Right-sided electrocardiographic and phonocardiographic predictors of functional tricuspid regurgitation severity

Background

Functional tricuspid regurgitation (FTR) is an independent predictor of adverse outcomes, yet diagnosis relies on echocardiography. Leads V1 and aVR overlie or face the right heart and may contain ECG signatures of haemodynamic derangements driving FTR. Phonocardiography can capture electromechanical coupling abnormalities at the tricuspid level. Whether right-sided ECG and phonocardiographic parameters predict FTR severity has not been systematically investigated.

Purpose

To evaluate the predictive value of ECG parameters from leads V1 and aVR, and phonocardiographic intervals, for moderate-to-severe FTR.

Methods

We prospectively enrolled 174 patients (age 62±14 years, 51% male; 73% with heart failure). All underwent 12-lead ECG with analysis of V1 repolarization intervals (QTcV1, JTpeak-V1, Tpeak-Tend-V1, Tend-P-V1) and aVR parameters (QRS amplitude, intrinsicoid deflection time), alongside comprehensive echocardiography. Phonocardiography (QRS–S1 and QRS–S2 intervals) was available in 118 patients (68%). TR was graded semi-quantitatively; the primary outcome was moderate-to-severe FTR (n=28, 16%). Univariate Mann-Whitney U tests and Spearman correlations quantified associations with TR grade. Multivariate logistic regression models were built exclusively from right-sided ECG and phonocardiographic parameters; discriminative performance was assessed by AUC.

Results

QRS amplitude in aVR was significantly lower in moderate-to-severe vs. none/mild FTR (0.82±0.40 vs. 1.19±0.66 mV, p=0.007), while JTpeak-V1 tended to be prolonged (217±34 vs. 198±51 ms, p=0.095) and QTcV1 showed a trend toward prolongation (450±36 vs. 438±38 ms, p=0.062). The phonocardiographic QRS–S1 interval correlated with TR severity (ρ=0.186, p=0.044) and tended to be prolonged in moderate-to-severe FTR (85±18 vs. 77±24 ms, p=0.053).

The best single right-sided ECG predictor was QRS amplitude in aVR (AUC=0.663). Combining JTpeak-V1 with QRS aVR amplitude improved discrimination to AUC=0.729. The best four-variable model — JTpeak-V1, QRS aVR amplitude, QRS–S1 interval, and heart rate — achieved AUC=0.813, integrating RV repolarization, right-sided voltage changes, tricuspid electromechanical coupling, and chronotropic load. For comparison, the best echocardiographic predictor was TAPSE/PSAP (AUC=0.870) and the best echo-inclusive model reached AUC=0.928.

Conclusions

Right-sided ECG parameters from V1 and aVR, combined with phonocardiographic QRS–S1 interval, achieve good discrimination (AUC=0.813) for moderate-to-severe FTR using only non-imaging bedside tools. JTpeak-V1 and QRS aVR amplitude emerge as key markers of RV repolarization prolongation and right-sided volume/pressure changes. These accessible parameters may serve as screening tools for significant FTR, guiding echocardiographic referral in resource-limited settings.Figure