Left Atrial Appendage Closure in Patients With a Mechanical Mitral Valve Prosthesis: A Multicentre Italian Pilot Study.

BACKGROUND: In patients with atrial fibrillation (AF) on vitamin K antagonist (VKA) therapy and therapeutic international normalized ratio (INR) range, the incidence of cardiac thromboembolism is not negligible, and the subgroup of patients who have a mechanical prosthetic mitral valve (PMV) has the highest risk. We aimed to assess the long-term effects of left atrial appendage closure (LAAC) in AF patients with a mechanical PMV who experienced a failure of VKA therapy. METHODS: In this retrospective, multicentre study, patients underwent LAAC because of thrombotic events including transient ischemic attack and/or stroke, systemic embolism, and evidence of left atrial appendage thrombosis and/or sludge, despite VKA therapy, were enrolled. Patients with a mechanical PMV were included and compared with those affected by nonvalvular AF. The primary endpoint was the composite of all-cause death, major cardiovascular events, and major bleedings at follow-up. The feasibility and safety of LAAC also were assessed. RESULTS: A total of 55 patients (42% female; mean age, 70 ± 9 years), including 12 with a mechanical PMV, were enrolled. The most-frequent indication to LAAC (71%) was LAA thrombosis or sludge. Procedural success was achieved in 96% of overall cases, and in 100% of patients with a PMV. In 35 patients, a cerebral protection device was used. During a median follow-up of 6.1 ± 4.3 years, 4 patients with a PMV, and 20 patients without a PMV, reported adverse events (hazard ratio 0.73 [95% confidence interval 0.25-2.16, P = 0.564]). CONCLUSIONS: LAAC seems to be a valuable alternative in patients with AF who have a mechanical PMV, with failure of VKA therapy. This off-label, real-world clinical practice indication deserves validation in further studies.

Long-term safety and efficacy of left atrial appendage occlusion in dialysis patients with atrial fibrillation: a multi-center, prospective, open label, observational study.

Background: The prevalence of atrial fibrillation (AF) in end stage kidney disease (ESKD) patients undergoing dialysis is high, however, the high risk of bleeding often hampers with a correct anticoagulation in ESKD patients with AF, despite high thromboembolic risk. Left atrial appendage (LAA) occlusion is a anticoagulation (OAT) for thromboembolism prevention in AF populations with high hemorrhagic risk. Methods and Results: The purpose of the study was to evaluate the efficacy and safety of LAA occlusion in a cohort of dialysis patients undergoing the procedure (LAA occlusion cohort, n = 106), in comparison with two other ESKD cohorts, one taking warfarin (Warfarin cohort, n = 114) and the other without anticoagulation therapy (No-OAT cohort, n = 148). After a median follow-up of 4 years, a Cox regression model, adjusted for possible confounding factors, showed that the hazard ratios (HRs) of thromboembolic events in the LAA occlusion cohort were 0.19 (95%CI 0.04-0.96; p = 0.045) and 0.16 (95%CI 0.04-0.66; p = 0.011) as compared with Warfarin and No-OAT cohorts, respectively. The HR of bleeding in the LAA occlusion cohort was 0.37 (95%CI 0.16-0.83; p = 0.017) compared to Warfarin cohort, while there were no significant differences between the LAA occlusion and the No-OAT cohort (HR 0.51; 95%CI 0.23-1.12; p = 0.094). Adjusted Cox regression models showed lower mortality in patients undergoing LAA occlusion as compared with both the Warfarin cohort (HR 0.60; 95%CI 0.38-0.94; p = 0.027) and no-OAT cohort (HR 0.52; 95%CI 0.34-0.78; p = 0.002). Thromboembolic events in the LAA occlusion cohort were lower than expected according to the CHA2DS2VASc score (1.7 [95%CI 0.3-3.0] vs 6.7 events per 100 person/years, p < 0.001). Conclusion: In ESKD patients with AF, LAA occlusion is safe and effective and is associated with reduced mortality compared with OAT or no therapy.

A new echocardiographic index to select patients for PFO suture-mediated percutaneous closure.

