Tomohide Endo

Plasma Soluble Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 as a Novel Prognostic Biomarker in Patients With ST-Segment Elevation Acute Myocardial Infarction

BACKGROUND Soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) level is a reliable prognostic biomarker in acute coronary syndrome. However, it is unclear whether its plasma level at acute phase is related to the long-term prognosis in patients with ST-segment elevation acute myocardial infarction (STEMI). METHODS AND RESULTS: We prospectively examined the relation between plasma sLOX-1 level on admission and prognosis in 153 consecutive STEMI patients admitted within 24 h of onset. Primary percutaneous coronary intervention was performed in 144 patients. The patients were divided into 2 groups by the median value (71 pg/ml) of plasma sLOX-1 level on admission [sLOX-1 level ≤71 pg/ml (n=77) and >71 pg/ml (n=76)], and were followed for median of 1,156 days. All-cause mortality and the combined endpoints of major adverse cardiovascular events (MACE) defined as cardiovascular mortality and recurrent MI were both significantly higher in patients with sLOX-1 values above median than in those below median (25.0% vs. 3.9%, P<0.001, and 19.4% vs. 6.5%, P=0.019 by log-rank test, respectively). Even after adjustment for confounders, a level of sLOX-1 above median was an independent predictor for all-cause mortality (hazard ratio (HR): 5.893; 95% confidence interval (CI): 1.665-20.854, P=0.006) and MACE (HR: 3.457; 95% CI: 1.164-10.270, P=0.030). CONCLUSIONS Elevated plasma sLOX-1 level on admission independently predicts long-term all-cause mortality and MACE after STEMI.

Low serum eicosapentaenoic acid level is a risk for ventricular arrhythmia in patients with acute myocardial infarction: a possible link to J-waves

Eicosapentaenoic acid (EPA) has antiarrhythmic effects. The J-wave on an electrocardiogram is associated with a high incidence of ventricular tachycardia/fibrillation (VT/VF). We evaluated relationships between EPA and J-waves, and their involvement in the occurrence of VT/VF in acute myocardial infarction (AMI). Two hundred consecutive patients undergoing successful percutaneous coronary intervention within 12 h after AMI onset were enrolled. Serum EPA level and J-waves at admission were evaluated. The patients were divided into two groups according to the optimal cutoff value (2.94) of serum EPA level (% of total fatty acids): LOW (<2.94, 61 ± 11 years, n = 103) and HIGH groups (≥2.94, 70 ± 13 years, n = 81). J-waves were observed more frequently in the LOW (36/103, 35 %) than in HIGH group (16/81, 20 %) (P = 0.020). The 30-day incidence of VT/VF including those occurring before admission was higher in the LOW (19.5 %) than in HIGH group (6.2 %) (P = 0.009). The patients with J-waves showed a higher incidence of VT/VF (23.1 %) than those without J-waves (9.9 %) (P = 0.019). Kaplan–Meier analysis showed that the highest incidence of VT/VF was observed in the LOW with J-wave group (27.8 %), followed by the LOW without J-wave (15.0 %), HIGH with J-wave (12.5 %), and HIGH without J-wave (4.6 %) (P = 0.013). Cox proportional hazard analysis revealed that Killip grade and low serum EPA level or presence of J-waves were significantly associated with the incidence of VT/VF. Low serum EPA level is a risk for incidence of VT/VF in the acute phase of myocardial infarction. Involvement of the J-wave and its possible link with EPA in the pathogenesis of ischemia-induced VT/VF are suggested.

Re-elevation of T-wave from day 2 to day 4 after successful percutaneous coronary intervention predicts chronic cardiac systolic dysfunction in patients with first anterior acute myocardial infarction

This study evaluates the clinical significance of re-elevation of T-wave in patients with ST segment elevation acute myocardial infarction (STEMI) undergoing successful percutaneous coronary intervention (PCI). Resolution of ST elevation within 24 h after reperfusion is associated with better outcome. However, little is known about the serial electrocardiography (ECG) changes and their significance. Seventy-five patients (52 men; 66 ± 1 years) with the first anterior STEMI in whom 12-lead ECG was recorded every day from day 0 to day 8 after PCI were studied. JT interval was quartered (points 1–5), and the deviations from isoelectric line at each point were analyzed in leads V2, V3, and V4. Serial ECG showed ST resolution and T-wave inversion within 2 days after PCI in all patients at the middle of JT interval (point 3), and subsequent re-elevation of T-wave on day 4 in 73 patients (97.3 %). The patients were divided into two groups: Group A (n = 37) with less JT deviation changes (<0.25 mV) from day 2 to day 4 at point 3; and Group B (n = 38) with greater JT deviation changes (≥0.25 mV). Group B had less retrograde collateral flow and longer JT interval in the acute phase, and lower left ventricular ejection fraction (LVEF), worse regional contractility, and higher plasma brain natriuretic peptide levels at 6 months after the onset than Group A (all P < 0.05). The JT deviation change was negatively correlated with and an independent predictor for LVEF in the chronic phase. Re-elevation ≥0.25 mV of T-wave at the middle of JT interval after successful PCI predicts chronic cardiac systolic dysfunction in patients with first anterior STEMI.

