Myocardial Infarction With Non-obstructive Coronary Arteries: A Clinical Conundrum.

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is defined by the presence of positive cardiac biomarkers with clinical evidence of infarction, the absence of significant coronary stenosis (≥50%) on angiography, and the lack of alternative diagnosis for the index presentation. MINOCA poses a diagnostic and therapeutic challenge due to the various pathophysiologic mechanisms underlying its presentation. Coronary artery plaque disruption is recognized as a crucial mechanism contributing to MINOCA. Plaque rupture and thrombus formation with subsequent myocardial ischemia may occur without significant luminal narrowing. A high index of suspicion is needed to make an early diagnosis. Here, a 68-year-old African American male patient presented with substernal chest pain, nonspecific ST segment changes on electrocardiogram, and elevation in cardiac biomarkers only one day after undergoing diagnostic cardiac catheterization that revealed non-obstructed coronary arteries. This case provides an example of MINOCA occurring secondary to suspected coronary artery plaque disruption in the setting of recent cardiac catheterization.

The Abnormal Sinus Rhythm: Myxedema Coma Complicated by Subacute Cardiac Tamponade.

Subacute cardiac tamponade (SCT) is a potentially life-threatening condition that requires immediate medical attention. Combining careful history taking, focused physical exam, and the use of point of care ultrasound (POCUS) for early diagnosis with aggressive management can minimize potential complications. In patients with severe hypothyroidism and myxedema coma, clinical signs of cardiac tamponade may be masked and lead to delayed diagnosis. We present a case of a 67-year-old female with SCT secondary to myxedema coma, necessitating emergent pericardiocentesis following the identification of a large pericardial effusion with tamponade physiology. This case highlights the importance of thorough history taking with focused diagnostic workup, including POCUS in patients with an insidious presentation of SCT.

Novel Coronavirus-Induced Right Ventricular Failure and Point of Care Echocardiography: A Case Report.

Various cardiovascular complications have been reported in patients with coronavirus disease 2019. Common complications include acute myocardial injury, myocarditis, arrhythmia, pericarditis, heart failure, and shock. We present a case of cor pulmonale diagnosed with serial point of care ultrasound. Given the current shortage of personal protective equipment (PPE) and high infectivity of this virus, we acknowledge the utility of this tool in obtaining important clinical information while minimizing exposure and PPE consumption.

Frequency of Complete Atrioventricular Block Complicating ST-Elevation Myocardial Infarction in Patients Undergoing Primary Percutaneous Coronary Intervention.

OBJECTIVES: ST-segment elevation myocardial infarction (STEMI) can be associated with many conduction disturbances including complete atrioventricular block (CAVB). CAVB complicating STEMI resulted in an increased mortality before the modern era of primary percutaneous coronary intervention (PCI). The aim of this study was to ascertain the rate and risk factors for CAVB in STEMI patients undergoing rapid reperfusion with PCI. METHODS: We analyzed 223 patients presenting with STEMI. Patient characteristics, procedural characteristics, and in-hospital data were compared between patients with and without CAVB. RESULTS: Out of 223 patients, 174 underwent PCI; the majority (87%) was African-American. CAVB was present in 8 patients (4.6%), and 6 of them had RCA occlusion. Independent predictors of CAVB included diabetes mellitus, female gender, lower systolic and diastolic blood pressure, and inferior-lateral/lateral STEMI. Ten patients (5.7%) required temporary pacing at presentation; only 1 patient required permanent pacing before discharge. No patient with anterior STEMI developed CAVB. CONCLUSIONS: The incidence and in-hospital mortality rate of CAVB in patients with STEMI who underwent primary PCI was reduced when compared to data from the thrombolytic era. This may be due to faster flow recovery in the infarct-related artery achieved with PCI.

Low defibrillation threshold in a patient with a dual-coil defibrillator lead implanted through a persistent left superior vena cava.

