Regularity: irregular

Rate: atrial rate 300 bpm;

ventricular rate 90 bpm

P Waves: sawtooth

appearance

PRI: unable

QRS: 0.08 second

Interp: Atrial Flutter with

variable response

5.55

Regularity: slightly irregular

Rate: 80 bpm

P Waves: changing

morphology

PRI: varies

QRS: 0.10 second

Interp: Wandering

Pacemaker

5.56

Regularity: regular

Rate: atrial rate 376 bpm;

ventricular rate 188 bpm

P Waves: sawtooth

appearance

PRI: unable

QRS: 0.08 second

Interp: Atrial Flutter with

2:1 response

5.57

Regularity: regular underlying rhythm interrupted

by an ectopic

Rate: 107 bpm

P Waves: uniform P waves

except one missing before ectopic QRS

PRI: 0.16 second and

constant

QRS: 0.08 second; QRS

of ectopic beat is same

size and shape as QRS

of underlying rhythm

Interp: Sinus Tachycardia

with one PJC

6.1

Regularity: regular

Rate: 83 bpm

P Waves: no visible

P waves

PRI: none

QRS: 0.08 second

Interp: Accelerated Junctional Rhythm

6.2

Regularity: regular

Rate: 100 bpm

P Waves: all P waves are

inverted

PRI: 0.10 second and

constant

QRS: 0.06 second

Interp: Junctional

Tachycardia

6.3

558 Answers Key

Regularity: regular

Rate: 43 bpm

P Waves: no visible

P waves

PRI: none

QRS: 0.08 second

Interp: Junctional Escape

Rhythm

6.4

Regularity: slightly irregular

underlying rhythm interrupted by an ectopic

Rate: 50 bpm

P Waves: uniform, upright

P waves; one inverted

P wave before ectopic

QRS

PRI: 0.16 second and

constant for underlying

rhythm; 0.11 second for

ectopic

QRS: 0.08 second; QRS of

ectopic is same shape

and width as QRS of underlying rhythm

Interp: Sinus Bradycardia

with one PJC

6.5

Regularity: regular

Rate: 71 bpm

P Waves: no visible

P waves

PRI: none

QRS: 0.10 second

Interp: Accelerated Junctional Rhythm

6.6

Regularity: regular

Rate: 167 bpm

P Waves: P waves are not

visible

PRI: none

QRS: 0.06 second

Interp: Supraventricular

Tachycardia

6.7

Regularity: regular

Rate: 79 bpm

P Waves: no visible

P waves

PRI: none

QRS: 0.06 second

Interp: Accelerated Junctional Rhythm

6.8

Regularity: regular

Rate: 214 bpm

P Waves: P waves are not

visible

PRI: none

QRS: 0.08 second

Interp: Supraventricular

Tachycardia

6.9

Regularity: regular underlying rhythm interrupted

by an ectopic

Rate: 81 bpm

P Waves: uniform and

upright except for one

inverted P wave in front

of ectopic QRS

PRI: 0.16 second and

constant for underlying

rhythm; 0.10 second for

ectopic

QRS: 0.08 second for both

underlying rhythm and

ectopic

Interp: Sinus Rhythm with

one PJC

6.10

Regularity: regular

Rate: 150 bpm

P Waves: P waves are not

visible

PRI: none

QRS: 0.10 second

Interp: Supraventricular

Tachycardia

6.11

Regularity: regular

Rate: 43 bpm

P Waves: P waves are not

visible

PRI: none

QRS: 0.10 second

Interp: Junctional Escape

Rhythm

6.12

Regularity: regular

Rate: 88 bpm

P Waves: inverted and uniform P waves

PRI: 0.11 second and

constant

QRS: 0.10 second

Interp: Accelerated Junctional Rhythm

6.13

Regularity: regular

Rate: 50 bpm

P Waves: none visible

PRI: unable

QRS: 0.14 second

Interp: Junctional Escape

Rhythm (with wide QRS)