OBJECTIVES: To identify a simple echocardiographic predictor of procedural success to select patient for percutaneous suture-mediated patent fossa ovalis (PFO) closure. BACKGROUND: Percutaneous suture-mediated PFO closure has been shown as a safe and advantageous alternative to device-based PFO closure, yet its overall success is slightly lower in unselected patients. METHODS: Preprocedural transesophageal echocardiogram (TEE) of 302 patients (113 men, 45 ± 12 years) who underwent percutaneous suture-mediated PFO closure were reviewed. RESULTS: At echocardiographic follow-up (3-6 months), residual right-to-left shunt (RLS) ≥2 was found in 60 (19.9%) patients. At multivariable analysis, only two anatomical variables measured at preprocedural TEE were found as independent predictors of residual RLS ≥ 2 at follow-up: PFO maximum width (odds ratio [OR] 1.89, 95% confidence interval [CI] 1.16-3.40, p = 0.02) and PFO minimal septa overlapping (OR 0.58, 95% CI 0.35-0.88, p = 0.02). An index based on the ratio of PFO maximum width to PFO minimum septal overlapping (W/SO) proved to be the most powerful predictor of RLS ≥ 2 at follow-up (OR 48.1, 95% CI 9.3-352.2, p < 0.01). The ROC curve for the W/SO ratio was found to have an AUC of 0.84 (95% CI 0.75-0.93) and a cut-off value of 0.61 yielding a sensitivity of 80% and specificity of 78% with a negative predictive value of 94%. A decision tree methodology's AUC was 0.75 (95% CI 0.67-0.83). CONCLUSIONS: The results of this study indicate that the ratio between the maximum amplitude of the PFO and the minimum overlap of the septa is the best predictive index of a favorable result by using one stitch only.

A comprehensive and easy-to-use ECG algorithm to predict the coronary occlusion site in ST-segment elevation myocardial infarction.

BACKGROUND: Several electrocardiogram (ECG) criteria have been proposed to predict the location of the culprit occlusion in specific subsets of patients presenting with ST-segment elevation myocardial infarction (STEMI). The aim of this study was to develop, through an independent validation of currently available criteria, a comprehensive and easy-to-use ECG algorithm, and to test its diagnostic performance in real-world clinical practice. METHODS: We analyzed ECG and angiographic data from 419 consecutive STEMI patients submitted to primary percutaneous coronary intervention over a one-year period, dividing the overall population into derivation (314 patients) and validation (105 patients) cohorts. In the derivation cohort, we tested >60 previously published ECG criteria, using the decision-tree analysis to develop the algorithm that would best predict the infarct-related artery (IRA) and its occlusion level. We further assessed the new algorithm diagnostic performance in the validation cohort. RESULTS: In the derivation cohort, the algorithm correctly predicted the IRA in 88% of cases and both the IRA and its occlusion level (proximal vs mid-distal) in 71% of cases. When applied to the validation cohort, the algorithm resulted in 88% and 67% diagnostic accuracies, respectively. In a real-world comparative test, the algorithm performed significantly better than expert physicians in identifying the site of the culprit occlusion (P = .026 vs best cardiologist and P < .001 vs best emergency medicine doctor). CONCLUSIONS: Derived from an extensive literature review, this comprehensive and easy-to-use ECG algorithm can accurately predict the IRA and its occlusion level in all-comers STEMI patients.

Clinical impact of the extent of jeopardized myocardium in patients undergoing transcatheter aortic valve intervention.

INTRODUCTION AND OBJECTIVES: Coronary artery disease (CAD) is found in 30%-50% of patients with severe aortic stenosis (AS) undergoing treatment. The best management of CAD in AS patients undergoing transcatheter aortic valve implantation (TAVI) is still unclear. We investigated the clinical impact of the extent of jeopardized myocardium in patients with concomitant CAD and severe AS treated by TAVI. METHODS: Consecutive patients who underwent TAVI procedures at our hospital were identified. In the presence of CAD, the myocardium jeopardized before TAVI was graded using the British Cardiovascular Intervention Society (BCIS) jeopardy score (JS). The study population was divided in 3 groups: patients without concomitant CAD (no-CAD), patients with CAD and BCIS-JS ≤ 4 (CAD BCIS-JS ≤ 4) and patients with concomitant CAD and BCIS-JS> 4 (CAD BCIS-JS> 4). The primary study endpoint was major adverse cardiovascular and cerebrovascular events (MACCE). RESULTS: A total of 403 patients entered the study: 223 no-CAD, 94 CAD BCIS-JS ≤ 4 and 86 CAD BCIS-JS> 4. At> 3 months of follow-up [range 104-3296 days], patients without CAD and CAD patients with BCIS-JS ≤ 4 had better survival free from MACCE compared with those with less extensive revascularization (BCIS-JS> 4) (P=.049). This result was driven by a significant reduction in death (P=.031). On multivariate analysis, residual BCIS-JS ≤ 4 and NYHA class III-IV independently predicted MACCE. CONCLUSIONS: In patients with concomitant CAD and severe AS, the extent of jeopardized myocardium before TAVI impacts on clinical outcomes.

