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ABSTRACT: BACKGROUND: We aimed to evaluate the feasibility of an oral direct thrombin inhibitor, dabigatran, as a periprocedural anticoagulant for use with ablation of atrial fibrillation (AF). METHODS: Consecutive patients scheduled to undergo an AF ablation were randomly assigned to receive dabigatran (n = 45) or warfarin (n = 45) to compare their clinical feasibility. Both of those oral anticoagulants were discontinued the day before the ablation and were resumed after confirming hemostasis of the venipuncture site. A bridging therapy with heparin was not used in either of the patient groups. RESULTS: Dabigatran was switched to warfarin before the ablation because of dyspepsia in three patients. An occurrence of rebleeding from the venipuncture site was less common in dabigatran-allocated patients than in warfarin-allocated patients (20% vs 44%; P = 0.013). The reduction in the D-dimer level after the initiation of oral anticoagulants was greater in the dabigatran-allocated patients than in the warfarin-allocated patients. The time from the initiation of the anticoagulants to the ablation was significantly shorter in the dabigatran-allocated patients than in the warfarin-allocated patients (43 ± 7 vs 63 ± 13 days; P < 0.0001). There was only one fatal periprocedural complication in a patient receiving warfarin, who had a mesenteric arterial thrombosis after the ablation. CONCLUSIONS: An anticoagulation strategy with dabigatran may surpass that with warfarin in reducing both the periprocedural risk of minor bleeding and a hypercoagulable state, and the time to ablation in patients undergoing ablation of AF.
Pacing and Clinical Electrophysiology 11/2012; · 1.35 Impact Factor
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Yutaka Aoyama,
Haruo Hirayama,
Hideki Ishii,
Koichi Kobayashi,
Kiyotake Ishikawa,
Masateru Takigawa, Mamoru Nanasato,
Yukihiko Yoshida,
Toru Aoyama,
Daiji Yoshikawa,
Tatsuaki Matsubara,
Toyoaki Murohara
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ABSTRACT: OBJECTIVES: Recurrent in-stent restenosis remains an important clinical issue after a percutaneous coronary intervention even after treatment with a sirolimus-eluting stent (SES) especially in patients with chronic kidney disease. We evaluated the impact of renal insufficiency on the clinical and angiographic outcomes after treatment for SES restenosis. METHODS AND RESULTS: A total of 74 patients with 76 lesions underwent subsequent revascularization with a drug-eluting stent for SES restenosis. Patients were classified into three groups: group 1 included 29 patients with an estimated glomerular filtration rate more than 60 ml/min/1.73 m; group 2 included 27 patients with lower estimated glomerular filtration rate (<60 ml/min/1.73 m) without hemodialysis (HD) dependence; and group 3 included 18 patients on HD. Clinical and angiographic follow-up was carried out at 8 months. Late lumen loss at the 8-month follow-up angiography showed progressive increases from group 1 to 2 to 3 (group 1: 0.36±0.39 mm, group 2: 1.11±0.61 mm, group 3: 1.30±0.85 mm, P<0.001). Similarly, compared with group 1, groups 2 and 3 had significantly higher rates of major adverse cardiac events (6.9, 37.0, and 38.9%, respectively, P=0.001), primarily because of a high frequency of target lesion revascularization (8.0, 34.8, and 33.3%, respectively, P=0.019). CONCLUSION: Non-HD-dependent chronic kidney disease patients had increased neointimal growth in the follow-up phase after percutaneous coronary intervention, with a drug-eluting stent for SES restenosis almost equivalent to patients on HD, resulting in higher rates of recurrent restenosis than patients with preserved renal function.
