Mechanism and Impact of Left Atrial Dyssynchrony on Long-Term Clinical Outcome During Cardiac Resynchronization Therapy.

Background: Left bundle branch block (LBBB) causes left atrial (LA) dyssynchrony. It is unknown if LA dyssynchrony impacts long-term prognosis.

Objectives: The purpose of this study was to determine mechanisms of LA dyssynchrony in LBBB and if LA dyssynchrony impacts long-term prognosis.

Pulse arrival time variation as a non-invasive marker of acute response to cardiac resynchronization therapy.

Aims: Successful cardiac resynchronization therapy (CRT) shortens the pre-ejection period (PEP) which is prolonged in the left bundle branch block (LBBB). In a combined animal and patient study, we investigated if changes in the pulse arrival time (PAT) could be used to measure acute changes in PEP during CRT implantation and hence be used to evaluate acute CRT response non-invasively and in real time.

Methods And Results: In six canines, a pulse transducer was attached to a lower limb and PAT was measured together with left ventricular (LV) pressure by micromanometer at baseline, after induction of LBBB and during biventricular pacing.

Tracking Early Systolic Motion for Assessing Acute Response to Cardiac Resynchronization Therapy in Real Time.

An abnormal systolic motion is frequently observed in patients with left bundle branch block (LBBB), and it has been proposed as a predictor of response to cardiac resynchronization therapy (CRT). Our goal was to investigate if this motion can be monitored with miniaturized sensors feasible for clinical use to identify response to CRT in real time. Motion sensors were attached to the septum and the left ventricular (LV) lateral wall of eighteen anesthetized dogs.

Lateral Wall Dysfunction Signals Onset of Progressive Heart Failure in Left Bundle Branch Block.

Objectives: This study sought to investigate if contractile asymmetry between septum and left ventricular (LV) lateral wall drives heart failure development in patients with left bundle branch block (LBBB) and whether the presence of lateral wall dysfunction affects potential for recovery of LV function with cardiac resynchronization therapy (CRT).

Background: LBBB may induce or aggravate heart failure. Understanding the underlying mechanisms is important to optimize timing of CRT.

How to measure left ventricular myocardial work by pressure-strain loops.

Myocardial work is calculated from non-invasive left ventricular pressure and strain by speckle tracking echocardiography. Myocardial work provides diagnostic information beyond what is achieved from left ventricular ejection fraction and strain since it incorporates afterload, and provides a measure of myocardial efficiency. The method can be used to calculate global as well as segmental work.