Left atrial appendage closure: a new strategy for cardioembolic events despite oral anticoagulation.

BACKGROUND: Patients with non-valvular atrial fibrillation (nvAF) who experienced a cardioembolic (CE) event despite adequate oral anticoagulation (OAC) are at high risk of recurrence, and further prevention strategies are deemed necessary. The present study aimed to evaluate the safety and efficacy of off-label use of left atrial appendage closure (LAAC) in this subset of patients. METHODS: Seventy-five consecutive patients with nvAF who experienced a CE event despite adequate OAC therapy were retrospectively enrolled from two Italian centers. Patients were divided according to the treatment strategy following the index event: DOAC group (49 patients who continued OAC therapy with DOACs) and LAAC group (26 patients who underwent LAAC procedure). 1:1 propensity-score matching between the two groups was performed. LAAC group was made up of two subgroups according to the post-procedural pharmacological regimen: 1) dual antiplatelet therapy (DAPT) for 3 months followed by indefinite single antiplatelet therapy (LAAC+SAPT); or 2) aspirin plus DOAC for 3 months followed by indefinite DOAC therapy (LAAC+DOAC). The primary endpoint was a composite of CE event, major bleeding, or procedure-related major complication. RESULTS: During a median follow-up of 3.4 years (IQR: 2.0-5.3), LAAC was a predictor of primary endpoint-free survival (HR=0.28, 95% CI: 0.08-0.97; P=0.044); within LAAC group, no procedure-related major complication occurred. Moreover, a trend toward a lower rate of both CE events and major bleedings was observed in LAAC group, particularly in the subgroup LAAC+DOAC. CONCLUSIONS: LAAC is a reasonable therapeutic option in nvAF patients who suffered a CE event despite adequate OAC therapy.

Atrial function analysis after percutaneous umbrella device and suture-mediated patent fossa ovalis closure.

BACKGROUND: Atrial fibrillation is an undesirable event following percutaneous patent fossa ovalis (PFO) closure with metallic occluders, suggesting that implanting a rigid closure device could alter atrial function. Suture-mediated PFO closure is a new technique, achieving closure of the PFO by means of a simple suture. Aim of this study was to evaluate left atrial function after closure of PFO by direct suture and traditional occluders. METHODS: We studied 40 age and sex homogeneous patients, 20 undergoing PFO closure by device (OCL) and 20 by suturing (NS). Twenty healthy sex-age matched subjects made up the control group (CT). Left atrial function was evaluated by using volumetric and speckle-tracking analysis assessing the following parameters: total emptying fraction (EF), Expansion Index (EI), active emptying fraction (AEF), strain values of the reservoir (r-ED), conduit (cd-ED) and contraction phase (ct-ED). RESULTS: Compared to CT and NS, OCL patients had significantly worst indices of left atrial reservoir function (EF P=0.001, EI P=0.003, r-ED P<0.001), conduit function (cd-ED P=0.018) and contraction function (AEF P=0.010; ct-ED P<0.001). No significant differences were observed in left atrial function indices between CT and NS patients. CONCLUSIONS: Suture-mediated PFO closure does not alter left atrial function. Conversely, metallic occluder is associated with worse left atrium function. This detrimental effect on atrial function could favor the development of atrial arrhythmias.

Dual pathway inhibition in atherothrombosis prevention: yes, now we can!

Despite ongoing developments, prevention and treatment of atherothrombotic cardiovascular disease remains a common challenge. Antithrombotic options for cardiocerebrovascular disease prevention involves a choice between dual antiplatelet therapy (DAPT) and dual pathway inhibition (DPI), which includes an antiplatelet agent and a reduced dose anticoagulant agent. In selected patients at high risk of event and low risk of bleeding, especially those undergoing recent and complex coronary revascularization using drug-eluting stents (DES) ("revascularization-driven effect"), DAPT is superior to single antiplatelet therapy with aspirin. DPI involves a wider potential range of treatment and is superior to single antiplatelet therapy with aspirin, particularly in patients with atherothrombotic involvement in different vascular beds both previously revascularized and not ("no revascularization-driven effect"). After nearly thirty years of randomized trials and observational registries, we have sufficient data to customize antithrombotic therapy in patients at high cardiovascular risk. Therefore, "atherothrombosis stakeholders" must identify the right patient for the right therapy to ensure high levels of efficacy and safety with the best of current therapeutic opportunities.

