Tomohiko Sakatani

Chronotropic incompetence and autonomic dysfunction in patients without structural heart disease.

AIMSnAn attenuated heart rate response to exercise, termed chronotropic incompetence (CI), has been reported to be an independent predictor of cardiovascular mortality. We examined the change in autonomic function during exercise testing and correlated the results with CI.nnnMETHODS AND RESULTSnExercise testing using a bicycle ergometer was performed in 172 patients who had no evidence of cardiac disease. Chronotropic incompetence was defined as the failure to achieve 85% of the age-predicted maximum heart rate, heart rate reserve <80%, or chronotropic response index <0.80. We analysed the relationship between CI and the change in two components of heart rate variability during exercise testing: high-frequency (HF) component (0.15-0.40 Hz) as an index of vagal modulation and the ratio of low-frequency (LF) component (0.04-0.15 Hz) to HF component as an index of sympathovagal balance. Heart rate variability indexes before exercise were similar in patients with and without CI. Percentage changes after exercise in the ratio of LF to HF component were higher in patients with CI than in those without CI (84 +/- 15 vs. 41 +/- 16%, P < 0.05), whereas percentage changes in an HF component were similar in the two groups.nnnCONCLUSIONnOur data suggested that CI in patients without structural heart disease was mainly caused by a pathophysiological condition in which sympathetic activation was not well translated into heart rate increase. Further study is needed to determine the post-synaptic sensitivity of the beta-adrenergic receptor pathway in relation to CI.

Clinical implications of coronary pressure measurement after stent implantation

This study investigated the effect of fractional flow reserve (FFR) after stent implantation on clinical outcomes. Pressurewire measurements and follow-up data were obtained after stent implantation. Regarding the end point, target lesion revascularization (TLR) occurred in 11 patients (15.9xa0%). Patients with TLR had higher frequencies of multiple stenting (54.5 vs. 19.0xa0%, pxa0=xa00.01), lower post-interventional FFRs (0.84 vs. 0.88, pxa0=xa00.01), and longer stent lengths (42.20 vs. 27.69xa0mm, pxa0=xa00.01) than patients without TLR. The post-interventional FFR cutoff for TLR was 0.79, although this value had a weak discriminatory ability. However, multivariate analysis did not show any significant independent predictors of TLR (odds ratio 6.33; confidence interval 0.75–53.4, pxa0=xa00.09). Post-interventional FFR values were not significantly associated with TLR when a sub-analysis was performed in patients who underwent only drug-eluting stent (DES) implantation. It was difficult to achieve post-interventional FFRs of 0.9 or greater. DES implantation eliminated the effect of post-interventional FFR on TLR. Post-interventional FFR was not able to predict TLR in the present study.

Importance of measuring the fractional flow reserve in patients receiving hemodialysis.

Angiography is not always an accurate indicator of physiologically significant stenosis. We examined the usefulness of functional evaluation of coronary stenosis severity by determining the fractional flow reserve (FFR) using a pressure wire in patients who received hemodialysis with angiographically intermediate lesions. We recruited 44 patients with intermediate lesions; of these, 22 were undergoing hemodialysis while 22 were not. Quantitative coronary angiography (QCA) was performed to measure the minimal lumen diameter (MLD) and calculate the percent diameter stenosis (%DS). The FFR was calculated as the ratio of the coronary pressure at the distal stenotic site to the mean aortic pressure during maximum hyperemia. In each group, we investigated the relationship between the FFR and %DS and FFR and MLD. The patients in the hemodialysis group were significantly younger and had more calcified and type B2/C lesions than those in the non-dialysis group. Although the FFR was correlated with both %DS (rxa0=xa00.71, pxa0<xa00.01) and MLD (rxa0=xa00.58, pxa0<xa00.01) in the non-dialysis group, the FFR was not correlated with either MLD or %DS in the hemodialysis group. In the hemodialysis group, there was a discordance between the QCA- and FFR-based assessments of the severity of coronary stenosis. In patients receiving hemodialysis, both anatomical and functional assessments should be conducted to determine the physiological significance of the stenosis accurately.