Coronary artery disease 09/2012; · 1.56 Impact Factor
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Masateru Takigawa,
Takumi Yamada,
Yukihiko Yoshida,
Kiyotake Ishikawa,
Yutaka Aoyama,
Takashi Yamamoto,
Natsuo Inoue,
Yasushi Tatematsu, Mamoru Nanasato,
Kazuo Kato,
Naoya Tsuboi,
Haruo Hirayama
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ABSTRACT: AIMS: Encircling ipsilateral pulmonary veins (PVs) isolation (EIPVsI) with the double-Lasso technique has proven to be effective to cure atrial fibrillation (AF). However, in this technique, PV mapping with circular catheters may miss a non-isolation of the PV carina. The purpose of this study was to reveal the incidence and clinical significance of a non-isolation of the PV carina after EIPVsI.METHODS AND RESULTS: We studied 81 consecutive paroxysmal AF patients (age 61 ± 12 years, 56 men), in whom EIPVsI was successfully performed in one encircling line with the endpoint of the demonstration of bidirectional conduction block between the PVs and left atrium (LA) with the double-Lasso technique. After a successful EIPVsI, pacing from the PV carina was performed and it captured the LA in 17 (21.0%) patients. During a mean follow-up period of 19 ± 13 months, AF recurred in 13 (16.0%) patients. A multivariate Cox proportional analysis revealed that a non-isolation of the PV carina after the EIPVsI was a significant predictor (hazard ratio = 3.91, 95% confidence interval = 1.13-14.16, P = 0.03) of AF recurrence.CONCLUSIONS: Pulmonary vein mapping with the double-Lasso technique did miss the non-isolation of the PV carina after a successful EIPVsI, which was an independent predictor of AF recurrence after the EIPVsI. Pacing from the PV carina may be required to confirm the electrical isolation of the PV carina after EIPVsI with the double-Lasso technique.
Europace 08/2012; · 1.98 Impact Factor
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ABSTRACT: Background: Whether or not automated scores obtained from myocardial single-photon emission computed tomography (SPECT) imaging using software correlate with the visual interpretations by experts remains obscure. Methods and Results: Eighty-seven consecutive patients with known or suspected angina pectoris underwent (201)thallium stress/rest SPECT followed by coronary angiography and the summed difference scores (SDS) were calculated using Heart Score View software. The SDS was substantially associated with coronary stenosis and accurately detected culprit lesions, because the diagnostic accuracy was comparable to that of expert visual evaluation. Conclusions: Automated scores obtained from myocardial SPECT can help detect coronary artery disease. (Circ J 2012; 76: 2280-2282).
Circulation Journal 08/2012; 76(9):2280-2. · 3.77 Impact Factor
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ABSTRACT: AF Ablation in HD Patients. Introduction: It is not common for patients on chronic hemodialysis (HD) to undergo catheter ablation of atrial fibrillation (AF). We aimed to show the outcomes of AF ablation in the HD patients. Methods and Results: Thirty HD patients who underwent pulmonary vein (PV) isolation for drug refractory paroxysmal AF were retrospectively studied, and their AF recurrence free rate and frequency of periprocedural complications were compared to 60 age- and gender-matched control patients not requiring HD. A nonirrigated ablation catheter was used in both patient groups. During a mean follow-up period of 821 ± 218 days, 16 (54%) of the HD patients remained free from AF recurrence without any antiarrhythmic agents versus 47 (78%) of the control patients with an initial ablation (P = 0.013). A second ablation procedure was performed in 12 patients with an AF recurrence, and consequently 20 (67%) of the HD patients were in sinus rhythm compared to 53 (88%) of the controls during a follow-up duration of 747 ± 221 after the last ablation (P = 0.012). Bleeding from the venipuncture site requiring a prolonged hospital stay was identified in 2 HD patients and 1 control subject, while no life-threatening complications were observed in either patient group. Conclusion: Although the success rate of the PV isolation in HD patients was far from satisfactory, it may be considered as one of the therapeutic options for them. (J Cardiovasc Electrophysiol, Vol. pp. 1-6).
