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Weather conditions affect the incidence of acute myocardial infarction (AMI). However, little is known on the association of weather temperature and humidity with AMI hospitalizations in a super-aging society. This study sought to examine this association. We included 87,911 consecutive patients with AMI admitted to Japanese acute-care hospitals between April 1, 2012 and March 31, 2015. The primary outcome was the number of AMI hospitalizations per day. Multilevel mixed-effects linear regression models were used to estimate the association of the average temperature and humidity, 1 day before hospital admission, with AMI hospitalizations, after adjusting for weather, hospital, and patient demographics.Lower temperature and humidity were associated with an increased number of AMI hospitalizations (coefficient - 0.500 [- 0.524 to - 0.474] per °C change, p < 0.001 and coefficient - 0.012 [- 0.023 to - 0.001] per % change, p = 0.039, respectively). The effects of temperature and humidity on AMI hospitalization did not differ by age and sex (all interaction p > 0.05), but differed by season. However, higher temperatures in spring (coefficient 0.089 [0.025 to 0.152] per °C change, p = 0.010) and higher humidity in autumn (coefficient 0.144 [0.121 to 0.166] per % change, p < 0.001) were risk factors for AMI hospitalization. Increased average temperatures and humidity, 1 day before hospitalization, are associated with a decreased number of AMI hospitalizations., (© 2021. The Author(s).)

Although exposure to particulate matter with aerodynamic diameters ≤ 2.5 µm (PM 2.5 ) influences cardiovascular disease (CVD), its association with CVD-related hospitalizations of super-aged patients in Japan remains uncertain. We investigated the relationship between short-term PM 2.5 exposure and CVD-related hospitalizations, lengths of hospital stays, and medical expenses. We analyzed the Japanese national database of patients with CVD (835,405) admitted to acute-care hospitals between 2012 and 2014. Patients with planned hospitalizations and those with missing PM 2.5 exposure data were excluded. We classified the included patients into five quintiles based on their PM 2.5 exposure: PM-5, -4, -3, -2, and -1 groups, in descending order of concentration. Compared with the PM-1 group, the other groups had higher hospitalization rates. The PM-3, -4, and -5 groups exhibited increased hospitalization durations and medical expenses, compared with the PM-1 group. Interestingly, the hospitalization period was longer for the ≥ 90-year-old group than for the ≤ 64-year-old group, yet the medical expenses were lower for the former group. Short-term PM 2.5 exposure is associated with increased CVD-related hospitalizations, hospitalization durations, and medical expenses. The effects of incident CVDs were more marked in elderly than in younger patients. National PM 2.5 concentrations should be reduced and the public should be aware of the risks.

Complete atrioventricular block (CAVB) is a common complication of ST-segment elevation myocardial infarction (STEMI). Although STEMI patients complicated with CAVB had a higher mortality in the thrombolytic era, little is known about the impact of CAVB on STEMI patients who underwent primary percutaneous coronary intervention (PCI). The study aimed at evaluating the clinical impact of CAVB on STEMI patients in the primary PCI era. We consecutively enrolled 1295 STEMI patients undergoing primary PCI within 24 hours from onset. Patients were divided into two groups according to the infarct location: anterior STEMI (n = 640) and nonanterior STEMI (n = 655). The outcomes were all-cause death and major adverse cardiocerebrovascular events (MACCE) with a median follow-up period of 3.8 (1.7-6.6) years. Eighty-one patients (6.3%) developed CAVB. The incidence of CAVB was lower in anterior STEMI patients than in nonanterior STEMI (1.7% vs 10.7%, p < .05). Anterior STEMI patients with CAVB had a higher incidence of all-cause deaths (82% vs 20%, p < .05) and MACCE (82% vs 25%, p < .05) than those without CAVB. Although higher incidence of all-cause deaths was found more in nonanterior STEMI patients with CAVB compared with those without CAVB (30% vs 18%, p < .05), there was no significant difference in the incidence of MACCE (24% vs 19%). Multivariate analysis showed that CAVB was an independent predictor for all-cause mortality and MACCE in anterior STEMI patients, but not in nonanterior STEMI. CAVB is rare in anterior STEMI patients, but remains a poor prognostic complication even in the primary PCI era., (© 2020 The Authors. Clinical Cardiology published by Wiley Periodicals LLC.)

Background Seasonal variations in acute coronary syndromes (ACS) have been reported, with incidence and mortality peaking in the winter. However, the underlying pathophysiology for these variations remain speculative. Methods and Results Patients with ACS who underwent optical coherence tomography were recruited from 6 countries. The prevalence of the 3 most common pathologies (plaque rupture, plaque erosion, and calcified plaque) were compared between the 4 seasons. In 1113 patients with ACS (885 male; mean age, 65.8±11.6 years), the rates of plaque rupture, plaque erosion, and calcified plaque were 50%, 39%, and 11% in spring; 44%, 43%, and 13% in summer; 49%, 39%, and 12% in autumn; and 57%, 30%, and 13% in winter ( P =0.039). After adjusting for age, sex, and other coronary risk factors, winter was significantly associated with increased risk of plaque rupture (odds ratio [OR], 1.652; 95% CI, 1.157-2.359; P =0.006) and decreased risk of plaque erosion (OR, 0.623; 95% CI, 0.429-0.905; P =0.013), compared with summer as a reference. Among patients with rupture, the prevalence of hypertension was significantly higher in winter ( P =0.010), whereas no significant difference was observed in the other 2 groups. Conclusions Seasonal variations in the incidence of ACS reflect differences in the underlying pathobiology. The proportion of plaque rupture is highest in winter, whereas that of plaque erosion is highest in summer. A different approach may be needed for the prevention and treatment of ACS depending on the season of its occurrence. Registration URL: https://www.clini​caltr​ials.gov. Unique identifier: NCT03479723.

