-
[show abstract]
[hide abstract]
ABSTRACT: Background: The aim of this study was to carry out 3-dimensional speckle tracking imaging (3DSTI) of the right ventricle (RV) and evaluate RV regional wall deformation. Methods and Results: 3DSTI of the RV was performed in 35 normal subjects, 8 patients with arrhythmogenic right ventricular cardiomyopathy, and 8 patients with pulmonary arterial hypertension. Peak systolic area change ratio and regional contraction timing relative to global systolic time (time to peak strain/time to end-systole×100) were measured in each segment. Good-quality images were acquired of the inflow segment in 87%, apex in 87%, outflow in 57%, and septum in 94% of the 35 normal subjects. In normal subjects, peak systolic area change ratio of the inflow anterior wall was -41±14%; inflow inferior wall, -35±9%; apical anterior wall, -41±10%; apical inferior wall, -31±11%; outflow, -31±9%; and septum wall, -36±11%. Contraction timing of the apical anterior wall and septum wall were earlier than those of other segments. In patients with RV dysfunction, 3DSTI indicated low peak systolic area change ratio in the damaged area. Conclusions: RV 3DSTI indicated segmental heterogeneity in magnitude and timing of RV contraction. 3DSTI may be a promising modality for providing precise quantitative information on complex RV wall motion.
Circulation Journal 04/2013; · 3.77 Impact Factor
-
Tomoko Machino-Ohtsuka, Yoshihiro Seo,
Tomoko Ishizu,
Satomi Yanaka,
Hideki Nakajima,
Akiko Atsumi,
Masayoshi Yamamoto,
Ryo Kawamura,
Yuki Koshino,
Takeshi Machino,
Kenji Kuroki,
Hiro Yamasaki,
Miyako Igarashi,
Yukio Sekiguchi,
Hiroshi Tada,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: Background: The long-term effects of catheter ablation (CA) on the left atrium and left atrial appendage (LAA) are unknown in persistent atrial fibrillation (AF). This study investigated left atrial (LA) reverse remodeling and evolution of LA/LAA function after successful CA for persistent AF and identified predictors for maintenance of sinus rhythm (SR) and LA reverse remodeling. Methods and Results: CA was performed in 123 patients with persistent AF. LA volumes, LA strain and LAA wall velocity were assessed both at baseline and at 12 months after ablation. Patients who maintained SR were divided into 2 groups according to whether LA volume decreased by ≥15% at follow-up (responders) or not (non-responders). During a follow-up period of 18±2 months, AF recurred in 45 patients (37%). Of the remaining 78 patients (63%) without recurrent AF, 62 patients (79%) were classified as responders. LA/LAA function significantly improved and the prevalence of spontaneous echo contrast decreased only in responders at follow-up. LA systolic strain and LAA wall velocity were independent predictors of both maintenance of SR (odds ratio [OR], 2.57; P=0.003; OR, 3.02; P=0.002, respectively) and LA reverse remodeling (OR, 4.44; P=0.007; OR, 3.52; P=0.01, respectively). Conclusions: Successful CA is associated with LA reverse remodeling and LA/LAA functional recovery in patients with persistent AF. LA systolic strain and LAA wall velocity at baseline predicted both maintenance of SR and LA reverse remodeling.
Circulation Journal 03/2013; · 3.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND: Recent advances in very high frame rate use of ultrasonography have enabled the application of two-dimensional speckle-tracking echocardiography (STE) to small animal cardiac functional assessments. In this study, two-dimensional STE was applied to a rat model of hypertensive heart failure with preserved ejection fraction to clarify consequences of left ventricular (LV) wall deformation in the progression of heart failure with preserved ejection fraction. METHODS: STE was performed every 2 weeks in Dahl salt-sensitive rats fed a 0.3% (control group) or 8% (hypertension [HT] group) sodium chloride diet from 6 to 14 weeks of age. Longitudinal, radial, and circumferential global strain and strain rate were measured, and the time courses of these parameters were observed. RESULTS: Deterioration of longitudinal strain occurred in the early phase of the progression of LV hypertrophy and continued to worsen until congestive heart failure developed (longitudinal strain in the HT group: 25 ± 3% at 10 weeks, 21 ± 4% at 12 weeks, and 18 ± 2% at 14 weeks; longitudinal strain in controls was preserved during the experimental period). At 12 weeks, radial strain (HT group, 35 ± 7%; controls, 41 ± 10%) had deteriorated at the late stage of manifest diastolic dysfunction. Throughout the experiments, circumferential strain was preserved (HT group, 35 ± 6%; control group, 35 ± 5%), and no significant increase in short-axis function was observed. CONCLUSIONS: STE is applicable to the small animal heart and detected LV wall long-axis dysfunction preceding short-axis dysfunction or overt congestive heart failure in the progression of hypertensive LV hypertrophy in a rat model.
Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 01/2013; · 2.98 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: AIMS: Recently developed vector flow mapping (VFM) enables evaluation of local flow dynamics without angle dependency. This study used VFM to evaluate quantitatively the index of intraventricular haemodynamic kinetic energy in patients with left ventricular (LV) diastolic dysfunction and to compare those with normal subjects. METHODS AND RESULTS: We studied 25 patients with estimated high left atrial (LA) pressure (pseudonormal: PN group) and 36 normal subjects (control group). Left ventricle was divided into basal, mid, and apical segments. Intraventricular haemodynamic energy was evaluated in the dimension of speed, and it was defined as the kinetic energy index. We calculated this index and created time-energy index curves. The time interval from electrocardiogram (ECG) R wave to peak index was measured, and time differences of the peak index between basal and other segments were defined as ΔT-mid and ΔT-apex. In both groups, early diastolic peak kinetic energy index in mid and apical segments was significantly lower than that in the basal segment. Time to peak index did not differ in apex, mid, and basal segments in the control group but was significantly longer in the apex than that in the basal segment in the PN group. ΔT-mid and ΔT-apex were significantly larger in the PN group than the control group. Multiple regression analysis showed sphericity index, E/E' to be significant independent variables determining ΔT apex. CONCLUSION: Retarded apical kinetic energy fluid dynamics were detected using VFM and were closely associated with LV spherical remodelling in patients with high LA pressure.
European heart journal cardiovascular Imaging. 07/2012;
-
Kenji Kuroki,
Hiroshi Tada, Yoshihiro Seo,
Tomoko Ishizu,
Masayuki Igawa,
Hiro Yamasaki,
Miyako Igarashi,
Takeshi Machino,
Yoshihisa Naruse,
Yukio Sekiguchi,
Nobuyuki Murakoshi,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: Aim Frequent ventricular premature contractions (VPCs) may cause haemodynamic deterioration and reversible left ventricular (LV) dysfunction. We aimed to clarify this mechanism. METHODS AND RESULTS: The haemodynamics, echocardiographic parameters, and plasma brain natriuretic peptide (BNP) level were assessed in 31 patients with idiopathic, frequent VPCs undergoing radiofrequency catheter ablation. The patients were classified into two groups according to the presence (n = 19) or absence (n = 12) of marked augmentation of the pulmonary capillary wedge pressure (PCWP) following VPCs (VPC-induced-PCWP augmentation; VI-PA). The VI-PA(+) group was defined as those with a peak PCWP of >15 mmHg measured after a VPC. Before the ablation, the mean PCWP, right atrial pressure (RAP), left ventricular end-diastolic pressure (LVEDP), and plasma BNP level were significantly greater in the VI-PA(+) group than in the VI-PA(-) group. In the VI-PA(+) group, the mean PCWP, RAP, LVEDP, and cardiac index all improved immediately after a successful ablation. At 7.4 ±0.9 months after the ablation, almost all the echocardiographic parameters and plasma BNP level also significantly improved in the VI-PA(+) group, and the magnitude of the improvement in those parameters measured was greater in the VI-PA(+) group than in the VI-PA(-) group. The left atrial contractions during mitral valve closure during VPCs caused a marked pulmonary venous flow regurgitation and VI-PA. VPC coupling intervals of <500 ms and the presence of a following P-wave of <300 ms predicted VI-PAs with a high accuracy. CONCLUSIONS: The VI-PA may be the main mechanism of the haemodynamic deterioration in patients with frequent VPCs. This haemodynamically deteriorating subgroup could be identified by the surface electrocardiogram and improved dramatically with catheter ablation.
