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Heart rhythm practice. See the pattern before you name it.

Learn the visual cues commonly used to describe introductory rhythm patterns, then practice identifying simplified illustrative strips in a scored quiz.

Begin with the rhythm library

A simple visual sequence

Start with spacing, then scan the shapes.

Rate is one visual clue, not a standalone diagnosis. Compare it with beat spacing, atrial activity, and QRS appearance in the simplified examples below.

  1. 01

    Check the beat spacing

    Look for regular, irregular, or unexpectedly early beats.

  2. 02

    Look before the QRS

    Notice whether a consistent P wave is visible before each complex.

  3. 03

    Compare rate and width

    Use BPM as one clue, then compare narrow, wide, organized, and chaotic patterns.

Rhythm library

Nine simplified patterns to compare.

Each vector strip below is an original, simplified educational diagram made for this page. Rate is one identification clue—not a standalone diagnosis—and these examples are not clinical tracings.

Regular sinus pattern

Normal sinus rhythm

Illustrative

Rate criteria

Ventricular rate: 60–100 bpm

A simplified 6-second, 80 bpm baseline pattern with eight evenly spaced beats and a small P wave before each narrow QRS complex.

What to look for

  • R–R spacing appears even.
  • A similar P wave precedes each QRS.
  • QRS complexes look narrow in this illustration.
  • Ventricular rate is typically 60–100 bpm.

Compare it with: Unlike sinus bradycardia or sinus tachycardia, the same sinus pattern is neither notably slow nor notably fast.

A simplified 6-second, 80 bpm baseline pattern with eight evenly spaced beats and a small P wave before each narrow QRS complex. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 8 QRS × 10 = 80 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
8 countable QRSRate: 8 QRS × 10 = 80 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

8 organized QRS complexes × 10 = 80 bpm · R–R = 0.75 sec (18.75 small boxes)

Simplified original rhythm-strip diagram for educational comparison.

Slow regular sinus pattern

Sinus bradycardia

Illustrative

Rate criteria

Ventricular rate: below 60 bpm

A simplified 6-second, 50 bpm sinus pattern with five evenly spaced beats and a visible P-to-QRS relationship.

What to look for

  • R–R spacing is regular and noticeably wide.
  • A P wave appears before each QRS.
  • QRS complexes remain narrow in this illustration.
  • Ventricular rate is below 60 bpm.

Compare it with: Unlike a junctional rhythm, this diagram retains a consistent visible P wave before each QRS.

A simplified 6-second, 50 bpm sinus pattern with five evenly spaced beats and a visible P-to-QRS relationship. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 5 QRS × 10 = 50 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
5 countable QRSRate: 5 QRS × 10 = 50 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

5 organized QRS complexes × 10 = 50 bpm · R–R = 1.20 sec (30 small boxes)

Simplified original rhythm-strip diagram for educational comparison.

Fast regular sinus pattern

Sinus tachycardia

Illustrative

Rate criteria

Ventricular rate: above 100 bpm (often 100–180)

A simplified 6-second, 120 bpm sinus pattern with 12 regular beats; each narrow QRS remains preceded by a recognizable P wave.

What to look for

  • R–R spacing is regular and compressed.
  • A similar P wave leads each QRS.
  • QRS complexes are narrow in this illustration.
  • Ventricular rate is above 100 bpm, often about 100–180 bpm.

Compare it with: Unlike supraventricular tachycardia, this illustration still shows a recognizable P wave before each beat.

A simplified 6-second, 120 bpm sinus pattern with 12 regular beats; each narrow QRS remains preceded by a recognizable P wave. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 12 QRS × 10 = 120 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
12 countable QRSRate: 12 QRS × 10 = 120 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

12 organized QRS complexes × 10 = 120 bpm · R–R = 0.50 sec (12.5 small boxes)

Simplified original rhythm-strip diagram for educational comparison.