Relationship Between Serum Eicosapentaenoic Acid Levels and J-Waves in a General Population in Japan: Analysis of the Iwaki Health Promotion Project

We previously showed that J-waves were found more frequently in patients with low levels of serum eicosapentaenoic acid (EPA) in the acute phase of myocardial infarction, and were associated with the incidence of ischemia-related ventricular arrhythmias. However, the relationship between J-waves and serum EPA levels in a general population remains to be elucidated.The Iwaki Health Promotion Project is an ongoing community-based health promotion study in Iwaki, Hirosaki, which is in northern Japan. A total of 1,052 residents (mean age, 53.9 ± 15.4 years; 390 men) who participated in this project in 2014 were studied. A standard 12-lead electrocardiogram (ECG) was recorded and serum EPA levels were measured to evaluate the relationship between J-waves and serum EPA levels. J-waves were found in 52 (5%) subjects and were observed more frequently in male than female subjects (44 [11%] versus 8 [1%], P < 0.0001). More than half of the J-waves were the notched type (60%), and J-waves were detected most frequently in inferior leads on ECG (52%). The RR interval was longer and QTc duration shorter in subjects with J-waves than those without. No significant difference was found in serum EPA levels between subjects with and without J-waves (70 [49-116] versus 65 [41-106] μg/mL, P = 0.40). In multivariate analysis, male gender and RR interval were independent factors associated with the presence of J-waves.There was no significant relationship between J-waves and serum EPA levels in this general population in Japan. Various mechanisms for manifestation of the J-waves are suggested.

Enhanced transient receptor potential channel‐mediated Ca2+ influx in the cells with phospholipase C‐δ1 overexpression: its possible role in coronary artery spasm

We reported that coronary spasm was induced in the transgenic mice with the increased phospholipase C (PLC)‐δ1 activity. We investigated the effect of enhanced PLC‐δ1 on Ca2+ influx and its underlying mechanisms. We used human embryonic kidney (HEK)‐293 and coronary arteries smooth muscle cells (CASMC). Intracellular free Ca2+ concentration ([Ca2+]i; nm) was measured by fura‐2, and Ca2+ influx was evaluated by the increase in [Ca2+]i after addition of extracellular Ca2+. Acetylcholine (ACh) was used to induce Ca2+ influx. ACh‐induced peak Ca2+ influx was 19 ± 3 in control HEK‐293 cells and 71 ± 8 in the cells with PLC‐δ1 overexpression (P < 0.05 between two groups). Nifedipine partially suppressed this Ca2+ influx, whereas either 2‐APB or knockdown of classical transient receptor potential channel 6 (TRPC6) blocked this Ca2+ influx. In the human CASMC, ACh‐induced peak Ca2+ influx was 29 ± 6 in the control and was increased to 45 ± 16 by PLC‐δ1 overexpression (P < 0.05). Like HEK‐293 cells, pretreatment with nifedipine partially suppressed Ca2+ influx, whereas either 2‐APB or knockdown of TRPC6 blocked it. ACh‐induced Ca2+ influx was enhanced by PLC‐δ1 overexpression, and was blocked partially by nifedipine and completely by 2‐APB. TRPC‐mediated Ca2+ influx may be related to the enhanced Ca2+ influx in PLC‐δ1 overexpression.

A case of inappropriate implantable cardioverter defibrillator shock due to epileptic seizures: A possible limitation of the Wavelet discrimination algorithm

In the present report, we describe the case of a 63‐year‐old man who received an inappropriate implantable cardioverter defibrillator (ICD) shock due to an epileptic seizure. He experienced an acute myocardial infarction 12 months previously, and his left ventricular (LV) ejection fraction was markedly reduced (21.1%) due to the presence of advanced LV remodeling and an LV aneurysm. An implantable cardioverter‐defibrillator (ICD, Medtronic Protecta XT VR) was implanted for the primary prevention of sudden cardiac death. After the implantation, ICD shock data were transmitted via a remote monitoring system. Although many episodes of tachycardia due to atrial fibrillation (AF) were detected, inappropriate discharge was avoided by the use of the Wavelet™ morphology discrimination algorithm (Medtronic Inc., MN, USA). However, an ICD shock was inappropriately delivered for AF tachycardia accompanied by frequent noise detected in the intracardiac electrocardiogram. A detailed analysis showed that the observed noise was derived from the myopotential induced by an epileptic seizure, which overlapped with the QRS wave. This resulted in inappropriate ICD shock delivery that could not be avoided with the use of Wavelet algorithm. To eliminate the involvement of the myopotential derived from an epileptic seizure, the nominal direction of the intracardiac electrocardiogram was changed. This adjustment prevented inappropriate ICD shock delivery during subsequent epileptic seizures. Here, we describe for the first time a case of inappropriate ICD shock delivery induced by an epileptic seizure, suggesting a possible limitation of the Wavelet discrimination algorithm.

Prognostic impact of atrial fibrillation in patients with acute myocardial infarction

Atrial fibrillation (AF) is the most common supraventricular tachyarrhythmia in patients with acute myocardial infarction (AMI). However, little is known about the impact of AF on in‐hospital and long‐term mortalities in patients with AMI in the era of primary percutaneous coronary intervention (PCI).