Kengo Fukushima

Dispersion of regional wall motion abnormality in patients with long QT syndrome

Objective To examine the left ventricular regional wall motion abnormality and to evaluate dispersion of this abnormality in patients with long QT syndrome. Design Left ventricular short axis images at basal and middle levels were recorded on videotape and digitised to reconstruct digitised M mode echocardiograms, from which left ventricular wall thickness curves were obtained. The wall thickening time (ThT) was defined as the period in which the instantaneous wall thickness exceeded 90% of the maximum wall thickness. ThT was measured at three segments in each of the septal and free wall sides of the left ventricle, a total of 12 segments. To examine the mechanical dispersion of the left ventricle, the difference between the maximum and minimum ThT of 12 segments in each subject was obtained. Patients Eight patients with congenital long QT syndrome (averaged QTc interval (SD) 509 (27) ms1/2) and 10 control subjects (QTc interval 397 (26) ms1/2) were examined. Results The averaged ThT values of the 12 segments pooled from all subjects were correlated with the QT intervals (r = 0.72, p < 0.005). Thus the averaged ThT in the long QT syndrome patients was longer than in the control subjects (p < 0.005). The segmental variation of ThT in the patients was greater than in the control subjects (p < 0.001). The dispersion of ThT in the patients was therefore larger than in control subjects (p < 0.005). However, the pattern of ThT variation in the patients varied according to the individual subject. Conclusions There is not only electrical but also mechanical dispersion in the left ventricle of long QT syndrome patients. Regional assessment of ventricular wall motion may allow quantification of the spatial variation of wall motion abnormality.

Asymptomatic Form of Brugada Syndrome

We describe a patient with the asymptomatic form of Brugada syndrome. His electrographical, electropharmacological, and electrophysiological characteristics were similar to those reported in patients with the symptomatic form of Brugada syndrome. We believe that he has the same arrhythmogenic substrate as that of patients with Brugada syndrome. The fact that he had no episode of spontaneous ventricular fibrillation might be explained by his absence of the triggering factors.

Effects of cardiac sympathetic innervation on regional wall motion abnormality in patients with long QT syndrome

AIM To assess the spatial relation between regional cardiac sympathetic innervation and regional ventricular repolarisation indicated by ventricular wall motion abnormality in patients with congenital long QT syndrome. DESIGN Regional percentage uptake and washout rate of123I metaiodobenzylguanidine (MIBG) were measured to assess cardiac sympathetic innervation in septum, anterior wall, lateral wall, and posterior wall. Left ventricular short axis images on echocardiography were digitised to reconstruct digitised M mode echocardiograms, from which left ventricular wall thickness curves were obtained. The wall thickening time (ThT) was defined as the period in which the instantaneous wall thickness exceeded 90% of the maximum wall thickness. The ThT was measured from the ventricular wall thickness curve at the same segments where regional percentage uptake and washout rate of 123I MIBG were measured. PATIENTS Seven patients with long QT syndrome. RESULTS The regional washout rate (mean (SD)) of123I MIBG in patients with long QT syndrome was greater in the segments with decreased percentage uptake of 123I MIBG than in those without (17.4 (10.6)% v 9.7 (16.5)%, p < 0.03). ThT in segments both with and without decreased percentage uptake of 123I MIBG was longer than in control subjects (p < 0.0001). ThT was longer in the segments with decreased percentage uptake of 123I MIBG than in those without (199 (70) ms v 150 (66) ms, p = 0.0018). CONCLUSIONS Activation of regional cardiac sympathetic terminals is likely to participate in additional regional prolongation of ventricular repolarisation in patients with long QT syndrome.

Atrial Electrograms and Activation Sequences in the Transition Between Atrial Fibrillation and Atrial Flutter

Transition Between Atrial Fibrillation and Flutter. Introduction: The eletrophysiologic mechanism of atrial fibrillation (AF) has a wide spectrum, and it seems that some atrial regions are essential for the occurrence of a particular type of AF. We focused on one type of AF: AF associated with typical atrial flutter (AFI), which was right atrial (RA) arrhythmia, and sought to investigate intra‐atrial electrograms and activation sequences in the transition between AF and AFL.

