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1.
Circ Arrhythm Electrophysiol ; 13(1): e007548, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31937118

RESUMO

BACKGROUND: Asymptomatic cerebral emboli (ACE) are commonly seen on cerebral magnetic resonance imaging (MRI) after atrial fibrillation ablation, but the incidence in previous studies varies widely. No data exists to compare the effects of different diffusion-weighted imaging (DWI) settings on detecting ablation-related ACE. This self-control study sought to compare the incidence and characteristics of ablation-related ACE between high-resolution DWI and conventional DWI. METHODS: A total of 55 consecutive patients referred for atrial fibrillation ablation between December 2017 and September 2018 were enrolled. Patients underwent high-resolution DWI 1 day before ablation and repeated high-resolution DWI and conventional DWI within 48 hours post-ablation. The incidence, number, size, and location of ACE were compared between 2 DWI settings in the same patients. RESULTS: The high-resolution DWI revealed a higher incidence of acute ACE compared with conventional DWI (67.3% versus 41.8% of patients, P<0.001) and significantly more ACE (106 versus 45 lesions, P=0.001). For ACE seen on both scans, the size measured by high-resolution DWI was larger (5.42 versus 4.21 mm, P<0.001). No patients had any impaired neurocognitive performance during follow-up. Impaired left ventricular ejection fraction (P=0.012) and low intraoperative activated clotting time (P=0.009) level were associated with the occurrence of ACE in a multivariate analysis. CONCLUSIONS: High-resolution DWI revealed a higher incidence and greater details of post-ablation ACE in patients with atrial fibrillation. MRI settings significantly impact the detection of ACE and should be considered when comparing incidence rates of ACE among different studies. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01761188.

2.
JACC Clin Electrophysiol ; 6(1): 94-106, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31709982

RESUMO

OBJECTIVES: This study reports on the performance of a leadless ventricular pacemaker with automated, enhanced accelerometer-based algorithms that provide atrioventricular (AV) synchronous pacing. BACKGROUND: Despite many advantages, leadless pacemakers are currently only capable of single-chamber ventricular pacing. METHODS: The prospective MARVEL 2 (Micra Atrial tRacking using a Ventricular accELerometer 2) study assessed the performance of an automated, enhanced accelerometer-based algorithm downloaded to the Micra leadless pacemaker for up to 5 h in patients with AV block. The primary efficacy objective was to demonstrate the superiority of the algorithm to provide AV synchronous (VDD) pacing versus VVI-50 pacing in patients with sinus rhythm and complete AV block. The primary safety objective was to demonstrate that the algorithm did not result in pauses or heart rates of >100 beats/min. RESULTS: Overall, 75 patients from 12 centers were enrolled; an accelerometer-based algorithm was downloaded to their leadless pacemakers. Among the 40 patients with sinus rhythm and complete AV block included in the primary efficacy objective analysis, the proportion of patients with ≥70% AV synchrony at rest was significantly greater with VDD pacing than with VVI pacing (95% vs. 0%; p < 0.001). The mean percentage of AV synchrony increased from 26.8% (median: 26.9%) during VVI pacing to 89.2% (median: 94.3%) during VDD pacing. There were no pauses or episodes of oversensing-induced tachycardia reported during VDD pacing in all 75 patients. CONCLUSIONS: Accelerometer-based atrial sensing with an automated, enhanced algorithm significantly improved AV synchrony in patients with sinus rhythm and AV block who were implanted with a leadless ventricular pacemaker. (Micra Atrial Tracking Using a Ventricular Accelerometer 2 [MARVEL 2]; NCT03752151).

4.
Pacing Clin Electrophysiol ; 40(12): 1389-1395, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29090491

RESUMO

BACKGROUND: Utilization of cardiac magnetic resonance imaging (cMRI) as an imaging modality in clinical practice is rapidly increasing. More evidence from randomized studies establishing clinical safety and performance of pacing systems in patients undergoing a cMRI scan is needed. OBJECTIVES: The purpose of this prospective, multicenter, randomized study was to demonstrate safety and efficacy of the Accent MRI™ conditional pacing systems (St. Jude Medical, St. Paul, MN, USA) in patients undergoing cMRI scan. METHODS: Patients (n  =  283) indicated for dual-chamber pacemaker implant were randomized to either the MRI Group (MG) (n  =  140) or the Control Group (CG) (n  =  143) after successful device implantation of the Accent MRI™ system. Clinical evaluation and device interrogation were performed at pre- and post-MRI scan, and 1 month post-MRI for all patients. At 9-12 weeks postimplant, patients in MG underwent a nondiagnostic cMRI scan at 1.5 Tesla (T), while patients in CG underwent device interrogation and clinical evaluation twice with a 45-minute waiting period in between. The safety endpoint was freedom from MRI scan-related complications and that for efficacy was significant changes in right atrial/ventricular capture threshold and sensing amplitude between right before MRI, immediately after MRI, and 1 month post-MRI. RESULTS: Results showed 100% freedom from MRI scan-related complications. There were no significant changes in device performance between pre-MRI scan and 1 month post-MRI scan time points in both study groups. CONCLUSIONS: cMRI scanning with 1.5 T scanners is safe in patients implanted with the Accent MRI™ conditional pacing system and has no significant effect on the electrical parameters of the device and leads.