Journal of Cardiovascular Electrophysiology 07/2012; · 3.06 Impact Factor
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Masateru Takigawa,
Takumi Yamada,
Yukihiko Yoshida,
Monami Ando,
Kiyotake Ishikawa,
Yutaka Aoyama,
Takashi Yamamoto,
Natsuo Inoue,
Yasushi Tatematsu, Mamoru Nanasato,
Kazuo Kato,
Naoya Tsuboi,
Haruo Hirayama
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ABSTRACT: INTRODUCTION: : The purpose of this study was to investigate whether the effects of renin-angiotensin system inhibitors (RASIs) after encircling ipsilateral pulmonary veins isolation (EIPVsI) for atrial fibrillation (AF) differed between patients with non-dilated and dilated left atria. MATERIALS AND METHODS: : We retrospectively studied 292 consecutive patients (mean age=61±11 years, 75% males) who underwent successful EIPVsI for paroxysmal or persistent AF. RASIs' effects were compared between the patients with a non-dilated left atrium of <40 mm (n=178) and dilated left atrium of ≥40 mm (n=114). RESULTS: : During a mean follow-up period of 18.9±12.7 months, AF recurred in 38 (21.4%) and 45 (39.5%) patients with non-dilated and dilated left atria, respectively. A multivariate Cox proportional analysis revealed that treatment with RASIs (hazard ratio (HR) 0.30, 95% confidence interval (CI) =0.13-0.66, p=0.003), the duration of AF (HR 1.08/year, 95% CI=1.01-1.16, p=0.03), a history of hypertension (HR 2.86, 95% CI=1.21-6.85, p=0.02) and the left ventricular ejection fraction (HR 0.54/10%↑, 95% CI=0.34-0.87, p=0.01) were associated with AF recurrences in patients with a non-dilated left atrium. On the other hand, only the duration of AF (HR 1.11/year, 95% CI=1.01-1.21, p=0.03) was associated with AF recurrences in those with a dilated LA, and RASIs had no effect on AF recurrences (p=0.65). CONCLUSIONS: : RASIs suppressed AF recurrences after EIPVsI only in patients with a non-dilated left atrium.
Journal of Renin-Angiotensin-Aldosterone System 05/2012; · 2.44 Impact Factor
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ABSTRACT: High-frequency stimulation (HFS) of the atria induces atrial fibrillation (AF) when applied during sinus rhythm and elicits a parasympathetic response when delivered at sites where ganglionated plexi (GPs) are located. However, little is known about its impact after an electrophysiological study.
To evaluate the impact of HFS on the short-term and long-term outcomes after the ablation of persistent AF.
Thirty consecutive patients with persistent or long-standing persistent AF were randomly assigned to either receive HFS of the left atrium (n = 15) or not (n = 15) during their electrophysiological studies. Patients receiving HFS were examined to determine whether or not a vagal response was elicited by the HFS at sites where GPs were located before and after conventional pulmonary vein isolation without any ablation targeting the GPs. Patients not receiving the HFS underwent the ablation procedure alone. The rate of recurrence of AF within 3 months of the procedure (early recurrence [ER]) and the frequency of that occurring after that period (late recurrence) were compared between the patient groups.
The incidence of ER occurred more frequently in patients with HFS than in those without (80% vs 40%; P = .015), whereas the occurrence of late recurrence was similar between the 2 groups (27% vs 33%; P = .73). In the HFS group, the number of GPs decreased from 3.4 ± 1.1 to 1.5 ± 0.8 after the pulmonary vein isolation (P < .0001), and the decrease was smaller in the patients experiencing ER than in those without.
HFS increases the incidence of ER in patients with persistent AF despite a partial GP modification resulting from the pulmonary vein isolation.
Heart rhythm: the official journal of the Heart Rhythm Society 05/2012; 9(9):1386-92. · 4.56 Impact Factor
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ABSTRACT: A 56-year-old man with atrial fibrillation and complete left bundle branch block (CLBBB) developed heart failure refractory to the initial medical treatment. Both the CLBBB and cardiac dysfunction completely recovered only with an advanced medical regimen for rate control and heart failure. This report describes a case with reversible CLBBB following tachycardia-induced cardiomyopathy, who was not a candidate for cardiac resynchronization therapy.