Background: Although left bundle-branch block (LBBB) is a known conduction disorder that occurs after transcatheter aortic valve implantation (TAVI), its clinical impact in the Japanese population remains unclear., Methods and results: Of the 298 consecutive patients who underwent TAVI from January 2016 to December 2018 in a high-volume center in Japan, 68 with prior or periprocedural permanent pacemaker implantation (PPI), pre-existing LBBB, death during hospitalization, aborted procedure, or incomplete data were excluded. Among the final cohort of 230 patients, new-onset LBBB occurred in 90 (39%) after TAVI and persisted at 1-month follow up in 29 patients (13%; persistent new-onset LBBB, PN-LBBB). On multivariable analysis, self-expandable valve (SEV) use was found to be the only predictor of PN-LBBB (odds ratio: 4.39, 95% confidence interval: 1.69-11.41, P=0.002). There were no differences between patients with and without PN-LBBB in terms of overall mortality (18.8% vs. 26.0%, log-rank P=0.90) or need for late PPI (4.0% vs. 3.5%, log-rank P=0.74), yet there was an increased re-admission rate for heart failure (HF) in the PN-LBBB group (15.6% vs. 8.0%, log-rank P=0.046) at a median follow up of 431 (interquartile range, 271-733) days., Conclusions: PN-LBBB following TAVI was not associated with mortality or late PPI, but with a higher incidence of HF-related re-hospitalization at the mid-term follow up.

Patients with acute myocardial infarction (AMI) with low body mass index (BMI) have worse outcomes than obese patients, and this phenomenon is recognized as "obesity paradox." Coronary calcification is associated with cardiac events. However, the association between BMI and calcification and their involvement in the mortality of AMI patients remain unknown. This study consecutively enrolled 517 patients with AMI who underwent emergent coronary intervention within 24 h after onset. Patients were divided into four groups according to the baseline BMI interquartile ranges: Q1 (BMI < 21.9 kg/m 2 ), Q2 (21.9 ≤ BMI < 24.0 kg/m 2 ), Q3 (24.0 ≤ BMI < 26.0 kg/m 2 ), and Q4 (BMI ≥ 26.0 kg/m 2 ). Calcification in the culprit lesion was also evaluated. The Q1 group was older and had a lower frequency of coronary risk factors. Moderate/severe calcification was most frequently observed in Q1, followed by Q2, Q3, and Q4. The Q1 group had the highest all-cause mortality, and patients with moderate/severe calcification had a higher all-cause mortality than that in patients without calcification. The highest all-cause mortality was observed in Q1with calcification, and the lowest was in Q4 without calcification. Q1 and the presence of moderate/severe calcification were independently associated with all-cause mortality. Although low-BMI patients with AMI had a lower frequency of coronary risk factors, they had a worse all-cause mortality than that in high-BMI patients. Our findings suggest that lesion calcification and its possible association with low BMI are involved in the higher mortality rate in these patients.

Background: The entirely subcutaneous implantable cardioverter defibrillator (S-ICD) was introduced as a new alternative to conventional transvenous ICD (TV-ICD) in Japan in February 2016, but its safety and efficacy are unclear.Methods and Results:A total of 60 patients (48 men, median age, 60 years; IQR, 44-67 years; primary prevention, n=24) underwent S-ICD implantation between February 2016 and August 2017. The device pocket was formed in the intermuscular space between the serratus anterior muscle and the latissimus dorsi muscle, and the parasternal S-ICD lead was placed according to pre-implant screening. Defibrillation test was performed in 56 patients (93%). Ventricular fibrillation (VF) was induced in 55 patients and terminated by a single 65-J shock in all patients. The median time to shock therapy was 13.4 s (IQR, 12.1-14.9 s) and the median post-shock impedance of the S-ICD lead was 64 Ω (IQR, 58-77 Ω). There were no operation-related complications or subsequent infectious complications. During follow-up (median, 275 days; IQR, 107-421 days), 1 patient (1.7%) had appropriate shock for VF with successful termination, whereas 5 patients (8.3%) had inappropriate shock due to oversensing of myopotential (n=3) or T-wave (n=1), and detection of supraventricular tachycardia (n=1)., Conclusions: S-ICD is a safe and effective alternative to conventional TV-ICD. The long-term safety and efficacy of the S-ICD need further investigation.

