Quantitative Analysis of Left Ventricular Flow Dynamics in Latent Obstructive Hypertrophic Cardiomyopathy Using Vector Flow Mapping

Vector flow mapping: A review from theory to practice

BACKGROUND

The interest in intra-cardiac blood flow analysis is rapidly growing, and it has encouraged the development of different non-invasive imaging techniques. Among these, Vector Flow Mapping (VFM), combing Color-Doppler imaging and speckle tracking data, seems to be a promising approach, feasible in adult and children population.

AIM OF THE REVIEW

The aim of this review is to give a historical perspective on the development of VFM method and a summary of the current algorithms and parameters potentially evaluable. Then, we will present the current state-of-the-art of VFM with an overview of clinical studies and applications of this technique.

Energy loss by right ventricular pacing: Patients with versus without hypertrophic cardiomyopathy

BACKGROUND

Right ventricular (RV) pacing causes left ventricular (LV) dyssynchrony sometimes resulting in pacing-induced cardiomyopathy. However, RV pacing for hypertrophic obstructive cardiomyopathy is one of the treatment options. LV flow energy loss (EL) using vector flow mapping (VFM) is a novel hemodynamic index for assessing cardiac function. Our study aimed to elucidate the impact of RV pacing on EL in normal LV function and hypertrophic cardiomyopathy (HCM) patients.

METHODS

A total of 36 patients with dual-chamber pacemakers for sick sinus syndrome or implantable cardioverter defibrillators for fatal ventricular tachyarrhythmias were enrolled. All patients were divided into two groups: 16 patients with HCM (HCM group) and others (non-HCM group). The absolute changes in EL under AAI (without RV pacing) and DDD (with RV pacing) modes were assessed using VFM on color Doppler echocardiography.

RESULTS

In the non-HCM group, the mean systolic EL significantly increased from the AAI to DDD modes (14.0 ± 7.7 to 17.0 ± 8.6 mW/m, P = .003), whereas the mean diastolic EL did not change (19.0 ± 12.3 to 17.0 ± 14.8 mW/m, P = .231). In the HCM group, the mean systolic EL significantly decreased from the AAI to DDD modes (26.7 ± 14.2 to 21.6 ± 11.9 mW/m, P < .001), whereas the mean diastolic EL did not change (28.7 ± 16.4 to 23.9 ± 19.7 mW/m, P = .130).

CONCLUSIONS

RV pacing increased the mean systolic EL in patients without HCM. Conversely, RV pacing decreased the mean systolic EL in patients with HCM.