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1.
ESC Heart Fail ; 8(5): 3472-3482, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34390219

RESUMO

Despite significant advances in drug-based and device-based therapies, heart failure remains a major and growing public health problem associated with substantial disability, frequent hospitalizations, and high economic costs. Keeping patients well and out of the hospital has become a major focus of heart failure disease management. Achieving and maintaining such stability in heart failure patients requires a holistic approach, which includes at least the management of the underlying heart disease, the management of comorbidities and the social and psychological aspects of the disease, and the management of haemodynamic/fluid status. In this regard, accurate assessment of elevated ventricular filling pressures or volume overload, that is, haemodynamic or pulmonary congestion, respectively, before the onset of worsening heart failure symptoms represents an important management strategy. Unfortunately, conventional methods for assessing congestion, such as physical examination and monitoring of symptoms and daily weights, are insensitive markers of worsening heart failure. Assessment tools that directly measure congestion, accurately and in absolute terms, provide more actionable information that enables the application of treatment algorithms designed to restore patient stability, in a variety of clinical settings. Two such assessment tools, implantable haemodynamic monitors and remote dielectric sensing (ReDS), meet the prerequisites for useful heart failure management tools, by providing accurate, absolute, and actionable measures of congestion, to guide patient management. This review focuses on the use of such technologies, across the spectrum of heart failure treatment settings. Clinical data are presented that support the broad use of pulmonary artery pressure-guided and/or ReDS-guided heart failure management in heart failure patients with reduced and preserved left ventricular ejection fraction.


Assuntos
Insuficiência Cardíaca , Função Ventricular Esquerda , Gerenciamento Clínico , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/terapia , Humanos , Monitorização Fisiológica , Volume Sistólico
2.
Circ Heart Fail ; 13(4): e006731, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32295407

RESUMO

Acute decompensated heart failure remains the most common cause of hospitalization in older adults, and studies of pharmacological therapies have yielded limited progress in improving outcomes for these patients. This has prompted the development of novel device-based interventions, classified mechanistically based on the way in which they intend to improve central hemodynamics, increase renal perfusion, remove salt and water from the body, and result in clinically meaningful degrees of decongestion. In this review, we provide an overview of the pathophysiology of acute decompensated heart failure, current management strategies, and failed pharmacological therapies. We provide an in depth description of seven investigational device classes designed to target one or more of the pathophysiologic derangements in acute decompensated heart failure, denoted by the acronym DRI2P2S. Dilators decrease central pressures by increasing venous capacitance through splanchnic nerve modulation. Removers remove excess fluid through peritoneal dialysis, aquaphoresis, or hemodialysis. Inotropes directly modulate the cardiac nerve plexus to enhance ventricular contractility. Interstitial devices enhance volume removal through lymphatic duct decompression. Pushers are novel descending aorta rotary pumps that directly increase renal artery pressure. Pullers reduce central venous pressures or renal venous pressures to increase renal perfusion. Selective intrarenal artery catheters facilitate direct delivery of short acting vasodilator therapy. We also discuss challenges posed in clinical trial design for these novel device-based strategies including optimal patient selection and appropriate end points to establish efficacy.


Assuntos
Denervação Autônoma/instrumentação , Cateterismo/instrumentação , Terapia por Estimulação Elétrica/instrumentação , Insuficiência Cardíaca/terapia , Hemodinâmica , Rim/fisiopatologia , Diálise Renal/instrumentação , Animais , Denervação Autônoma/efeitos adversos , Cateterismo/efeitos adversos , Tomada de Decisão Clínica , Terapia por Estimulação Elétrica/efeitos adversos , Desenho de Equipamento , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/fisiopatologia , Humanos , Seleção de Pacientes , Recuperação de Função Fisiológica , Diálise Renal/efeitos adversos , Fatores de Risco , Resultado do Tratamento
3.
Eur J Heart Fail ; 21(9): 1103-1113, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30652394