European Journal of Heart Failure 06/2012; 14(10):1112-20. · 4.90 Impact Factor
-
Kentaro Yoshida,
Hiroshi Tada,
Kuniomi Ogata,
Yukio Sekiguchi,
Takeshi Inaba,
Yoko Ito,
Yoko Sato,
Akira Sato, Yoshihiro Seo,
Akihiko Kandori,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND: Despite the informative nature of atrial fibrillation (AF) electrograms, electrophysiological aspects of predicting reversal of structural remodeling of the left atrium (LA) have not been evaluated. OBJECTIVES: To identify predictors of reverse remodeling after restoration of sinus rhythm by catheter ablation in patients with persistent AF. METHODS: This study included 90 patients with persistent AF and enlarged LA (left atrial volume indexed to body surface area [LAVi] ≥32 mL/m(2)). LAVi was measured by echocardiography before ablation and 12 months after sinus rhythm restoration. We divided 73 (81%) patients free from recurrences into 2 groups according to reduction in LAVi: responders, reduction ≥23% (n = 35); nonresponders, reduction <23% (n = 38). Serological testing and electrophysiological characteristics on electrocardiogram and magnetocardiogram were analyzed. RESULTS: LAVi decreased from 43 ± 12 to 27 ± 7 mL/m(2) in responders and from 37 ± 8 to 33 ± 8 mL/m(2) in nonresponders. Higher LAVi at baseline (P = .01), lower age (59 ± 7 years vs 63 ± 7 years; P <.05), higher brain natriuretic peptide level (median = 92, interquartile range [IQR] = 98 pg/mL vs median = 60, IQR = 64 pg/mL; P = 0.01), higher atrial natriuretic peptide level (median = 73, IQR = 74 pg/mL vs median = 54, IQR = 70 pg/mL; P = .02), and higher organization index of AF signals (0.51 ± 0.11 vs 0.42 ± 0.09; P = .0001) were observed in responders. There was a linear correlation between organization index and % reduction in LAVi (R = 0.63; P <.0001). Multiple linear regression analysis showed relations between reverse remodeling and age (η = -0.28; P = .002), atrial natriuretic peptide level (η = 0.21; P = .03), and organization index (η = 0.53; P <.0001). CONCLUSIONS: Electrogram organization was a robust predictor of reverse remodeling of the enlarged LA after sinus rhythm restoration by catheter ablation in patients with persistent AF.
Heart rhythm: the official journal of the Heart Rhythm Society 06/2012; · 4.56 Impact Factor
-
Hiroaki Watabe,
Akira Sato,
Daiki Akiyama,
Yuki Kakefuda,
Toru Adachi,
Eiji Ojima,
Tomoya Hoshi,
Nobuyuki Murakoshi,
Tomoko Ishizu, Yoshihiro Seo,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: The authors used multidetector computed tomography (MDCT) to study the relation between culprit plaque characteristics and cardiac troponin T (cTnT) elevation after percutaneous coronary intervention (PCI).
Percutaneous coronary intervention is often complicated by post-procedural myocardial necrosis manifested by elevated cardiac biomarkers.
Stable angina patients (n = 107) with normal pre-PCI cTnT levels underwent 64-slice MDCT before PCI to evaluate plaque characteristics of culprit lesions. Patients were divided into 2 groups according to presence (group I, n = 36) or absence (group II, n = 71) of post-PCI cTnT elevation ≥3 times the upper limit of normal (0.010 ng/ml) at 24 h after PCI.
Computed tomography attenuation values were significantly lower in group I than in group II (43.0 [26.5 to 75.7] HU vs. 94.0 [65.0 to 109.0] HU, p < 0.001). Remodeling index was significantly greater in group I than in group II (1.20 ± 0.18 vs. 1.04 ± 0.15, p < 0.001). Spotty calcification was observed significantly more frequently in group I than in group II (50% vs. 11%, p < 0.001). Multivariate analysis showed presence of positive remodeling (remodeling index >1.05; odds ratio: 4.54; 95% confidence interval: 1.36 to 15.9; p = 0.014) and spotty calcification (odds ratio: 4.27; 95% confidence interval: 1.30 to 14.8; p = 0.016) were statistically significant independent predictors for cTnT elevation. For prediction of cTnT elevation, the presence of all 3 variables (CT attenuation value <55 HU; remodeling index >1.05, and spotty calcification) showed a high positive predictive value of 94%, and their absence showed a high negative predictive value of 90%.