6.14

Regularity: regular

Rate: 188 bpm

P Waves: inverted following QRS

PRI: unable

QRS: 0.08 second

Interp: Junctional

Tachycardia

6.15

Regularity: regular

Rate: 188 bpm

P Waves: unable

PRI: unable

QRS: 0.08 second

Interp: Supraventricular

Tachycardia (with baseline artifact)

6.16

Regularity: regular (slightly

irregular)

Rate: 140 bpm

P Waves: none visible

PRI: unable

QRS: 0.08 second

Interp: Junctional

Tachycardia

6.17

Regularity: slightly irregular

Rate: 44 bpm

P Waves: none visible

PRI: none

QRS: 0.08 second

Interp: Junctional Escape

Rhythm

6.18

Regularity: regular

Rate: 75 bpm

P Waves: none visible

PRI: unable

QRS: 0.08 second

Interp: Accelerated Junctional Rhythm

6.19

Regularity: regular underlying rhythm interrupted

by ectopic

Rate: 56 bpm

P Waves: upright in underlying rhythm

PRI: 0.16 second in underlying rhythm; unable to

measure in ectopic

QRS: 0.08 second

Interp: Sinus Bradycardia

with one PJC

6.20

Regularity: regular

Rate: 188 bpm

P Waves: unable

PRI: unable

QRS: 0.08 second

Interp: Supraventricular

Tachycardia

6.21

Regularity: regular

Rate: 71 bpm

P Waves: none visible

PRI: unable

QRS: 0.08 second

Interp: Accelerated Junctional Rhythm

6.22

Regularity: regular

Rate: 167 bpm

P Waves: upright and

uniform

PRI: unable

QRS: 0.08 second

Interp: Supraventricular

Tachycardia

6.23

Regularity: regular

Rate: 125 bpm

P Waves: none visible

PRI: unable

QRS: 0.10 second

Interp: Junctional

Tachycardia

6.24

Regularity: slightly irregular

Rate: 58 bpm

P Waves: none visible

PRI: unable

QRS: 0.08 second

Interp: Junctional Escape

Rhythm

6.25

Regularity: regular underlying rhythm interrupted

by ectopic

Rate: 45 bpm

P Waves: upright in underlying rhythm; absent in

ectopic

PRI: 0.12 second in underlying rhythm; unable to

measure in ectopic

QRS: 0.10 second (in both

underlying rhythm and

ectopic)

Interp: Sinus Bradycardia

with one PJC

6.26

Answers Key 559

Regularity: regular

Rate: 45 bpm

P Waves: none

PRI: unable

QRS: 0.08 second

Interp: Junctional Escape

Rhythm

6.27

Regularity: regular

Rate: 214 bpm

P Waves: unable

PRI: unable

QRS: 0.08 second

Interp: Supraventricular

Tachycardia

6.28

Regularity: regular

Rate: 58 bpm

P Waves: none

PRI: unable

QRS: 0.08 second

Interp: Junctional Escape

Rhythm

6.29

Regularity: regular underlying rhythm interrupted

by ectopics

Rate: 54 bpm

P Waves: upright in underlying rhythm

PRI: 0.16 second in underlying rhythm; unable to

measure in ectopics

QRS: 0.08 second (in both

underlying rhythm and

ectopics)

Interp: Sinus Bradycardia

with two PJCs

6.30

Regularity: regular

Rate: 79 bpm

P Waves: none

PRI: unable

QRS: 0.08 second

Interp: Accelerated Junctional Rhythm

6.31

Regularity: regular

Rate: 150 bpm

P Waves: unable

PRI: unable

QRS: 0.08 second

Interp: Supraventricular

Tachycardia

6.32

Regularity: regular

Rate: 150 bpm

P Waves: unable

PRI: unable

QRS: 0.10 second

Interp: Supraventricular

Tachycardia

6.33

Regularity: regular

Rate: 214 bpm

P Waves: unable

PRI: unable

QRS: 0.08 second

Interp: Supraventricular

Tachycardia

6.34

Regularity: irregular in

a pattern of grouped

beating

Rate: 100 bpm (including

ectopics)

