are not originating from the sinus node). Atrial activity is chaotic (resulting in an irregularly irregular rate). Common, affects 2-4%, up to 5-10% if > 80 years old
24 Atrial Fibrillation Etiology: due to multiple re-entrant wavelets conducted between the R & L atria and the impulses are formed in a totally unpredictable fashion. The AV node allows some of the impulses to pass through at variable intervals (so rhythm is irregularly irregular). Recent theories suggest that it is due to multiple re-entrant wavelets conducted between the R & L atria. Either way, impulses are formed in a totally unpredictable fashion. The AV node allows some of the impulses to pass through at variable intervals (so rhythm is irregularly irregular).
25 Rhythm #6 Rate? 70 bpm Regularity? regular P waves? flutter wavesPR interval? none QRS duration? 0.06 s Interpretation? Atrial Flutter
26 Atrial Flutter Deviation from NSRNo P waves. Instead flutter waves (note “sawtooth” pattern) are formed at a rate of bpm. Only some impulses conduct through the AV node (usually every other impulse).
27 Atrial Flutter Etiology: Reentrant pathway in the right atrium with every 2nd, 3rd or 4th impulse generating a QRS (others are blocked in the AV node as the node repolarizes).
28 Rhythm #7 Rate? 74 148 bpm Regularity? Regular regular P waves?Normal none PR interval? 0.16 s none QRS duration? 0.08 s Paroxysmal Supraventricular Tachycardia (PSVT) Interpretation?
29 PSVT: Paroxysmal Supra Ventricular TachycardiaDeviation from NSR The heart rate suddenly speeds up, often triggered by a PAC (not seen here) and the P waves are lost.
30 Rhythm #8 Rate? 60 bpm Regularity? regular P waves? normalPR interval? 0.36 s QRS duration? 0.08 s Interpretation? 1st Degree AV Block
31 1st Degree AV Block Etiology: Prolonged conduction delay in the AV node or Bundle of His.
32 Rhythm #9 Rate? 50 bpm Regularity? regularly irregular P waves?nl, but 4th no QRS PR interval? lengthens QRS duration? 0.08 s Interpretation? 2nd Degree AV Block, Type I
33 2nd Degree AV Block, Type IEtiology: Each successive atrial impulse encounters a longer and longer delay in the AV node until one impulse (usually the 3rd or 4th) fails to make it through the AV node.
34 Rhythm #10 Rate? 40 bpm Regularity? regular P waves? nl, 2 of 3 no QRSPR interval? 0.14 s QRS duration? 0.08 s Interpretation? 2nd Degree AV Block, Type II
35 Rhythm #11 Rate? 40 bpm Regularity? regular P waves?no relation to QRS PR interval? none QRS duration? wide (> 0.12 s) Interpretation? 3rd Degree AV Block
36 3rd Degree AV Block Etiology: There is complete block of conduction in the AV junction, so the atria and ventricles form impulses independently of each other. Without impulses from the atria, the ventricles own intrinsic pacemaker kicks in at around beats/minute.
37 RHYTHM # 12
38 Ventricular FibrillationRhythm: irregular-coarse or fine, wave form varies in size and shape Fires continuously from multiple foci No organized electrical activity No cardiac output Causes: MI, ischemia, untreated VT, underlying CAD, acid base imbalance, electrolyte imbalance, hypothermia,
39 RHYTHM # 13
40 Ventricular TachycardiaVentricular cells fire continuously due to a looping re-entrant circuit Rate usually regular, bpm P wave: may be absent, inverted or retrograde QRS: complexes bizarre, > .12 Rhythm: usually regular
41 RHYTHM #14
42 Asystole Ventricular standstill, no electrical activity, no cardiac output – no pulse! Cardiac arrest, may follow VF or PEA Remember! No defibrillation with Asystole Rate: absent due to absence of ventricular activity. Occasional P wave may be identified.
43 RHYTHM #15
44 IdioVentricular RhythmEscape rhythm (safety mechanism) to prevent ventricular standstill HIS/purkinje system takes over as the heart’s pacemaker Treatment: pacing Rhythm: regular Rate: bpm P wave: absent QRS: > .12 seconds (wide and bizarre)
45
46 WHAT RHYTHMS ARE SHOWN?
47 What rhythm is shown?
48 WOLF-PARKINSON-WHITE PATTERN
49 WHAT IS THE RHYTHM?
50 AVNRT
51 THANK YOU TO BE CONTINUED (MYOCARDIAL INFARCTION)