Narrowing the QRS, Expanding the Function: Left Bundle Branch Pacing in Dilated Cardiomyopathy

Figure 1. Pre- and post-procedural echocardiographic assessment demonstrating left ventricular reverse remodeling after left bundle branch pacing. (a) Baseline apical four-chamber view showing a severely reduced systolic function (left ventricular ejection fraction [LVEF] ≈30%). (b) Follow-up at six months after left bundle branch pacing reveals substantial reduction in chamber size and improvement in systolic performance (LVEF ≈ 52%), consistent with significant structural and functional reverse remodeling

Figure 2. Global longitudinal strain improvement following left bundle branch pacing. (a) Baseline strain bull’s-eye map showing markedly reduced and heterogeneous longitudinal deformation (GLS = −8.2%) with regional dyssynchrony, consistent with left bundle branch block-related mechanical discoordination. (b) Six months after left bundle branch pacing, strain analysis demonstrates homogeneous and synchronous contraction with restoration of normal deformation patterns (global longitudinal strain = −18.8%), indicating substantial improvement in mechanical synchrony and systolic function

Figure 3. Multiplanar three-dimensional reconstructions from coronary computed tomography angiography demonstrating normal coronary anatomy without evidence of obstructive disease. The images illustrate different rotational views of the left ventricle and coronary tree, confirming the absence of coronary artery stenosis and supporting the diagnosis of non-ischemic dilated cardiomyopathy

Figure 4. Cardiac magnetic resonance with parametric mapping. (a) Native T1 map in a mid-ventricular short-axis slice showing diffusely elevated T1 values, consistent with diffuse interstitial fibrosis (arrow). (b1-b3) Bull’s eye plots of native T1, post-contrast T1, and extracellular volume quantification demonstrate globally increased values, confirming diffuse myocardial involvement in the absence of focal late gadolinium enhancement

Figure 5. Cardiac magnetic resonance late gadolinium enhancement imaging. (a) Short-axis and (b) long-axis views show no areas of subendocardial or transmural enhancement (arrows), confirming the absence of ischemic scar and supporting the diagnosis of nonischemic dilated cardiomyopathy