MDCT may be useful in detecting which lesions are at high risk for myocardial necrosis after PCI.
Journal of the American College of Cardiology 05/2012; 59(21):1881-8. · 14.16 Impact Factor
-
Kiyoko Uno, Yoshihiro Seo,
Tomoko Ishizu,
Takeshi Inaba,
Fumiko Sakamaki,
Noriko Iida,
Hideki Nakajima,
Yasuyuki Oyake,
Sadanori Ohtsuka,
Yumiko Tanaka,
Manabu Minami,
Shigeyuki Watanabe,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: BackgroundThe left atrial volume (LAV) is an important indicator of the severity of certain diseases, and measuring LAV through the
cardiac cycle may enable the evaluation of various left atrium (LA) functional parameters. The results of two-dimensional
(2D) echocardiographic LAV measurement methods vary, and no technique is accepted as being optimal.
ObjectiveThis study compared the accuracy of end-systolic and end-diastolic LAV measurements by 2D echocardiography with those obtained
by magnetic resonance imaging (MRI).
MethodsFifty consecutive patients who underwent both echocardiography and MRI due to clinical reasons with nonselective cardiac disease
were studied. LAVs by 2D echocardiography were obtained with the prolate ellipsoid (PE), biplane area-length (AL), and modified
Simpson’s (MS) methods.
ResultsEnd-systolic and end-diastolic LAVs calculated by each method correlated significantly with MRI results (P<0.0001). The prolate ellipsoid method provided LAVs that most correlated with MRI results, and the biplane area-length
and modified Simpson’s methods provided LAVs with small mean differences (<5ml) compared to MRI results.
ConclusionAll three methods of 2D echocardiographic LAV measurement provide valuable LAV data, suggesting the possibility of evaluating
various LA functional parameters.
KeywordsLeft atrial volume-2D echocardiography-Magnetic resonance imaging
Journal of Echocardiography 04/2012; 8(2):52-58.
-
Yoko Sato,
Kentaro Yoshida,
Kuniomi Ogata,
Takeshi Inaba,
Hiroshi Tada,
Yukio Sekiguchi,
Yoko Ito,
Tomoko Ishizu, Yoshihiro Seo,
Iwao Yamaguchi,
Akihiko Kandori,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: Differences in electrical properties between left and right atria (LA and RA) after pulmonary vein isolation (PVI) for atrial fibrillation (AF) are currently poorly understood. Magnetocardiograms were used to investigate the effect of PVI on bi-atrial magnetic field changes and their relationship to clinical outcomes.
This study included 71 patients undergoing PVI for paroxysmal AF. Magnetocardiograms were recorded at baseline and 1 day, 8 weeks, and 24 weeks after ablation. Peak magnitude of LA and RA segments on P waves was separately compared before and after PVI. During a 16-month post-ablation period, 53 (75%) patients were free from AF recurrences. LA magnetic strength in patients without recurrence persistently decreased for 24 weeks and was significantly lower at 8 weeks than that in patients with recurrence (1.28±0.69 vs. 1.74±0.71 pico-Tesla, P=0.02). RA magnetic strength in patients with recurrence persistently rose for 24 weeks and was significantly higher at 8 weeks than that in patients without recurrence (2.17±0.82 vs. 3.00±1.12 pico-Tesla, P=0.001). Multivariate analysis showed RA magnetic strength at 8 weeks to be the strongest predictor of AF recurrence (odds ratio=3.335; 95% confidence interval=1.181-9.416; P=0.02).
PVI resulted in distinct changes in magnetic strength in both the LA and the RA. A persistent rise in RA magnetic strength might be a robust predictor of AF recurrence after ablation.
Circulation Journal 04/2012; 76(7):1601-8. · 3.77 Impact Factor
-
Noriko Iida, Yoshihiro Seo,
Tomoko Ishizu,
Hideki Nakajima,
Akiko Atsumi,
Masayoshi Yamamoto,
Tomoko Machino-Ohtsuka,
Ryo Kawamura,
Mami Enomoto,
Yasushi Kawakami,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: In patients with chronic aortic regurgitation (AR), systolic wall stress and volume overload affects left ventricular (LV) systolic function and remodeling. The aim of this study was to assess transmural rearrangements of myocardial deformation to preserve LV ejection performances using speckle-tracking echocardiography in patients with chronic AR.
