Yuji Muraoka

Relation between QT dispersion and adenosine triphosphate stress thallium-201 single-photon emission computed tomographic imaging for detecting myocardial ischemia and scar

It is not known if QT dispersion is useful for detecting coronary artery disease. We investigated whether QT dispersion at baseline and during adenosine triphosphate (ATP) infusion correlate with the imaging patterns obtained from ATP stress thallium-201 single-photon emission computed tomography (ATP-SPECT). QT dispersion was determined in 169 patients who underwent ATP-SPECT from 12-lead electrocardiograms obtained at baseline and 3 minutes after the beginning of ATP infusion. Based on the results of ATP-SPECT, patients were divided into 4 groups: normal (n = 55), ischemia (n = 38), ischemia and scar (n = 42), and scar (n = 34). Baseline QT dispersions (mean +/- SD) in the normal, ischemia, ischemia and scar, and scar groups were 48 +/- 15, 50 +/- 17, 69 +/- 25, and 70 +/- 24 ms, respectively. Baseline QT dispersion was significantly greater in the groups with myocardial scar. QT dispersions during ATP infusion were 43 +/- 16, 63 +/- 20, 76 +/- 20, and 62 +/- 25 ms in the normal, ischemia, ischemia and scar, and scar groups, respectively. QT dispersion increased with ATP infusion in patients with myocardial ischemia. QT dispersion at baseline and during ATP infusion correlated with the ATP-SPECT imaging pattern. These findings suggest that baseline QT dispersion and ATP-induced changes in QT dispersion may help detect the presence of myocardial ischemia and scar.

Validation of lactate level as a predictor of early mortality in acute decompensated heart failure patients who entered intensive care unit

BACKGROUND The significance of routine measurement of lactate level is unclear in patients with critical acute decompensated heart failure (ADHF). METHODS AND RESULTS Consecutive 754 patients who were admitted to the intensive care unit (ICU) in our hospital from January 2007 to March 2012 and given a diagnosis of ADHF were eligible for retrospective entry into the registry. Lactate level was measured on admission from routine arterial blood sample and we investigated by comparing the lactate level and parameters of conventional in-hospital mortality predictors. Among the patients, 88 (12%) died during hospitalization. The lactate level had great power to predict in-hospital mortality, as suggested by the c-statistics of 0.71. The occurrence of in-hospital death was more pronounced in patients with high levels of lactate (>3.2mmol/l) and the tendency was observed in patients in both the acute coronary syndrome (ACS) group and non-ACS group. In multivariate analysis, elevated lactate levels remained an independent predictor of in-hospital death (odds ratio, 2.14; 95% confidence interval, 1.10-4.21; p=0.03). CONCLUSIONS Elevated levels of arterial lactate on admission were related to worse in-hospital mortality in patients with ADHF either with or without ACS, suggesting that the presence of high lactate in patients who enter the ICU with ADHF could help stratify the initial risk of early mortality.

Comparison of heart-type fatty acid binding protein and sensitive troponin for the diagnosis of early acute myocardial infarction

BACKGROUND The current development of serological biomarkers allows detection of smaller myocardial necrosis and early acute myocardial infarction (AMI). We evaluated the relevance of the heart-type fatty acid binding protein (H-FABP) assay, which has recently been approved in Japan, for early diagnosis of AMI as compared with the sensitive troponin assay. METHODS This is an observational study in a single center. From 2010 July to 2011 January, 114 patients who presented with symptoms suggestive of AMI were enrolled. RESULTS AMI was adjudicated in 45 patients (40%). The diagnostic accuracy of measurements obtained at presentation for AMI, as quantified by the area under the receiver-operating-characteristic curve (AUC), was significantly lower with H-FABP assay than the sensitive troponin assay [AUC for H-FABP, 0.59; 95% confidence interval (CI) 0.48-0.70; and for troponin I, 0.89; 95% CI, 0.83-0.94; P<.0001]. Among patients who presented within 2h after the onset of chest pain, the AUC for H-FABP was even low as compared with sensitive troponin (0.55; 0.39-0.72 vs. 0.89; 0.80-0.98, p<0.001). The clinical sensitivity for the diagnosis of AMI with the cutoff point of 99 th percentile was similar in both assays (81% and 81%, respectively), however, the specificity was extremely low in the H-FABP assay as compared with sensitive troponin assay (19% and 79%, respectively). CONCLUSION The measurement of H-FABP in 114 consecutive patients with chest pain suggestive of AMI showed no improvement of diagnosis for early AMI as compared with the current sensitive troponin assay because of its extremely low specificity.

