title: Elevated Heart Rate is Associated with Cardiac Denervation in Patients with Heart Failure: A 123-Iodine-MIBG Myocardial Scintigraphy Study.
abstract: In the Systolic Heart Failure Treatment With the If Inhibitor Ivabradine Trial (SHIFT), heart rate (HR) reduction with ivabradine was associated with improved survival and reduced hospitalizations in patients with heart failure (HF). The mechanisms by which elevated HR increases mortality are not fully understood.
  To assess the relationship of baseline HR with clinical, neurohormonal and cardiac sympathetic activity in patients with chronic HF and elevated HR.
  Patients with chronic HF who were in sinus rhythm and had resting HR>70 bpm despite optimal medical treatment were included in a randomized, double-blind study comparing ivabradine versus pyridostigmine. This report refers to the baseline data of 16 initial patients. Baseline HR (before randomization to one of the drugs) was assessed, and patients were classified into two groups, with HR below or above mean values. Cardiac sympathetic activity was assessed by 123-iodine-metaiodobenzylguanidine myocardial scintigraphy.
  Mean HR was 83.5±11.5 bpm (range 72 to 104), and seven (43.7%) patients had HR above the mean. These patients had lower 6-min walk distance (292.3±93 vs 465.2±97.1 m, p=0.0029), higher values of N-Terminal-proBNP (median 708.4 vs 76.1, p=0.035) and lower late heart/mediastinum rate, indicating cardiac denervation (1.48±0.12 vs 1.74±0.09, p<0.001).
  Elevated resting HR in patients with HF under optimal medical treatment was associated with cardiac denervation, worse functional capacity, and neurohormonal activation.
  No SHIFT (Systolic Heart Failure Treatment With the If Inhibitor Ivabradine Trial, ou Estudo do Tratamento da Insuficiência Cardíaca Sistólica com o Inibidor de If Ivabradina), a redução da frequência cardíaca (FC) com ivabradina associou-se com melhor sobrevida e redução das hospitalizações em pacientes com insuficiência cardíaca (IC). Os mecanismos pelos quais a FC elevada aumenta a mortalidade não são totalmente compreendidos.
  Avaliar a relação da FC basal com atividade clínica, neuro-hormonal e simpática cardíaca em pacientes com IC crônica e FC elevada.
  Pacientes com IC crônica em ritmo sinusal e FC≥70 apesar de tratamento adequado foram incluídos em um estudo duplo-cego, randomizado, que comparou ivabradina com piridostigmina. Este artigo refere-se a dados basais dos primeiros 16 pacientes. A FC basal (antes da randomização para um dos medicamentos) foi avaliada, e os pacientes classificados em dois grupos, com FC abaixo ou acima dos valores médios. A atividade simpática cardíaca foi avaliada por cintilografia com metaiodobenzilguanidina marcada com iodo 123.
  A FC média foi 83,5±11,5 bpm (intervalo 72 a 104), e sete pacientes (43.7%) tinham FC acima da média. Esses pacientes apresentaram menor distância percorrida no teste de caminhada de 6 minutos (292,3±93 vs 465,2±97,1 m, p=0,0029), valores mais altos de N-terminal do pró-BNP (mediana 708,4 vs 76,1, p=0,035) e menor relação coração/mediastino tardia, indicando desnervação cardíaca (1,48±0,12 vs 1,74±0,09, p<0,001).
  A FC de repouso elevada em pacientes com IC em tratamento médico adequado associou-se com desnervação cardíaca, pior capacidade funcional e ativação neuro-hormonal.
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Aline Sterque
authors.initials: AS
authors.lastname: Villacorta
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Humberto
authors.initials: H
authors.lastname: Villacorta
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Jenne Serrão de
authors.initials: JS
authors.lastname: Souza
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: José Antônio Caldas
authors.initials: JA
authors.lastname: Teixeira
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Maria Clara S S S
authors.initials: MC
authors.lastname: Muradas
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Christiane Rodrigues
authors.initials: CR
authors.lastname: Alves
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Bernardo Campanário
authors.initials: BC
authors.lastname: Precht
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Pilar
authors.initials: P
authors.lastname: Porto
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Letícia
authors.initials: L
authors.lastname: Ubaldo
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Cláudio Tinoco
authors.initials: CT
authors.lastname: Mesquita
authors.affiliation: Universidade Federal Fluminense, Niterói, RJ - Brazil.
authors.forename: Antônio Cláudio Lucas da
authors.initials: AC
authors.lastname: Nóbrega
mesh_terms: D019797:3-Iodobenzylguanidine; D000328:Adult; D002317:Cardiovascular Agents / Q000627:therapeutic use; D002908:Chronic Disease; D003714:Denervation; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000294:innervation*; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000188:drug therapy; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging* / Q000502:physiology
chemical_list: D002317:Cardiovascular Agents; D019797:3-Iodobenzylguanidine