Irregularly irregular pattern

Atrial fibrillation

Illustrative

Rate criteria

Variable ventricular response: slow <60, controlled 60–100, rapid >100 bpm

A simplified 6-second strip with eight irregularly spaced narrow QRS complexes and no repeating, organized P-wave pattern.

What to look for

  • R–R spacing varies without an obvious repeating cycle.
  • Distinct repeating P waves are not seen.
  • The baseline looks uneven between QRS complexes.
  • QRS complexes may remain narrow in this illustration.
  • Ventricular response varies: slow below 60, controlled 60–100, or rapid above 100 bpm.

Compare it with: Unlike atrial flutter, this pattern does not show a regular, repeating sawtooth-like atrial activity.

A simplified 6-second strip with eight irregularly spaced narrow QRS complexes and no repeating, organized P-wave pattern. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 8 QRS × 10 = 80 bpm average. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
8 countable QRSRate: 8 QRS × 10 = 80 bpm average
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

8 organized QRS complexes × 10 = 80 bpm average · intentionally variable R–R spacing

Simplified original rhythm-strip diagram for educational comparison.

Organized flutter-wave pattern

Atrial flutter

Illustrative

Rate criteria

Atrial rate: about 250–350 bpm; ventricular rate depends on conduction

A simplified 6-second strip with 30 organized flutter cycles (300/min) and 15 regular narrow QRS complexes (150/min), illustrating 2:1 conduction.

What to look for

  • A repeating flutter-wave contour is visible between QRS complexes.
  • Atrial activity appears organized rather than chaotic.
  • The ventricular response may be regular in this illustration.
  • QRS complexes appear narrow here.
  • Atrial rate is often about 250–350 bpm; 2:1 conduction can produce a ventricular rate near 150 bpm.

Compare it with: Unlike atrial fibrillation, the atrial activity follows a repetitive visual pattern rather than a variable baseline.

A simplified 6-second strip with 30 organized flutter cycles (300/min) and 15 regular narrow QRS complexes (150/min), illustrating 2:1 conduction. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 15 QRS × 10 = 150 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
15 countable QRSRate: 15 QRS × 10 = 150 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

15 QRS complexes × 10 = 150 bpm · regular 2:1-conduction illustration

Simplified original rhythm-strip diagram for educational comparison.

Very rapid narrow-complex pattern

Supraventricular tachycardia

Illustrative

Rate criteria

Ventricular rate: usually 150–250 bpm

A simplified 6-second, rapid, regular 180 bpm narrow-complex pattern; P waves are not clearly separated at this illustrated speed.

What to look for

  • R–R spacing is very regular and close together.
  • Ventricular rate is usually about 150–250 bpm.
  • QRS complexes are narrow in this illustration.
  • P waves are not clearly separate from the fast rhythm.

Compare it with: Unlike sinus tachycardia, this simplified example does not show a clearly separated P wave before every QRS.

A simplified 6-second, rapid, regular 180 bpm narrow-complex pattern; P waves are not clearly separated at this illustrated speed. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 18 QRS × 10 = 180 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
18 countable QRSRate: 18 QRS × 10 = 180 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

18 QRS complexes × 10 = 180 bpm · R–R ≈ 0.33 sec (8.3 small boxes)

Simplified original rhythm-strip diagram for educational comparison.

Early wide-complex interruption

Premature ventricular complexes

Illustrative

Rate criteria

Rate: describe the underlying rhythm; a PVC has no separate BPM

A simplified 6-second, 80 bpm underlying sinus schedule interrupted by one early, wider-looking beat; its coupling interval plus pause equals two expected sinus cycles.

What to look for

  • Most beats follow a regular sinus-like pattern.
  • One beat arrives earlier than expected.
  • The early beat has a wider, different-looking QRS shape.
  • A longer pause follows the early beat in this illustration.
  • Describe the underlying rhythm rate rather than assigning the premature beat its own BPM.