Europace 12/2011; 14(6):915-7. · 1.98 Impact Factor
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KIYOTAKE ISHIKAWA M.D,
TAKUMI YAMADA M.D,
YUKIHIKO YOSHIDA M.D,
MASATERU TAKIGAWA M.D,
YUTAKA AOYAMA M.D,
NATSUO INOUE M.D,
YASUSHI TATEMATSU M.D,
MAMORU NANASATO M.D,
KAZUO KATO M.D,
NAOYA TSUBOI M.D, [......],
TAKUMI YAMADA,
YUKIHIKO YOSHIDA,
MASATERU TAKIGAWA,
YUTAKA AOYAMA,
NATSUO INOUE,
YASUSHI TATEMATSU, MAMORU NANASATO,
KAZUO KATO,
NAOYA TSUBOI,
HARUO HIRAYAMA
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ABSTRACT: Introduction:An additional approach may be essential to reduce recurrences of atrial fibrillation (AF) after pulmonary vein isolation (PVI). We examined the efficacy of renin-angiotensin system blockers (RAS-B) in suppressing AF recurrences after PVI.Methods and Results:We retrospectively studied 264 consecutive patients (195 male, median age: 63 years) who underwent successful PVI of paroxysmal (n = 94) or persistent AF (n = 170). RAS-B treatment was performed in 145 patients (angiotensin-converting enzyme inhibitors; n = 13, angiotensin receptor blockers; n = 129, both; n = 3). Echocardiography was performed before and 3 months after the ablation to examine the occurrence of left atrial structural reverse remodeling (LA-RR). After a median follow-up of 195 (interquartile range: 95–316) days, AF recurred in 51 (19.3%) patients. A Cox regression analysis revealed that AF recurrence was significantly lower in the patients with RAS-B than in those without (hazard ratio [HR] = 0.41 [95% confidence interval (CI): 0.23–0.71], P = 0.002). After a multivariate adjustment for potential confounders, the use of RAS-B (HR = 0.39 [95% CI: 0.19–0.77], P = 0.007) and type of AF (HR = 0.30 [95% CI: 0.13–0.66], P = 0.003) were the independent predictors for AF recurrence during the entire follow-up. Although effect of RAS-B was not significant during the early follow-up (<3 month), it was the only independent predictor during the late follow-up (>3 months) (HR = 0.21 [95% CI: 0.08–0.53], P = 0.001). There were no significant differences in LA-RR occurrence regarding RAS-B medication. The use of RAS-B was an independent predictor of late AF recurrences irrespective of an early LA-RR occurrence.Conclusions:Treatment with RAS-B significantly reduced the AF recurrence after PVI. This benefit became more prominent 3 months after the PVI. (PACE 2011; 34:296–303)
Pacing and Clinical Electrophysiology 02/2011; 34(3):296 - 303. · 1.35 Impact Factor
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Kiyotake Ishikawa,
Takumi Yamada,
Yukihiko Yoshida,
Masateru Takigawa,
Yutaka Aoyama,
Natsuo Inoue,
Yasushi Tatematsu, Mamoru Nanasato,
Kazuo Kato,
Naoya Tsuboi,
Haruo Hirayama
[show abstract]
[hide abstract]
ABSTRACT: An additional approach may be essential to reduce recurrences of atrial fibrillation (AF) after pulmonary vein isolation (PVI). We examined the efficacy of renin-angiotensin system blockers (RAS-B) in suppressing AF recurrences after PVI.
We retrospectively studied 264 consecutive patients (195 male, median age: 63 years) who underwent successful PVI of paroxysmal (n = 94) or persistent AF (n = 170). RAS-B treatment was performed in 145 patients (angiotensin-converting enzyme inhibitors; n = 13, angiotensin receptor blockers; n = 129, both; n = 3). Echocardiography was performed before and 3 months after the ablation to examine the occurrence of left atrial structural reverse remodeling (LA-RR). After a median follow-up of 195 (interquartile range: 95-316) days, AF recurred in 51 (19.3%) patients. A Cox regression analysis revealed that AF recurrence was significantly lower in the patients with RAS-B than in those without (hazard ratio [HR] = 0.41 [95% confidence interval (CI): 0.23-0.71], P = 0.002). After a multivariate adjustment for potential confounders, the use of RAS-B (HR = 0.39 [95% CI: 0.19-0.77], P = 0.007) and type of AF (HR = 0.30 [95% CI: 0.13-0.66], P = 0.003) were the independent predictors for AF recurrence during the entire follow-up. Although effect of RAS-B was not significant during the early follow-up (<3 month), it was the only independent predictor during the late follow-up (>3 months) (HR = 0.21 [95% CI: 0.08-0.53], P = 0.001). There were no significant differences in LA-RR occurrence regarding RAS-B medication. The use of RAS-B was an independent predictor of late AF recurrences irrespective of an early LA-RR occurrence.
Treatment with RAS-B significantly reduced the AF recurrence after PVI. This benefit became more prominent 3 months after the PVI.