Assuntos
Técnicas de Imagem Cardíaca , Desfibriladores Implantáveis , Imagem por Ressonância Magnética , Marca-Passo Artificial , Adulto , Idoso , Idoso de 80 Anos ou mais , Técnicas de Imagem Cardíaca/efeitos adversos , Feminino , Humanos , Imagem por Ressonância Magnética/efeitos adversos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
6.
Int J Cardiol ; 168(2): 723-8, 2013 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-22944596

RESUMO

BACKGROUND: Right ventricular apical (RVA) pacing is associated with adverse left ventricular (LV) remodeling and biventricular (BiV) pacing may prevent it although the mechanisms remain unclear. The current study aimed to assess the role of early pacing-induced systolic dyssynchrony (DYS) to predict adverse LV remodeling. METHODS: Patients with standard pacing indications and normal LV ejection fraction were randomized either to BiV (n=89) or RVA pacing (n=88). Pacing-induced DYS, defined as the standard deviation of the time to peak systolic velocity (Dyssynchrony Index) >33 ms in a 12-segmental model of LV, was measured by tissue Doppler echocardiography at 1 month. RESULTS: At 1 month, 59 patients (33%) had DYS which was more prevalent in RVA than BiV pacing group (52% vs. 15%, χ(2)=28.3, p<0.001), though Dyssynchrony Index was similar at baseline (30 ± 14 vs. 26 ± 11 ms, p=0.06). At 12 months, those developing DYS had significantly lower LV ejection fraction (55.1 ± 9.7 vs. 62.2 ± 7.9%, p<0.001) and larger LV end-systolic volume (35.3 ± 14.3 vs. 27.0 ± 10.4 ml, p<0.001) when compared to those without DYS. Reduction of ejection fraction ≥ 5% occurred in 67% (39 out of 58) of patients with DYS, but only in 18% (21 out of 115) in those without DYS (χ(2)=40.8, p<0.001). Both DYS at 1 month (odds ratio [OR]: 4.725, p=0.001) and RVA pacing (OR: 3.427, p=0.009) were independent predictors for reduction of ejection fraction at 12 months. CONCLUSION: Early pacing-induced DYS is a significant predictor of LV adverse remodeling and the observed benefit of BiV pacing may be related to the prevention of DYS. CLINICAL TRIAL REGISTRATION: Centre for Clinical Trials number, CUHK_CCT00037 (URL: http://www.cct.cuhk.edu.hk/Registry/publictrialrecord.aspx?trialid=CUHK_CCT00037).


Assuntos
Estimulação Cardíaca Artificial/métodos , Cardiomegalia/diagnóstico , Cardiomegalia/fisiopatologia , Remodelação Ventricular/fisiologia , Idoso , Idoso de 80 Anos ou mais , Cardiomegalia/prevenção & controle , Método Duplo-Cego , Feminino , Inquéritos Epidemiológicos/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Sístole/fisiologia , Fatores de Tempo
7.
Int J Cardiol ; 167(5): 2167-71, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-22704862

RESUMO

BACKGROUND: Coronary blood flow (CBF) is improved by cardiac resynchronization therapy (CRT) and impaired by right ventricular apical (RVA) pacing in patients with heart failure. However, the underlying mechanism remains unclear. METHODS: Twenty-nine non-ischemic heart failure patients who responded to CRT underwent transthoracic echocardiography examination including both left anterior descending (LAD) CBF and tissue Doppler imaging in 3 pacing modes: intrinsic conduction, RVA pacing and biventricular (BiV) pacing. LAD velocity-temporal integral (LAD-VTI) and duration were measured. Systolic dyssynchrony was assessed with the standard deviation of a 12-left ventricular segmental model (Ts-SD). RESULTS: BiV pacing improved while RVA pacing reduced CBF compared to intrinsic conduction (all p<0.05). Both Ts-SD and ventricular septal velocity deteriorated during RVA pacing but improved during BiV pacing (all p<0.05). When systolic dyssynchrony was induced, lower LAD-VTI (9.5 ± 3.4 versus 12.7 ± 5.1cm, p=0.001) and shorter LAD diastolic duration (483 ± 92 versus 542 ± 106 ms, p=0.010) were detected than synchronous status. Systolic dyssynchrony was inversely related to septal velocity (r=-0.41), p<0.001 and LAD-VTI (r=-0.30, p=0.007), with the latter found to be moderately correlated to septal velocity (r=0.30, p=0.007). CONCLUSION: Regional LAD flow was improved in patients subjected to BiV but worsened in those treated with RVA pacing in non-ischemic heart failure CRT responders. Systolic dyssynchrony was more commonly observed in patients subjected to RVA pacing. Reduction of septal velocity with dyssynchrony may directly lead to reduced LAD flow. Improvement of septal velocity by CRT and hence LAD flow may be an important mechanism in determining the response to CRT.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Terapia de Ressincronização Cardíaca/tendências , Cardiomiopatias/diagnóstico por imagem , Cardiomiopatias/terapia , Circulação Coronária/fisiologia , Vasos Coronários/fisiologia , Idoso , Idoso de 80 Anos ou mais , Cardiomiopatias/fisiopatologia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sístole/fisiologia , Ultrassonografia
8.
Pacing Clin Electrophysiol ; 35(7): 856-62, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22540397