P Waves: upright in underlying rhythm; absent in

ectopics

PRI: 0.14 second in underlying rhythm; unable to

measure in ectopics

QRS: 0.08 second in underlying rhythm; 0.10

second in ectopics

Interp: Sinus Rhythm with

bigeminy of PJCs. When

every other beat is an

ectopic, the pattern is

called “bigeminy.” It will

be explained further in

Chapter 8.

6.35

Regularity: regular

Rate: 100 bpm

P Waves: inverted before

every QRS complex

PRI: 0.08 second

QRS: 0.08 second

Interp: Accelerated Junctional Rhythm

6.36

Regularity: regular

Rate: 150 bpm

P Waves: unable

PRI: unable

QRS: 0.12 second

Interp: Supraventricular

Tachycardia

6.37

Regularity: regular

Rate: 79 bpm

P Waves: none

PRI: unable

QRS: 0.10 second

Interp: Accelerated Junctional Rhythm

6.38

Regularity: regular

Rate: 150 bpm

P Waves: unable

PRI: unable

QRS: 0.10 second

Interp: Supraventricular

Tachycardia

6.39

Regularity: regular underlying rhythm interrupted

by ectopic

Rate: 75 bpm

P Waves: upright in underlying rhythm; absent in

ectopic

PRI: 0.16 second in underlying rhythm; unable to

measure in ectopic

QRS: 0.08 second (in both

underlying rhythm and

ectopic)

Interp: Sinus Rhythm with

one PJC

6.40

Regularity: regular

Rate: 214 bpm

P Waves: unable

PRI: unable

QRS: 0.08 second

Interp: Supraventricular

Tachycardia

6.41

Chapter 7

Regularity: regular

Rate: 51 bpm

P Waves: uniform and upright; regular P–P interval

PRI: 0.24 second and

constant

QRS: 0.10 second

Interp: Sinus Bradycardia

with First-Degree Heart

Block

7.1

Regularity: irregular with

a pattern of grouped

beating

Rate: atrial rate 115 bpm;

ventricular rate approximately 90 bpm

P Waves: uniform; regular

P–P intervals; more P

waves than QRS

complexes

PRI: changes; progressively lengthens from

0.20 second to 0.32

second

QRS: 0.08 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block)

7.2

Regularity: regular

Rate: atrial rate 157 bpm;

ventricular rate 33 bpm

P Waves: uniform; regular P–P intervals; more

P waves than QRS

complexes

PRI: P waves are not associated with QRS

complexes

QRS: 0.12 second

Interp: Third-Degree Heart

Block (CHB) with ventricular escape focus

7.3

Regularity: regular

Rate: atrial rate 115 bpm;

ventricular rate 73 bpm

P Waves: non-conducted

P waves are more apparent after mapping the

P–P interval, since some

P waves are hidden

within the QRS complexes and T waves

PRI: P waves are not associated with QRS

complexes

QRS: 0.08 second

Interp: Third-Degree Heart

Block (CHB) with junctional escape focus

7.4

560 Answers Key

Regularity: regular

Rate: 88 bpm

P Waves: uniform and upright; regular P–P interval

(Note: P wave of last

complex is distorted by

artifact.)