573 Antihypertensive efficacy and safety of Losartan/hydrochlorothiazide vs. high-dose angiotensin receptor blocker (ARB) in patients with uncontrolled hypertension: Kamanza Anti-Hypertensive Treatment Trial (KAHT-Trial)

Objectives: According to the current guidelines, archiving strict blood pressure control is essential to reduce cardiovascular events in patients with hypertension. The aim of this study was to evaluate antihypertensive efficacy and safety of losartan/hydrochlorothiazide (Los/HCTZ) combination drug vs. high-dose angiotensin receptor blocker (ARB) in patients with uncontrolled hypertension. Methods: This study was conducted at 11 centers for the KAHT-Trial group. A total of 65 hypertensive patients receiving regular-dose ARB therapy whose BP remained above 140/90 mmHg were prospectively enrolled. The patients were randomly assigned to receive Los/HCTZ combination drug (Los/HTCZ group, n = 67) or high-dose ARB (high-dose ARB group, n = 68) and followed for 1year. Results: After 3 months of treatment, BP significantly decreased from 157 ± 12/87 ± 9 mmHg to 137 ± 14/78 ± 8 mmHg in the Los/HCTZ group and from 158 ± 12 /91 ± 12 mmHg to 139 ± 12/80 ± 8 mmHg in the high-dose ARB group. Decreases in BP were well-maintained for 1year in the both groups. However, decreases in BP were not different between the two groups. After 1 year of treatment, levels of HbA1c, eGFR, plasma glucose, cholesterol and uric acid showed no significant changes in the both groups. Conclusions: Our results suggest that Los/HCTZ combined therapy was effective in reducing uncontrolled hypertension without deteriorating glucose, lipid and uric acid metabolism as well as high-dose ARB. Los/HCTZ combined therapy may have beneficial effect in terms of tolerability and medical economics.

Prognostic Value of Plasma Aldosterone Levels on the Future Risk of New-Onset Atrial Fibrillation

Background: Renin-angiotensin-aldosterone system has been reported as one of the risk factors of atrial fibrillation (Af). However, roles of aldosterone (ALD) and predictor of new-onset Af are still unclear. We therefore evaluated predictive value of plasma ALD levels on the incidence of Af. Methods: The levels of plasma ALD were quantified in a prospective cohort study of 796 consecutive outpatient clinic patients initially free from Af (age 68.5±12.6). The subjects were divided into two groups of elevated ALD group (group H) and non-elevated ALD group (group L) according to the median value of baseline plasma ALD. The end point of the study was new-onset Af. Results: The median value of baseline ALD was 89.0 pg/mL in all patients. During a median follow-up of 941 days, incidence of new-onset Af was 7.5%. Patients of group H had a significantly higher Af incidence rates, as compared to those of group L (12.5% vs. 2.5%, P<0.0001). Elevated ALD were independent predictor of increased future incident Af risk in Cox regression analyses adjusted for age, sex, body mass index, C-reactive protein and brain natriuretic peptide. The adjusted hazard ratio was 3.691 (95% CI, 1.962–6.942; P<0.0001). Conclusions: In Japanese patients without Af, higher ALD was independent predictor of developing Af.

A case report: 201Tl/99mTc-Pyrophosphate dual-isotope myocardial SPECT for detecting annular subendocardial infarction induced by a transient shock

The patient was a 74-year-old woman with angina pectoris, who had undergone percutaneous coronary intervention with stent placement in the right coronary artery on October 2, 2007. On November 12 of the same year, she suffered from paroxysmal atrial fibrillation. She was treated with pilsicainide hydrochloride administered by intravenous injection, which was followed by a sudden sinus standstill, with marked bradycardia and a shock state. The patient was then treated with a catecholamine, however, the shock state persisted for about an hour. An electrocardiogram revealed persistent ST depression in leads V4-6 along with elevation of the serum creatinine kinase. A coronary angiography performed on the admission day revealed no abnormality. On the third hospital day, a dual-isotope myocardial SPECT using 201Tl and 99mTc-pyrophosphate demonstrated an annular accumulation of 99mTc-pyrophosphate concordant with the endocardium from apex to the mid-portion of the left ventricle, suggestive of subendocardial infarction. The case is reported here, as there are few reports of subendocardial infarction developing due to ischemia arising from a shock state.