RESUMO

AIMS: Cardiac contractility modulation (CCM) improves symptoms and exercise tolerance and reduces heart failure (HF) hospitalizations over 6-month follow-up in patients with New York Heart Association (NYHA) class III or IV symptoms, QRS < 130 ms and 25% ≤ left ventricular ejection fraction (LVEF) ≤ 45% (FIX-HF-5C study). The current prospective registry study (CCM-REG) aimed to assess the longer-term impact of CCM on hospitalizations and mortality in real-world experience in this same population. METHODS AND RESULTS: A total of 140 patients with 25% ≤ LVEF ≤ 45% receiving CCM therapy (CCM-REG25-45 ) for clinical indications were included. Cardiovascular and HF hospitalizations, Minnesota Living with Heart Failure Questionnaire (MLHFQ) and NYHA class were assessed over 2 years. Mortality was tracked through 3 years and compared with predictions by the Seattle Heart Failure Model (SHFM). A separate analysis was performed on patients with 35% ≤ LVEF ≤ 45% (CCM-REG35-45 ) and 25% ≤ LVEF < 35% (CCM-REG25-34 ). Hospitalizations decreased by 75% (from 1.2/patient-year the year before, to 0.35/patient-year during the 2 years following CCM, P < 0.0001) in CCM-REG25-45 and by a similar amount in CCM-REG35-45 (P < 0.0001) and CCM-REG25-34 . MLHFQ and NYHA class improved in all three cohorts, with progressive improvements over time (P < 0.002). Three-year survival in CCM-REG25-45 (82.8%) and CCM-REG24-34 (79.4%) were similar to those predicted by SHFM (76.7%, P = 0.16; 78.0%, P = 0.81, respectively) and was better than predicted in CCM-REG35-45 (88.0% vs. 74.7%, P = 0.046). CONCLUSION: In real-world experience, CCM produces results similar to those of previous studies in subjects with 25% ≤ LVEF ≤ 45% and QRS < 130 ms; cardiovascular and HF hospitalizations are reduced and MLHFQ and NYHA class are improved. Overall mortality was comparable to that predicted by the SHFM but was lower than predicted in patients with 35% ≤ LVEF ≤ 45%.


Assuntos
Terapia por Estimulação Elétrica/métodos , Insuficiência Cardíaca/terapia , Hospitalização/estatística & dados numéricos , Mortalidade , Qualidade de Vida , Idoso , Feminino , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Contração Miocárdica , Volume Sistólico
4.
ESC Heart Fail ; 6(6): 1178-1187, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31997539

RESUMO

AIMS: The objective of this paper is to assess whether cardiac contractility modulation (via the Optimizer System) plus standard of care (SoC) is a cost-effective treatment for people with heart failure [New York Heart Association (NYHA) III, left ventricular ejection fraction of 25-45%, and narrow QRS] compared against SoC alone from the perspective of the English National Health Service. METHODS AND RESULTS: We developed a regression equation-based cost-effectiveness model, using individual patient data from three randomized control trials (FIX-HF-5 Phases 1 and 2, and FIX-HF-5C) to populate the majority of parameters. A series of regression equations predicted NYHA class over time, mortality, all-cause hospitalization rates, and health-related quality of life. We conducted the analysis in line with the National Institute for Health and Care Excellence reference case, modelling costs from an English National Health Service perspective, and considering outcomes in quality-adjusted life years (QALYs) over a patient lifetime perspective. Our base case analysis produced an incremental cost per additional QALY of GBP22 988 (€25 750) when comparing Optimizer + SoC to SoC alone. This result was not sensitive to parameter uncertainty but was sensitive to the time horizon over which costs and QALYs were captured and the duration over which a survival benefit with Optimizer + SoC can be assumed to apply. CONCLUSIONS: Cardiac contractility modulation is likely to be cost-effective in people with heart failure with reduced ejection fraction, NYHA III, and narrow QRS, provided that the treatment benefit can be maintained beyond the duration of the existing clinical trial follow-up. This analysis supports the current recommendations of the European Society of Cardiology that this therapy may be considered for such patients.


Assuntos
Terapia por Estimulação Elétrica , Insuficiência Cardíaca , Marca-Passo Artificial , Idoso , Análise Custo-Benefício , Terapia por Estimulação Elétrica/efeitos adversos , Terapia por Estimulação Elétrica/economia , Terapia por Estimulação Elétrica/instrumentação , Terapia por Estimulação Elétrica/mortalidade , Eletrocardiografia , Feminino , Coração/fisiopatologia , Insuficiência Cardíaca/economia , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/terapia , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Marca-Passo Artificial/efeitos adversos , Marca-Passo Artificial/economia , Marca-Passo Artificial/estatística & dados numéricos , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto
5.
Circ Heart Fail ; 11(10): e005082, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30354397