PRI: 0.26 second and

constant

QRS: 0.12 second

Interp: Sinus Rhythm with

First-Degree Heart Block

(with wide QRS)

7.5

Regularity: irregular with

a pattern of grouped

beating

Rate: atrial rate 100 bpm;

ventricular rate 80 bpm

P Waves: uniform; regular

P–P interval

PRI: changing; progressively lengthens

from 0.16 second to

0.24 second

QRS: 0.08 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block)

7.6

Regularity: irregular with

a pattern of grouped

beating

Rate: atrial rate 75 bpm;

ventricular rate approximately 60 bpm

P Waves: uniform; regular

P–P interval; more

P waves than QRS

complexes

PRI: changing; progressively lengthens

from 0.20 second to

0.30 second

QRS: 0.06 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block)

7.7

Regularity: regular

Rate: atrial rate 120 bpm;

ventricular rate 60 bpm

P Waves: uniform and

upright; regular P–P interval; consistently two

P waves for every QRS

complex

PRI: 0.38 second and

constant on conducted

beats

QRS: 0.10 second

Interp: Type II SecondDegree Heart Block with

2:1 conduction

7.8

Regularity: irregular with

a pattern of grouped

beating

Rate: atrial rate 125 bpm;

ventricular rate approximately 80 bpm

P Waves: uniform; regular

P–P interval; more

P waves than QRS

complexes

PRI: changing;

progressively lengthens

from 0.20 second to

0.28 second

QRS: 0.12 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block) (with wide QRS)

7.9

Regularity: irregular (see

note)

Rate: atrial rate 63 bpm;

ventricular rate approximately 25 bpm

P Waves: uniform; regular

P–P intervals; more

P waves than QRS

complexes

PRI: the P waves are not

associated with the QRS

complexes

QRS: 0.20 second

Interp: Third-Degree Heart

Block (CHB) with ventricular escape focus.

7.10

Note: The ventricular pacemaker site usually has a

regular firing mechanism; but if a dangerous ventricular

rhythm is allowed to continue untreated, its serious effects on the myocardium will ultimately cause the firing

site to slow or die out. In this strip, the change in ventricular rate demonstrates this slowing phenomenon.

Regularity: regular

Rate: 75 bpm

P Waves: uniform; regular

P–P interval

PRI: 0.30 second and

constant

QRS: 0.14 second

Interp: Sinus Rhythm with

First-Degree Heart Block

(with wide QRS)

7.11

Regularity: regular

Rate: atrial rate 74 bpm;

ventricular rate 37 bpm

P Waves: uniform; regular

P–P interval; consistently

two P waves for every

QRS complex

PRI: 0.26 second and

constant on conducted

beats

QRS: 0.12 second

Interp: Type II SecondDegree Heart Block with

2:1 conduction

7.12

Regularity: irregular with

a pattern of grouped

beating

Rate: atrial rate 83 bpm;

ventricular rate approximately 60 bpm

P Waves: uniform; regular

P–P interval

PRI: changes; progressively lengthens

from 0.28 second to

0.48 second

QRS: 0.06 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block)

7.13

Regularity: regular

Rate: atrial rate 100 bpm;

ventricular rate 35 bpm

P Waves: uniform; regular

P–P interval; more P

waves than QRS

complexes

PRI: the P waves are not

associated with the QRS

complexes

QRS: 0.12 second

Interp: Third-Degree Heart

Block (CHB) with ventricular escape focus

7.14

Regularity: regular

Rate: 65 bpm

P Waves: uniform and upright; regular P–P interval

PRI: 0.26 second and

constant

QRS: 0.10 second

Interp: Sinus Rhythm with

First-Degree Heart Block

7.15

Regularity: slightly irregular

Rate: atrial rate 64 bpm;

ventricular rate 32 bpm

P Waves: uniform; slight

irregularity of the P–P

interval (see note); consistently two P waves for

every QRS complex

PRI: 0.20 second

QRS: 0.12 second

Interp: Type II SecondDegree Heart Block with

2:1 conduction

7.16

Note: A rhythm with a consistent 2:1 conduction ratio

usually produces a regular rhythm. In this strip, however, the presence of an underlying sinus arrhythmia

results in an irregular P–P, with an ultimate irregularity of

the ventricular response.

