Satofumi Morishita

Influence of mosapride citrate on gastric motility and autonomic nervous function: evaluation by spectral analyses of heart rate and blood pressure variabilities, and by electrogastrography

Background: Mosapride citrate selectively acts on serotonin (5-HT4) receptors, thus accelerating gastrointestinal motility via acetylcholine. However, few studies have evaluated the influence of mosapride citrate on autonomic nervous activity and hemodynamics. Methods: The changes in autonomic nervous activity, QT interval, and QT dispersion resulting from the administration of mosapride citrate were studied. Blood pressure, electrocardiograms (ECGs), percutaneous electrogastrograms (EGGs), and ultrasonography were recorded in 20 healthy adult volunteers before and after mosapride citrate (10 mg) was administered. Autonomic nervous activity was evaluated by spectral analyses of heart rate and blood pressure variabilities. Serial changes in low-frequency components (LF, 0.04–0.15 Hz), high-frequency components (HF, 0.15–0.40 Hz), and the LF/HF ratio were investigated. Results: The mean peak power of EGG increased significantly, from 86 ± 34 μV to 131 ± 49 μV, after the administration of mosapride citrate (P < 0.05). Gastric emptying significantly increased after the administration of mosapride citrate (P < 0.05). However, neither blood pressure nor heart rate changed significantly after the drug was administrated. In addition, spectral analyses of heart rate and blood pressure variabilities showed no significant changes in autonomic nervous activity parameters, QT intervals, or QT dispersions. Conclusions: Mosapride citrate increased gastric motility and emptying without influencing autonomic nervous activity, suggesting that it may be very useful for elderly patients or patients with autonomic imbalance.

Interatrial dyssynchrony on tissue Doppler imaging predicts progression to chronic atrial fibrillation in patients with non-valvular paroxysmal atrial fibrillation

Objective: To determine prospectively whether interatrial dyssynchrony detected by tissue Doppler imaging (TDI) is useful for predicting the progression to chronic atrial fibrillation (CAF) in patients with non-valvular paroxysmal AF (PAF). Methods: Thirty-seven patients with non-valvular PAF were prospectively followed after echocardiography. The interval of time from initiation of the P wave on the electrocardiogram (ECG) until the beginning of the late diastolic TDI signal at the lateral border of the mitral annulus (P-A′(M)) and the tricuspid annulus (P-A′(T)) was measured. Interatrial dyssynchrony was defined as the difference between the P-A′(M) and P-A′(T) intervals (A′(M)-A′(T)). The study endpoint was the onset of CAF (>6 months). Results: During a follow-up period of 28 (SD 23) months, eight patients developed CAF. Compared with those without CAF, the patients who developed CAF had a significantly lower atrial systolic mitral (A′(M)) (7.7 (1.7) vs 10.7 (2.9) cm/s, p<0.01) and tricuspid (A′(T)) (12.9 (3.5) vs 16.6 (5.1) cm/s, p<0.05) annular tissue Doppler velocity, as well as a longer A′(M)-A′(T) interval (47 (13) vs 24 (10) ms, p<0.0001). Kaplan–Meier analysis, using cut-off values determined by analysis of receiver-operating characteristics curves, revealed that progression to CAF was significantly more frequent when the A′(M)-A′(T) interval was ⩾34 ms (p<0.01), the A′(M) velocity was ⩽9 cm/s (p<0.05) and the A′(T) velocity was ⩽16 cm/s (p<0.05). Conclusions: This prospective study suggests that non-valvular PAF patients with a high risk of developing CAF have “interatrial dyssynchrony” and “atrial systolic dysfunction” on atrial TDI.

Impaired Retention of Technetium-99m Tetrofosmin in Hypertrophic Cardiomyopathy

The purpose of this study was to determine whether myocardial imaging using technetium-99m tetrofosmin can noninvasively identify myocardial damage in hypertrophic cardiomyopathy (HC). The study consisted of 10 patients with apical HC, 10 with asymmetric septal HC (ASH) group, 5 with dilated cardiomyopathy (DC)-like group, and 20 healthy subjects. With use of a bulls-eye map of single-photon emission computed tomographic imaging, the total defect score of tetrofosmin and the washout rate were assessed in 5 segments (septum, and anterior, lateral, and inferior walls, and apex) of the left ventricle. A localized increase in defect score and washout rate was observed in the hypertrophied region in the group with apical HC. An increased washout rate was observed in the ASH group regardless of hypertrophy, suggesting that tetrofosmin retention by the mitochondria was impaired in the entire left ventricular wall. The washout rate was further increased at all segments in the DC-like group versus the ASH group. Tetrofosmin retention by mitochondria was impaired in the entire left ventricular wall in the ASH group and was increased further in the DC-like group. The dysfunction of myocardial cells was limited to the hypertrophied region in the apical HC group.

