Pathophysiology and Current Evidence for Detection of Dyssynchrony

Doppler-derived pulmonary pulse transit time measurements in chronic obstructive pulmonary disease: Reproducibility and cardiopulmonary function

INTRODUCTION

Doppler-derived pulmonary pulse transit time (pPTT) is an auspicious hemodynamic marker in chronic pulmonary diseases. The aim is to compare four distinct pPTT measurements and its relation to right cardiac and pulmonary function.

METHODS

Prospectively, 25 chronic obstructive pulmonary disease (COPD) patients (four patients excluded) and 32 healthy subjects underwent repeated distinct pPTT measurements, standard echocardiography, and pulmonary function testing on the same day. pPTT was defined as the interval from the R or Q-wave in the electrocardiogram to the corresponding pulse wave Doppler peak late systolic (S) 2 or diastolic (D) pulmonary vein flow velocity (pPTT R-S, Q-S, R-D, Q-D). Reproducibility was assessed using Bland-Altman analysis, coefficient of variation (COV), intraclass correlation coefficient (ICC), and power calculations. Associations with right ventricular RV tissue and pulse wave Doppler velocities (RV E', RV S', RV A', RV E, RV A, RV E/E', RV E/A), TAPSE, right ventricular fractional area change, left ventricular systolic and diastolic function (LV ejection fraction, E, A, E/A, E/E', septal E', lateral E'), LA diameters, as well as forced expiratory volume in 1 s, forced vital capacity (FVC) predicted (%), and in liters were analyzed.

RESULTS

There was no significant difference and no bias between pPTT measures (p range: .1-.9). COV was in COPD 1.2%-2.3%, in healthy subjects 1.0%-3.1%. ICC ranged from .92 (COPD) to .96 (healthy subjects). In COPD significant correlations were found for pPTT R-S, Q-S and R-D with RV E`, (all > ρ: .49, < p = .0364), pPTT R-S, Q-S with RV E/E` (both > ρ: .49, < p = .0291), pPTT Q-S with RV S´ (ρ: .58, p = .0134), RV A (ρ: .59, p = .0339) and heart rate > ρ: -.39, < p = .0297). pPTT R-S, R-D showed significant correlations with FVC predicted (%) (ρ: .48 p = .0224) and FVC (l) (ρ:.47 p = .0347).

CONCLUSIONS

All pPTT measures exhibited high reproducibility. In COPD patients pPTT measures correlate with diastolic right ventricular function. Defining Q as starting point seems clinically advantageous considering electromechanical desynchrony in patients with conduction disorders.

Comparison of Global Longitudinal Strain in Dual-chamber versus Ventricular Pacemaker in Complete Heart Block

Context

Bradycardia caused by total atrioventricular block (TAVB) is treated by implantation of permanent pacemakers (PPMs) in either dual-chamber (DDD) versus ventricular (VVI) pacing modes. DDD is considered a more physiological pacing mode than VVI as it avoids atrioventricular dyssynchrony. However, previous trials have failed to demonstrate the superiority of DDD in improving quality of life and morbidity.

Aims

This study aims to provide postpacemaker function of the left ventricle (LV) measured with global longitudinal strain (GLS), in TAVB patients.

Settings and Design

This is a comparative study; samples included in the study are adult TAVB patients undergoing PPM implantation, without significant heart function, and structural abnormality. Echocardiographic parameters are obtained before, after 1 month, and after 3 months post-PPM.

Subjects and Methods

A total of 98 TAVB patients undergoes PPM implantation during the study period, 55 patients were excluded, and in the end, only 43 patients fulfill the inclusion criteria.

Statistical Analysis Used

Baseline data between DDD and VVI are compared using unpaired t-test. Statistical significance 1 month post-PPM and 3 months post-PPM is analyzed using paired t-test.

Results

There were no significant differences between both groups at baseline. However, significant GLS changes are observed 1 month after PPM in the VVI group (P = 0.002), but no significant change was observed in the DDD group even after 3 months (P = 0.055).

Conclusions

In our study, we conclude that DDD is superior in maintaining LV function in the short term in TAVB patients after PPM implantation.