Regularity: regular

Rate: atrial rate 100 bpm;

ventricular rate 24 bpm

P Waves: uniform; regular P–P interval; more

P waves than QRS

complexes

PRI: the P waves are not

associated with the QRS

complexes

QRS: 0.08 second

Interp: Third-Degree Heart

Block (CHB) with a junctional escape focus

7.17

Note: The ventricular rate in this strip is slower than the

usual junctional rate, but the QRS measurement of 0.08

second could not have been produced by a ventricular

pacemaker; thus, the escape focus must have been

junctional.

Answers Key 561

Regularity: irregular with

a pattern of grouped

beating

Rate: atrial rate 107 bpm;

ventricular rate approximately 90 bpm

P Waves: uniform; regular P–P interval; more

P waves than QRS

complexes

PRI: changes; progressively lengthens

from 0.20 second to

0.36 second

QRS: 0.10 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block)

7.18

Regularity: regular

Rate: 54 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant

QRS: 0.16 second

Interp: Sinus Bradycardia

with First-Degree Heart

Block (with wide QRS)

7.19

Regularity: regular P–P; irregular R–R

Rate: atrial rate 107 bpm;

ventricular rate 90 bpm

P Waves: upright and

uniform

PRI: progressively lengthens until one P wave is

not conducted

QRS: 0.08 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block)

7.20

Regularity: regular R–R;

regular P–P

Rate: atrial rate 56 bpm;

ventricular rate 36 bpm

P Waves: upright and

uniform

PRI: not related

QRS: 0.16 second

Interp: Third-Degree Heart

Block (CHB) with ventricular escape focus

7.21

Regularity: regular

Rate: 83 bpm

P Waves: upright and

uniform

PRI: 0.22 second and

constant

QRS: 0.10 second

Interp: Sinus Rhythm with

First-Degree Heart Block

7.22

Regularity: regular

Rate: 65 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant

QRS: 0.08 second

Interp: Sinus Rhythm with

First-Degree Heart Block

7.23

Regularity: regular P–P;

regular R–R

Rate: atrial rate 43 bpm;

ventricular rate 31 bpm

P Waves: upright and

uniform

PRI: unrelated; P waves

“march through” QRS

complexes

QRS: 0.10 second

Interp: Third-Degree Heart

Block (CHB) with junctional escape focus

7.24

Regularity: regular P–P;

irregular R–R

Rate: atrial rate 65 bpm;

ventricular rate 40 bpm

P Waves: upright and

uniform

PRI: 0.20 second and

constant on conducted

beats

QRS: 0.08 second

Interp: Type II SecondDegree Heart Block with

variable conduction

7.25

Regularity: slightly irregular

Rate: 83 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant

QRS: 0.08 second

Interp: Sinus Rhythm with

First-Degree Heart Block

7.26

Regularity: regular

Rate: 65 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant

QRS: 0.08 second

Interp: Sinus Rhythm with

First-Degree Heart Block

7.27

Regularity: irregular

Rate: 62 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant

QRS: 0.10 second

Interp: Sinus Arrhythmia

with First-Degree Heart

Block

7.28

Regularity: regular P–P;

irregular R–R

Rate: atrial rate 79 bpm;

ventricular rate 60 bpm

P Waves: upright and

uniform

PRI: progressively lengthens until one P wave is

not conducted

QRS: 0.08 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block)

7.29

Regularity: regular

Rate: 65 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant

QRS: 0.10 second

Interp: Sinus Rhythm with

First-Degree Heart Block

7.30

Regularity: regular

Rate: 52 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant

QRS: 0.08 second

Interp: Sinus Bradycardia

with First-Degree Heart

Block

7.31

Regularity: P–P very

slightly irregular; R–R

irregular

Rate: atrial rate 79 bpm;

ventricular rate 70 bpm

P Waves: upright and

uniform

PRI: progressively lengthens until one P wave is

not conducted

QRS: 0.12 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block) (with wide QRS)

