1,721,066 research outputs found
Changes in global longitudinal strain during rest and exercise in patients treated with cardiac resynchronization therapy.
No full textRelatively few data have been reported on prospective changes in global longitudinal strain (GLS) following cardiac resynchronization therapy (CRT), and none are available on GLS during physical exercise. We investigated the effects of CRT on GLS, assessed by speckle tracking two-dimensional (2D) echocardiography, at rest and during exercise after a mid-term follow-up. Twenty consecutive CRT patients (45% ischaemic) were assessed prospectively by speckle tracking 2D echocardiography before implant (at rest) and at mid-term follow-up (during rest and bicycle exercise). GLS, septum and lateral wall longitudinal strain, left ventricular ejection fraction (LVEF), and conventional functional variables were evaluated at baseline and follow-up. All patients completed the study protocol at rest. Exercise images were available in 90% of the patients. At follow-up, GLS improved at rest from -7·1 ± 2·6% to -9·1 ± 4·5% (P<0·01), with a further increase to -11 ± 5·1% during exercise (P<0·001). Longitudinal strain increased at rest both in the septum and in the lateral wall, with an additional increase during exercise in the lateral wall (P<0·05). GLS correlated with LVEF both at rest (r = -0·55 and r = -0·91 at baseline and 3 months, respectively; P<0·05) and during exercise (r = -0·89, P<0·05). Improvement in GLS during rest and exercise can be observed in CRT patients at mid-term follow-up and seems to correlate with changes in LVEF. GLS may be a valuable method to assess left ventricular function during rest and exercise
Cardiac resynchronization therapy during rest and exercise: comparison of two optimization methods.
No full textEffects of cardiac resynchronization therapy on myocardial contractile reserve during exercise.
No full textAimsMyocardial contractile reserve (MCR) is a marker of myocardial viability. The impact of cardiac resynchronization therapy (CRT) on MCR during exercise has been little studied. Our aim was to investigate the effects of CRT on global and regional MCR by exercise echocardiography.Methods and resultsTwenty-seven CRT responders (56 ischaemic) were assessed by echocardiography during rest and bicycle exercise. Images were acquired during spontaneous rhythm ('off) and active CRT ('on). Global MCR was expressed as the change (Δ) in left ventricular ejection fraction (LVEF) and aortic velocity-time integral (VTI) from rest to exercise. Regional MCR was expressed as the change in peak systolic tissue velocity (Sm) of the septum and lateral wall. Left ventricular ejection fraction and aortic VTI increased at 'on during rest and exercise, and the increase in global MCR during exercise was higher during 'on than 'off (Δ LVEF 6 ± 6 vs. 3 ± 3; P 0.009). Septum Sm increased during 'on at rest, and it was still higher during exercise (P≤ 0.01), although the absolute change from rest to exercise was similar during 'on and 'off. Lateral wall Sm did not change at rest during 'on, but basal lateral wall MCR during exercise was higher at 'on than 'off (P 0.036).ConclusionIn CRT responders, there is a pacing-dependent increase in global MCR during exercise. The changes in regional MCR of the septum and lateral wall show different patterns. These factors may help to understand the determinants of improved exercise tolerance in CRT responder
Cardiac resynchronization therapy during rest and exercise: comparison of two optimization methods.
No full textOptimal exercise programming of cardiac resynchronization therapy (CRT) devices is unknown. We aimed to: (i) investigate variations in optimal atrioventricular (AV) and interventricular (VV) delays from rest to exercise, assessed by both echocardiography and an automated intracardiac electrogram (IEGM) method; (ii) evaluate the acute haemodynamic impact of CRT optimization performed during exercise
Effects of cardiac resynchronization therapy on myocardial contractile reserve during exercise.