Background: There are few reports examining regional differences between rural prefectures and metropolitan areas in the management of acute myocardial infarction (AMI) in Japan.Methods and Results:In the Rural AMI registry, a prospective, multi-prefectural registry of AMI in 4 rural prefectures (Ishikawa, Aomori, Ehime and Mie), a total of 1,695 consecutive AMI patients were registered in 2013. Among them, 1,313 patients who underwent primary percutaneous coronary intervention (PPCI) within 24 h of onset were enrolled in this study (Rural group), and compared with the cohort data from the Tokyo CCU Network registry for AMI in the same period (Metropolitan group, 2,075 patients). The prevalence of direct ambulance transport to PCI-capable facilities in the Rural group was significantly lower than that in the Metropolitan group (43.8% vs. 60.3%, P<0.01), which resulted in a longer onset-to-balloon time (OTB: 225 vs. 210 min, P=0.02) and lower prevalence of PPCI in a timely fashion (OTB ≤2 h: 11.5% vs. 20.7%, P<0.01) in the Rural group. Multivariate analysis revealed that direct ambulance transport was the strongest predictor for PPCI in a timely fashion (odds ratio=4.13, P<0.001)., Conclusions: AMI patients in rural areas were less likely to be transported directly to PCI-capable facilities, resulting in time delay to PPCI compared with those in metropolitan areas.

Background: The wearable cardioverter-defibrillator (WCD) has been expected to play a role as an effective bridge therapy to implantable cardioverter-defibrillator (ICD) implantation in patients at high risk of ventricular tachyarrhythmias (VA). Although WCD has been available since April 2014 in Japan, its usefulness remains unclear., Methods and Results: During the early period after hospitalization, patients at high risk of VA after excluding some elderly patients were prescribed WCD. The consecutive 50 patients with WCD use (median age 56 years, 38 for secondary prevention) were studied. We analyzed clinical efficacy and safety of WCD, and examined its potential roles. Of the 50 patients, 38 used WCD only during hospitalization. During WCD use [median 16 (IQR 8-33) days], all patients wore WCD for 98% of a day regardless of in or out-of-hospital use. Sustained VA was detected in 4 patients (8%; for primary prevention in 1) with 7 episodes, and 6 of 7 episodes required shock therapy. Of the 6 shock therapies, 4 were for sustained ventricular tachycardia with the median rate of 236beats/min (IQR 203-250), and the other 2 for ventricular fibrillation. Subsequently, only 27 patients (54%) of all underwent ICD implantation following the WCD use, because of reduced risk of VA after optimal pharmacological therapy or improvement in the left ventricular function., Conclusions: The WCD use for the acute phase care of patients at high risk of VA can be safe and effective, and may be useful for evaluating indication of ICD implantation., (Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Objectives: We compared the efficacy of once-daily administration of nifedipine CR 40 mg (N) with that of twice-daily diltiazem R 100mg (D) in patients with vasospastic angina (VSA) registered in 8 cardiovascular institutes in Aomori Prefecture., Methods and Results: VSA was diagnosed by the ischemic ST segment changes during chest pain attacks at rest and/or acetylcholine induction test done during coronary angiography. Thirty-seven patients were randomly allocated to either the N (n=20) or D group (n=17). The number of symptomatic attacks and amount of short-acting nitrate use were examined based on data in diaries written by the patients. There were no significant differences in the baseline characteristics between the two groups. The mean number (median number) of attacks per week was significantly decreased in the N group from 2.56 (2.0) at baseline to 0.41 (0.0) after 4 weeks of treatment, to 0.24 (0.0) after 8 weeks, and to 0.36 (0.0) after 12 weeks (all p<0.05 vs. baseline). It was also decreased in D group from 2.71 (2.0) at baseline to 0.55 (0.0) after 4 weeks, to 0.32 (0.0) after 8 weeks, and to 0.27 (0.0) after 12 weeks (all p<0.05 vs. baseline). The numbers of attacks before and after treatment were comparable between N and D groups. In one patient in each of the N and D groups, the allocated drug was crossed over to the other due to recurrence of the attacks. One patient in each group experienced adverse effects and the drug was changed to the other., Conclusion: Once-daily administration of nifedipine CR was as effective as twice-daily diltiazem R in the prevention of VSA attacks., (Copyright © 2010 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

The etiology of coronary spastic angina (CSA) remains uncertain. Mice lacking the gene encoding the inwardly rectifying K(+) channel Kir6.1 were developed as an animal model of CSA. We investigated whether mutation in the coding region of the Kir6.1 gene is detected in Japanese patients with CSA. The study population included 19 Japanese patients with CSA (10 men and 9 women with a mean age of 61+/-14 years). Mutational analysis of the coding region of Kir6.1 was performed by direct sequencing. We found no missense or nonsense mutations in these samples, but we found in one female CSA patient, a single base substitution (C to T) at nucleotide position 111 in exon 2 of the coding region, which was heterozygous and did not cause amino acid substitution (Ile37Ile, silent mutation). In the remaining 18 patients, no base substitution was detected in the coding region of the Kir6.1 gene. No mutation that alters primary structure of Kir6.1 was detected in Japanese patients with CSA. The results indicate that abnormality in the primary structure of Kir6.1 may not be involved in the genetic pathogenesis of CSA in humans.