Normal Sinus Rhythm
Regular rhythm
60 – 100 bpm
P wave: small, round, positive & one to each QRS
PRI: 0.12 – 0.20 seconds, constant
QRS: less than 0.12 seconds
Note: Called SR if have all of these characteristics present but also abnormality present
Steps to Rhythm Interpretation
1. Regularity (R-R or P-P)
2. Rate: Regular (# sm. Boxes ÷1500)
Irregular (# R waves x 10)
3. P wave: Present? Changing shape? #?
4. PRI: Present? Constant? Pattern?
5. QRS: width? Shape?
Sinus Arrhythmias
Sinus Bradycardia
Key Characteristics (what makes it different from NSR)
Heart Rate 40 – 59 bpm
Sinus Tachycardia
Heart Rate 101 - 150
Sinus Arrhythmia
Irregular rhythm
Sinus Arrest with underlying rhythm
Exp. Sinus Rhythm with Sinus Arrest
Sinus Block with underlying rhythm
Exp. Sinus Rhythm with Sinus Block
Atrial Arrhythmias
Premature Atrial Contraction (PAC)
Exp. Sinus rhythm with a PAC
Paroxysmal Atrial Tachycardia (PAT)
Event that interrupts underlying rhythm; Irregular; missing QRS; new R-R regularity after missing QRS;
may have an escape beat
Event that interrupts underlying rhythm; Regular; appears to have a missing QRS
Atrial Fibrillation
GROSSLY IRREGULAR; no p wave but fib waves; controlled rate (under 100 bpm) or RVR (rapid ventricular
response-heart rate greater than 100 bpm)
Regular or irregular rhythm depending if a ration or variable conduction; no p wave but flutter waves
Atrial Flutter
Wandering Atrial Pacemaker
Key Characteristics (atrial arrhythmias will effect p wave shape and location)
Early beat coming from the atrium; interrupts underlying rhythm; has a p wave, new R-R regularity after the
PAC (non-compensatory pause) Interpretation must have underlying rhythm too. Exp. SR with PAC
Started by a PAC, three or more PACs occurring together interrupting the underlying rhythm
Atrial Tachycardia
Supraventricular Tachycardia (SVT)
Junctional Rhythms
Premature Junctional Contractions (PJC)
Exp. Sinus rhythm with a PJC
Junctional Bradycardia
Regular or irregular rhythm depending on presence of changing PRI; changing P wave shape (at least 2 or more
changes within a strip)
Heart rate 150 – 250 bpm; no p wave, narrow QRS.
SVT: term used when cannot determine if rhythm is AT or JT; heart rate between 150 – 200 bpm
Key Characteristics (all have p wave inverted before QRS, or inverted after QRS or hidden in QRS – not seen)
Early beat coming from the AV junction/node; interrupts underlying rhythm; inverted p wave before
QRS, no visible p wave or inverted p wave after QRS, new R-R regularity after premature beat
Heart rate slower than 40 bpm, p wave inverter before QRS or inverted after QRS or hidden in QRS (not seen)
Junctional Rhythm
Heart rate 40 – 59 bpm; inverted p wave before QRS, or p wave hidden in QRS, or inverted p wave after QRS
Accelerated Junctional Rhythm
Heart rate 60 – 100 bpm; inverted p wave before QRS or hidden p wave in QRS, or inverted p wave after QRS
Junctional Tachycardia
Heart rate:101 – 200 bpm; inverted p wave before QRS or hidden p wave in QRS or inverted p wave after QRS
AV BLOCKS
A rhythm with 1st degree AVB
Exp. Sinus Rhythm with 1st degree AVB
2nd degree AV Block, Type I
(little boy late for school bus)
2nd degree AV Block, Type II
(how many phone calls to get gossip)
3rd degree AV Block (Complete Heart
Block- CHB) (divorced couple)
Ventricular Rhythms
Premature Ventricular Contraction (PVC)
Exp. Sinus rhythm with a PVC
Ventricular or Idoventricular Rhythm
Key Characteristics (conduction delays; altered PRI and number of p waves)
Regular; long PRI (greater than .20 sec) and constant; state underlying rhythm
Accelerated Ventricular Rhythm
Regular rhythm: 50 – 100 bpm; no p wave; wide QRS
Ventricular Tachycardia
Regular rhythm: 150 – 250 bpm; no p wave; wide QRS
Torsades de pointes (polymorphic VT)
Regularly irregular; greater 200 bpm; no p wave; changing QRS width and amplitude of QRS
Ventricular Fibrillation
Chaotic waves without form, no QRS, no heart rate but movement in isoelectric line indicates fast activity.
Ventricular Standstill
Regular p waves only (no QRS complexes)
Ventricular Asystole
Asystole
Pulseless Electrical Activity
Wide QRS complex to no wave forms (isoelectric line)
No waveforms; isoelectric line
Looks like Normal Sinus Rhythm or Sinus Bradycardia but the patient does not have a pulse
Pacemaker Rhythm
Pacer spike either replacing or beginning of the p wave or the QRS complex or both
Number of
Small Boxes
5
6
7
8
9
10
11
12
13
14
Rate per
Minute
300
250
214
188
167
150
136
125
115
107
Irregular; more p waves than QRS complexes, progressively lengthening PRI until missing QRS and then it is
shorter after missing QRS than previous PRI
Regular or irregular depending on the conduction; ratio conduction if same number of p waves between QRS or
irregular if changing number of p waves between QRS; more p waves; constant PRI
Regular: more p waves than QRS; no constant PRI ; p waves may be hidden in other wave forms. Can march
out p waves. Both p waves and R waves are regular.
Key Characteristics (all rhythms have wide QRS and no p wave)
Early beat from the ventricles; rhythm regular or irregular; no p wave; wide QRS; R-R regularity is not reset
after the premature beat (compensatory pause); state underlying rhythm; T wave opposite direction of QRS
Regular rhythm: 20 – 40 bpm; no p wave; wide QRS;
Heart Rate Card
Number of
Small Boxes
15
16
17
18
19
20
21
22
23
24
Rate per
Minute
100
94
88
84
79
75
72
68
65
63
(1500 divided by number of small boxes counted between R waves)
Number of
Rate per
Number of
Rate per
Number of
Small Boxes
minute
Small Boxes
Minute
Small Boxes
25
60
35
43
45
26
58
36
42
46
27
56
37
41
47
28
54
38
40
48
29
52
39
39
49
30
50
40
38
50
31
48
41
37
32
47
42
36
33
45
43
35
34
44
44
34
Rate per
Minute
33
33
32
31
31
30