electromechanical delay and stroke

BACKGROUND: The acute response to cardiac resynchronization therapy (CRT) has been shown to be due to 3 mechanisms: resynchronization of ventricular contraction, efficient preloading of the ventricles by a properly timed atrial contraction, and mitral regurgitation reduction. However, the contribution of each of the 3 mechanisms to the acute response to CRT, specifically stroke work improvement, has not been quantified. OBJECTIVE: To use a magnetic resonance image-based anatomically accurate 3-dimensional model of failing canine ventricular electromechanics to quantify the contribution of each of the 3 mechanisms to stroke work improvement and identify the predominant mechanisms...

PURPOSE: Quadripolar left ventricular (LV) leads allow for several pacing configurations in candidates for cardiac resynchronization therapy (CRT). Whether different pacing configurations may affect LV dyssynchrony and systolic function is not completely known. We aimed to evaluate the acute effects of different pacing vectors on LV electromechanical parameters in patients implanted with a quadripolar LV lead. METHODS: In this two-centre study, within 1 month of implantation 21 CRT patients (65 ± 8 years, 76 % men, 38 % ischemic) receiving a quadripolar LV lead (Quartet 1458Q, St Jude Medical) underwent LV capture threshold assessment, intracardiac electrogram optimization, and two-dimensional echocardiography during four pacing configurations: D1-P4, P4-RV coil, D1-RV coil, and P4-M2...

BACKGROUND: The association between diastolic abnormality and postexercise contractile decompensation is uncertain in heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF). HYPOTHESIS: The higher mitral E/annular early diastolic velocity (E/e') is relevant to postexercise regional myocardial contractile maladaptation. METHODS: Seventy HF patients with LVEF <50 % (56 males, 58 ± 15 years) were studied pre- and postexercise using tissue Doppler echocardiography...

BACKGROUND: Rivaroxaban reduces stroke in patients with atrial fibrillation (AF). Left atrium (LA) plays a critical role in the pathophysiology of AF. However, the electromechanical effects of rivaroxaban on LA are not clear. RESULTS: Conventional microelectrodes and a whole-cell patch-clamp were used to record the action potentials (APs) and ionic currents in rabbit LA preparations and isolated single LA cardiomyocytes before and after the administration of rivaroxaban...

PURPOSE: In this study we aimed to investigate myocardial function and atrial electromechanical properties by conventional and tissue doppler echocardiography in patients with primary Sjögren syndrome. METHODS: Forty patients with Sjögren syndrome (SS) and 25 age- and sex-matched healthy volunteers were enrolled in the study. Using transthoracic echocardiography, myocardial performance index and atrial electromechanical properties were measured. RESULTS: Basal characteristics were similar between two groups...

Interatrial block (IAB; P-wave duration ≥110 milliseconds) denotes a conduction delay between the two atria. IAB has been shown to have a strong correlation with atrial arrhythmias, left atrial enlargement, left atrial electromechanical dysfunction and cerebral thromboembolism. Our study sought to determine whether there was an increased incidence of IAB in patients with acute occlusive mesenteric ischemia. Medical records of patients admitted with a diagnosis of acute mesenteric ischemia (AMeI) from January 2009 to March 2011 were reviewed retrospectively...

BACKGROUND: We hypothesized left ventricular (LV) dyssynchrony would affect postexercise accommodation of regional myocardial motion in patients with heart failure and a normal ejection fraction (HFNEF). METHODS AND RESULTS: Tissue-Doppler echocardiography was studied in 100 hypertensive patients with LV ejection fraction >50%. Among them, 70 HFNEF patients were classified into the systolic dyssynchrony (Dys: >65 ms difference of electromechanical delay between septal and lateral segments) (43 patients) and nondyssynchrony (Ndys: 27 patients) groups, and the other 30 patients were as the control (Ctrl)...

BACKGROUND: Arterial stiffness is strongly predictive for cardiovascular events in hypertensive individuals and it may increase the risk of stroke. This study was designed to evaluate the possible relationship between arterial stiffness and atrial electromechanical delay and P wave dispersion (PWD), as determinants of AF risk. MATERIALS AND METHODS: The study included 75 hypertensive patients and 45 healthy control subjects. Atrial electromechanical coupling (time interval from the onset of P wave on ECG to the beginning of A wave with tissue Doppler echocardiography [PA]), intraatrial and interatrial electromechanical delay (EMD) and PWD were measured...

AIMS: This study aimed to explore if the right ventricular outflow tract (RVOT) pacing is superior to right ventricular apical (RVA) pacing on the overall left ventricular (LV) function and regional wall motion. METHODS AND RESULTS: Sixty patients with atrio-ventricular (AV) block and normal ejection fraction undergoing dual-chamber pacemaker implantation were randomized to permanent ventricular stimulation either in the RVOT or the RVA. Left ventricular volume, ejection fraction, and LV regional wall motion were assessed by echocardiography...

OBJECTIVE: Although several risk factors for postoperative atrial fibrillation (AF) have been proposed, it remains the most common complication after cardiac surgery, even in low-risk patients. There is still no single reliable and reproducible parameter for predicting AF, and no standardized recommendation exists for this issue. Electromechanical delay (excitation-contraction coupling delay) is the time delay from the electrical activation to the actual systolic motion, and it reflects abnormality in calcium-handling proteins, which is considered one mechanism of postoperative AF...