Compare it with: Unlike ventricular tachycardia, this example shows an isolated early wide complex rather than a sustained fast run of wide complexes.

A simplified 6-second, 80 bpm underlying sinus schedule interrupted by one early, wider-looking beat; its coupling interval plus pause equals two expected sinus cycles. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 8 visible QRS × 10 = 80 bpm underlying sinus schedule. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
8 countable QRSRate: 8 visible QRS × 10 = 80 bpm underlying sinus schedule
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

7 sinus QRS plus 1 early PVC · full compensatory pause · a PVC has no separate BPM

Simplified original rhythm-strip diagram for educational comparison.

Fast wide-complex run

Ventricular tachycardia

Illustrative

Rate criteria

Ventricular rate: usually 100–250 bpm

A simplified 6-second, 150 bpm sustained pattern with 15 broad, repeating complexes at regular 0.40-second intervals.

What to look for

  • Ventricular rate is usually about 100–250 bpm and may be generally regular.
  • QRS complexes are wide and similar in shape.
  • A clear P-to-QRS relationship is not visible here.
  • The wide complexes continue as a run.

Compare it with: Unlike premature ventricular complexes, this diagram shows repeated wide complexes in succession rather than a single interruption.

A simplified 6-second, 150 bpm sustained pattern with 15 broad, repeating complexes at regular 0.40-second intervals. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 15 broad QRS × 10 = 150 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
15 countable QRSRate: 15 broad QRS × 10 = 150 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

15 broad QRS complexes × 10 = 150 bpm · R–R = 0.40 sec (10 small boxes)

Simplified original rhythm-strip diagram for educational comparison.

Chaotic disorganized pattern

Ventricular fibrillation

Illustrative

Rate criteria

Rate: no organized measurable ventricular rate

A simplified chaotic waveform with no organized repeating QRS complexes.

What to look for

  • No consistent QRS complexes can be identified.
  • The waveform varies in height and spacing.
  • There is no organized repeating rhythm.
  • There is no organized measurable ventricular rate.
  • This illustration is intentionally schematic, not a diagnostic tracing.

Compare it with: Unlike ventricular tachycardia, this pattern has no regular sequence of repeated wide complexes.

A simplified chaotic waveform with no organized repeating QRS complexes. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. Do not count: no organized QRS, so rate cannot be calculated. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
Noncountable rhythmRate: Do not count: no organized QRS, so rate cannot be calculated
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

No organized measurable rate · disorganized schematic activity

Simplified original rhythm-strip diagram for educational comparison.

Visual practice test

Identify ten simplified rhythm strips.

Choose the best label from the options. First identify whether a countable QRS pattern is present, then compare rate, regularity, width, and atrial activity. This quiz evaluates these diagrams—not a real patient tracing.

Selections work with a mouse, touch, or keyboard. Color is never the only answer cue.

1. Which rhythm best matches this strip?
A simplified 6-second, 80 bpm baseline pattern with eight evenly spaced beats and a small P wave before each narrow QRS complex. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 8 QRS × 10 = 80 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
8 countable QRSRate: 8 QRS × 10 = 80 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

8 organized QRS complexes × 10 = 80 bpm · R–R = 0.75 sec (18.75 small boxes)

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
2. Which rhythm best matches this strip?
A simplified 6-second, 50 bpm sinus pattern with five evenly spaced beats and a visible P-to-QRS relationship. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 5 QRS × 10 = 50 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
5 countable QRSRate: 5 QRS × 10 = 50 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

5 organized QRS complexes × 10 = 50 bpm · R–R = 1.20 sec (30 small boxes)

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
3. Which rhythm best matches this strip?
A simplified 6-second, 120 bpm sinus pattern with 12 regular beats; each narrow QRS remains preceded by a recognizable P wave. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 12 QRS × 10 = 120 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
12 countable QRSRate: 12 QRS × 10 = 120 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

