Phenotyping heart failure by echocardiography: imaging of ventricular function and haemodynamics at rest and exercise.

Traditionally, congestive heart failure (HF) was phenotyped by echocardiography or other imaging techniques according to left ventricular (LV) ejection fraction (LVEF). The more recent echocardiographic modality speckle tracking strain is complementary to LVEF, as it is more sensitive to diagnose mild systolic dysfunction. Furthermore, when LV systolic dysfunction is associated with a small, hypertrophic ventricle, EF is often normal or supernormal, whereas LV global longitudinal strain can reveal reduced contractility.

Left bundle branch block increases left ventricular diastolic pressure during tachycardia due to incomplete relaxation.

We investigated whether tachycardia in left bundle branch block (LBBB) decreases left ventricular (LV) diastolic distensibility and increases diastolic pressures due to incomplete relaxation, and if cardiac resynchronization therapy (CRT) modifies this response. Thirteen canines were studied at baseline heart rate (120 beats/min) and atrial paced tachycardia (180 beats/min) before and after induction of LBBB and during CRT. LV and left atrial pressures (LAP) were measured by micromanometers and dimensions by sonomicrometry.

Mechanical Effects on Right Ventricular Function From Left Bundle Branch Block and Cardiac Resynchronization Therapy.

Objectives: The purpose of this study was to investigate how LBBB and CRT modify RV free wall function by direct ventricular interaction.

Background: Right ventricular (RV) function influences prognosis in patients with left bundle branch block (LBBB) and cardiac resynchronization therapy (CRT). There is, however, limited insight into how LBBB and CRT affect RV function.

Left ventricular end-systolic volume is a more sensitive marker of acute response to cardiac resynchronization therapy than contractility indices: insights from an experimental study.

Aims: There are conflicting data and no consensus on how to measure acute response to cardiac resynchronization therapy (CRT). This study investigates, which contractility indices are best markers of acute CRT response.

Methods And Results: In eight anaesthetized dogs with left bundle branch block, we measured left ventricular (LV) pressure by micromanometer and end-diastolic volume (EDV) and end-systolic volume (ESV) by sonomicrometry.

Dysfunction of the systemic right ventricle after atrial switch: physiological implications of altered septal geometry and load.

Atrial switch operation in patients with transposition of the great arteries (TGA) leads to leftward shift and changes the geometry of the interventricular septum. By including the implications of regional work and septal curvature, this study investigates if changes in septal function and geometry contribute to reduced function of the systemic right ventricle (RV) in adult TGA patients. Regional myocardial work estimation has been possible by applying a recently developed method for noninvasive work calculation based on echocardiography.

Afterload Hypersensitivity in Patients With Left Bundle Branch Block.

Objectives: This study sought to investigate the hypothesis that patients with left bundle branch block (LBBB) are hypersensitive to elevated afterload.

Background: Epidemiological data suggest that LBBB can provoke heart failure in patients with hypertension.

Methods: In 11 asymptomatic patients with isolated LBBB and 11 age-matched control subjects, left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were measured by echocardiography.

Non-invasive myocardial work index identifies acute coronary occlusion in patients with non-ST-segment elevation-acute coronary syndrome.

Aims: Acute coronary artery occlusion (ACO) occurs in ∼30% of patients with non-ST-segment elevation-acute coronary syndrome (NSTE-ACS). We investigated the ability of a regional non-invasive myocardial work index (MWI) to identify ACO.

Methods And Results: Segmental strain analysis was performed before coronary angiography in 126 patients with NSTE-ACS.

Cardiac responses to left ventricular pacing in hearts with normal electrical conduction: beneficial effect of improved filling is counteracted by dyssynchrony.

Cardiac resynchronization therapy (CRT) has been proposed in heart failure patients with narrow QRS, but the mechanism of a potential beneficial effect is unknown. The present study investigated the hypothesis that left ventricular (LV) pacing increases LV end-diastolic volume (LVEDV) by allowing the LV to start filling before the right ventricle (RV) during narrow QRS in an experimental model. LV and biventricular pacing were studied in six anesthetized dogs before and after the induction of LV failure.