Reverse-Remodeling Effects of Angiotensin II Type 1 Receptor Blocker in a Canine Atrial Fibrillation Model

Nakashima, Hideko; Kumagai, Koji

doi:10.1253/circj.71.1977

Cited by 53 publications

(33 citation statements)

References 31 publications

(50 reference statements)

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“…13 Third, the ECV group included a much higher percentage of those who had hypertension and had more usage of ACEIs or ARBs than the ABL group, and these medications are likely to have had salutary effects on LA function and remodeling. 26 However, in our data, receiving ACEIs or ARBs did not significantly influence the reverse remodeling of the LA after ABL and ECV. The other limitation was that there was no baseline assessment of Doppler and tissue Doppler parameters because of the difficulty in taking measurements in patients with PeAF before the procedures.…”

Section: Study Limitationscontrasting

confidence: 67%

Changes in Left Atrial Structure and Function After Catheter Ablation and Electrical Cardioversion for Atrial Fibrillation

Choi

Seong

Park

et al. 2008

Circ J

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trial fibrillation (AF) occurs in 0.4% of the general population, increasing to 5% in those over 65 years of age, and it is the most common arrhythmia, increasing cardiac morbidity and mortality. 1 AF is related to the structural and functional remodeling of the left atrium (LA) and ventricle (LV) because of persistent arrhythmia. 2,3 To restore sinus rhythm (SR), both electrical cardioversion (ECV) and radiofrequency (RF) catheter ablation (ABL) have proven to be effective treatment modalities for patients with AF. 4 Reverse morphological remodeling of the LA and improvement in LV diastolic and systolic functions after restoration of SR by either treatment modality have been demonstrated. 5 However, differences in the degree and the time course of functional reverse remodeling of the LA according to the each treatment modality have not been investigated. The objective of this study was to investigate the morphological and functional changes of the LA and LV in patients with sustained SR either after ABL or ECV. Circulation Journal Vol.72, December 2008 Methods Study PopulationSixty-three AF patients who had maintained SR for 3 months after either ECV (n=30, M:F 24:6, mean age 58.6± 9.3 years) or ABL (n=33, M:F 27:6, mean age 55.9±10.2 years) were included. Patients who underwent re-do ablation were excluded. Paroxysmal AF (PAF) was defined as the occurrence of 2 or more episodes of AF during the previous 12 months, typically lasting fewer than 7 days and terminating spontaneously. Persistent AF (PeAF) was defined as AF episodes lasting more than 7 days typically requiring cardioversion for restoration of SR. 6 The 29 of 30 patients had PeAF in the ECV group and 21 of 33 patients had PAF in the ABL group. All clinical information was obtained from medical records, and all patients completed a written informed consent form to participate in the study. ECVECV was performed if LA thrombi were not seen on transesophageal echocardiography. Direct current (DC) shock was delivered during sedation induced with intravenous midazolam (0.04 mg/kg) and pentothal sodium (1.5 mg/kg). One defibrillator pad with a 10-cm diameter was placed in the second intercostal space on the right side parasternally, the other was placed in a left-sided lateral position along the midaxillary line. The cardioversion procedure started with 70 J or 100 J of stored energy followed by 125 J and 150 J until the restoration of SR or failure to convert. Continuous electrocardiographic (ECG) monitoring was performed for several hours after the procedure to assess the maintenance of SR. Background The aim of this study was to assess whether the morphological and functional changes of the left atrium (LA) differ after catheter ablation (ABL) from those after electrical cardioversion (ECV) in atrial fibrillation (AF). Methods and Results AF patients who had maintained sinus rhythm for 3 months after either ECV (n=30) or ABL (n=33) were studied. Both 2-dimensional and Doppler echocardiography were performed at baseline, 1 week, 1 month, and 3 months aft...

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Section: Study Limitationscontrasting

confidence: 67%

Changes in Left Atrial Structure and Function After Catheter Ablation and Electrical Cardioversion for Atrial Fibrillation

Choi

Seong

Park

et al. 2008

Circ J

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“…25 The findings in the present study suggested that RASIs might be effective in patients with a less fibrotic LA. Although many studies have shown that blocking the renin-angiotensin-aldosterone system leads to the prevention or inhibition of fibrosis, [26][27][28][29] it has not been demonstrated whether RASIs can pathologically reverse or normalize established fibrosis. This study may suggest that RASIs may suppress AF recurrences after PVI when the LA has not yet developed severe structural remodelling.…”

Section: La Size and Fibrosismentioning

confidence: 99%

Renin–angiotensin system inhibitors can suppress atrial fibrillation recurrence after encircling ipsilateral pulmonary vein isolation in patients with a non-dilated left atrium