No full textAimsMyocardial contractile reserve (MCR) is a marker of myocardial viability. The impact of cardiac resynchronization therapy (CRT) on MCR during exercise has been little studied. Our aim was to investigate the effects of CRT on global and regional MCR by exercise echocardiography.Methods and resultsTwenty-seven CRT responders (56 ischaemic) were assessed by echocardiography during rest and bicycle exercise. Images were acquired during spontaneous rhythm ('off) and active CRT ('on). Global MCR was expressed as the change (Δ) in left ventricular ejection fraction (LVEF) and aortic velocity-time integral (VTI) from rest to exercise. Regional MCR was expressed as the change in peak systolic tissue velocity (Sm) of the septum and lateral wall. Left ventricular ejection fraction and aortic VTI increased at 'on during rest and exercise, and the increase in global MCR during exercise was higher during 'on than 'off (Δ LVEF 6 ± 6 vs. 3 ± 3; P 0.009). Septum Sm increased during 'on at rest, and it was still higher during exercise (P≤ 0.01), although the absolute change from rest to exercise was similar during 'on and 'off. Lateral wall Sm did not change at rest during 'on, but basal lateral wall MCR during exercise was higher at 'on than 'off (P 0.036).ConclusionIn CRT responders, there is a pacing-dependent increase in global MCR during exercise. The changes in regional MCR of the septum and lateral wall show different patterns. These factors may help to understand the determinants of improved exercise tolerance in CRT responder
Changes in global longitudinal strain during rest and exercise in patients treated with cardiac resynchronization therapy.
No full textRelatively few data have been reported on prospective changes in global longitudinal strain (GLS) following cardiac resynchronization therapy (CRT), and none are available on GLS during physical exercise. We investigated the effects of CRT on GLS, assessed by speckle tracking two-dimensional (2D) echocardiography, at rest and during exercise after a mid-term follow-up. Twenty consecutive CRT patients (45% ischaemic) were assessed prospectively by speckle tracking 2D echocardiography before implant (at rest) and at mid-term follow-up (during rest and bicycle exercise). GLS, septum and lateral wall longitudinal strain, left ventricular ejection fraction (LVEF), and conventional functional variables were evaluated at baseline and follow-up. All patients completed the study protocol at rest. Exercise images were available in 90% of the patients. At follow-up, GLS improved at rest from -7·1 ± 2·6% to -9·1 ± 4·5% (P<0·01), with a further increase to -11 ± 5·1% during exercise (P<0·001). Longitudinal strain increased at rest both in the septum and in the lateral wall, with an additional increase during exercise in the lateral wall (P<0·05). GLS correlated with LVEF both at rest (r = -0·55 and r = -0·91 at baseline and 3 months, respectively; P<0·05) and during exercise (r = -0·89, P<0·05). Improvement in GLS during rest and exercise can be observed in CRT patients at mid-term follow-up and seems to correlate with changes in LVEF. GLS may be a valuable method to assess left ventricular function during rest and exercise
Electromechanical effects of cardiac resynchronization therapy during rest and stress in patients with heart failure.
No full textHaemodynamic and functional effects of cardiac resynchronization therapy (CRT) have been studied mostly at rest. CRT effects on left ventricular (LV) dyssynchrony and function during stress have not been evaluated in detail
Cardiac implantable electrical devices in patients with hypertrophic cardiomyopathy: single center implant data extracted from the Swedish pacemaker and ICD registry
No full textObjectives: To investigate cardiac implantable electrical device (CIED) first implants in patients with hypertrophic cardiomyopathy (HCM) in a Swedish tertiary university hospital. Design: Clinical and technical data on pacemaker, implantable cardioverter defibrillator (ICD), and cardiac resynchronization therapy (CRT) first implants performed in HCM patients at the Karolinska University Hospital from 2005 to 2016 were extracted from the Swedish Pacemaker and ICD Registry. Echocardiographic data were obtained by review of hospital recordings. Results: The number of first pacemaker implants in HCM patients was 70 (1.5% of total pacemaker implants). The mean age of HCM pacemaker patients was 71 ± 10 years. Pacemaker implants were almost uniformly distributed between genders. Dual-chamber pacemakers with or without CRT properties were prevalent (6 and 93%, respectively). The number of first ICD implants in HCM patients was 99 (5.1% of total ICD implants). HCM patients receiving an ICD were 53 ± 15 years and prevalently men (70%). Sixty-five (66%) patients were implanted for primary prevention. Dual-chamber ICDs with or without CRT were 21 and 65%, respectively. Obstructive HCM was present in 47% pacemaker patients and 25% ICD patients with available pre-implant echo. Conclusions: This retrospective registry-based study provides a picture of CIED first implants in HCM patients in a Swedish tertiary university hospital. ICDs were the most commonly implanted devices, covering 59% of CIED implants. HCM patients receiving a pacemaker or an ICD had different epidemiological and clinical profiles
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