Pacing and Clinical Electrophysiology 11/2010; 34(3):296-303. · 1.35 Impact Factor
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Satoko Nakamura,
Yuhei Kawano,
Hiroki Hase,
Tsuguru Hatta,
Shigeyuki Nishimura,
Masao Moroi,
Susumu Nakagawa,
Tokuo Kasai,
Hideo Kusuoka,
Yasuchika Takeishi,
Kenichi Nakajima,
Mitsuru Momose,
Kazuya Takehana, Mamoru Nanasato,
Syunichi Yoda,
Hidetaka Nishina,
Naoya Matsumoto,
Tsunehiko Nishimura
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ABSTRACT: Cardiovascular disease is the leading cause of morbidity and mortality in patients with chronic kidney disease. Recent studies have indicated that the incidence of cardiovascular disease increases inversely with estimated glomerular filtration rate. Although coronary angiography is considered the gold standard for detecting coronary artery disease, contrast-induced nephropathy or cholesterol microembolization remain serious problems; therefore, a method of detecting coronary artery disease without renal deterioration is desirable. From this viewpoint, stress myocardial perfusion single photon emission computed tomography (SPECT) might be useful for patients with chronic kidney disease. We recently performed the Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT (J-ACCESS) investigating patients with suspected or extant coronary artery disease and the J-ACCESS 2 study of patients with diabetes. The findings from these studies showed that SPECT can detect coronary artery disease and help to predict future cardiac events. Thus, we proposed a multicenter, prospective cohort study called "J-ACCESS 3" in patients with chronic kidney disease and cardiovascular risk. The study aimed at predicting cardiovascular and renal events based on myocardial perfusion imaging and clinical backgrounds. We began enrolling patients in J-ACCESS 3 at 74 facilities from April 2009 and will continue to do so until 31 March 2010, with the aim of having a cohort of 800 patients. These will be followed up for three years. The primary endpoints will be cardiac death and sudden death. The secondary endpoints will comprise any cardiovascular or renal events. This study will be completed in 2013. Here, we describe the design of the J-ACCESS 3 study.
Therapeutic apheresis and dialysis: official peer-reviewed journal of the International Society for Apheresis, the Japanese Society for Apheresis, the Japanese Society for Dialysis Therapy 08/2010; 14(4):379-85. · 1.39 Impact Factor
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Circulation Journal 02/2010; 74(3):432-3. · 3.77 Impact Factor
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ABSTRACT: Understanding the clinical characteristics of transthyretin familial amyloid polyneuropathy (TTR-FAP) is critical for early diagnosis and timely referral for liver transplantation. Here, we describe a 52-year-old man who had slight paresthesia for four years and whose final diagnosis of TTR-cardiac amyloidosis caused by sporadic FAP was delayed despite annual electrocardiography. Curative liver transplantation was postponed because of progressive cardiac involvement. This experience highlights the difficulties associated with diagnosing TTR-FAP, especially when it is sporadic, and underscores the importance of slight changes in ECG that could indicate FAP.
Internal Medicine 01/2010; 49(2):139-44. · 0.94 Impact Factor
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Mamoru Nanasato,
Norihiko Goto,
Satoshi Isobe,
Kazumasa Unno,
Haruo Hirayama,
Tetsuhiko Sato,
Susumu Matsuoka,
Takaharu Nagasaka,
Yoshihiro Tominaga,
Kazuharu Uchida,
Toyoaki Murohara
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ABSTRACT: A 62 year-old female hemodialysis patient underwent parathyroidectomy to treat secondary hyperparathyroidism. On the preoperative assessment, the plasma levels of parathyroid hormone (PTH) and B-type natriuretic peptide (BNP) were elevated. Echocardiography showed reduced left ventricular (LV) contraction. Myocardial iodine-123-15-(p-iodophenyl)-3-(R,S) methylpentadecanoic acid ((123)I-BMIPP) scintigraphy showed moderately reduced tracer uptake in the postero-inferior area on single-photon emission computed tomography and decreased washout on the planar images. After parathyroidectomy, the plasma levels of PTH and BNP decreased, followed by improvement in LV contraction. Myocardial (123)I-BMIPP scintigraphy revealed that the washout on planar images had increased, which suggests that myocardial (123)I-BMIPP scintigraphy is useful for estimating the effect of parathyroidectomy on cardiac function.
