Potential efficacy of multipoint pacing in the reduction of mitral regurgitation volume: a case report.

A 70-year-old woman who had cardiac sarcoidosis and severe tethering mitral regurgitation (MR) and had been implanted with a biventricular pacemaker experienced recurrent hospitalisation due to decompensated heart failure (HF). Application of MultiPoint™ pacing reduced the MR volume and maintained the symptoms under control; however, the predicted longevity of the device significantly decreased because of the very high threshold of the added pacing site. Transcatheter mitral valve repair (TMVR) using MitraClip® was performed to further diminish the severe MR, thereby enabling the switch from highly consumptive multipoint pacing (MPP) to energy-saving single-point pacing. MPP could further reduce MR compared to the conventional single-point pacing, and this could be a bridging therapy to TMVR in some patients implanted with a biventricular pacemaker. This is the first case to report that switching from conventional single-point pacing to MPP decreased the MR, to some extent, resulting in the improvement of HF symptoms.

Acute Heart Failure in an Almost-Centenarian Patient With Symptomatic Severe Aortic Stenosis Treated With Ivabradine.

We report the case of a 99-year-old woman with acute chest pain caused by myocardial ischemia due to severe aortic stenosis (AS) and severe anemia. Red blood cells were transfused; however, this increased the preload and worsened pulmonary congestion. Treatment with drugs and non-invasive positive pressure ventilation could not sufficiently improve the pulmonary congestion. Ivabradine was administered to control the resting heart rate, following which the pulmonary congestion significantly improved. Ivabradine is a promising drug for acute heart failure of patients with AS by improving cardiac output by prolonging the left ventricular diastolic filling time without a negative inotropic effect.

Heterogeneous expression of connexin 43 in the myocardium of rabbit right ventricular outflow tract.

The right ventricular outflow tract (RVOT) has been demonstrated as an important focus in idiopathic ventricular arrhythmias. However, the role of the gap junction in this region in arrhythmic events has not been fully investigated. The purpose of this study was to evaluate the expression and distribution of the gap junction protein connexin 43 (Cx43) in the myocardium of the RVOT area of normal adult rabbits. Tissue samples were obtained from 6 regions of normal rabbit heart, i.e. the left ventricle (LV) free wall, the LV papillary muscle, the RVOT free wall, and the RVOT septum which was subdivided into the RV side, the central layer, and the LV side. Immunohistochemical analysis was performed to investigate the characteristics of Cx43 distribution in the RVOT area. In the LV free wall and papillary muscle, Cx43 was abundantly, homogeneously, and approximately equally expressed in end-to-end- and side-to-side intercellular connections. In the free wall of the RVOT, Cx43 expression was poor compared to both these LV regions and side-to-side cell connections were predominant. Cx43 was as richly and homogeneously distributed in the central layer and LV side of the RVOT septum as in the two LV regions. However, in the RV side of the RVOT septum, its distribution was scant and an unstained area was noted. The heterogeneous expression of Cx43 in the RVOT area may serve as substrate for idiopathic ventricular arrhythmia.

Patients with mild hypertensive heart disease and left ventricular outflow tract obstruction: treatment with angiotensin II antagonists.

Systolic anterior motion of the mitral leaflet (SAM) combined with obstruction at the left ventricular (LV) outflow tract is often observed on echocardiography in elderly hypertensive patients with severe concentric LV hypertrophy. We experienced, however, two patients with mild hypertension who had an ejection systolic murmur, SAM, and LV outflow tract obstruction with a pressure gradient of 46 and 45 mmHg, respectively, despite very mild symmetric hypertrophy of LV wall (12 mm) by echocardiography. Treatment with angiotensin II type 1 receptor blocker improved intraventricular obstruction and LV hypertrophy in both patients. Left ventricular outflow tract obstruction should be suspected in hypertensive patients with mild LV hypertrophy, particularly in those with an ejection systolic murmur. Angiotensin II antagonists could be considered as the treatment of choice for such patients.

Characteristics of new-onset ventricular arrhythmias in pregnancy.

The characteristics and underlying mechanisms of new-onset ventricular arrhythmia during pregnancy have not been adequately investigated. We studied 11 pregnant women aged 35.4 +/- 3.1 years who experienced new-onset ventricular arrhythmias during pregnancy. The onset of their first episode of ventricular arrhythmia was distributed equally over the 3 trimesters. Ventricular premature contractions (VPCs) and ventricular tachycardia (VT) exhibited a monomorphic configuration in all patients; in 8 (73%) they originated from the right ventricular outflow tract. The frequency of VPCs decreased by more than 95% in 83% of the patients; couplets and VTs disappeared completely in all patients during the postpartum period. All parameters of heart rate variability were significantly lower during pregnancy than postpartum (P < .05). QT and QTc intervals were normal during pregnancy in all patients. The slope and the intersect of the QT/RR relationship obtained from Holter ECGs were not significantly different during pregnancy and in the postpartum period. New-onset ventricular arrhythmias in pregnancy manifest characteristics similar to those of idiopathic VT. Our findings suggest that various hemodynamic and neurohormonal changes associated with pregnancy play an important role in ventricular arrhythmogenesis.

Dynamics of T-U wave in patients with idiopathic ventricular tachycardia originating from the right ventricular outflow tract.