RESUMO

BACKGROUND: The acute effects of right ventricular apical (RVA) pacing on left atrial (LA) function in patients with normal ejection fraction are not clear. METHODS: A total of 94 patients (age 68.1 ± 11.1 years, 26 men) with implanted RVA-based dual-chamber pacemakers were recruited into this study. Patients who were pacemaker-dependent, in persistent atrial fibrillation or left ventricular ejection fraction <45% were excluded. Echocardiography (iE33, Philips, Andover, MA, USA) was performed during intrinsic ventricular conduction (V-sense) and RVA pacing (V-pace) with 15 minutes between switching modes. The total maximal LA volume (LAV(max)), preatrial contraction volume (LAV(pre)), and minimal volume (LAV(min)) were assessed by area-length method. Peak systolic, early diastolic, and peak late diastolic (atrial contractile) velocity (Sm-la, Em-la, and Am-la) and strain (ɛs-la, ɛe-la, and ɛa-la) were measured by color-coded tissue Doppler imaging (TDI) in four mid-LA walls at apical four- and two-chamber views. RESULTS: During V-pace, LA volumes increased significantly compared with V-sense (LAV(max): 52.0 ± 18.8 vs 55.2 ± 21.1 mL, P = 0.005; LAV(pre): 39.8 ± 16.4 vs 41.3 ± 16.6 mL, P = 0.014; LAV(min): 27.4 ± 14.0 vs 29.1 ± 15.1 mL, P = 0.001). TDI parameters showed significant reduction in Sm-la and Em-la. Furthermore, ɛs-la, ɛe-la, and ɛa-la decreased significantly, especially in patients with preexisting diastolic dysfunction (all P < 0.01). CONCLUSIONS: RVA pacing acutely induced LA enlargement and impaired atrial contractility. Patients with preexisting diastolic dysfunction may be more vulnerable to develop LA dysfunction and remodeling after acute RVA pacing.


Assuntos
Estimulação Cardíaca Artificial , Átrios do Coração/diagnóstico por imagem , Ventrículos do Coração , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/prevenção & controle , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Resultado do Tratamento , Ultrassonografia
9.
Int J Cardiol ; 157(3): 364-9, 2012 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-21239072

RESUMO

BACKGROUND: This prospective study was to examine the impact of right ventricular apical (RVA) pacing on atrial remodeling and function. METHODS AND RESULTS: 103 patients (age 70 ± 11 years; 53 men) with preserved left ventricular (LV) ejection fraction (LVEF>45%) who received RVA pacing had Doppler echocardiography performed at baseline and after one year follow up. At one year follow up, left atrial (LA) volumes (pre-atrial contraction volume and the minimal volume) and their indexes were significantly increased with reduction in passive emptying fraction and total emptying fraction (all p<0.05). LA segmental tissue velocities - mean peak systolic (Sm-la), peak early diastolic (Em-la) and late diastolic (Am-la) - were also significantly reduced (all p<0.001). A reduction of Am-la>30% occurred in 24% of patients, and was more prevalent in patients with an elevation of LV filling pressure (E/e'>15) at one year (44.1% vs. 11.7%, χ(2)=12.75, p<0.001) as well as those with a reduction of LVEF ≥ 5% (34.0% vs. 14.3%, χ(2)=5.140, p=0.023). By multivariate regression analysis, E/e'>15 at one year (odds ratio [OR] 5.213; 95% confidence interval [CI] 1.778-15.281) and reduction of LVEF ≥ 5% (OR 3.181; 95% CI 1.045-9.686) were independent predictors of reduction of Am-la>30%. CONCLUSIONS: Chronic RVA pacing results in LA remodeling and reduced atrial function. This is related to elevated filling pressures and impairment of LV systolic function.


Assuntos
Função do Átrio Esquerdo/fisiologia , Terapia de Ressincronização Cardíaca/efeitos adversos , Átrios do Coração/diagnóstico por imagem , Volume Sistólico/fisiologia , Função Ventricular Direita/fisiologia , Idoso , Idoso de 80 Anos ou mais , Terapia de Ressincronização Cardíaca/métodos , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Tempo , Ultrassonografia
10.
Eur Heart J ; 32(20): 2533-40, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21875860