Circulation Journal 02/2009; 73(10):1956-60. · 3.77 Impact Factor
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Satoshi Isobe,
Yasuo Takada,
Akitada Ando,
Satoru Ohshima,
Kiyoyasu Yamada, Mamoru Nanasato,
Kazumasa Unno,
Takuo Ogawa,
Takahisa Kondo,
Hideo Izawa,
Yasuya Inden,
Makoto Hirai,
Toyoaki Murohara
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ABSTRACT: The physiological mechanism of the increase in the electrocardiographic (ECG) R-wave voltage after revascularization in patients with acute myocardial infarction (MI) needs to be elucidated.
One hundred and thirty-eight MI patients (83: anterior MI, 45: inferior MI, 10: lateral MI) underwent ECG and echocardiography in both the acute and subacute phases after emergency revascularization, as well as a resting thallium-201/iodine-123 15-p-iodophenyl-3-(R,S)-methyl pentadecanoic acid myocardial scintigraphy in the acute phase. The total sum of the R-wave voltage (SigmaR) was calculated over multiple leads on ECG for each infarcted lesion. Scintigraphic defect on each tracer was expressed as the percentage (%) defect of the total left ventricular (LV) myocardium. The % defect-discordance on both images in the acute phase and the % increase in SigmaR and the absolute increase in LV ejection fraction from the acute to the subacute phase (DeltaEF) were also calculated. The SigmaR in the subacute phase was significantly greater than that in the acute phase (p<0.0001). The % increase in SigmaR significantly correlated with the DeltaEF (r=0.57, p<0.0001). The % increase in SigmaR also correlated with the % defect-discordance (r=0.68, p<0.0001).
The increase in the ECG R-wave voltage reflects not only the improvement in myocardial perfusion but also the presence of salvaged myocardium after revascularization in acute MI patients.
Circulation Journal 11/2006; 70(11):1385-91. · 3.77 Impact Factor
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Satoru Ohshima,
Satoshi Isobe,
Hideo Izawa, Mamoru Nanasato,
Akitada Ando,
Akira Yamada,
Kiyoyasu Yamada,
Tomoko S Kato,
Koji Obata,
Akiko Noda,
Takao Nishizawa,
Katsuhiko Kato,
Kohzo Nagata,
Kenji Okumura,
Toyoaki Murohara,
Mitsuhiro Yokota
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ABSTRACT: We investigated the relationship between iodine-123-metaiodobenzylguanidine (123I-MIBG) findings and myocardial contractile reserve in patients with mild to moderate dilated cardiomyopathy (DCM).
Little is known regarding the relationship between cardiac sympathetic nervous function and myocardial contractile reserve in DCM.
Twenty-four DCM patients who showed sinus rhythm underwent echocardiography, biventricular catheterization, and myocardial 123I-MIBG scintigraphy. Left ventricular (LV) pressures were measured using a micromanometer-tipped catheter. The myocardial contractile function (LV dP/dt(max)) was determined at rest and during atrial pacing. The messenger ribonucleic acid (mRNA) expressions of intracellular Ca2+-regulatory proteins were analyzed by real-time quantitative reverse transcription-polymerase chain reaction. Myocardial 123I-MIBG accumulation was quantified as a heart-mediastinum ratio (HMR).
A significant correlation was observed between the delayed 123I-MIBG HMR and the percentage change in LV dP/dt(max) from the baseline to the peak or critical heart rate (r = 0.64; p < 0.001). The delayed 123I-MIBG HMR was significantly lower in patients showing a worsening change in LV dP/dt(max) than in those showing a favorable change (p < 0.005). The maximum LV dP/dt(max) during pacing and the sarcoplasmic reticulum Ca2+-ATPase (SERCA2) mRNA levels were significantly more reduced in patients with a delayed HMR < or =1.8 than in those with a delayed HMR >1.8 (p < 0.05, respectively).
Abnormal myocardial 123I-MIBG accumulation is related to an impaired myocardial contractile reserve and down-regulation of SERCA2 mRNA in DCM. Myocardial 123I-MIBG scintigraphy can be useful in noninvasively evaluating myocardial contractile reserve in patients with mild to moderate DCM.
