Utility of the surface ECG before VDD pacemaker implantation

Area of Science:

• Cardiology
• Biomedical Engineering
• Electrophysiology

Background:

• Ventricular Demand pacing (VDD) pacemakers are used for atrioventricular block with preserved sinus function, offering a single-lead advantage over DDD systems.
• A significant challenge with VDD pacemakers is the potential for atrial undersensing due to low-amplitude atrial electrograms (EGMs) from the free-floating atrial electrode.
• Currently, there is no reliable method to predict atrial EGM amplitude before implantation, hindering the selection of appropriate candidates for VDD pacing.

Purpose of the Study:

• To determine if the P-wave amplitude measured on a standard surface electrocardiogram (ECG) correlates with the atrial EGM amplitude recorded by a single-pass lead during VDD pacemaker implantation.
• To identify potential predictors of adequate atrial electrogram amplitude for VDD pacemaker recipients.

Main Methods:

• A retrospective review of data from 122 patients who received a VDD pacemaker was conducted.
• Atrial EGM amplitudes measured at the time of implantation were correlated with the maximal P-wave amplitude observed on the surface ECG recorded immediately prior to the procedure.

Main Results:

• A statistically significant positive correlation was found between maximal surface P-wave amplitude and atrial EGM amplitude (Pearson's r=0.313, P<0.001).
• Multivariate analysis confirmed that maximal P-wave amplitude was an independent predictor of atrial EGM amplitude (p=0.003).
• A low atrial EGM amplitude (<0.9 mV) was infrequent overall (9%) but occurred more often in patients with a surface P-wave amplitude ≤0.1 mV (14%) compared to those with >0.1 mV (2%).

Conclusions:

• Low atrial EGM amplitudes requiring potential pacemaker reprogramming are uncommon in patients with single-pass leads for VDD pacing.
• A maximal surface P-wave amplitude greater than 0.1 mV is a strong indicator that a patient is unlikely to experience low atrial EGM amplitude.
• Patients exhibiting a P-wave amplitude >0.1 mV on surface ECG are favorable candidates for VDD pacemaker implantation due to a lower risk of atrial undersensing.