RESUMO

AIMS: The Pacing to Avoid Cardiac Enlargement (PACE) trial is a prospective, double-blinded, randomized, multicentre study that reported the superiority of biventricular (BiV) pacing to right ventricular apical (RVA) pacing in the prevention of left ventricular (LV) adverse remodelling and deterioration of systolic function at 1 year. In the current analysis, we report the results at extended 2-year follow-up for changes in LV function and remodelling. METHODS AND RESULTS: Patients (n = 177) with bradycardia and preserved LV ejection fraction (EF ≥45%) were randomized to receive RVA or BiV pacing. The co-primary endpoints were LVEF and LV end-systolic volume (LVESV). Eighty-one (92%) of 88 in the RVA pacing group and 82 (92%) of 89 patients in the BiV pacing group completed 2-year follow-up with a valid echocardiography. In the RVA pacing group, LVEF further decreased from the first to the second year, but it remained unchanged in the BiV pacing group, leading to a significant difference of 9.9 percentage points between groups at 2-year follow-up (P < 0.001). Similarly, LVESV continues to enlarge from the first to the second year in the RVA pacing group, leading to a difference of 13.0 mL (P < 0.001) between groups. Predefined subgroup analysis showed consistent results with the whole study population for both co-primary endpoints, which included patients with pre-existing LV diastolic dysfunction. Eighteen patients in the BiV pacing group (20.2%) and 55 in the RVA pacing group (62.5%) had a significant reduction of LVEF (of ≥5%, P < 0.001). CONCLUSION: Left ventricular adverse remodelling and deterioration of systolic function continues at the second year after RVA pacing. This deterioration is prevented by BiV pacing.


Assuntos
Bradicardia/terapia , Terapia de Ressincronização Cardíaca/métodos , Remodelação Ventricular/fisiologia , Bradicardia/fisiopatologia , Método Duplo-Cego , Humanos , Variações Dependentes do Observador , Qualidade de Vida , Volume Sistólico/fisiologia , Resultado do Tratamento
11.
Clin Cardiol ; 34(8): 507-12, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21717470

RESUMO

BACKGROUND: Elevated admission glucose level is a strong predictor of short-term adverse outcome in patients with acute coronary syndrome (ACS). However, the prognostic value of diabetic control (ie, hemoglobin A(1c) levels) in patients with ACS is still undefined. HYPOTHESIS: Hemoglobin A(1c) level may predict short-term outcome in patients with ACS. METHODS: We conducted a retrospective study with prospective follow-up in 317 diabetic patients with ACS. Patients were stratified into 2 groups based on HbA(1c) level, checked within 8 weeks of the index admission (optimal control group, HbA(1c) ≤7%; suboptimal control group, HbA(1c) >7%). All patients were followed up prospectively for major adverse cardiovascular events (MACE) and mortality for 6 months. Short-term clinical outcomes were also compared between the 2 study groups. RESULTS: In our cohort, 27.4%, 46.4%, and 26.2% patients had unstable angina, non-ST-segment elevation myocardial infarction, and ST-segment elevation myocardial infarction, respectively. In-hospital mortality was similar in both HbA(1c) groups (3.37% vs 2.88%, P = 0.803). Six-month MACE was also similar (26.40% vs 26.47%, P = 0.919). All-cause mortality, cardiovascular mortality, symptom-driven revascularization, rehospitalization for angina, and hospitalization for heart failure were also similar in both groups. The hazard ratios for 6-month MACE and individual endpoints were also similar in both groups. CONCLUSIONS: This study suggests that HbA(1c) levels before admission are not associated with short-term cardiovascular outcome in diabetic patients subsequently admitted with ACS.


Assuntos
Síndrome Coronariana Aguda/sangue , Angina Instável/sangue , Diabetes Mellitus/sangue , Hemoglobina A Glicada/análise , Cardiopatias/etiologia , Infarto do Miocárdio/sangue , Admissão do Paciente , Síndrome Coronariana Aguda/complicações , Síndrome Coronariana Aguda/mortalidade , Síndrome Coronariana Aguda/terapia , Idoso , Idoso de 80 Anos ou mais , Angina Instável/complicações , Angina Instável/mortalidade , Angina Instável/terapia , Biomarcadores/sangue , Distribuição de Qui-Quadrado , China , Diabetes Mellitus/mortalidade , Intervalo Livre de Doença , Feminino , Cardiopatias/sangue , Cardiopatias/mortalidade , Cardiopatias/terapia , Mortalidade Hospitalar , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/complicações , Infarto do Miocárdio/mortalidade , Infarto do Miocárdio/terapia , Readmissão do Paciente , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo
12.
Int J Cardiol ; 147(1): 32-7, 2011 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-19709767

RESUMO

BACKGROUND: This study adopted a new multi-layer approach of measuring myocardial deformation by two-dimensional (2D) speckle tracking imaging to examine whether a transmural gradient exists in normal subjects and cardiac diseases. METHODS: Eighty patients were included with 20 in each group: (1) normal control; (2) acute coronary syndrome (ACS) with ejection fraction (EF) >45%; (3) right ventricular apical (RVA) pacing with EF>45%; (4) systolic heart failure (SHF) with EF<45%. Circumferential strain (ε-circum), torsion (Tor) and systolic dyssynchrony defined as the maximal difference in the time to peak circumferential strain were measured in the subendocardial and subepicardial myocardium layers (QLab 6.0, Philips). RESULTS: In all the 4 groups, a subendocardial to subepicardial gradient was present in both ε-circum (-20.7 ± 7.6 vs. -14.9 ± 5.6%, p<0.001) and Tor (12.0 ± 6.0 vs. 9.3 ± 4.7°, p<0.05), with higher values in the subendocardial layer. However, it was significantly narrowed for ε-circum (2.7 ± 1.2%) and Tor (0.8 ± 0.9°) in SHF patients (all p ≤ 0.001 vs. other groups). On the contrary, systolic dyssynchrony measured in the 2 layers showed no difference (264 ± 107 vs. 273 ± 110 ms, p = NS) and a homogenous distribution in ε-circum was observed from basal to apical planes (-17.0 ± 6.8 vs. -18.1 ± 7.4 vs. -18.1 ± 7.8%, all p = NS). CONCLUSIONS: A transmural gradient exists in circumferential strain and torsion, with higher values in the subendocardial layer. It might be reduced when systolic function is impaired. Therefore, the multi-layer approach of 2D speckle tracking imaging provides further information on assessment of myocardial diseases.