Ninety patients with AR were enrolled. On LV short-axis images, total, inner, and outer radial strain and circumferential strain at the inner, mid, and outer layers were calculated. On apical four-chamber images, endocardial longitudinal strain was calculated. End-systolic wall stresses were calculated using previous methods.
AR severities were classified as moderate in 31 patients, severe and preserved LV ejection fraction (LVEF) (≥50%) in 42 patients, and severe and reduced LVEF (<50%) in 17 patients. Longitudinal strain was decreased even in the moderate AR group, despite normal end-systolic wall stress. Inner radial strain progressively decreased with increasing end-systolic wall stress, whereas outer radial strain in the moderate and severe AR and preserved LVEF groups was higher than in the control group. Consequently, total radial strain was preserved even in the severe AR and preserved LVEF groups with increased end-systolic wall stress. Similarly, despite reduced inner circumferential strain, outer circumferential strain was higher in the severe AR and preserved LVEF group than in the control group. All strain parameters were lower in the severe AR and reduced LVEF group with dramatically increased end-systolic wall stress than in other groups.
Transmural strain analysis revealed that subendocardial dysfunction accompanied by increased wall thickening at the subepicardium may be a compensatory mechanism of wall thickening to preserve LVEF in patients with chronic AR.
Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 03/2012; 25(6):620-8. · 2.98 Impact Factor
-
Fumiko Sakamaki, Yoshihiro Seo,
Tomoko Ishizu,
Satomi Yanaka,
Akiko Atsumi,
Masayoshi Yamamoto,
Tomoko Machino-Ohtsuka,
Ryo Kawamura,
Hiro Yamasaki,
Miyako Igarashi,
Kentaro Yoshida,
Yukio Sekiguchi,
Hiroshi Tada,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: The aim of this study was to propose modified tissue Doppler imaging (TDI) parameters derived from the first active wall motion and to assess them for the better prediction of cardiac resynchronization therapy (CRT) responders in comparison with to original TDI parameters.
In 61 patients with CRT, time from QRS onset to peak velocities by TDI (Ts), which were derived from active wall motion identified by longitudinal strain rate (LSR) value, were assessed. Time from QRS onset to the negative peak of LSR (TLSR) was also assessed. Modified standard deviation of Ts in 12 left ventricular (LV) segments (Ts-SD), that of TLSR (TLSR-SD), differences of Ts between septum and lateral wall (Ts-SL), and that of TLSR (TLSR-SL) were calculated. Original Ts-SD and Ts-SL were calculated by previously described methods. Responders were defined as patients with LV end-systolic volume reduction (>15%) at 6 months after CRT: 35 patients (57%) were identified as CRT responders. Area under the receiver-operating characteristics curve (AUC) of modified Ts-SD (0.87) was significantly higher than that of Ts-SD (0.65), Ts-SL (0.62), and TLSR-SL (0.69). AUC of modified Ts-SL was significantly higher than those of Ts-SD, and Ts-SL. AUC of TLSR-SD (0.82) also was significantly higher than that of Ts-SD.
Modified TDI dyssynchrony parameters derived from the first active wall motion improve the ability to predict responders to CRT.
Circulation Journal 02/2012; 76(3):689-97. · 3.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The in vivo role of peroxisome proliferator-activated receptor (PPAR)-γ, an essential transcriptional mediator of lipid and glucose metabolism, in atrial fibrillation (AF) remains to be fully elucidated. We investigated the effects of pioglitazone, a PPAR-γ activator, in an in vivo AF rat model.