RESUMO

Background Gastrointestinal bleeding (GIB) is a common complication seen in patients supported with left ventricular assist devices (LVADs) and is related to increased inflammation and angiogenesis. Omega-3 is an unsaturated fatty acid that possesses anti-inflammatory and antiangiogenic properties. This study aims to assess the prophylactic efficacy of treatment with omega-3 on the incidence of GIB in LVAD patients. Methods and Results Among consecutive 166 LVAD patients enrolled in this analysis, 30 patients (49 years old and 26 male) received 4 mg/d of omega-3 therapy for 310±87 days and 136 patients in the control group (58 years old and 98 male) were observed for 302±102 days. One-year GIB-free rate was significantly higher in the omega-3 group as compared with the control group (97% versus 73%; P=0.02). Omega-3 therapy was associated with the occurrence of GIB in both the univariate (hazard ratio, 0.12; 95% CI, 0.02-0.91; P=0.040) and multivariate Cox proportional hazard ratio analyses (hazard ratio, 0.13; 95% CI, 0.02-0.98; P=0.047). The frequency of GIB was significantly lower in the omega-3 group (0.08±0.42 versus 0.37±0.93 events/y; P=0.01), accompanied by significantly lower blood product transfusion and shorter days in the hospital. The frequency of GIB remained lower among the omega-3 group after matching for patient background characteristics (96% versus 73%, P=0.028). Conclusions LVAD patients treated with omega-3 had a significant increase in freedom from GIB. A randomized controlled study is warranted to evaluate the use of omega-3 in LVAD patients.


Assuntos
Ácidos Graxos Ômega-3/uso terapêutico , Hemorragia Gastrointestinal/prevenção & controle , Insuficiência Cardíaca/terapia , Coração Auxiliar , Função Ventricular Esquerda/efeitos dos fármacos , Adulto , Idoso , Anticoagulantes/efeitos adversos , Feminino , Hemorragia Gastrointestinal/etiologia , Coração Auxiliar/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento , Função Ventricular Esquerda/fisiologia
6.
Curr Opin Cardiol ; 30(3): 267-76, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25807225

RESUMO

PURPOSE OF REVIEW: Despite improvements in medical and device therapies for the treatment of heart failure, the incidence and prevalence of heart failure continue to increase. Given the relative stagnation in new pharmacologic therapies, considerable attention has been given in recent years to device therapies to supplement care in patients with advanced heart failure. Recent successful clinical trial results with an angiotensin-neprilysin inhibitor are not expected to change this situation significantly; the drug has been shown to delay, not eliminate, the progression of heart failure. This review focuses on the technologies that are currently in development for the treatment of advanced heart failure. RECENT FINDINGS: Novel devices that involve electrical, neurohormonal or structural remodeling of the heart that can be inserted either percutaneously or with a minimally invasive surgery are currently at various stages of clinical development. All, however, have shown promising clinical results in preclinical and early clinical studies. SUMMARY: Novel device therapies for advanced heart failure continue to show promising clinical results. Randomized controlled trials are still needed to better evaluate their efficacy. Nevertheless, it can be anticipated that at least several of these devices will be among the armamentarium of treatment options for advanced heart failure in the future.


Assuntos
Insuficiência Cardíaca/terapia , Contração Miocárdica , Estimulação da Medula Espinal/métodos , Estimulação do Nervo Vago/métodos , Septo Interatrial/cirurgia , Barorreflexo , Seio Carotídeo , Terapia por Estimulação Elétrica , Equipamentos e Provisões , Ventrículos do Coração/cirurgia , Humanos , Procedimentos de Cirurgia Plástica
7.
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
8.
J Pharmacol Exp Ther ; 321(2): 469-76, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17277196

RESUMO

Both beta-adrenergic blockade and bradycardia may contribute to the therapeutic effect of beta-blockers in chronic heart failure (CHF). This study tested the relative importance of bradycardia by comparing cilobradine (Cilo), a sinus node inhibitor, with a beta-blocker, metoprolol (Meto), in an established canine model of CHF. Dogs were chronically instrumented for hemodynamic and left ventricular (LV) volume measurements. CHF was created by daily coronary embolization via a chronically implanted coronary (left anterior descending coronary artery) catheter. After establishment of CHF, control (n=6), Meto (30 mg/day, n=5), Cilo (low) (1 mg/kg/day, n=5), or Cilo (high) (3 mg/kg/day, n=5) was given orally for 12 weeks. Systemic hemodynamics, echocardiography, and pressure volume analysis were measured at baseline, at CHF, and 3 months after treatment in an awake state. Protein levels of cardiac sarcoplasmic reticulum calcium-ATPase (SERCA2a), ryanodine receptor (RyR2), and Na+-Ca2+ exchanger (NCX1) were measured by Western blot. RyR2 protein kinase A (PKA) phosphorylation was determined by back-phosphorylation. After 12 weeks, Meto and Cilo (high and low) produced similar bradycardic effects, accompanied by a significantly improved LV dP/dt versus control [Meto, 2602+/-70; Cilo (low), 2517+/-45; Cilo (high), 2579+/-78; control, 1922+/-115 mm Hg/s; p<0.05]. Both Meto and Cilo (high) normalized protein levels of SERCA2a and NCX1 and reversed PKA hyperphosphorylation of RyR2, in contrast to controls. High-dose cilobradine effectively produced bradycardia and improved cardiac function after CHF, comparable with metoprolol. Restored protein levels of SERCA2a and improved function of RyR2 may be important mechanisms associated with cilobradine therapy.