Assuntos
Ecocardiografia/métodos , Cardiopatias/diagnóstico por imagem , Miocárdio/patologia , Torção Mecânica , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Cardiopatias/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
J Am Soc Echocardiogr ; 23(11): 1160-7, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20800439

RESUMO

BACKGROUND: Functional mitral regurgitation (MR) at different phases of the regurgitant period may respond differently to cardiac resynchronization therapy (CRT). The aims of this study were to examine the impact of CRT on the phasic changes of MR (early vs late systole) and to explore the mechanisms of such changes. METHODS: Instantaneous MR flow rate and total MR volume were evaluated in 60 patients who had more than mild functional MR before and 3 months after CRT. In addition, indices of global left ventricular (LV) remodeling, mitral deformation, and LV systolic dyssynchrony were assessed. RESULTS: CRT diminished MR volume (38 ± 18 vs 32 ± 20 mL) by reducing both the early (72 ± 47 vs 58 ± 48 mL/sec) and late (48 ± 42 vs 40 ± 42 mL/sec) systolic components (all p values < .01). In patients with ≥10% reductions in total MR volume but not in patients without this improvement, there were significant reductions in LV end-systolic volume, increases in LV +dP/dt, decreases in mitral valvular tenting, and improvements of systolic dyssynchrony at 3 months (all P values < .05). By multivariate regression, the reductions in LV end-systolic volume and tenting area were independent determinants of a reduction in total MR volume: the reductions in LV end-systolic volume and global dyssynchrony determined the reduction in early systolic MR, and the reductions in tenting area and global dyssynchrony determined reduction in late systolic MR. CONCLUSIONS: CRT decreases MR volume by reducing both early and late systolic MR. The determinants of the phasic improvement in functional MR are different.


Assuntos
Terapia de Ressincronização Cardíaca/métodos , Insuficiência Cardíaca Sistólica/prevenção & controle , Insuficiência da Valva Mitral/diagnóstico por imagem , Insuficiência da Valva Mitral/terapia , Remodelação Ventricular/fisiologia , Adulto , Idoso , Análise de Variância , Estudos de Coortes , Intervalos de Confiança , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Marca-Passo Artificial , Estudos Retrospectivos , Medição de Risco , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do Tratamento , Ultrassonografia , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/fisiopatologia
14.
Eur Heart J ; 31(19): 2359-68, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20501482

RESUMO

AIMS: To examine whether the presence of pre-pacing functional mitral regurgitation (MR) and its improvement would affect the extent of left ventricular (LV) reverse remodelling after cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Echocardiographic assessment was performed in 83 patients before and 3 months after CRT. Total MR volume and the early- and late-systolic MR flow rate were assessed. At 3 months, there was reduction in total MR volume (38 ± 20 vs. 33 ± 21 mL) with decrease in both early- (71 ± 52 vs. 60 ± 51 mL/s) and late-systolic (49 ± 46 vs. 42 ± 46 mL/s) MR flow rate (all P < 0.05). Receiver-operating characteristic curve found that an 11% decrease in total MR volume was associated with LV reverse remodelling [defined by the reduction in LV end-systolic volume (LVESV) of ≥15%] [sensitivity, 90%; specificity, 80%; area under the curve (AUC), 0.85; P < 0.001]. The improvement in early- and late-systolic MR was also associated with LV reverse remodelling, in which improvement in early-systolic MR had higher sensitivity, specificity, and AUC than late-systolic MR. The extent of reverse remodelling with gain in LV ejection fraction and forward stroke volume was greatest in patients with improvement in total MR, intermediate in those with mild or no MR at baseline, and the least in those without improvement in total MR (LVESV, -29.8 ± 12.0 vs. -18.6 ± 16.6 vs. -5.5 ± 8.6%; ejection fraction, 11.8 ± 6.2 vs. 7.0 ± 6.8 vs. 3.0 ± 5.0%; forward stroke volume, 43.1 ± 37.9 vs. 21.1 ± 26.1 vs. 6.8 ± 34.6%; all P < 0.05). CONCLUSION: Improvement of functional MR contributes to LV reverse remodelling after CRT, whereas reduction of early-systolic MR is more powerful than late-systolic MR.


