Electrocardiographic predictors of atrial mechanical sensing in leadless pacemakers

Leadless pacemakers (LPs) capable of VDD pacing allow for atrioventricular synchrony through mechanical sensing of atrial contraction. However, mechanical sensing is less reliable and less predictable than electrical sensing.

The purpose of this study was to evaluate P-wave amplitude during sinus rhythm from preoperative 12-lead electrocardiograms (ECGs) as a predictor for atrial mechanical sensing in patients undergoing VDD LP implantation.

Consecutive patients undergoing VDD LP implantation were included in this 2-center prospective cohort study. ECG parameters were evaluated separately and in combination for association with the signal amplitude of atrial mechanical contraction (A4).

Eighty patients (median age 82 years; female 55%; mean body mass index [BMI] 25.8 kg/m²) were included in the study and 61 patients in the A4 signal analysis (19 patients in VVI mode during follow-up). Absolute (aVL, aVF, V₁, V₂) and BMI-adjusted (I, II, aVL, aVF, aVR, V₁, V₂) P-wave amplitudes from baseline ECGs demonstrated a statistically significant positive correlation with A4 signal amplitude (all P <.05). A combined P-wave signal amplitude of at least 0.2 mV in V₁ and aVL was predictive, with specificity of 83% (95% confidence interval 67%-100%) for A4 signal ≥1 m/s². We found a significant correlation of A4 signal amplitude and overall atrioventricular synchrony (P = .013).

P-wave amplitudes in ECG leads aVL and V₁ can predict A4 signal amplitude in patients with VDD LP and therefore the probability of successful AV synchronous pacing.