Exogenous adenosine triphosphate disodium administration during primary percutaneous coronary intervention reduces no-reflow and preserves left ventricular function in patients with acute anterior myocardial infarction: A study using myocardial contrast echocardiography

BACKGROUND It is unknown whether adenosine triphosphate disodium (ATP) administration during primary percutaneous coronary intervention (PCI) is useful in anterior acute myocardial infarction (AMI). METHODS The study was a prospective, non-randomized, open-label trial. Primary PCI was successfully performed in 204 consecutive patients with first anterior AMI. ATP at a mean dose of 117 microg/kg/min for 45 min on an average was infused intravenously during PCI in 100 patients (Group 1). In the other 104 patients, normal saline was administered (Group 2). ST-segment resolution (STR) was estimated 90 min after recanalization. The no-reflow ratio was measured 2 weeks later, using intravenous myocardial contrast echocardiography. Left ventricular ejection fraction (LVEF), LV regional wall motion (LVRWM), and LV end-diastolic volume index (LVEDVI) were measured 6 months later. RESULTS Baseline patient characteristics of the two groups were similar, including TIMI risk scores. Significant STR (> or =50% resolution compared to baseline) (66% versus 50%; Group 1 versus Group 2, p=0.02), no-reflow ratio (24% versus 34%, indicated by mean values, p=0.02), LVEF (61% versus 55%, p=0.0007), LVRWM (-1.56 versus -2.05, using the SD/chord, p=0.0001), and LVEDVI (60 ml/m(2) versus 71 ml/m(2), p=0.0007) were significantly better in Group 1, and the no-reflow ratio, LVEF, LVRWM and LVEDVI were significantly better in ATP-administered patients, regardless of antecedent angina or advanced age. ATP Administration was consistently identified as a significant determinant for STR, no-reflow ratio, LVEF, LVRWM, and LVEDVI. CONCLUSIONS Intravenous ATP administration during reperfusion is an independent determinant of STR and the no-reflow ratio, and LVEF, LVRWM, and LVEDVI at 6 months after primary PCI.

Clinical usefulness of drug-eluting stents in the treatment of dialysis patients with coronary artery disease

AIMS To investigate the clinical outcomes of paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) in patients on dialysis. METHODS AND RESULTS Between May 2004 and December 2008, 95 patients on dialysis with 124 lesions were treated with PES alone, and were compared to 184 patients on dialysis with 244 lesions treated with SES alone, retrospectively. One-year major adverse cardiac event (MACE) including stent thrombosis, target lesion revascularisation (TLR), myocardial infarction (MI) and cardiac death were compared. Baseline characteristics were similar except for previous CABG (p = 0.02) and reference vessel diameter (p = 0.04). During hospitalisation, all cause death was more frequently observed in the PES group (p = 0.004). In-hospital MACE was not significantly different (p = 0.8). The incidence of 1-year MACE in the PES group was lower than that in the SES group (14.7%, 28.3%, p = 0.04), mainly due to the reduction of TLR (11.6%, 25.0%, p = 0.03). Rates of stent thrombosis (0%, 2.7%, p = 0.1), MI (1.1%, 3.8%, p = 0.2), and cardiac death (3.2%, 4.4%, p = 0.6) were not significantly different. CONCLUSIONS PES appears to be more efficient in reducing angiographic and clinical restenosis in dialysis patients compared with SES.

Dependency on atrial electrophysiological properties of appearance of paroxysmal atrial fibrillation in patients with Wolff-Parkinson-White syndrome: evidence from atrial vulnerability before and after radiofrequency catheter ablation and surgical cryoablation.

The pathogenesis of paroxysmal atrial fibrillation in patients with Wolff‐Parkinson‐White syndrome and the effects of elimination of accessory pathways on the appearance of atrial fibrillation are still controversial. Fifty‐four patients with Wolff‐Parkinson‐White syndrome were classified into three groups: a No AFgroup (n = 24), patients without paroxysmal atrial fibrillation; an RF‐AF Group (n =12), patients with paroxysmal atrial fibrillation whose accessory pathways were eliminated using radiofrequency catheter ablation; and a Cryo‐AF Group (n = 18), patients with paroxysmal atrial fibrillation whose accessory pathways were eliminated with surgical Cryoablation. The electrophysiological characteristics of each group were evaluated prior to and following the elimination of their accessory pathways. As indices of atrial vulnerability, the presence of fragmented atrial activity and repetitive atrial firing zones were assessed. Deducibility of atrial fibrillation was significantly reduced following ablation of accessory pathways in the Cryo‐AF group (83.3%‐5.6%, P < 0.0001), while it was unchanged in the RF‐AF group (83.3%‐75%). In preablation studies, the effective refractory periods of the atrium in the RF‐AF group and the Cryo‐AF group were significantly shorter compared with the No AF group (204 ± 18 ms, 197 ± 16 ms vs 246 ± 44 ms, respectively, P < 0.0001). Following ablation, the effective refractory period for patients in the Cryo‐AF group was significantly prolonged compared with before ablation (197 ± 16 ms to 232 ± 24 ms, P < 0.0001). As a result of this prolongation of the effective refractory period of the atrium, the fragmented atrial activity and repetitive atrial response zones narrowed following ablation in the Cryo‐AF group, but not in the RF‐AF group. Therefore, the pathogenesis of atrial fibrillation in patients with Wolff‐Parkinson‐White syndrome may depend on the refractory period of the atrium rather than on the presence of accessory pathways.