We studied 3 groups of Wistar rats: young group, 3-month-old rats treated with vehicle; aged group, 9-month-old rats treated with vehicle; and aged+Pio group, 9-month-old rats treated with pioglitazone. After 4-week treatment, AF duration induced by 30-second burst pacing, gene and protein expressions, and atrial structural changes were compared between the 3 groups. Atrial oxidant reducing activity was measured by electron spin resonance method. AF duration was markedly prolonged in the aged group but significantly shortened in the aged+Pio group. Age-induced decrease in free radical reducing activity was reversed by pioglitazone. Gene and protein expression levels of antioxidant molecules Sod2 (MnSOD) and Hspa1a (heat shock 70 protein) were significantly enhanced, and p22(phox) and gp91(phox), two NADPH oxidase subunits, were significantly decreased in aged+Pio rats. Pioglitazone treatment significantly increased phosphorylated (p-) Akt but significantly reduced p-ERK1/2 and p-JNK. Pioglitazone significantly restored p-Bad and reduced cleaved caspase-3 and -9, indicating that pioglitazone prevented age-related enhancement of apoptotic signaling. Microscopic analysis revealed suppression of age-related histological changes (interstitial fibrosis and apoptosis) by pioglitazone.
Pioglitazone inhibited age-related arrhythmogenic atrial remodeling and AF perpetuation by improving antioxidant capacity and inhibiting the mitochondrial apoptotic signaling pathway. PPAR-γ activators could become a novel upstream therapy for age-related AF.
Journal of Cardiovascular Electrophysiology 09/2011; 23(2):209-17. · 3.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cardiac resynchronization therapy defibrillator (CRT-D) devices are now capable of monitoring changes in intrathoracic impedance. Intrathoracic impedance monitoring resulting in a fluid index threshold crossing has been proven to predict heart failure (HF) exacerbations. We retrospectively investigated the relationship between changes in intrathoracic impedance and the occurrence of arrhythmic events.
From 282 patients with New York Heart Association class III or IV HF who were implanted with a CRT-D device with a fluid index feature based on intrathoracic impedance monitoring capabilities, arrhythmic events were retrospectively analyzed in terms of the threshold crossings. The patients were divided into 2 groups: those with fluid index threshold crossings and those without threshold crossings. A total of 4,725 tachyarrhythmic events were reported in 129 patients (46%), and there were 221 fluid index crossing events in 145 patients (51%) during 10.0 ± 3.2 months. Tachyarrhythmic events were more frequently recorded in patients with threshold crossing events than in those who did not experience a threshold crossing (3,241 vs. 1,484 events, P<0.0001). Ventricular tachyarrhythmic events mainly occurred within the first 30 days after the threshold crossing event; however, a similar trend was not observed for the atrial tachyarrhythmic events.
Intrathoracic impedance monitoring may predict arrhythmic events, especially ventricular arrhythmias, in patients with HF and provides an additional management tool.
Circulation Journal 09/2011; 75(11):2614-20. · 3.77 Impact Factor
-
Hiro Yamasaki, Yoshihiro Seo,
Hiroshi Tada,
Yukio Sekiguchi,
Takanori Arimoto,
Miyako Igarashi,
Kenji Kuroki,
Takeshi Machino,
Kentaro Yoshida,
Nobuyuki Murakoshi,
Tomoko Ishizu,
Kazutaka Aonuma
[show abstract]
[hide abstract]
ABSTRACT: The advantages of triple-site ventricular pacing (Tri-V) compared to conventional biventricular site pacing (Bi-V) have been reported. We sought to identify the predictors of acute hemodynamic Tri-V responders. Acute hemodynamic studies were performed in 32 patients with advanced heart failure during Tri-V implantation. After the right ventricular (RV) and left ventricular (LV) leads were implanted for a conventional Bi-V system, an additional pacing lead was implanted in the RV outflow tract for Tri-V. The LV peak +dP/dt and tau were measured during AAI, Bi-V, and Tri-V pacing. A Tri-V responder was defined as a patient whose percentage of increase in the peak +dP/dt during Tri-V was >10% compared to of that during Bi-V. The baseline clinical variables and RV outflow tract lead location were analyzed to identify the characteristics of the Tri-V responders. Of the 32 patients, 10 (31%) were classified as Tri-V responders. The LV end-diastolic volume was greater (246 ± 48 vs 173 ± 53 ml, p <0.01), and the RV outflow tract lead was implanted at a greater outflow tract portion (p <0.05) in the Tri-V responders. Multivariate analysis revealed that only the baseline LV end-diastolic volume (per 50-ml greater) predicted the Tri-V response (odds ratio 2.87, 95% confidence interval 1.03 to 8.00, p <0.05). The area under the receiver operating characteristic curve for the LV end-diastolic volume was 0.84 (p <0.01) and an LV end-diastolic volume of >212 ml had a sensitivity of 80% and specificity of 77% to distinguish Tri-V responders. In conclusion, Tri-V provides greater hemodynamic effect for patients with a larger LV end-diastolic volume owing to its resynchronization effects on the LV anterior wall.