Postextrasystolic U wave augmentation is observed in patients with long QT syndrome and those with organic heart disease. This phenomenon is considered a marker of increased risk of arrhythmia. However, the characteristics of the U wave have not been evaluated in patients with idiopathic VT originating from the right ventricular outflow tract (RVOT-VT). The present study evaluated the dynamic change in the T-U wave in patients with RVOT-VT. Holter ECGs obtained from 14 patients with RVOT-VT and 11 healthy control subjects were analyzed. The amplitude of T and U waves (Tamp and Uamp) and preceding RR intervals were measured during stable sinus rhythm (rate dependent change) and in the postextrasystolic sinus complex (pause dependent change). Uamp correlated negatively and significantly with the preceding RR interval in 13 (93%) RVOT-VT patients but in only 2 (18%) control subjects. The average value of the slope of the Uamp/RR relationship was negative (-0.22 +/- 0.10 mV/s) in the RVOT-VT group, but was positive (0.04 +/- 0.07 mV/s, P < 0.001) in the control group. Pause dependent U wave augmentation was observed in 12 (86%) of 14 patients. Increased frequency of consecutive preceding premature ventricular contractions (PVCs) was associated with a larger postextrasystolic Uamp. PVC or the first ventricular beat of VT arose from near the peak of augmented U waves. The dynamic changes in the T-U wave were observed in patients with RVOT-VT. Further investigations are required to elucidate the precise role of the U wave in arrhythmogenesis in those patients.

Gender differences in ventricular repolarization: terminal T wave interval was shorter in women than in men.

The incidence of sudden death is lower in women than in men, although women have a longer QT interval and are more prone to develop torsades de points than men. It has been recently proposed that the time interval between the apex and end of the T wave (Ta-e) represents the transmural dispersion of ventricular repolarization. Gender and age differences in Ta-e interval have not been fully assessed previously. Standard surface 12-lead ECGs recorded in 760 healthy subjects (382 women, 0-88 years of age) were studied. The intervals from j-point to the apex of the T wave (JaT) and to the end of the T wave (JeT) were measured in lead V5 in each ECG and corrected by preceding RR intervals using the formula of Bazett (JaTc and JeTc). The Ta-e and Ta-e/JeT ratio were also evaluated. Both JaTc and JeTc intervals were significantly longer in women aged > 20 years than in men of the same age (P < 0.0001). The difference was due to shortening of these intervals after puberty in men. However, the Ta-e interval was significantly shorter in women than in men (P < 0.05) and subsequently the Ta-e/JeT ratio was significantly smaller in women than in men (P < 0.0001). The results showed gender differences in the Ta-e interval and JaTc and JeTc intervals in healthy adults, and suggest that the small transmural dispersion of repolarization in women, in spite of the long JaTc and JeTc intervals, might be a beneficial antiarrhythmic property.

Gender differences in various types of idiopathic ventricular tachycardia.

INTRODUCTION: The aim of this study was to evaluate gender differences in the incidence and age distribution of various types of idiopathic ventricular tachycardia (VT). METHODS AND RESULTS: We conducted a search of the medical literature on idiopathic VT. According to their site of origin, we divided the VTs into three types: right ventricular outflow tract (RVOT-VT), left ventricular outflow tract (LVOT-VT), and left ventricular (LV) septum (LV-VT). We reviewed 68 articles and a total of 748 patients. Among RVOT-VT patients, there were more females than males (311 vs 153, male/female ratio 0.49). In LV-VT, males prevailed over females (175 vs 52, male/female ratio 3.37), whereas LVOT-VT was distributed almost equally between males (n = 33) and females (n = 24). To determine the age distribution, we assessed 419 patients from 51 studies. In both males and females, the highest incidence of RVOT-VT occurred in the third to fifth decade of life (males, mean 43.5 +/- 18.7; females, mean 40.9 +/- 13.8 years). LV-VT occurred at a younger age in both males and females than did RVOT-VT (mean 33.0 +/- 13.9 and 25.7 +/- 12.0 years, respectively, P < 0.0001 vs RVOT-VT). LV-VT occurred at a younger age in females than males (P < 0.005). CONCLUSION: Gender-specific differences exist in the incidence and age distribution of the various types of idiopathic VT. Studies on gender-specific differences in arrhythmia will lead to a better understanding of its mechanism(s) and provide valuable information for the development of optimal treatment strategies.

Circadian variation of short-lasting asymptomatic paroxysmal supraventricular tachycardia.

This study determines the circadian variation of transient asymptomatic paroxysmal supraventricular tachycardia (PSVT). A total of 416 asymptomatic PSVT episodes (> or = 10 consecutive supraventricular beats) recorded in 62 patients were obtained from Holter monitoring. The incidence of the onset of PSVT was counted at the 1-hour interval. The duration (beats) and rate (beats/min) of PSVT and the preceding heart rate were also evaluated. The circadian variations of the onset, duration, and rate of PSVT were analyzed by the single cosinor method. The incidence of the onset of PSVT showed a significant circadian variation (P = .001); with high incidence in the daytime and low at nighttime. The rate and duration of PSVT also showed significant circadian variation (P = .02), faster and longer in daytime and slower and shorter at night, respectively. The rate (r = .45, P < .001) and duration (r = .22, P < .001) of PSVT correlated significantly with the preceding heart rate. Our findings suggest that the onset and persistence of short-lasting asymptomatic PSVT exhibit a circadian pattern and that autonomic tone might play an important role in the genesis of this form of PSVT.