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Rhythm City: A Map of the Heart’s Electrical System

Rhythm City is the heart’s conduction system drawn as a town. Each district is one place a rhythm can start, or one thing that can go wrong along the way. Learn where a rhythm lives and its name starts to make sense. Tap a district on the map to see its rhythms and where to study them.

By Mark K. Copeland, RCS, CRAT · Certified Rhythm Analysis Technician and Clinical ECG Trainer · Updated October 2026

Tap or click a district. On a phone, use Zoom or scroll down for the full list.

Full-size image
Rhythm City map. Choose a district to see its rhythms.

Above the river: sinus, atrial and junctional rhythms. Below it: the ventricles. The Relay Corridor is the only normal road across. The Feedback Loop’s extra wire is the shortcut.

The districts

One district for each rhythm family in the Rhythm Library. Library entries and chapters 3 to 14 are for members. Chapters 1 and 2 and the practice pages marked Free are open to everyone.

The DJ Booth

SA node · Sinus rhythms · Chapter 4

The SA node, high in the right atrium, is the heart’s normal pacemaker and fires about 60 to 100 times a minute. Every sinus rhythm starts here; what changes is the rate, the regularity, or a missing beat.

Rhythms

  • Normal Sinus Rhythm
  • Sinus Tachycardia
  • Sinus Bradycardia
  • Sinus Arrhythmia
  • Sinus Exit Block
  • Sinus Pause
  • Sinus Arrest

There is no sinus early beat or sinus escape beat. Those beats always come from somewhere else.

The Nightclub

Atria · Atrial rhythms · Chapter 5

When a spot in the atrial muscle fires instead of the SA node, the P wave changes shape or comes early. Atrial flutter makes sawtooth waves, and in atrial fibrillation the atria quiver and the rhythm is irregularly irregular.

Beats

  • PAC
  • PAC Pair
  • Non-conducted PAC
  • Atrial Escape Beat

Rhythms

  • Ectopic Atrial Rhythm
  • Wandering Atrial Pacemaker
  • Ectopic Atrial Tachycardia
  • Atrial Tachycardia
  • Multifocal Atrial Tachycardia
  • Atrial Flutter
  • Atrial Fibrillation

The Stage Manager’s Booth

AV node and junction · Junctional rhythms · Chapter 6

If the SA node goes quiet, the AV junction can take over as a backup pacemaker at about 40 to 60 a minute. The QRS stays narrow, and the P wave is missing, inverted just before or after the QRS, or hidden inside it.

Beats

  • PJC
  • Junctional Escape Beat

Rhythms

  • Junctional Rhythm
  • Accelerated Junctional Rhythm
  • Junctional Tachycardia

There is no junctional flutter or junctional fib.

The Feedback Loop

Reentry · Advanced rhythms · Chapter 10

Here the signal runs around a circuit and keeps coming back into the same path. In AVNRT the loop sits in or near the AV node; in AVRT it uses an extra wire, an accessory pathway like the one in WPW.

Rhythms

  • AVNRT
  • Orthodromic AVRT
  • Antidromic AVRT

Pattern

  • WPW pattern (the extra wire)

The Relay Corridor

AV blocks · Chapter 8

AV blocks are trouble on the road from the atria to the ventricles, not a new pacemaker. The signal is slowed (first-degree, PR longer than 0.20 s), dropped some of the time (second-degree), or stopped completely (third-degree).

Rhythms

  • 1st Degree AV Block
  • 2nd Degree Type I (Wenckebach)
  • 2nd Degree Type II
  • High-Grade AV Block
  • 3rd Degree (Complete) AV Block

The Power Plant

Ventricles · Ventricular rhythms · Chapter 7

When the ventricles start the beat, the signal spreads slowly from cell to cell instead of using the fast wiring, so the QRS is wide: more than 0.12 s. The last-resort pacemakers down here fire only about 20 to 40 times a minute.

Beats

  • PVC
  • Interpolated PVC
  • Ventricular Escape Beat

Rhythms

  • Idioventricular Rhythm
  • Accelerated Idioventricular Rhythm
  • Ventricular Tachycardia
  • Torsades de Pointes
  • Ventricular Flutter
  • Ventricular Fibrillation
  • Agonal Rhythm
  • Asystole (including P-wave asystole)

The Backup Generator Room

Artificial pacemakers · Chapter 9

An artificial pacemaker leaves a small spike on the strip just before the P wave or QRS it starts. Reading a paced strip means checking that each spike does its job, which is where the three failures come in.

Paced rhythms

  • Atrial Paced
  • Ventricular Paced
  • AV Paced
  • CRT (Biventricular) Paced

Failures

  • Failure to Pace
  • Failure to Capture
  • Failure to Sense

Filtering the Noise

Artifact · Chapter 12

Artifact is noise on the strip that does not come from the heart. Poor electrode contact and patient movement are common causes, and the monitor can name the wrong rhythm because of it, so look at the patient first.

Types

  • Motion artifact
  • Muscle tremor artifact
  • Loose lead artifact
  • 60 Hz interference

Landmarks and keys

The parts of the map that are not a rhythm family: the wiring between districts, the ECG itself, the place where you put a strip together, and the naming legend.

The Rhythm Naming Cheat Code

Map legend · Chapter 3

A rhythm’s name is where it starts plus what it is doing. An early beat from the atria is a PAC, and the same pattern from the ventricles is a PVC.

The five lots in each district

  • Early
  • Escape
  • Tach
  • Flutter
  • Fib

On the map, a filled lot means that beat or rhythm exists at that site. A dashed, empty lot means it does not.

The Wiring

The conduction system · Chapter 1

The normal path runs from the SA node through the atria to the AV node, then down the bundle of His, the bundle branches and the Purkinje fibers. If a bundle branch is blocked, a beat from above the ventricles comes out wide: a supraventricular rhythm with BBB/aberrancy.

Map key

  • SA node: the DJ Booth
  • Internodal pathways
  • AV node: the Stage Manager’s Booth
  • Bundle of His and branches: the Main Cable
  • Purkinje fibers: the Stage Lighting Grid
● About this map

Rhythm City comes from The Cardiac Dance, the ECG course behind Cardiac Cadence. The map is a teaching picture, not an anatomy drawing. Rates, intervals and ECG features on this page follow these sources:

QRS widths follow the course rule: 0.06 to 0.12 s is narrow, more than 0.12 s is wide.