Assuntos
Terapia de Ressincronização Cardíaca , Insuficiência Cardíaca/terapia , Insuficiência da Valva Mitral/terapia , Remodelação Ventricular/fisiologia , Idoso , Ecocardiografia Doppler , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Marca-Passo Artificial , Estudos Prospectivos , Curva ROC , Resultado do Tratamento
15.
Eur J Echocardiogr ; 11(2): 109-18, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19933290

RESUMO

AIMS: Right ventricular apical (RVA) pacing may induce mechanical dyssynchrony. However, its impact on patients with normal ejection fraction (EF) is not fully understood. This study examined the prevalence and predictors of RVA pacing-induced systolic dyssynchrony by real-time three-dimensional echocardiography (RT3DE), and evaluated its impact on left ventricular (LV) function. METHODS AND RESULTS: Ninety-three patients with sinus node dysfunction and normal EF (>50%) received RVA-based dual-chamber pacing were assessed by RT3DE during RVA pacing (V-pace) and intrinsic conduction (V-sense). Systolic dyssynchrony was evaluated using the standard deviation of the time to minimal regional volume of 16 LV segments (Tmsv-16SD), and a cutoff value of 16 ms was determined from 93 normal controls. Systolic dyssynchrony was induced in 49.5% of patients at V-pace with significant increase in LV end-systolic volume (LVESV), decrease in EF, and worsening of Tmsv-16SD (all P < 0.001). Furthermore, patients who developed dyssynchrony had larger LVESV (P < 0.001), lower EF (P < 0.001) at V-pace mode, and higher cumulative percentage of RVA pacing in the past 6 months (P < 0.001) than those without systolic dyssynchrony. In multivariate logistic regression analysis, independent predictors of developing LV systolic dyssynchrony during V-pace included a low normal EF at V-sense, pre-existing LV hypertrophy, and cumulative RVA pacing >40% in the past 6 months. CONCLUSION: For patients with preserved EF received RVA pacing, half of them would develop systolic dyssynchrony which was associated with EF deterioration and LV enlargement. A low normal EF, a high cumulative percentage of RVA pacing, and pre-existing LV hypertrophy were predictors of developing dyssynchrony.


Assuntos
Arritmias Cardíacas/diagnóstico por imagem , Estimulação Cardíaca Artificial , Ecocardiografia Tridimensional , Volume Sistólico , Disfunção Ventricular Esquerda/diagnóstico por imagem , Função Ventricular Direita , Idoso , Estudos de Casos e Controles , Estudos Transversais , Feminino , Frequência Cardíaca , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prevalência , Fatores de Risco , Nó Sinoatrial , Sístole , Função Ventricular Esquerda
16.
N Engl J Med ; 361(22): 2123-34, 2009 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-19915220

RESUMO

BACKGROUND: Observational studies suggest that conventional right ventricular apical pacing may have a deleterious effect on left ventricular function. In this study, we examined whether biventricular pacing is superior to right ventricular apical pacing in preventing deterioration of left ventricular systolic function and cardiac remodeling in patients with bradycardia and a normal ejection fraction. METHODS: In this prospective, double-blind, multicenter study, we randomly assigned 177 patients in whom a biventricular pacemaker had been successfully implanted to receive biventricular pacing (89 patients) or right ventricular apical pacing (88 patients). The primary end points were the left ventricular ejection fraction and left ventricular end-systolic volume at 12 months. RESULTS: At 12 months, the mean left ventricular ejection fraction was significantly lower in the right-ventricular-pacing group than in the biventricular-pacing group (54.8+/-9.1% vs. 62.2+/-7.0%, P<0.001), with an absolute difference of 7.4 percentage points, whereas the left ventricular end-systolic volume was significantly higher in the right-ventricular-pacing group than in the biventricular-pacing group (35.7+/-16.3 ml vs. 27.6+/-10.4 ml, P<0.001), with a relative difference between the groups in the change from baseline of 25% (P<0.001). The deleterious effect of right ventricular apical pacing occurred in prespecified subgroups, including patients with and patients without preexisting left ventricular diastolic dysfunction. Eight patients in the right-ventricular-pacing group (9%) and one in the biventricular-pacing group (1%) had ejection fractions of less than 45% (P=0.02). There was one death in the right-ventricular-pacing group, and six patients in the right-ventricular-pacing group and five in the biventricular-pacing group were hospitalized for heart failure (P=0.74). CONCLUSIONS: In patients with normal systolic function, conventional right ventricular apical pacing resulted in adverse left ventricular remodeling and in a reduction in the left ventricular ejection fraction; these effects were prevented by biventricular pacing. (Centre for Clinical Trials number, CUHK_CCT00037.)