Journal of the American College of Cardiology 12/2005; 46(11):2061-8. · 14.16 Impact Factor
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Satoshi Isobe,
Hideo Izawa,
Mitsunori Iwase, Mamoru Nanasato,
Makoto Nonokawa,
Akitada Ando,
Satoru Ohshima,
Kohzo Nagata,
Katsuhiko Kato,
Takao Nishizawa,
Toyoaki Murohara,
Mitsuhiro Yokota
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ABSTRACT: Little is known about the relation between left ventricular (LV) functional reserve in response to exercise and cardiac sympathetic nervous function in patients with nonobstructive hypertrophic cardiomyopathy (HCM). We investigated whether an assessment of cardiac sympathetic nervous function by myocardial (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy might provide a sign of an abnormal LV functional reserve in response to exercise-induced beta-adrenergic stimulation in patients with HCM.
Thirty HCM patients underwent (123)I-MIBG scintigraphy and echocardiography at rest and subsequent biventricular cardiac catheterization at rest and during dynamic exercise. LV pressures were measured using a micromanometer-tipped catheter system. The early and delayed (123)I-MIBG images were quantified as a heart-to-mediastinum ratio (H/M). The plasma levels of brain natriuretic peptide (BNP) and norepinephrine (NE) were also measured.
Patients were divided into 2 groups according to the delayed (123)I-MIBG H/M: group I consisted of 12 patients with a delayed H/M of < or =1.8 and group II had 18 patients with a delayed H/M of >1.8. Both the percentage increase from rest to exercise in LV isovolumic contraction (LV dP/dt(max)) and the percentage shortening of LV pressure half-time (T(1/2)) as an index of isovolumic relaxation were significantly less in group I than in group II (P < 0.05, respectively). A significant linear correlation was observed between the percentage increase in LV dP/dt(max) and (123)I-MIBG H/Ms (early H/M: r = 0.49, P < 0.01; delayed H/M: r = 0.54, P < 0.005, respectively). A significant linear correlation was also observed between the percentage shortening in T(1/2) and (123)I-MIBG H/Ms (early H/M: r = 0.58, P < 0.001; delayed H/M: r = 0.64, P < 0.0005, respectively). The plasma NE levels were significantly higher in group I than in group II (P < 0.01), whereas the plasma BNP levels were comparable in the 2 HCM groups.
beta-Adrenergic enhancement of LV function during exercise may depend on the extent of cardiac sympathetic nervous innervation in HCM patients. Resting myocardial (123)I-MIBG scintigraphy can noninvasively evaluate LV functional reserve in response to exercise in patients with nonobstructive HCM.
Journal of Nuclear Medicine 07/2005; 46(6):909-16. · 6.38 Impact Factor
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ABSTRACT: The purpose of this study was to evaluate whether an angiotensin II receptor blocker, candesartan cilexetil, reduced neointima formation after coronary stent implantation by way of serial intravascular ultrasound analysis.
Previous experimental studies have suggested that angiotensin II receptor blocker reduced neointima formation after vascular injury. However, it is unclear whether candesartan cilexetil has a similar effect on human coronary artery.
We recruited 50 consecutive patients with stable angina pectoris and 60 stenotic lesions. Patients were prospectively randomized into 2 groups: (1) 25 patients with 31 lesions received candesartan cilexetil (4-12 mg/d), and (2) 25 patients with 29 lesions did not receive the drug. Follow-up intravascular ultrasound was performed 6 m after the stent implantation. Cross-sectional images were obtained at 1-mm intervals within the stent, and the stent volume (SV), lumen volume (LV), and neointima volume (NV = SV - LV) were calculated using Simpson's rule. The percentage neointima volume obstruction (%NV) was calculated as NV/SV x 100.
Clinical and angiographic backgrounds were comparable between the 2 groups. At follow-up, the candesartan group had smaller SV and larger LV (SV, 156.3 +/- 53.7 vs 165.4 +/- 61.8 mm3 , ns; LV, 122.2 +/- 49.0 vs 113.1 +/- 45.5 mm3 , ns), and significantly smaller NV and significantly smaller %NV than the control group (NV, 34.2 +/- 16.6 vs 52.3 +/- 32.6 mm3 , P < .01; %NV, 22.7 +/- 10.9% vs 31.3 +/- 13.4%, P < .01).
