Transcript Arrhythmia - xjtu.edu.cn

Part IV Arrhythmia
薛小临
Classification
Abnormal origin
----sinus arrhythmia
----ectopic rhythm:passivity—escape
---premature contraction
tachycardia
flutter and fibrillation
Abnormal conduction
----physiological block:
----pathological block: S-AB; A-VB; LBBB; RBBB
----accessory pathway: pre-excitation syndrome
Electrophysiology
 Automaticity
 Excitability
 Absolute
refractory period (200ms)
 Effective
refractory period (210ms)
 Ralative
refractory period (50-100ms)
 Conductivity
SINUS RHYTHM AND
SINUS ARRHYTHMIAS
Sinus rhythm features :
(1) Every P wave is following by a QRS complex;
(2) P wave is upright in lead I, II, aVF, V4-V6,
inverse in aVR;
(3) P-R interval ≥ 0.12sec;
(4) Normal rate is 60-100 beats/min
Sinus Bradycardia
(1) Sinus rhythm
(2) Heart rate <60bpm
(R-R interval or P-P interval >1.0 sec )
Factors associated with sinus bradycardia
(1) Physiologic
Laborers and trained athletes
Emotional states leading to syncope
(2) Pathologic
-blocker
Hypothyroidism
Sinus Tachycardia
(1) Sinus rhythm, rate > 100 bpm
The R-R interval (or the P-P interval) <0.60 sec.
(2) P-R and Q-T interval are shorter than usual
(3) S-T segment is slight depression, T waves may
be flattened
Factors associated with sinus tachycardia
(1) Physiologic
Exercise
Strong emotion
Anxiety states
(2) Pathologic
Fever
Hemorrhage
Anemia
Myocarditis
Hyperthyroidism
Sinus arrhythmia
 Sinus rhythm and PR interval,
 Difference of P--P interval > 0.12sec
in the same lead
Sinus arrest
The P wave missed for a short time
Sick Sinus Syndrome (SSS)
(1) Sinus bradycardia (HR<50/min);
(2) Sinus arrest or SA block;
(3) Tachycardia: Atrial tachycardia,
Atrial Flutter,
Atrial fibrillation;
(4) AV block.
Premature contractions
1. Premature Ventricular Contraction
(1) Ventricular complex (QRS) is not
preceded by a premature P' wave.
(2) Premature QRS complex is the wider
and the bizarre , Duration of QRS> 0.12 sec.
T wave in direction is opposite to QRS
complex .
(3) Complete compensatory pause
bigeminy
trigeminy
2. Atrial Premature Contractions
(1) The premature P' wave differs in
contour from the normal P wave in the
same lead.
(2) The P'-R interval >0.12s.
(3) There may be a noncompensatory
pause.
3. Premature junctional contraction
(1) A premature normal-appearing QRS
complex.
(2) The junctional P wave (P’) may be
appear before, in, and after the QRS.
(3) Usually a complete compensatory pause.
Tachycardia
Reentry
Requires: Two conducting pathways
Unidirectional block in one
Slow conduction in the other
1. Paroxysmal supraventricular
tachycardia (PSVT)
a. Heart rate between 160 – 250 bpm.
b. A precisely regular rhythm
with normal QRS.
2. Ventricular Tachycardia
a) The rate is 140200/min and the rhythm is very
slightly irregular.
b) QRS complex is the wider and the bizarre ,
Duration of QRS >0.12 sec.
c)
P wave dissociated from QRS;
The rate of P wave is less than The rate of QRS
d) Ventricular capture ;
e) Fusion beats are present.
3. Nonparoxysmal Tachycardia
 Nonparoxysmal
junctional Tachycardia, The
heart rate is 70130/min
 Nonparoxysmal ventricular Tachycardia. The
heart rate is 60100/min
4. Torsde de pointes
Flutter and Fibrillation
1. Atrial Flutter
(1) Absence of normal P waves;
(2) P waves replaced by saw-tooth flutter wave (F
waves);
(3) Flutter waves seen best in leads II, III,aVF;
(4) F waves always uniform in size, shape and
frequency and absence of isoelectric line
between F waves;
(5) Regular atrial rhythm with a rate of 250-350 /min;
(6) Ventricular response of 1:1,2:1,3:1,4:1 or higher
2. Atrial Fibrillation
(1) Absence of clear P waves ;
(2) P waves replaced by f waves;
(3) f waves: irregular in size, shape, best
seen in lead V1;
(4) Rate of f waves is 350 - 600/min ;
(5) Irregularly irregular ventricular rate;
(6) Generally, duration of QRS complex
<0.12sec;
Ventricular Flutter and
Ventricular fibrillation
Ventricular flutter:
It is impossible to separate the QRS
complexes from the ST segment and the
T waves
Ventricular fibrillation:
The ECG shows fine or coarse waves that
are rapid, and irregular in size, shape,
and width .
Conduction Disturbances
1. First Degree A-V Block
 Prolonged P-R interval:
P-R interval > 0.20sec. in adults
(varies with heart rate)

2.Second Degree A-V Block
 (1) Mobitz type I
(Wenckebach phenomenon).
 The pattern is a progressive prolongation
of the P-R interval until a beat is dropped.
 The first beat after the pause has the
shortest P-R interval, which may or may
not be normal.
(2) Mobitz type II
 There is a fixed numerical relationship
between atrial and ventricular impulses,
which may be 2:1 (2 atrial beats to one
ventricular beat) or 3:1 or 4:1.
Third Degree A-V Block
(Complete heart block)
(1) The atrial and the ventricular rhythms
are absolutely, independent of one another.
(There is no relationship of P to QRS.)
(2) atrial rate > ventricular rate.

QRS is 0.12 sec. or greater.
4. Complete Right Bundle Branch Block
(1) Right axis deviation.
(2) QRS≥0.12 sec.
(3) rsR’ pattern (M pattern ) in V1 or V2;
(4) Wide and slurred S wave in leads 1, V5
and V6 .
(5) ST-T changes in leads V1 and V2 .
5. Complete Left Bundle Branch Block
(1) Left axis deviation.
(2) A wide, slurred R in I,V5 ,V6.
The
wide, aberrant QRS , QRS≥0.12 sec.
(3) The QRS in V1 may be QS or rS type.
(4) ST-T changes.
Wolff-Parkinson-White Syndrome
(pre-excitation syndrome)
1. P-R interval <0.12 sec.
2. QRS complex interval >0.12 sec.
3. Delta wave in the lower third of
theascending limb of the R wave.
4. ST-T changes.
5. Type A is characterized by dominantly
upright QRS complexes in the right
precordial leads, resulting in tall delta-R
waves in leads V1 and V2.
WPW
Type A
6. Type B is characterized by dominantly
negative QRS complexes in the right
precordial leads, with tall delta-R waves in
leads V5 and V6.
WPW Type B