Percutaneous suture-mediated patent foramen ovale closure: two-year clinical follow-up.

BACKGROUND: Percutaneous suture-mediated patent foramen ovale (PFO) closure has been recently introduced in clinical practice showing a favorable efficacy and safety profile in most PFO cases. The aim of this study was to assess the long-term outcomes of PFO closure by direct suture in a large consecutive series of patients. METHODS: We extracted all consecutive patients who underwent percutaneous closure of the PFO by suture technique (HeartStitch, Fountain Valley, CA, USA) from June 2016 with a follow-up of at least 2 years. After PFO closure, patients were followed-up clinically at 1, 6 and up to 12 months and microbubble transthoracic echocardiography (TTE) scheduled between 3 and 6 months, and at 12-month follow-up. After 12 months, patients were clinically checked every 6 months. RESULTS: As of September 1, 2020, 187 patients had undergone PFO closure with suture for at least two years and, of these, 181 (121 women and 60 men, mean age 45±13 years, range 15-75 years) had complete clinical and instrumental follow-up (97%). There were no peri-procedural complications. Mean follow-up was 1076±251 days (range 727-1574). At 12-month TTE, a significant residual atrial shunt was found in 39 patients (21%). At follow-up no recurrent thromboembolic or cerebral event occurred, no instrumental evidence of suture dehiscence detected and, 18 months after the procedure, one patient had an episode of transient atrial fibrillation lasting less than 24 hours and resolved spontaneously. CONCLUSIONS: Long-term follow-up data indicate that PFO closure by direct suturing is safe and effective. Two years after the procedure, there were no significant complications, no permanent arrhythmic complications and evidence of suture dehiscence.

[Italian Society of Interventional Cardiology (SICI-GISE) Position paper: Transcatheter left atrial appendage occlusion in patients with non-valvular atrial fibrillation]. / Documento di posizione della Società Italiana di Cardiologia Interventistica (SICI-GISE): Chiusura percutanea dell'auricola sinistra in pazienti affetti da fibrillazione atriale non valvolare.

Atrial fibrillation (AF) is the most common arrhythmia worldwide. Thromboembolism from the left atrial appendage (LAA) is the most feared complication in patients with AF. The cornerstone for the management of AF is oral anticoagulation to reduce the incidence of cardioembolic stroke. There is, however, a significant proportion of patients who cannot undergo long-term oral anticoagulation. Transcatheter LAA occlusion is an evolving technology with proven benefits in terms of AF-related stroke prevention, representing a valid alternative to anticoagulation for high-risk patients with contraindications for long-term oral anticoagulation. This has resulted in the development of a plethora of transcatheter devices to achieve endocardial occlusion or epicardial exclusion of the LAA.A panel of expert Italian cardiologists gathered under the aegis of the Italian Society of Interventional Cardiology (SICI-GISE) with the aim of reviewing the most relevant aspects of LAA occlusion, underlying anatomy and pathophysiology, summarizing current clinical knowledge, and discussing the practicalities of available devices and imaging techniques. Finally, the position paper highlights the importance of an adequate environment and of an appropriate organization in order to optimize all steps of the procedure.

Cluster analysis of weather and pollution features and its role in predicting acute cardiac or cerebrovascular events.