Candesartan treatment decreases neointima formation and hence may reduce in-stent restenosis.
American heart journal 02/2005; 149(1):e2. · 4.65 Impact Factor
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ABSTRACT: It is unclear whether 123I-labelled beta-methyl iodophenyl pentadecanoic acid (123I-BMIPP) myocardial scintigraphy adds further predictive value for future cardiac events compared with the variables obtained during cardiac catheterisation in patients with acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (PCI). We therefore investigated whether 123I-BMIPP imaging in patients with AMI treated by primary PCI was useful in predicting future cardiac events.
One hundred and fifty-nine patients with AMI who were treated with primary PCI and underwent left ventriculography (LVG) on admission underwent 201Tl and 123I-BMIPP myocardial scintigraphy. Scintigrams were visually classified, and the total defect score (TDS) was calculated. Major adverse cardiac events (MACE) were defined as cardiac death including sudden death, congestive heart failure and recurrence of acute coronary syndrome. Patients were followed up for a mean of 34.5 months (12-63 months).
Twenty-six patients had MACE. Kaplan-Meier analysis indicated that patients with the top 50% of 123I-BMIPP TDSs had a significantly higher rate of MACE (P=0.007). Patients with mismatch between 201Tl and 123I-BMIPP images also had significantly more MACE (P=0.02). In the prediction of MACE, the global chi-square value was 5.2 (P=0.001) based on LVEF (<45%) and the number of diseased vessels (two or three). Adding 123I-BMIPP TDS and the mismatch improved the global chi-square value (chi2=7.2)
Myocardial scintigraphy using 201Tl and 123I-BMIPP predicts future cardiac events in patients with AMI treated with primary PCI, and provides additional predictive value compared with the variables obtained with cardiac catheterisation alone.
European journal of nuclear medicine and molecular imaging 11/2004; 31(11):1512-21. · 4.99 Impact Factor
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ABSTRACT: Many studies have demonstrated that reduced left ventricular (LV) diastolic distensibility plays a key role in the pathophysiology of hypertrophic cardiomyopathy (HCM). However, the relationship between myocardial ischemia and reduced LV distensibility in HCM remains unclear. We aimed to clarify the relationship between exercise-induced ischemia and reduced LV distensibility in patients with HCM.
Twenty patients with HCM and 5 age-matched control subjects underwent stress-redistribution (201)Tl myocardial scintigraphy and biventricular cardiac catheterization and echocardiography at rest and during exercise. Scintigraphic defect analysis was interpreted using Berman's 20-segment model. The summed stress score (SSS) was calculated as the sum of scores of the 20 LV segments and the summed difference score (SDS) was calculated as the sum of differences between each of the 20 LV segments on stress and rest images.
Patients were divided into 2 groups according to the (201)Tl defect as follows: 9 patients with an SSS on (201)Tl of >or=10 and an SDS on (201)Tl of >or=5 (ischemic group) and 11 patients with an SSS of <10 or an SDS of <5 (nonischemic group). The absolute increases from rest to peak exercise in LV end-diastolic pressure (LVEDP) and pulmonary artery wedge pressure were significantly greater (15.5 +/- 5.2 vs. 7.6 +/- 5.5 mm Hg and 17.3 +/- 5.0 vs. 8.9 +/- 5.0 mm Hg, P < 0.01, respectively), and the percentage changes from rest to peak exercise in the maximum first derivative of LV pressure and LV pressure half-time were significantly smaller in the ischemic HCM group compared with the nonischemic HCM group (70% +/- 24% vs. 123% +/- 43% and -32% +/- 6.4% vs. -44% +/- 9.4%, P < 0.01, respectively). However, the end-diastolic dimensions did not differ between the 2 HCM groups. One of the 9 patients in the ischemic group, as revealed by fill-in on (201)Tl scintigraphy, showed increased (18)F-FDG uptake in the anteroseptal wall.
Some HCM patients show a significant increase in LVEDP without chamber dilatation, indicating reduced LV diastolic distensibility. Myocardial ischemia may at least in part contribute to this condition.
Journal of Nuclear Medicine 11/2003; 44(11):1717-24. · 6.38 Impact Factor
