Visual examples of different types of tachograms and Poincaré plots

How Poincaré plots and tachograms can be used to assist in the evaluation of arrhythmias

Below is a list of some possible assessments:

• Beat-to-beat patterns to identify
  • Atrial fibrillation versus atrial flutter versus atrial tachycardias
  • Sinus node exit block
  • Rate and rhythm changes leading to tachyarrhythmias
  • Sudden rate changes and recovery
• Perspective of ventricular rate response during atrial fibrillation before and after treatment
• Appraisal of autonomic tone and circadian rhythm
• Global and selected examination over time of beat density and identification

Video of 4 dogs with sinus node dysfunction likely the result of sinoatrial conduction pathway block (Each dog is represented by a different color dot)

Three-dimensional Poincaré plot from selected time

Bifurcation interval approximates 50% of interval durations displayed by long-long intervals of sinus arrhythmia supporting sinoatrial conduction block of 2:1.

Three-dimensional Poincaré plot over 24-hours

Tachy-brady sick sinus syndrome with sinoatrial exit block pattern. Tachycardias result in release of adenosine and acetylcholine which can cause block in the sinoatrial pathways and suppression of sinus pacemaker cell depolarization.

Time-selected Poincaré plot

Sick sinus syndrome dog with VVI pacemaker. (A) A hysteresis zone was programmed between 53 – 65 bpm. (B) Inherent sinus beats during the day are at rates in this zone illustrating effective hysteresis.

Two-dimensional Poincaré plots no lines from 2 different examinations

Initially, dog had sinus arrhythmia (blue), but one year later developed atrial fibrillation (red).

Three-dimensional Poincaré plots from 2 different examinations

Initially, dog had sinus arrhythmia (top), but one year later developed atrial fibrillation (bottom). Proportional beat density appreciated.

Two-dimensional Poincaré plots no lines from 2 different examinations

Dog with hypertrophic cardiomyopathy and outflow tract obstruction before (red) and after (blue) treatment with atenolol.

Two-dimensional Poincaré plot from selected time

Pattern relationships of premature ventricular complexes (red) and sinus beats (blue). Consistent ventricular intervals.

Two-dimensional tachogram from selected time

Pattern relationships of premature ventricular complexes (red) and sinus beats (blue). Consistent ventricular coupling intervals.

Two-dimensional Poincaré plot from selected time

Pattern relationships of premature ventricular complexes (red) and sinus beats (blue). Bigeminal and trigeminal ventricular rhythm.

Two-dimensional tachogram from selected time

Pattern relationships of ventricular tachycardia (red) and sinus beats (blue) revealed increasing sinus rate prior to runs of ventricular tachycardia.

Two-dimensional Poincaré plot from selected time

Pattern relationships of ventricular tachycardia (red) and sinus beats (blue) revealed increasing sinus rate prior to runs of ventricular tachycardia; consistent coupling interval before ventricular tachycardia; ventricular escape beats before ventricular tachycardia.

Three-dimensional Poincaré plots and tachograms (24-hours)

Histographic Poincaré plots (A and C) and density tachograms (B and D) graphically illustrate the reduction in atrial tachycardia (green) after treatment with amiodarone. The tachogram can permit identification of circadian development of arrhythmias.

Two-dimensional tachograms from selected times from two different dogs

What is the mechanism for the difference in the beat-to-beat relationship of the ventricular tachycardia (red) and sinus beats (blue)?

Two-dimensional Poincaré plot from selected time

Pattern relationships of premature ventricular complexes and ventricular tachycardia (red) with sinus beats (blue). What is the mechanism?

Three-dimensional Poincaré plot 24-hours

2nd degree heart block with ventricular complexes (red)

Three-dimensional tachogram 24-hours

Sinus node dysfunction dog with VVI pacemaker programmed with hysteresis demonstrating effective operation that has permitted  intrinsic beats with the longer hysteresis cycle.

Two-dimensional tachogram selected time interval

Dog in 3rd degree heart block with pacemaker programmed to VVI mode, but with different pacing intervals because of intermittent sensing of the T wave causing delay in pacing timeout.