7.32

Regularity: regular P–P

Rate: atrial rate 60 bpm;

ventricular rate 20 bpm

P Waves: upright and

uniform

PRI: P waves unrelated to

QRS complexes

QRS: 0.12 second

Interp: Third-Degree Heart

Block (CHB) with ventricular escape focus

7.33

Regularity: regular

Rate: 88 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant

QRS: 0.10 second

Interp: Sinus Rhythm with

First-Degree Heart Block

7.34

Regularity: regular

Rate: 35 bpm

P Waves: upright and

uniform

PRI: 0.28 second and

constant

QRS: 0.16 second

Interp: Sinus Bradycardia

with First-Degree Heart

Block (with wide QRS)

7.35

562 Answers Key

Regularity: regular P–P;

regular R–R

Rate: atrial rate 107 bpm;

ventricular rate 58 bpm

P Waves: upright and

uniform

PRI: P waves unrelated to

QRS complexes; more

P waves than QRS

complexes

QRS: 0.10 second

Interp: Third-Degree Heart

Block (CHB) with junctional escape focus

7.36

Regularity: regular P–P;

regular R–R

Rate: atrial rate 115 bpm;

ventricular rate 65 bpm

P Waves: upright; two P

waves for every QRS

complex

PRI: 0.28 second and

constant on conducted

beats

QRS: 0.08 second

Interp: Type II SecondDegree Heart Block with

2:1 conduction

7.37

Regularity: regular P–P;

irregular R–R

Rate: atrial rate 115 bpm;

ventricular rate 90 bpm

P Waves: upright and

uniform; more P waves

than QRS complexes

PRI: progressively lengthens until one P wave is

not conducted

QRS: 0.08 second

Interp: Wenckebach (Type

I Second-Degree Heart

Block)

7.38

Regularity: slightly irregular

P–P; regular R–R

Rate: atrial rate 88 bpm;

ventricular rate 32 bpm

P Waves: upright and

uniform

PRI: P waves unrelated

to QRS complexes; P

waves “march through”

QRS complexes

QRS: 0.08 second

Interp: Third-Degree Heart

Block (CHB) with junctional escape focus

7.39

Regularity: regular P–P;

regular R–R

Rate: atrial rate 94 bpm;

ventricular rate 47 bpm

P Waves: upright and

uniform

PRI: 0.24 second and

constant on conducted

beats; more P waves

than QRS complexes

QRS: 0.06 second

Interp: Type II SecondDegree Heart Block with

2:1 conduction

7.40

Regularity: regular P–P;

regular R–R

Rate: atrial rate 88 bpm;

ventricular rate 68 bpm

P Waves: upright and

uniform

PRI: P waves unrelated

to QRS complexes; P

waves “march through”

QRS complexes

QRS: 0.10 second

Interp: Third-Degree Heart

Block (CHB) with junctional escape focus

7.41

Chapter 8

Regularity: regular underlying rhythm interrupted

by ectopics

Rate: 75 bpm

P Waves: uniform; regular

P–P interval

PRI: 0.18 second

QRS: 0.12 second in

underlying complex;

0.12 second in ectopics;

ectopics have bizarre

configuration

Interp: Sinus Rhythm (with

wide QRS) with two

PVCs

8.1

Regularity: regular underlying rhythm interrupted by

ectopics in a pattern of

grouped beating

Rate: 39 bpm according to

visible P waves; true sinus

rate is probably 78 bpm

P Waves: uniform; regular

P–P interval

PRI: 0.18 second

QRS: 0.08 second in

underlying rhythm;

0.14 second in ectopic

Interp: Sinus Rhythm with

bigeminy of PVCs

8.2

Regularity: regular underlying rhythm interrupted

by an ectopic

Rate: 58 bpm

P Waves: uniform; regular

P–P interval

PRI: 0.20 second

QRS: 0.10 second in

underlying rhythm;