The American journal of cardiology 08/2011; 108(9):1297-304. · 3.58 Impact Factor
-
Circulation Journal 07/2011; 75(11):2711-3. · 3.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The early diagnosis of myocardial ischemia is still challenging. The aim of the present study was to determine whether subendocardial hypokinesis and post-systolic contraction could be early markers of myocardial ischemia.
Thirty-one consecutive patients with flow-limiting severe coronary stenosis but without visually abnormal left ventricular wall motion underwent quantitative echocardiography. Myocardial strain was measured using layer-by-layer analysis in severely hypoperfused segments. Radial strain (RS) was measured in the subendocardial, subepicardial, and total wall (innerRS, outerRS, and totalRS, respectively). Circumferential strain (CS) was also measured as 3 separate layers: subendocardial, mid-layer, and subepicardial layers (innerCS, midCS, and outerCS, respectively). Post-systolic shortening (PSS) was defined as the peak strain after end systole, and post-systolic strain index (PSI) was calculated as PSS divided by end-systolic strain. TotalRS was similar between ischemic and normally perfused segments, but innerRS and inner/outer RS ratio were significantly smaller in the ischemic segments than in corresponding segments in healthy subjects. Receiver operating characteristic analysis identified an optimum cut-off for PSI of 0.6. The combined criteria of inner/outer RS ratio <1.0 and PSI >0.6 achieved 95% specificity for the presence of flow-limiting stenosis.
Combined assessment of both subendocardial contractile impairment and PSS is very useful in identifying a severely hypoperfused left ventricular wall even without visual wall motion abnormality.
Circulation Journal 05/2011; 75(8):1934-41. · 3.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: An increased left atrial (LA) stiffness reflects the structural remodeling and deterioration of the LA function. This study was designed to estimate LA stiffness by measuring a combination of the strain and LA pressure in patients undergoing pulmonary vein isolation (PVI) of atrial fibrillation (AF) and to evaluate the influence of the LA stiffness on the cardiac function, serum markers, and recurrence of AF after PVI.
In 155 consecutive patients with AF, the brain natriuretic peptide (BNP) and aminoterminal procollagen type III propeptide (PIIIP) plasma levels were measured before the PVI. The difference between the minimum and maximum LA systolic pressures was directly measured by a transseptal puncture. The ratio of the difference in the LA pressures to the peak systolic LA strain evaluated by speckle-tracking echocardiography was used as an index of the LA stiffness.
The calculated LA stiffness index was related to the BNP level (r(s) = 0.444, P < 0.001), E/E' ratio (r(s) = 0.444, P < 0.001), LA volume index (r(s) = 0.370, P < 0.001), and PIIIP level (r(s) = 0.305, P = 0.002). During a mean follow-up period of 33.8 ± 12.2 months, 45 patients (29%) presented with AF recurrences. A Cox proportional hazard regression analysis showed the LA stiffness index was an independent predictor of recurrence of AF (HR 2.88; 95% CI 1.75 to 4.73, P < 0.001).
In patients with AF, the LA stiffness index is related to left ventricular diastolic dysfunction, LA dilatation, and collagen synthesis and may predict AF recurrences after PVI.
Journal of Cardiovascular Electrophysiology 04/2011; 22(9):999-1006. · 3.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of this experimental study was to validate area tracking by 3-dimensional (3D) speckle tracking imaging (STI) as a method to measure changes in regional left ventricular (LV) endocardial surface area with sonomicrometry and to assess the usefulness as a wall motion evaluation method compared with 1-dimensional strain parameters.
A 3D-STI allows for tracking a regional endocardial surface area during a cardiac cycle. Area tracking is a new concept that regional wall motion is quantified through the magnitude of deformation in an endocardial surface area.