Intravenous administration of adenosine triphosphate disodium during primary percutaneous coronary intervention attenuates the transient rapid improvement of myocardial wall motion, not myocardial stunning, shortly after recanalization in acute anterior myocardial infarction.

BACKGROUND AND PURPOSE Administration of adenosine attenuates myocardial stunning after reperfusion in a canine experimental ischemic model. However, it is unknown whether administration of adenosine triphosphate disodium (ATP) during reperfusion can attenuate myocardial stunning after coronary recanalization in patients with acute myocardial infarction (MI). Therefore, we sought to elucidate the effects of ATP administration on serial changes of left ventricular systolic function before and after coronary recanalization. METHODS In 27 patients with first ST-elevation acute anterior MI, in whom primary percutaneous coronary intervention (PCI) was completed within 10 h after symptom onset, ATP at a mean rate of 103 microg/kg/min (n=16) or normal saline (n=11) was intravenously administered for 1 h during reperfusion. Left ventricular regional wall motion within the initially severely ischemic region was serially analyzed using the standard wall motion score index (WMSI) by transthoracic echocardiography. RESULTS Means of WMSIs were similar shortly before primary PCI in both groups (2.79 in ATP group and 2.69 in controls). They changed to 2.56 and 2.22 shortly after PCI, 2.49 and 2.39 on day 2, 2.34 and 2.30 on day 3, 2.19 and 2.25 on day 10, and 1.85 and 2.02, 6 months later, respectively. Transient improved regional wall motion within the initially severely ischemic region was observed shortly after PCI in controls (10.3% of observed segments); however, it was significantly suppressed in the ATP group (2.55%). The percent recovery of WMSI on day 10, which was defined as WMSI on day 10 normalized by improvement of WMSI for 6 months, was 63.8% in ATP group and 65.7% in controls, implying ATP administration could not reduce myocardial stunning by day 10 after primary PCI. CONCLUSIONS The high-dose administration of ATP during primary PCI prevented transient improved wall motion shortly after coronary recanalization rather than preventing left ventricular stunning. These results suggest that ATP can prevent reperfusion injury during primary PCI.

Comparison of thrombolysis in myocardial infarction perfusion grades 2 and 3 after anterior wall infarction

Abstract It has been shown that coronary thrombolysis is an effective therapy for patients with acute myocardial infarction (AMI) and benefits from thrombolytic therapy are greatest in patients with anterior wall AMI. 1 Although the success of reperfusion therapy should be evaluated by left ventricular function and survival, the patency status of the infarct-related artery at coronary angiography early after thrombolysis has been used as, an alternative end point. The most frequently used grading system has been proposed by the Thrombolysis in Myocardial Infarction (TIMI) study group. 2 The TIMI study group considered grade 0 or 1 to signify a closed artery and grade 2 or 3 an open artery; however, it is unclear whether grade 2 represents successful treatment as well as grade 3. To assess this issue, we examined the influence of TIMI perfusion grade on left ventricular function and survival in patients with anterior wall AMI.

A case of acute coronary syndrome caused by extrinsic compression of the left main coronary artery due to pulmonary hypertension

Stenosis of the left main coronary artery (LMCA) due to extrinsic compression, producing symptoms of myocardial ischemia, is called left main compression syndrome. We report on a 43-year-old male with acute coronary syndrome who developed left main compression syndrome while waiting for a lung transplantation secondary to interstitial pneumonia, but underwent successful LMCA stenting as emergent treatment. Coronary angiography 3 months after the operation showed good stent patency in the LMCA, and the clinical course was favorable.

Atrial electrical abnormality in patients with Brugada syndrome assessed by signal-averaged electrocardiography

Background Ventricular fibrillation and atrial fibrillation are well-known arrhythmias in patients with Brugada syndrome. This study evaluated the characteristics of the atrial arrhythmogenic substrate using the signal-averaged electrogram (SAECG) in patients with Brugada syndrome. Methods SAECGs were performed during normal sinus rhythm in 23 normal volunteers (control group), 21 patients with paroxysmal atrial fibrillation (PAF; PAF group), and 21 with Brugada syndrome (Brugada group). Results The filtered P wave duration (fPd) in the control, Brugada, and PAF groups was 113.9 ± 12.9 ms, 125.3 ± 15.0 ms, and 137.1 ± 16.3 ms, respectively. The fPd in the PAF group was significantly longer compared to that in the control and Brugada groups (p < 0.05). The fPd in the Brugada group was significantly longer than that in the control group (p < 0.05) and significantly shorter than that in the PAF group (p < 0.05). Conclusion Patients with Brugada syndrome had abnormal P waves on the SAECG. The abnormal P waves on the SAECG in Brugada syndrome patients may have intermediate characteristics between control and PAF patients.