Assuntos
Benzazepinas/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Piperidinas/uso terapêutico , Função Ventricular Esquerda/efeitos dos fármacos , Remodelação Ventricular/efeitos dos fármacos , Antagonistas Adrenérgicos beta/uso terapêutico , Animais , Cálcio/metabolismo , Estenose Coronária/complicações , Cães , Ecocardiografia , Feminino , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Masculino , Metoprolol/uso terapêutico , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/análise , Trocador de Sódio e Cálcio/fisiologia
9.
Curr Heart Fail Rep ; 3(1): 21-4, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16684493

RESUMO

Major advances have been made over the past two decades in the pharmacologic treatment of chronic heart failure (HF). Angiotensin-converting enzyme inhibitors, beta-blockers, and aldosterone antagonists have had a substantial impact on reducing mortality and morbidity in patients with HF and low left ventricular ejection fraction. These treatments delayed the progression toward advanced intractable HF but did not arrest progressive worsening of the disease. Patients on optimal medical therapy continued to deteriorate, albeit at a much slower pace, ultimately requiring further intervention. This gave rise to a host of device-based therapies that emerged in recent years to address this unmet need. Device therapies such as cardiac resynchronization, the CorCap cardiac support device (Acorn Cardiovascular, Inc., St. Paul, MN), and the OPTIMIZER System (Impulse Dynamics USA, Inc., Orangeburg, NY) are a few examples. This review addresses the progress made to date in the development and implementation of cardiac contractility modulation (CCM) as a device-based therapy for the treatment of patients with advanced HF. Treatment of patients with HF using CCM electrical signals is at present an investigational form of therapy.


Assuntos
Terapia por Estimulação Elétrica/métodos , Insuficiência Cardíaca/terapia , Contração Miocárdica/fisiologia , Transdução de Sinais/fisiologia , Animais , Cães , Terapia por Estimulação Elétrica/instrumentação , Humanos , Marca-Passo Artificial , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento , Disfunção Ventricular Esquerda/terapia
10.
Am Heart J ; 149(4): 573-9, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15990736

RESUMO

Despite the availability of interventional catheterization for patients with acute coronary syndromes, there is an unavoidable delay until the occluded coronary artery(s) can be revascularized, during which time persistent ischemia may lead to irreversible myocardial damage despite subsequently high patency rates. Accordingly, there has been an intense effort to develop early interventions that will preserve the viability of ischemic myocardium before revascularization. A number of novel strategies have been studied, including hemoglobin-based oxygen carriers. These compounds transport oxygen in the plasma to help maintain more normal oxygen delivery to the myocardium supplied by a thrombosed vessel, and they also release oxygen to tissue more efficiently than intraerythrocytic hemoglobin.


Assuntos
Substitutos Sanguíneos/uso terapêutico , Cardiotônicos/uso terapêutico , Hemoglobinas/uso terapêutico , Isquemia Miocárdica/terapia , Revascularização Miocárdica , Cuidados Pré-Operatórios , Adulto , Idoso , Substitutos Sanguíneos/administração & dosagem , Substitutos Sanguíneos/química , Substitutos Sanguíneos/farmacocinética , Cardiotônicos/administração & dosagem , Cardiotônicos/química , Cardiotônicos/farmacocinética , Ensaios Clínicos Fase II como Assunto , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Feminino , Hemoglobinas/administração & dosagem , Hemoglobinas/química , Hemoglobinas/farmacocinética , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Multicêntricos como Assunto , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/cirurgia , Infarto do Miocárdio/terapia , Isquemia Miocárdica/tratamento farmacológico , Isquemia Miocárdica/cirurgia , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miocárdio/metabolismo , Oxigênio/metabolismo , Projetos Piloto , Ensaios Clínicos Controlados Aleatórios como Assunto
11.
Eur Heart J ; 25(8): 650-5, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15084369