In each of 8 anesthetized sheep, sonomicrometry crystals were implanted on the endocardium at the LV mid and apical anterior walls. Area change ratio (ACR) that was a novel parameter obtained by area tracking was measured as percentage change in a segmental area during systole. Segmental longitudinal (LS) and circumferential strain (CS) also were measured by 3D-STI. The ACR, LS, and CS were compared with those by sonomicrometry at baseline and during pharmacological stress tests (dobutamine and propranolol infusion) and acute myocardial ischemia induced by occlusion of mid-left ascending artery.
The strong correlation was observed between ACR measurements by 3D-STI and those by sonomicrometry (Y = -4.20 + 0.84X, r = 0.87, p < 0.001). The ACR showed significant relations with both LS and CS (LS: Y = -15.1 + 1.73X, r = 0.73, p < 0.001; CS: Y = -5.85 + 1.06X, r = 0.79, p < 0.001). ACR showed significant differences among baseline, pharmacological stress, and acute myocardial ischemia. In contrast, LS and CS were reduced significantly during acute ischemia studies compared with those during the other studies; no differences were observed among baseline, propranolol infusion, and dobutamine infusion studies.
Area tracking by 3D-STI can estimate changes in LV regional area and might be promising for regional wall motion evaluations.
JACC. Cardiovascular imaging 04/2011; 4(4):358-65. · 14.29 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This multicenter prospective cohort study aimed to identify both ability of echocardiographic parameters to detect cardiac resynchronization therapy (CRT) volume responders and relation of these parameters with clinical outcomes.
CRT responder was defined as ≥ 15% reduction of left ventricular (LV) end-systolic volume at 6 months. Seven echocardiographic dyssynchrony parameters were evaluated. The clinical endpoint comprised time to death from any cause or unplanned hospitalization for a major cardiovascular event. Of the 217 patients enrolled, 63 percent were classified as volume responders, in whom significantly fewer events occurred than in non-responders (log rank, P < 0.001). No single echocardiographic criterion had significant power to detect volume responders, but a combining measurement of dyssynchrony between septum and LV free wall with M-mode and tissue Doppler imaging was independently associated with volume responders. In addition, this combined parameter was associated with the endpoint (hazard ratio, 0.66, 95% confidence interval 0.30-0.98, P = 0.04). In contrast, left bundle branch block was identified as an independent predictor of volume responders and more strongly associated with the endpoint (hazard ratio, 0.38, 95% confidence interval 0.20-0.72, P = 0.003).
Echocardiographic parameters did not show significant power to detect CRT responders independently.
Circulation Journal 03/2011; 75(5):1156-63. · 3.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The incremental prognostic impact on cardiovascular outcomes of assessment of carotid plaque ultrasound characteristics in addition to inflammatory biomarkers remains controversial in coronary artery disease (CAD) patients receiving optimal medical treatment. The present study prospectively compared carotid ultrasonic imaging with several biomarkers to stratify cardiovascular risk.
One hundred and sixty patients with angiographically confirmed stable CAD underwent carotid ultrasonography and were prospectively followed with optimal medical therapy including statins. Carotid atherosclerotic burden was assessed by mean intima-media thickness (IMT) at the far-wall from the common carotid to proximal internal carotid artery. Carotid plaque echolucency was quantified by measuring gray-scale median value (GSM). Major cardiovascular event was defined as cardiovascular death, newly developed myocardial ischemia, or cerebrovascular infarction.
Of 154 subjects completing follow-up, 27 experienced a major cardiovascular event during a median 41-month follow-up period. Events comprised cardiovascular death (n = 6), newly developed myocardial ischemia (n = 16), and ischemic stroke (n = 5). Univariate Cox regression analysis showed C-reactive protein (CRP) and several ultrasonic parameters to be significant determinants for cardiovascular events. Multivariate Cox analysis determined CRP and plaque echolucency to be independent variables predicting cardiovascular events after adjustment for classic CAD risk factors. In Kaplan-Meier plots, patients with both high CRP (≥ 1.0mg/L) and echolucent plaque (GSM ≤ 65) showed higher event rates than did patients with high CRP but without echolucent plaque.
Ultrasonic findings of echolucent carotid plaque may have incremental prognostic impact on risk assessment by CRP in CAD patients receiving contemporary optimal medical therapy.
Atherosclerosis 02/2011; 216(1):120-4. · 3.79 Impact Factor