Delayed improvement of autonomic nervous abnormality after the Maze procedure: time and frequency domain analysis of heart rate variability using 24 hour Holter monitoring

Objective To analyse heart rate variability in patients with atrial fibrillation after the Maze procedure, to investigate whether the procedure damages the cardiac autonomic fibres supplying the sinus node. Design and patients Time and frequency domain analyses of RR variability were performed using 24 hour Holter monitoring one month after surgery in 12 patients with atrial fibrillation who underwent the Maze procedure (Maze group) and in seven patients who underwent cardiac surgery without the Maze procedure (control group). Mean RR intervals (mRR) and the standard deviation of successive RR intervals (SDRR) were determined by time domain analysis, and high frequency (HF), low frequency (LF), and total power (TP) spectral components of RR variability were calculated by frequency domain analysis. Holter monitoring was also performed at six and 12 months after cardiac surgery in the Maze group. Results Circadian variation (mean (SD)) in mRR (daytime to night time difference: 119 (60) v302 (143) ms), SDRR (daytime: 8.4 (3.3) v37.0 (12.0) ms), TP (daytime: 46.7 (16.0) v171.8 (30.4) ms), HF (daytime: 19.6 (9.9) v36.7 (7.1) ms2), and LF/HF (daytime: 0.31 (0.07)v 1.18 (0.46)) was decreased in the Maze group at one month compared with the control group (p < 0.01), but showed improvement at six and 12 months (p < 0.05). Conclusions Surgery combined with the Maze procedure markedly suppressed the circadian variation of heart rate over a 24 hour period within one month after surgery, mainly because of damage to the innervation of the sinus node. However, at six and 12 months there was restoration of circadian variation, probably as the result of reinnervation of the sinus node.

Ventricular tachycardia in a patient with cardiac lipoma.

These images demonstrate ventricular tachycardia (VT) associated with cardiac lipoma in the left ventricle. A 22-year-old man suffered from an attack t)f palpitations and faintness, for which he was admitted to our hospital. He was found to have regular tachycardia at a rate of 230/min. The tachycardia was terminated by lidocaine. Echocardiography and cardiac catheterization revealed a large mass in the left ventricle beneath the mitral valve.

Morning increase in hemodynamic response to exercise in patients with angina pectoris

SummaryThe present study was conducted to determine whether or not there is diurnal variation in the hemodynamic responses to stimuli that increase myocardial oxygen demand, and the effects of such variation on electrocardiograms (ECG). Fifteen patients with angina pectoris, 17 patients with old myocardial infarction, and 8 healthy controls were examined in this study. Graded exercise stress testing was conducted in the supine position, once in the morning and once in the afternoon, using a bicycle ergometer. A standard 12-lead ECG was recorded before, immediately after, and 3, 5, and 10 min after the end of the exercise. The exercise ECG and blood pressure changes were compared among the groups and, within each group, the results after morning and afternoon exercise were compared. Hemodynamic responses, including heart rate, blood pressure, and the pressure-rate product, showed greater increases in the morning than in the afternoon in angina patients and controls, in association with greater depression of the electrocardiographic ST-segment. In contrast, patients with old myocardial infarction exhibited no difference in hemodynamic responses or the ST-pattern from morning to afternoon. The results suggest that diurnal variation of hemodynamic responses to increased oxygen demand may explain, at least partly, why myocardial ischemia of effort angina is more severe in the morning than in the afternoon.

Effects of Myocardial Perfusion on QT Dispersion in Patients with Hypertrophic Cardiomyopathy

Background:In patients with hypertrophic cardiomyopathy (HCM), myocardial ischemia and myocardial fibrosis as well as ventricular tachyarrhythmia are frequently observed. An increase of heterogeneity of repolarization provided the development of ventricular tachyarrhythmia. The aims of the present study are to evaluate the influence of exercise‐induced myocardial perfusion abnormalities on QT dispersion and to assess whether QT dispersion was involved in ventricular tachycardia (VT) in patients with HCM.