BACKGROUND: Despite mounting evidence, the impact of the interplay between weather and pollution features on the risk of acute cardiac and cerebrovascular events has not been entirely appraised. The aim of this study was to perform a comprehensive cluster analysis of weather and pollution features in a large metropolitan area, and their association with acute cardiac and cerebrovascular events. METHODS: Anonymized data on acute myocardial infarction (AMI) and acute cerebrovascular events were obtained from 3 tertiary care centers from a single large metropolitan area. Weather and pollution data were obtained averaging measurements from several city measurement stations managed by the competent regional agency for enviromental protection, and from the Metereological Center of Italian Military Aviation. Unsupervised machine learning was performed with hierarchical clustering to identify specific days with distinct weather and pollution features. Clusters were then compared for rates of acute cardiac and cerebrovascular events with Poisson models. RESULTS: As expected, significant pairwise correlations were found between weather and pollution features. Building upon these correlations, hierarchical clustering, from a total of 1169 days, generated 4 separate clusters: mostly winter days with low temperatures and high ozone concentrations (cluster 1, N.=60, 5.1%), days with moderately high temperatures and low pollutants concentrations (cluster 2, N.=419, 35.8%), mostly summer and spring days with high temperatures and high ozone concentrations (cluster 3, N.=673, 57.6%), and mostly winter days with low temperatures and low ozone concentrations (cluster 4, N.=17, 1.5%). Overall cluster-wise comparisons showed significant differences in adverse cardiac and cerebrovascular events (P<0.001), as well as in cerebrovascular events (P<0.001) and strokes (P=0.001). Between-cluster comparisons showed that cluster 1 was associated with an increased risk of any event, cerebrovascular events, and strokes in comparison to cluster 2, cluster 3 and cluster 4 (all P<0.05), as well as AMI in comparison to cluster 3 (P=0.047). In addition, cluster 2 was associated with a higher risk of strokes in comparison to cluster 4 (P=0.030). Analysis adjusting for season confirmed the increased risk of any event, cerebrovascular events and strokes for cluster 1 and cluster 2. CONCLUSIONS: Unsupervised machine learning can be leveraged to identify specific days with a unique clustering of adverse weather and pollution features which are associated with an increased risk of acute cardiovascular events, especially cerebrovascular events. These findings may improve collective and individual risk prediction and prevention.

Reduction in emergency access for acute myocardial infarction during the COVID-19 pandemic: a survey from the greater area of Rome.

BACKGROUND: On March 9, 2020, the Italian government imposed a national lockdown to tackle the COronaVIrus Disease 19 (COVID-19) pandemic, including stay at home recommendations. The precise impact of COVID-19 scare and lockdown on emergency access for acute myocardial infarction (MI) is still subject to debate. METHODS: Data on all patients undergoing invasive coronary angiography at 9 hospitals in the greater area of Rome, Italy, between February 19, 2020 and March 29, 2020 were retrospectively collected. Incidence of ST-elevation MI (STEMI), and non-ST-elevation MI (NSTEMI), as well as corresponding percutaneous coronary intervention (PCI), was compared distinguishing two different 20-day time periods (before vs. on or after March 10, 2020). RESULTS: During the study period, 1068 patients underwent coronary angiography, 142 (13%) with STEMI and 169 (16%) with NSTEMI. The average daily number of STEMI decreased from 4.3 before the lockdown to 2.9 after the lockdown (P=0.021). Similarly, the average daily number of NSTEMI changed from 5.0 to 3.5 (P=0.028). The average daily number of primary PCI changed from 4.2 to 2.9 (P=0.030), while the average daily number of PCI for NSTEMI changed from 3.5 to 2.5 (P=0.087). For STEMI patients, the time from symptom onset to hospital arrival (onset-to-door time less than three hours) showed a significant increase after the lockdown (P=0.018), whereas door-to-balloon time did not change significantly from before to after the lockdown (P=0.609). CONCLUSIONS: The present study, originally reporting on the trends in STEMI and NSTEMI in the Rome area, highlights that significant decreases in the incidence of both acute coronary syndromes occurred between February 19, 2020 and March 29, 2020, together with increases in time from symptom onset to hospital arrival, luckily without changes in door-to-balloon time.

Impact of environmental pollution and weather changes on the incidence of ST-elevation myocardial infarction.

BACKGROUND: Environmental pollution and weather changes unfavorably impact on cardiovascular disease. However, limited research has focused on ST-elevation myocardial infarction (STEMI), the most severe yet distinctive form of acute coronary syndrome. METHODS AND RESULTS: We appraised the impact of environmental and weather changes on the incidence of STEMI, analysing the bivariate and multivariable association between several environmental and atmospheric parameters and the daily incidence of STEMI in two large Italian urban areas. Specifically, we appraised: carbon monoxide (CO), nitrogen dioxide (NO2), nitric oxide (NOX), ozone, particulate matter smaller than 10 µm (PM10) and than 2.5 µm (PM2.5), temperature, atmospheric pressure, humidity and rainfall. A total of 4285 days at risk were appraised, with 3473 cases of STEMI. Specifically, no STEMI occurred in 1920 (44.8%) days, whereas one or more occurred in the remaining 2365 (55.2%) days. Multilevel modelling identified several pollution and weather predictors of STEMI. In particular, concentrations of CO (p = 0.024), NOX (p = 0.039), ozone (p = 0.003), PM10 (p = 0.033) and PM2.5 (p = 0.042) predicted STEMI as early as three days before the event, as well as subsequently, and NO predicted STEMI one day before (p = 0.010), as well as on the same day. A similar predictive role was evident for temperature and atmospheric pressure (all p < 0.05). CONCLUSIONS: The risk of STEMI is strongly associated with pollution and weather features. While causation cannot yet be proven, environmental and weather changes could be exploited to predict STEMI risk in the following days.