RESUMO

AIM: In experimental studies, nonexcitatory electrical stimulation delivered at the time of absolute myocardial refractoriness resulted in cardiac contractility modulation (CCM) with improved systolic function. This study reports the initial experience with CCM in patients with chronic heart failure. METHODS AND RESULTS: Twenty-five patients, 23 males, with a mean age of 62+/-9 years and drug-refractory NYHA class III heart failure were assigned to CCM-generator implantation. The underlying heart disease was idiopathic dilated cardiomyopathy in 12 patients and coronary heart disease in 13 patients. Acute efficacy of CCM with 7.73-V stimuli delivered via two right ventricular leads was evaluated by measuring the time derivative of left ventricular pressure (dP/dt). After implantation, the CCM generator was activated for 3 h daily over 8 weeks. In 23/25 patients the CCM system was implanted successfully. Heart failure significantly improved from NYHA class III to class II in 15 patients and to class I in 4 patients (p < 0.000001), left ventricular ejection fraction improved from 22+/-7% to 28+/-8% (p = 0.0002), and the Minnesota Living with Heart Failure Score improved from 43+/-22 to 25+/-18 (p = 0.001). The 6-min walk test increased from 411+/-86 to 465+/-81 m (p= 0.02). Nine patients (39%) had intermittent sensations associated with CCM delivery. There were two (8%) non-device-related deaths during follow-up. CONCLUSIONS: These preliminary data indicate that CCM by delivery of intermittent nonexcitatory electrical stimuli is a promising technique for improving ventricular systolic function and symptoms in patients with drug-refractory NYHA class III heart failure.


Assuntos
Cardiomiopatia Dilatada/terapia , Doença da Artéria Coronariana/terapia , Terapia por Estimulação Elétrica/métodos , Insuficiência Cardíaca/terapia , Doença Crônica , Estudos de Viabilidade , Feminino , Insuficiência Cardíaca/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Próteses e Implantes , Resultado do Tratamento
12.
Am J Cardiol ; 90(12): 1307-13, 2002 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-12480039

RESUMO

We assessed the feasibility of cardiac contractility modulation (CCM) by electric currents applied during the refractory period in patients with heart failure (HF). Extracellular electric currents modulating action potential and calcium transients have been shown to potentiate myocardial contractility in vitro and in animal models of chronic HF. CCM signals were biphasic square-wave pulses with adjustable amplitude, duration, and time delay from sensing of local electric activity. Signals were applied to the left ventricle through an epicardial vein (in 12 patients) or to the right ventricular (RV) aspect of the septum endocardially (in 6 patients). Simultaneous left ventricular (LV) and aortic pressure measurements were performed using a Millar catheter (Millar Instruments, Houston, Texas). Hemodynamics during RV temporary dual-chamber pacing was regarded as the control condition. Both LV and RV CCM stimulation increased dP/dt(max) to a similar degree (9.1 +/- 4.5% and 7.1 +/- 0.8%, respectively; p <0.01 vs controls), with associated aortic pulse pressure changes of 10.3 +/- 7.2% and 10.8 +/- 1.1% (p <0.01 vs controls). Regional systolic wall motion assessed quantitatively by color kinesis echocardiography was markedly enhanced near the CCM electrode, and the area of increased contractility involved 4.6 +/- 1.2 segments per patient. In 6 patients with HF with left bundle branch block, CCM signals delivered during biventricular pacing (BVP) produced an additional 16.1 +/- 3.7% increase in dP/dt(max) and a 17.0 +/- 7.5% increase in pulse pressure compared with BVP alone (p <0.01). CCM stimulation in patients with HF enhanced regional and global measures of LV systolic function, regardless of the varied delivery chamber or whether modulation was performed during RV pacing or BVP.


Assuntos
Estimulação Cardíaca Artificial/métodos , Cardiomiopatia Dilatada/fisiopatologia , Técnicas Eletrofisiológicas Cardíacas/métodos , Contração Miocárdica/fisiologia , Função Ventricular Esquerda/fisiologia , Função Ventricular , Aorta/fisiologia , Pressão Sanguínea/fisiologia , Bloqueio de Ramo/fisiopatologia , Cardiomiopatia Dilatada/complicações , Ecocardiografia Doppler em Cores , Condutividade Elétrica , Estimulação Elétrica/métodos , Eletrocardiografia , Eletrodos , Estudos de Viabilidade , Hemodinâmica/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Volume Sistólico/fisiologia
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