12 organized QRS complexes × 10 = 120 bpm · R–R = 0.50 sec (12.5 small boxes)

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
4. Which rhythm best matches this strip?
A simplified 6-second strip with eight irregularly spaced narrow QRS complexes and no repeating, organized P-wave pattern. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 8 QRS × 10 = 80 bpm average. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
8 countable QRSRate: 8 QRS × 10 = 80 bpm average
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

8 organized QRS complexes × 10 = 80 bpm average · intentionally variable R–R spacing

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
5. Which rhythm best matches this strip?
A simplified 6-second strip with 30 organized flutter cycles (300/min) and 15 regular narrow QRS complexes (150/min), illustrating 2:1 conduction. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 15 QRS × 10 = 150 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
15 countable QRSRate: 15 QRS × 10 = 150 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

15 QRS complexes × 10 = 150 bpm · regular 2:1-conduction illustration

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
6. Which rhythm best matches this strip?
A simplified 6-second, rapid, regular 180 bpm narrow-complex pattern; P waves are not clearly separated at this illustrated speed. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 18 QRS × 10 = 180 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
18 countable QRSRate: 18 QRS × 10 = 180 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

18 QRS complexes × 10 = 180 bpm · R–R ≈ 0.33 sec (8.3 small boxes)

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
7. Which rhythm best matches this strip?
A simplified 6-second, 80 bpm underlying sinus schedule interrupted by one early, wider-looking beat; its coupling interval plus pause equals two expected sinus cycles. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 8 visible QRS × 10 = 80 bpm underlying sinus schedule. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
8 countable QRSRate: 8 visible QRS × 10 = 80 bpm underlying sinus schedule
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

7 sinus QRS plus 1 early PVC · full compensatory pause · a PVC has no separate BPM

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
8. Which rhythm best matches this strip?
A simplified 6-second, 150 bpm sustained pattern with 15 broad, repeating complexes at regular 0.40-second intervals. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 15 broad QRS × 10 = 150 bpm. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
15 countable QRSRate: 15 broad QRS × 10 = 150 bpm
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

15 broad QRS complexes × 10 = 150 bpm · R–R = 0.40 sec (10 small boxes)

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
9. Which rhythm best matches this strip?
A simplified chaotic waveform with no organized repeating QRS complexes. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. Do not count: no organized QRS, so rate cannot be calculated. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
Noncountable rhythmRate: Do not count: no organized QRS, so rate cannot be calculated
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

No organized measurable rate · disorganized schematic activity

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.
10. Which rhythm best matches this strip?
A simplified 6-second, 80 bpm underlying sinus schedule interrupted by one early, wider-looking beat; its coupling interval plus pause equals two expected sinus cycles. This original educational diagram spans 6 seconds and 150 small boxes. Each small box represents 0.04 seconds; each bold box represents 0.20 seconds. The 0-, 3-, and 6-second markers are emphasized. 8 visible QRS × 10 = 80 bpm underlying sinus schedule. It is not a diagnostic ECG recording.6-SECOND RHYTHM STRIP · 150 SMALL BOXES0s1s2s3s4s5s6s25 mm/s · 1 s markers1 mV
8 countable QRSRate: 8 visible QRS × 10 = 80 bpm underlying sinus schedule
Timing: 1 small box = 0.04 secbold box = 0.20 sec5 bold boxes = 1 sec0, 3, and 6 sec markers emphasized

7 sinus QRS plus 1 early PVC · full compensatory pause · a PVC has no separate BPM

Original simplified rhythm-strip illustration. Use the rate calculation as one clue, then confirm it with spacing, atrial activity, and QRS shape.

0 of 10 answered. Answer every question to score the quiz.

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Safety reminder: this educational content cannot assess symptoms or determine a diagnosis. Seek urgent medical care or local emergency help for concerning symptoms such as chest pain, fainting, severe shortness of breath, or a sudden sense that something is seriously wrong.