Advantages and disadvantages of various pacing modes

By Alex Yartsev - 30/06/2015

A more detailed discussion of pacemaker technology is conducted elsewhere. Specifically, single and dual chamber pacing modes have their own dedicated chapter.

Previous questions about pacing modes include:

Question 1 from the first paper of 2022
Question 15 from the second paper of 2010
Question 20 from the first paper of 2007

This is a brief point-form summary.

Single chamber pacing modes

Single-chamber atrial pacing
- AOO - asynchronous atrial pacing
- AAI - atrial demand pacing
- AAT - atrial pacing
Single-chamber ventricular pacing
- VOO - asynchronous ventricular pacing
- VVI - ventricular demand pacing
- VVT - ventricular pacing

Dual chamber pacing modes

VAT - atrial sensing, ventricular pacing
DDD - dual chamber demand pacing

Nomenclature of Pacing Modes
Position 1: chamber paced	Position 2: chamber sensed	Position 3: response to sensing
O = none	O = none	O = none
A = atrium	A = atrium	T = triggered
V = ventricle	V = ventricle	I = inhibited
D = dual	D = dual	D = dual (triggered and inhibited)

A Comparison of Single and Dual Chamber Pacing Modes
Pacing Mode	Description	Advantages	Disadvantages
AOO	asynchronous atrial pacing.	Only one lead required Preserves AV synchrony in the presence of an intact AV node Protects against interference by diathermy	contraindicated in the presence of intrinsic cardiac rhythms. If the rate is not high enough, you will have an underlying rhythm competing with the pacemaker. Useless if the AV node is dysfunctional Useless in the presence of AF Increased risk of perforating the thin atrial wall
AAI	atrial demand pacing	Only one lead required Preserves AV synchrony in the presence of an intact AV node Only paces on demand; allows intrinsic rhythm while the rate is high enough	Useless if the AV node is dysfunctional Useless in the presence of AF Increased risk of perforating the thin atrial wall
AAT	atrial pacing	Only one lead required Preserves AV synchrony in the presence of an intact AV node Useful for testing atrial sensing (using the pacing spike)	Useless if the AV node is dysfunctional Useless in the presence of AF Unproductive in general (paces in response to normal atrial contraction, while the atrium is in a refractory period); thus, not a useful permanent mode Increased risk of perforating the thin atrial wall
VOO	asynchronous ventricular pacing	Only one lead required Protects against interference by diathermy	Asynchronous AV contraction May result in the R - on - T phenomenon Difficult to assess ST changes (LBBB-like QRS morphology)
VVI	ventricular demand pacing	Only one lead required Only paces on demand; allows intrinsic rhythm while the rate is high enough	Asynchronous AV contraction Difficult to assess ST changes (LBBB-like QRS morphology)
VVT	ventricular pacing	Useful for testing ventricular sensing (using the pacing spike)	Asynchronous AV contraction Unproductive in general (paces in response to normal ventricular contraction, while the ventricle is in a refractory period); thus, not a useful permanent mode Difficult to assess ST changes (LBBB-like QRS morphology) Possibility of "endless loop" tachycardia
VAT	atrial sensing, ventricular pacing	AV synchrony is preserved "Pacemaker syndrome" is thus avoided Advantageous in patients with normal atrial activity and a dysfunctional AV node	Two leads required Bundle of His is bypassed Difficult to assess ST changes (LBBB-like QRS morphology) Increased risk of perforating the thin atrial wall
DDD	dual chamber demand pacing	AV synchrony is preserved "Pacemaker syndrome" is thus avoided Advantageous in patients with normal atrial activity and a dysfunctional AV node Versatile mode, with hemodynamic	Two leads required Bundle of His is bypassed Possibility of "endless loop" tachycardia Increased risk of perforating the thin atrial wall

References

Reade, M. C. "Temporary epicardial pacing after cardiac surgery: a practical review." Anaesthesia 62.3 (2007): 264-271.

Reade, M. C. "Temporary epicardial pacing after cardiac surgery: a practical review: Part 2: Selection of epicardial pacing modes and troubleshooting."ANAESTHESIA-LONDON- 62.4 (2007): 364.

Gammage, Michael D. "Temporary cardiac pacing." Heart 83.6 (2000): 715-720.

Sanders, Richard S. "The Pulse Generator." Cardiac Pacing for the Clinician. Springer US, 2008. 47-71.

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