Giant pericardial mass case report: role of echocardiography.

Cardiac masses are rare and they are distinguished in tumors and non-tumoral masses. Primary pericardial masses are very rare and they are often asymptomatic, even if they can present with sudden cardiac death. The diagnosis of these masses is often accidental and they are generally identified with echocardiography; their characterization is usually performed by cardiac magnetic resonance imaging (MRI) but the definitive diagnosis is achieved by tissue biopsy. We described a case of primary pericardial mass in an old patient with history of hypertension, which presented at our hospital with dyspnea and low-extremity edema. The echocardiography described a giant iso/hypoechoic pericardial mass that extended on anterior, posterior and lateral walls of left ventricle and atrium, associated with pericardial effusion without hemodynamic compromise. We discovered that the mass was identified twenty years ago on a chest-computed tomography (CT). Even if we do not manage in performing a cardiac MRI, from echo characteristics we supposed that the mass was a lipoma. Lipomas are benign tumors that can develop from pericardium and they have slow growth so they can be asymptomatic for several years. Their excision is important because they may be responsible for pericardial tamponade or heart failure. Echocardiography is an economic non-invasive exam and it is helpful in differential diagnosis, treatment, follow-up and prognosis of this cardiac masses.

Percutaneous Retrieval of a Left Atrial Appendage Closure Device: The Device Waltz.

Embolization of a device in patients undergoing percutaneous left atrial appendage closure is an uncommon complication. We present an illustrative case of successful percutaneous retrieval of an embolized LAmbre device (Lifetech Scientific, Shenzhen, China) that was achieved with a combination of a snaring technique and forceps grasping and by using a steerable guiding catheter. (Level of Difficulty: Advanced.).

Interplay between COVID-19, pollution, and weather features on changes in the incidence of acute coronary syndromes in early 2020.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has caused an unprecedented change in the apparent epidemiology of acute coronary syndromes (ACS). However, the interplay between this disease, changes in pollution, climate, and aversion to activation of emergency medical services represents a challenging conundrum. We aimed at appraising the impact of COVID-19, weather, and environment features on the occurrence of ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) in a large Italian region and metropolitan area. METHODS AND RESULTS: Italy was hit early on by COVID-19, such that state of emergency was declared on January 31, 2020, and national lockdown implemented on March 9, 2020, mainly because the accrual of cases in Northern Italy. In order to appraise the independent contribution on changes in STEMI and NSTEMI daily rates of COVID-19, climate and pollution, we collected data on these clinical events from tertiary care cardiovascular centers in the Lazio region and Rome metropolitan area. Multilevel Poisson modeling was used to appraise unadjusted and adjusted effect estimates for the daily incidence of STEMI and NSTEMI cases. The sample included 1448 STEMI and 2040 NSTEMI, with a total of 2882 PCI spanning 6 months. Significant reductions in STEMI and NSTEMI were evident already in early February 2020 (all p<0.05), concomitantly with COVID-19 spread and institution of national countermeasures. Changes in STEMI and NSTEMI were inversely associated with daily COVID-19 tests, cases, and/or death (p<0.05). In addition, STEMI and NSTEMI incidences were associated with daily NO2, PM10, and O3 concentrations, as well as temperature (p<0.05). Multi-stage and multiply adjusted models highlighted that reductions in STEMI were significantly associated with COVID-19 data (p<0.001), whereas changes in NSTEMI were significantly associated with both NO2 and COVID-19 data (both p<0.001). CONCLUSIONS: Reductions in STEMI and NSTEMI in the COVID-19 pandemic may depend on different concomitant epidemiologic and pathophysiologic mechanisms. In particular, recent changes in STEMI may depend on COVID-19 scare, leading to excess all-cause mortality, or effective reduced incidence, whereas reductions in NSTEMI may also be due to beneficial reductions in NO2 emissions in the lockdown phase.