Atrial septal aneurysm (ASA) is a saccular deformity located in the atrial septum. Atrial arrhythmias are common in patients with ASA. Atrial electromechanical delay (AEMD) can be used to evaluate development of atrial arrhythmias in various settings. The aim of the study was to investigate the relationship between ASA, cardiac arrhythmias and AEMD. Seventy patients with ASA served as the study group (30 men; mean age, 33.6 ± 10.9 years) and 70 healthy volunteers served as the control group (34 men; mean age, 31...

BACKGROUND: Reproducibility of Doppler echocardiography for assessment of inter-ventricular and intra-left ventricular (LV) dyssynchrony, and its clinical implications, have not been established. METHODS: Twenty-eight subjects (heart failure stages A-C, 61% with QRS ≥ 120 ms, ejection fraction (EF) ≤ 35%) underwent two consecutive echo-studies within 24h to evaluate test-re-test reproducibility of inter-ventricular electromechanical delay (VV delay, by traditional pulsed-Doppler), and intra-LV electromechanical delay between opposite LV walls by color-coded Doppler tissue-velocity (COLOR-DTI), and by pulsed-Doppler tissue spectrum (PW-DTI)...

OBJECTIVES: The aim of this study was to evaluate atrial electromechanical delay measured by tissue Doppler imaging (TDI) and left atrial (LA) mechanical functions in patients with rheumatoid arthritis (RA). STUDY DESIGN: The study included 68 patients (53 females, 15 males; mean age 43.7 years) with RA. Using TDI, atrial electromechanical coupling (PA) was measured from the lateral mitral annulus (PA lateral), septal mitral annulus (PA septum), and right ventricular tricuspid annulus (PA tricuspid)...

BACKGROUND: There is no gold standard technique for quantification of ventricular dyssynchrony. AIM: To investigate whether additional real-time three-dimensional morphologic assessment of ventricular dyssynchrony affects response after biventricular pacing. METHODS: Forty-one patients with severe heart failure were implanted with a biventricular pacing device and underwent two-dimensional (time dispersion of 12 left ventricular electromechanical delays) and three-dimensional echocardiographic assessment of ventricular dyssynchrony (dispersion of time to minimum regional volume for 16 left ventricular segments), before implantation, 2 days postimplantation with optimization of the pacing interventricular delay and 6 months postimplantation...

Tissue Doppler imaging-derived intra-left ventricular (LV) contractile dyssynchrony is an evolving prognostic parameter for patients with systolic heart failure (HF). However, whether and how exercise could abolish the synchronicity in HF patients with narrow QRS remains less studied. We evaluated a total of 33 HF patients with impaired LV ejection fraction (<50%), QRS duration < or =120 ms, and baseline dyssynchrony index (DI; standard deviation of electromechanical delay of 12 LV segments by tissue Doppler imaging) <33 ms...

BACKGROUND: There is an accumulating data suggesting the deleterious effects of right ventricular pacing on left ventricular performance. Such pacing mimics left bundle branch block resulting in a prolonged QRS duration and causes ventricular asynchrony. AIMS: The purpose of this study is to assess heart failure and left ventricular systolic function after cardiac pacemaker implantation in patients with atrioventricular block and preserved systolic left ventricular function...

BACKGROUND: Patients with heart failure (HF) and a normal left ventricular ejection fraction usually present with diastolic dysfunction (DD). Whether intraleft ventricular contractile dyssynchrony (IVCD) coexists with DD and contributes to the clinical manifestations of HF remains unclear. The study investigated the IVCD at rest and after exercise in hypertensive patients with diastolic HF (DHF). METHODS: Echocardiography was performed in 60 hypertensive patients with narrow QRS, left ventricular ejection fraction > or = 50%, and no active ischemia...

BACKGROUND: Cardiac resynchronization therapy (CRT) is an effective therapy for heart failure patients with electromechanical delay. Optimization of atrioventricular interval (AVI) is a cardinal component for the benefits. However, it is unknown if the AVI needs to be re-optimized during long-term follow-up. METHODS: Thirty-one patients (66+/-11 years, 20 males) with sinus rhythm who received CRT underwent serial optimization of AVI at day 1, 3-month and during long-term follow-up by pulse Doppler echocardiography (PDE)...

Heart failure is among the most common chronic diseases in the modem era. It is the major cause of morbi--mortality and hospitalization in patients aged more than 60 years. Dilatation of left ventricle frequently induces intracardiac conduction delays resulting. in asynchronous left ventricular motion. Showing as left bundle branch block in the surface EKG. Diagnosis of asynchrony based only on electrocardiogram criteria (wide QRS complex and left bundle branch block(LBBB)) proves to be non satisfactory considering the absence of parallelism between conduction unrests and cardiac dyssynchrony: 35% of LBBB are not associated with interventricular asynchrony and 20% without intraventricular asynchrony...

AIMS: Cardiac resynchronization therapy (CRT) has become an attractive therapeutic option for patients with end-stage heart failure (HF). Currently, patients are selected for CRT on ECG and on echocardiographic criteria analysed at rest. Whether the physical effort may further increase myocardial dyssynchrony is not fully established. The aim of the study was to test by the use of Doppler myocardial imaging (DMI) if dynamic left ventricular (LV) dyssynchrony during physical effort may be a determinant of dynamic mitral regurgitation in patients with dilated cardiomyopathy and 'narrow' QRS...