0.18 second in ectopic; ectopic has bizarre

configuration

Interp: Sinus Bradycardia

with one PVC

8.3

Regularity: slightly irregular

Rate: approximately

170 bpm

P Waves: not visible

PRI: none

QRS: 0.12 second; configuration is bizarre

Interp: Ventricular

Tachycardia

8.4

Regularity: regular underlying rhythm interrupted

by ectopics

Rate: 79 bpm (underlying

rhythm)

P Waves: uniform; regular

P–P interval

PRI: 0.16 second

QRS: 0.06 second in

underlying rhythm;

0.20 second in ectopics;

ectopics have bizarre

configuration

Interp: Sinus Rhythm with

three unifocal PVCs

(possibly trigeminy)

8.5

Regularity: totally chaotic

baseline

Rate: cannot be

determined

P Waves: none

PRI: none

QRS: none

Interp: Ventricular

Fibrillation

8.6

Regularity: regular underlying rhythm interrupted

by ectopics

Rate: 107 bpm (underlying

rhythm)

P Waves: uniform; regular

P–P interval interrupted

by ectopics

PRI: 0.14 second

QRS: 0.10 second in

underlying rhythm;

0.14 second in ectopics;

ectopics have bizarre

configuration

Interp: Sinus Rhythm

with two unifocal PVCs

and a short burst of

Ventricular Tachycardia

8.7

Regularity: regular

Rate: 167 bpm

P Waves: not visible

PRI: none

QRS: 0.16 second; bizarre

configuration

Interp: Ventricular

Tachycardia

8.8

Regularity: regular underlying rhythm interrupted

by ectopics

Rate: 83 bpm

P Waves: uniform; regular

P–P interval

PRI: 0.16 second

QRS: 0.14 second in

underlying rhythm;

0.16 second in ectopics;

ectopics have bizarre

configuration

Interp: Sinus Rhythm (with

wide QRS) with two

multifocal PVCs

8.9

Answers Key 563

Regularity: regular

Rate: 150 bpm

P Waves: not visible

PRI: none

QRS: 0.20 second; bizarre

configuration

Interp: Ventricular

Tachycardia

8.10

Regularity: regular underlying rhythm interrupted

by ectopics

Rate: 100 bpm

P Waves: uniform; regular

P–P interval

PRI: 0.14 second

QRS: 0.06 second in

underlying rhythm;

0.12 second in ectopics;

ectopics have bizarre

configuration

Interp: Sinus Tachycardia

with three unifocal PVCs

8.11

Regularity: regular

Rate: 167 bpm

P Waves: not visible

PRI: none

QRS: 0.16 second; bizarre

configuration

Interp: Ventricular

Tachycardia

8.12

Regularity: regular underlying rhythm interrupted

by ectopics in a pattern

of grouped beating

Rate: 38 bpm according

to visible P waves; true

sinus rate is probably

76 bpm

P Waves: uniform; regular

P–P interval

PRI: 0.20 second

QRS: 0.10 second in

underlying rhythm;

0.14 second in ectopics;

ectopics have bizarre

configuration

Interp: Sinus Rhythm with

bigeminy of PVCs

8.13

Regularity: totally chaotic

baseline

Rate: cannot be

determined

P Waves: none

PRI: none

QRS: none

Interp: Ventricular

Fibrillation

8.14

Regularity: regular

Rate: 40 bpm

P Waves: none

PRI: none

QRS: 0.20 second; bizarre

configuration

Interp: Idioventricular

Rhythm

8.15

Regularity: regular underlying rhythm interrupted

by ectopics

Rate: 94 bpm

P Waves: uniform; regular

P–P interval

PRI: 0.12 second

QRS: 0.10 second in

underlying rhythm;

0.16 second in ectopics;

ectopics have bizarre

configuration; ectopics

occur consecutively

Interp: Sinus Rhythm with

a run of three PVCs

8.16