Takigawa

Yamada

Yoshida

et al. 2012

J Renin Angiotensin Aldosterone Syst

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Introduction: The purpose of this study was to investigate whether the effects of renin-angiotensin system inhibitors (RASIs) after encircling ipsilateral pulmonary veins isolation (EIPVsI) for atrial fibrillation (AF) differed between patients with non-dilated and dilated left atria. Materials and methods: We retrospectively studied 292 consecutive patients (mean age=61±11 years, 75% males) who underwent successful EIPVsI for paroxysmal or persistent AF. RASIs' effects were compared between the patients with a non-dilated left atrium of <40 mm (n=178) and dilated left atrium of ≥40 mm (n=114). Results: During a mean follow-up period of 18.9±12.7 months, AF recurred in 38 (21.4%) and 45 (39.5%) patients with non-dilated and dilated left atria, respectively. A multivariate Cox proportional analysis revealed that treatment with RASIs (hazard ratio (HR) 0.30, 95% confidence interval (CI) =0.13-0.66, p=0.003), the duration of AF (HR 1.08/year, 95% CI=1.01-1.16, p=0.03), a history of hypertension (HR 2.86, 95% CI=1.21-6.85, p=0.02) and the left ventricular ejection fraction (HR 0.54/10%↑, 95% CI=0.34-0.87, p=0.01) were associated with AF recurrences in patients with a non-dilated left atrium. On the other hand, only the duration of AF (HR 1.11/year, 95% CI=1.01-1.21, p=0.03) was associated with AF recurrences in those with a dilated LA, and RASIs had no effect on AF recurrences (p=0.65). Conclusions: RASIs suppressed AF recurrences after EIPVsI only in patients with a non-dilated left atrium.

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“…The activation of stretch-activated channels contributes to depolarization of the membrane potential, shortened refractoriness, slowed conduction, and increased spatial dispersion. 54 Several types of SAC have been described in the cardiac cell: potassium-selective channels, 55 chloride-selective anion channels, 56,57 and non-selective cation channels. 58 Bode et al showed that atrial fibrillation potentiated by dilatation in rabbit heart can be inhibited by blocking SAC with GsMTx4, a peptide isolated from tarantula venom and the first specific reagent for non-selective cation SAC.…”

Section: Trp Channels Participate In Arrhythmogenesismentioning

confidence: 99%

The Pathological Role of Transient Receptor Potential Channels in Heart Disease

Watanabe

Murakami

Ohba

et al. 2009

Circ J

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alcium ion (Ca 2+ ) is a major intracellular messenger with a vital role in many cellular responses. In cardiac myocytes, Ca 2+ not only transmits an electrical signal to the sarcomere thereby triggering a mechanical event, but also induces the expression of genes responsible for hypertrophy or apoptosis. Signaling via Ca 2+ occurs through transient changes in the intracellular Ca 2+ concentration ([Ca 2+ ]i), which is maintained between 10 nmol/L and 10 μmol/L with physiological Ca 2+ transients occurring within this range. The diversity of Ca 2+ -mediated effects is attributable to differences in the amplitude and spatiotemporal pattern of Ca 2+ transients. 1 In cardiac myocytes, intracellular Ca 2+ has 2 origins: the extracellular space and the sarcoplasmic reticulum (SR). The roles of the SR and ryanodine receptors in heart disease have been described by Yano. 2 Here, we focus here on the involvement of Ca 2+ -entry channels in the development of heart disease.The extracellular milieu is a ready source of Ca 2+ , and several ion channels allow Ca 2+ to enter the cell. In cardiac myocytes, voltage-gated Ca 2+ channels (VGCC) mediate Ca 2+ entry upon depolarization of the cell membrane above a threshold potential during an action potential. Ca 2+ entry is mediated partly by the Na + /Ca 2+ exchanger (NCX) running in 'reverse mode'. Other Ca 2+ -entry pathways include ligandgated cation channels (LGC), stretch-activated cation channels (SAC), thermosensitive channels, and receptor-activated cation channels (RAC).LGC are gated by the binding of a ligand to the channel itself. SAC and thermosensitive channels are activated by mechanical stretching and changes in the ambient temperature, respectively. RAC are gated by agonist binding to a receptor distinct from the channel protein. RAC subtypes exist with different Ca 2+ selectivities, activation mechanisms, and physiological functions; these include store-operated Ca 2+ channels (SOC), which are activated upon depletion of the intracellular Ca 2+ store, and receptor-operated Ca 2+ channels (ROC), which are activated by diacylglycerol (DAG).With the exceptions of VGCC and NCX, the molecular identities of Ca 2+ -entry channels have not yet been completely determined, although new findings have emerged in recent years. Novel players regulating Ca 2+ entry have been found in the still-growing family of transient receptor potential (TRP) cation channels. The identification of mammalian TRP channels was a new starting point in the search for the molecular identification of Ca 2+ -entry pathways that contribute to the development of heart disease. This review discusses the expression and function of TRP channels in the heart, their endogenous agonists, the pathophysiological conditions that can modulate these channels, and the potential involvement of TRP channels in the pathogenesis of certain heart diseases such as cardiac hypertrophy, muscular dystrophy associated cardiomyopathy and arrhythmias under Ca 2+ -overload conditions. TRP SuperfamilyDrosophila with mutatio...

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Reverse-Remodeling Effects of Angiotensin II Type 1 Receptor Blocker in a Canine Atrial Fibrillation Model

Cited by 53 publications

References 31 publications

Changes in Left Atrial Structure and Function After Catheter Ablation and Electrical Cardioversion for Atrial Fibrillation

Changes in Left Atrial Structure and Function After Catheter Ablation and Electrical Cardioversion for Atrial Fibrillation

Renin–angiotensin system inhibitors can suppress atrial fibrillation recurrence after encircling ipsilateral pulmonary vein isolation in patients with a non-dilated left atrium

The Pathological Role of Transient Receptor Potential Channels in Heart Disease

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