Relation of gender and interatrial dyssynchrony on tissue Doppler imaging to the prediction of the progression to chronic atrial fibrillation in patients with nonvalvular paroxysmal atrial fibrillation

This prospective study aimed to identify the relation of gender and interatrial dyssynchrony on tissue Doppler imaging (TDI) to the prediction of the progression to chronic atrial fibrillation (CAF) in nonvalvular paroxysmal AF (PAF) patients. Nineteen consecutive men and 19 women with nonvalvular PAF were prospectively followed after echocardiography. We measured the interval of time from initiation of the P wave on the electrocardiogram until the beginning of the late diastolic TDI signal at the lateral border of the mitral (P-A′(M)) and the tricuspid annulus (P-A′(T)). Interatrial dyssynchrony was defined as the difference between the P-A′(M) and P-A′(T) intervals (A′(M)-A′(T)). The study endpoint was the onset of CAF (>6 months). Six men developed CAF during a follow-up of 32 ± 26 months, and 3 women developed CAF during a follow-up of 25 ± 19 months. Compared to those without CAF, the patients with CAF had significantly longer A′(M)- A′(T) intervals (men: 41 ± 10 vs 27 ± 12 ms, women: 64 ± 4 vs 23 ± 9 ms; P < 0.01) in both genders. Kaplan-Meier analysis, using cutoff values determined by analysis of receiveroperating characteristics curves, revealed that the progression to CAF was significantly observed more often when A′(M)-A′(T) interval was >34 ms in men and >43 ms in women. This prospective study suggests that nonvalvular PAF men and women with a high risk of developing CAF have “interatrial dyssynchrony” on atrial TDI, whose cutoff values are shorter and may affect the vulnerability of AF in men.

Prediction of Transition to Chronic Atrial Fibrillation in Elderly Patients with Nonvalvular Paroxysmal Atrial Fibrillation by Transthoracic Doppler Echocardiography

It is well known that paroxysmal atrial fibrillation (PAF) often precedes the development of chronic atrial fibrillation (CAF).

Preventive effect of renin–angiotensin system inhibitor on left atrial remodelling in patients with chronic atrial fibrillation: long-term echocardiographic study

AIMS Left atrium (LA) gradually enlarges with the time course of atrial fibrillation (AF). The aim of this study was to examine whether the renin-angiotensin system (RAS) inhibitor could prevent LA remodelling in patients with chronic AF. METHODS AND RESULTS Forty-one patients with chronic non-valvular AF were enrolled and divided into the following two groups: the RAS group taking an RAS inhibitor and the non-RAS group not taking it. We compared echocardiographic parameters including LA volume at the beginning and the end of follow-up. Percent change of these parameters was calculated from the value at the end of follow-up divided by the value at the beginning of follow-up. An enlargement of LA volume index and a decrease in LA expansion fraction was significantly prevented in the RAS group. Administration of RAS inhibitors was significantly associated with the prevention of increasing LA volume in multivariate analysis. CONCLUSION RAS inhibitors may prevent structural and functional degradation of LA in chronic non-valvular AF.

Transthoracic echocardiography during sinus rhythm identifies elderly patients with nonvalvular paroxysmal atrial fibrillation at high risk of cerebral infarction

We performed transthoracic echocardiography during sinus rhythm in elderly nonvalvular paroxysmal atrial fibrillation (NV-PAF) patients (> or =65 years) with cerebral infarction and in patients without cerebral infarction. This study suggests that elderly NV-PAF patients at high risk for cerebral infarction seem to have a pseudonormalization pattern of transmitral inflow, and decreased atrial reversal flow of pulmonary venous flow, and increased left atrial volume.

P-109 Mitral Valve Motion and Mitral Inflow Dynamics in Aortic Regurgitation, with Reference to the Relation with Regurgitant Jet Direction

(2.6±0.9 vs. 3.4±0.9 cm/s, P= 0.028) and longer interatrial time delay (33±25 vs. 12±19ms, P= 0.022). However, there were no differences in Va of RA and intra-atrial synchronicity between two groups. The lower mitral A velocity and prolonged inter-atrial time delay (OR, 95%CI: 1.12, 1.01 1.24 p = 0.025; 1.08, 1.01 1.16 p = 0.020 resp.) were the strongest predictors on presence of PAF. Conclusion: Compared to these without AF, pts with SND and PAF had worsening of LA mechanical function. The occurrence of inter-atrial dyssychrony may have implications to the mechanical benefit of alternative atrial pacing.