Assuntos
Bradicardia/terapia , Estimulação Cardíaca Artificial/métodos , Volume Sistólico , Disfunção Ventricular Esquerda/etiologia , Remodelação Ventricular , Idoso , Bloqueio Atrioventricular/complicações , Bradicardia/etiologia , Bradicardia/fisiopatologia , Estimulação Cardíaca Artificial/efeitos adversos , Volume Cardíaco , Método Duplo-Cego , Ecocardiografia Tridimensional , Feminino , Humanos , Masculino , Marca-Passo Artificial , Estudos Prospectivos , Qualidade de Vida , Síndrome do Nó Sinusal/complicações , Disfunção Ventricular Esquerda/prevenção & controle , Disfunção Ventricular Esquerda/terapia , Função Ventricular Esquerda
17.
JACC Cardiovasc Imaging ; 2(12): 1341-9, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20083066

RESUMO

OBJECTIVES: This study aimed to evaluate the impact of cardiac contractility modulation (CCM) on left ventricular (LV) size and myocardial function. BACKGROUND: CCM is a device-based therapy for patients with advanced heart failure. Previous studies showed that CCM improved symptoms and exercise capacity; however, comprehensive assessment of LV structure, function, and reverse remodeling is not available. METHODS: Thirty patients (60 + or - 11 years, 80% male) with New York Heart Association (NYHA) functional class III heart failure, ejection fraction <35%, and QRS <120 ms were assessed at baseline and 3 months. LV reverse remodeling was measured by real-time 3-dimensional echocardiography. Using tissue Doppler imaging, the peak systolic velocity (Sm) and peak early diastolic velocity (Em) were calculated for LV function, while the standard deviation of the time to peak systolic velocity (Ts-SD) and the time to peak early diastolic velocity (Te-SD) were calculated for mechanical dyssynchrony. RESULTS: LV reverse remodeling was evident, with a reduction in LV end-systolic volume by -11.5 + or - 10.5% and a gain in ejection fraction by 4.8 + or - 3.6% (both p < 0.001). Myocardial contraction was improved in all LV walls, including sites remote from CCM delivery (all p < 0.05); hence, the mean Sm of 12 (2.2 + or - 0.6 cm/s vs. 2.5 + or - 0.7 cm/s) or 6 basal LV segments (2.5 + or - 0.6 cm/s vs. 3.0 + or - 0.7 cm/s) were increased significantly (both p < 0.001). In contrast, CCM had no impact on regional or global Em (2.9 + or - 1.3 cm/s vs. 2.9 + or - 1.1 cm/s), whereas Ts-SD (28.2 + or - 11.2 ms vs. 27.9 + or - 12.7 ms) and Te-SD (30.0 + or - 18.3 ms vs. 30.1 + or - 20.7 ms) remained unchanged (all p = NS). Mitral regurgitation was reduced (22 + or - 14% vs. 17 + or - 15%, p = 0.02). Clinically, there was improvement of NYHA functional class (p < 0.001) and 6-min hall walk distance (p = 0.015). A 24-h Holter monitor showed that premature ventricular contractions were not increased during CCM. CONCLUSIONS: CCM improves both global and regional LV contractility, including regions remote from the impulse delivery, and may contribute to LV reverse remodeling and gain in systolic function. Such improvement is unrelated to diastolic function or mechanical dyssynchrony.


Assuntos
Terapia por Estimulação Elétrica , Insuficiência Cardíaca/terapia , Contração Miocárdica , Função Ventricular Esquerda , Remodelação Ventricular , Idoso , Ecocardiografia Doppler em Cores , Ecocardiografia Tridimensional , Terapia por Estimulação Elétrica/instrumentação , Eletrocardiografia Ambulatorial , Tolerância ao Exercício , Feminino , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Recuperação de Função Fisiológica , Índice de Gravidade de Doença , Volume Sistólico , Fatores de Tempo , Resultado do Tratamento , Caminhada
18.
Am Heart J ; 156(5): 989-95, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19061717

RESUMO

BACKGROUND: This study compared the prevalence and pattern of mechanical dyssynchrony in patients with normal heart and right ventricular apical (RVA) pacing versus patients with systolic heart failure (SHF) and spontaneous left bundle branch block (LBBB). METHODS: A total of 112 patients having LBBB pattern on surface electrocardiogram were included (57 with ejection fraction>50% received RVA pacing; 55 had SHF with ejection fraction<35%). Using tissue Doppler imaging, systolic and diastolic dyssynchrony was defined by the standard deviation of the time to peak systolic and peak early diastolic velocity, respectively. RESULTS: Despite comparable QRS duration and LBBB pattern, the prevalence of electromechanical dyssynchrony was significantly lower in the patients with RVA pacing (systolic: 54% vs 73%, chi2=4.058, P=.044; diastolic: 32% vs 61%, chi2=9.738, P=.002). The presence of coexisting systolic and diastolic dyssynchrony, isolated systolic dyssynchrony, isolated diastolic dyssynchrony, and no dyssynchrony also showed a different distribution between the 2 groups (RVA pacing: 14%, 40%, 18%, and 28%; SHF: 51%, 22%, 11%, and 16%; chi2=17.498, P=.001). Furthermore, the SHF group had a higher prevalence of medial wall (ie, septal, anteroseptal, and inferior) delay (56% vs 30%), whereas RVA pacing resulted in more free wall (ie, lateral, posterior and anterior) delay (44% vs 70%) (chi2=8.050, P=.005). CONCLUSIONS: The prevalence of mechanical dyssynchrony is lower in patients with normal ejection fraction and RVA pacing when compared with patients with SHF and spontaneous LBBB. The pattern of delay in contraction also appears to be different between the 2 groups.


Assuntos
Bloqueio de Ramo/fisiopatologia , Estimulação Cardíaca Artificial , Insuficiência Cardíaca Sistólica/fisiopatologia , Idoso , Bloqueio de Ramo/etiologia , Estimulação Cardíaca Artificial/efeitos adversos , Insuficiência Cardíaca Sistólica/complicações , Humanos , Prevalência
19.
Int J Cardiol ; 125(1): 16-21, 2008 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-17433840

RESUMO

OBJECTIVE: Angiotensin-converting enzyme inhibitor (ACEI) is beneficial in patients with congestive heart failure (CHF). Some, but not all, angiotensin receptor blocker (ARB) was demonstrated to be effective as "add-on" therapy. We investigated whether irbesartan is useful as an add-on therapy in CHF. DESIGN: Randomized control trial. SETTING: Single center. PATIENTS: 50 CHF patients on stable doses of ACEI. INTERVENTIONS: Add-on therapy with irbesartan (300 mg/day) or continuation of conventional therapy (control group) for 1 year. MAIN OUTCOME MEASURES: Serial clinical and echocardiographic assessment were performed as baseline, 3 months and 1 year after therapy. RESULTS: There was no difference in clinical characteristics between 2 groups. Patients in the add-on therapy group had significant increase in 6-Minute Hall-Walk distance (351+/-89 to 392+/-84 m, P<0.01), achieved higher METs exercise time on treadmill test (3.9+/-1.1 to 4.6+/-1.3 METs, P=0.01), reduction of NYHA Class (2.4+/-0.5 to 2.0+/-0.8, P<0.005) and improvement of QOL score (28+/-19 to 17+/-18, P<0.05). These parameters were not improved in the control group and a worsening of exercise capacity was observed (P<0.05). A reduction of left ventricular end-systolic diameter (4.94+/-0.85 vs 4.30+/-1.17 cm, P<0.05) was observed in the add-on group. At the end of 1 year, more patients have normal or abnormal relaxation pattern in the add-on group than the control group (82% vs 53% chi(2)=7.1, P=0.02). Blood pressure and renal function were unchanged in both groups. CONCLUSION: The addition of irbesartan to conventional ACEI therapy in CHF further improves symptoms, exercise capacity and quality of life without adverse effects on hemodynamics and renal function.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Compostos de Bifenilo/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Tetrazóis/uso terapêutico , Idoso , Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Compostos de Bifenilo/administração & dosagem , Diástole , Quimioterapia Combinada , Tolerância ao Exercício , Feminino , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/fisiopatologia , Humanos , Irbesartana , Masculino , Qualidade de Vida , Volume Sistólico/efeitos dos fármacos , Inquéritos e Questionários , Sístole , Tetrazóis/administração & dosagem , Resultado do Tratamento , Ultrassonografia
20.
J Am Coll Cardiol ; 50(8): 778-85, 2007 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-17707183

RESUMO

OBJECTIVES: We sought to examine whether cardiac resynchronization therapy (CRT) improves atrial function and induces atrial reverse remodeling. BACKGROUND: Cardiac resynchronization therapy is an established therapy for advanced heart failure with prolonged QRS duration, which improves left ventricle (LV) function and is associated with LV reverse remodeling. METHODS: A total of 107 heart failure patients (66 +/- 11 years) who received CRT and were followed up for 3 months were studied. Atrial function was assessed by M-mode, 2-dimensional echocardiography, transmitral Doppler, tissue Doppler velocity, and strain (epsilon) imaging. Left atrial (LA) emptying fraction based on the change in areas (LAA-EF) and volumes (LAV-EF) were calculated. The LV reverse remodeling was defined by a reduction of LV end-systolic volume >10%. RESULTS: In the responders of LV reverse remodeling (n = 62), LAA-EF and LAV-EF were significantly increased (p < 0.001). Responders also had significant decrease in LA size area and volumetric measurements, both before (p < 0.05) and after atrial systole (p < 0.001). However, these parameters were unchanged in the nonresponders (n = 45, p = NS). In the responders, tissue Doppler velocity analysis showed improvement of contraction velocity in both left (p = 0.005) and right atria (p = 0.018), whereas epsilon in both atria were increased in all the phases of cardiac cycle, namely ventricular end-systole (p < 0.001), early diastole (p < 0.001), and late diastole (p = 0.007). CONCLUSIONS: Cardiac resynchronization therapy improves both left and right atrial pump function. The increase in atrial epsilon throughout the cardiac cycle is likely reflecting the improvement of atrial compliance. These changes lead to LA reverse remodeling with reduction of LA size before and after atrial systole.


Assuntos
Função Atrial/fisiologia , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/terapia , Marca-Passo Artificial , Idoso , Ecocardiografia Doppler , Feminino , Seguimentos , Átrios do Coração/patologia , Insuficiência Cardíaca/diagnóstico por imagem , Ventrículos do Coração/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Função Ventricular/fisiologia , Remodelação Ventricular/fisiologia
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