Several reports have described the successful insertion of implantable cardioverter defibrillator (ICD) in patients with a persistent left superior vena cava (PLSVC). The implanters have used various techniques to achieve appropriate lead placement. In our case, the use of a long sheath, guided by a deflectable catheter, not only facilitated proper implantation of the lead, but also provided a unique position of the dual-coil lead. This resulted in a very low defibrillation threshold (DFT). We describe a case of a patient found to have a PLSVC at implant who after successful insertion of the ICD exhibited DFT ≤ 5 J.

[Use of non-contact mapping to localise distant from endocardium origin of atrial tachycardia].

A 65 year-old woman developed tachycardia and hypotension during haemodialysis. The non-contact mapping system was used to localise the origin of focal atrial tachycardia, and showed a remote from the endocardium focus. We discuss techniques that are helpful in identifying the origin, the area of preferential conduction, and the endocardial breakthrough of tachycardia.

Effect of obstructive sleep apnea on QT dispersion: a potential mechanism of sudden cardiac death.

OBJECTIVES: QT dispersion (QT(d)) measures the variability of the ventricular recovery time. QT(d) may identify patients at risk for ventricular arrhythmias and sudden cardiac death (SCD). The purpose of our study was to determine the effect of obstructive sleep apnea (OSA) on QT(d). METHODS: There were 199 patients studied: 101 patients (28 women, 73 men) with OSA diagnosed in our sleep center and 98 patients (49 women, 49 men) without OSA from the outpatient clinic, representing the control group. QT intervals (milliseconds) were measured in each of the 12 leads of a standard surface electrocardiogram during wakefulness and QT(d) calculated (QT(max) - QT(min)). QT(c)(d), which corrects for heart rate, was also calculated. RESULTS: Mean age and heart rate were similar in men and women with or without OSA. Control patients exhibited a significant difference (p < 0.001) in QT(d) between men (48 ± 19) and women (31 ± 13). Men and women with OSA had similar QT(d) (56 ± 35 vs. 54 ± 21) but higher QT(d) compared to the control group. QT(c)(d) results were similar to QT(d). CONCLUSIONS: Patients with OSA and no structural heart disease have a higher QT(d)/QT(c)(d) compared to an overtly healthy patient population, possibly serving as a marker for an increased risk of SCD.

[Ventricular fibrillation effectively treated by wearable automatic defibrillator - a case report]. / Migotanie komór przerwane wyladowaniem automatycznej kamizelki defibrylujacej.

We present a patient at risk of sudden cardiac death in whom ventricular fibrillation was effectively treated by wearable automatic defibrillator. We discuss the technical aspects of the device, current indications for this therapy and outcomes.

Benefit of bolus-only platelet glycoprotein IIb/IIIa inhibition during percutaneous coronary intervention: insights from the very early outcomes in the Evaluation of 7E3 for the Prevention of Ischemic Complications (EPIC) trial.

BACKGROUND: Platelet glycoprotein IIb/IIIa inhibitors are administered during percutaneous coronary intervention as a bolus followed by infusion. The need for an infusion was established by the Evaluation of 7E3 for the Prevention of Ischemic Complications (EPIC) trial conducted during the percutaneous transluminal coronary balloon angioplasty (PTCA) era, when the threat of acute thrombotic complications prevailed over concerns regarding bleeding, and stenting was considered an adverse event. METHODS: The EPIC trial randomized high-risk PTCA patients to 3 arms: placebo, abciximab bolus only, and abciximab bolus plus infusion. The present analysis of the EPIC outcomes was done at 6-hour intervals during the first 24 hours after PTCA to identify any early benefit derived from the abciximab bolus-only arm. RESULTS: At 6 hours after randomization, the primary composite end point of death, myocardial infarction, or urgent intervention was significantly reduced by 46% with abciximab bolus-only compared with placebo (2.9% vs 5.3%; P = .022), which is mainly due to a reduced rate of urgent intervention. There was also a numerical but not statistically significant reduction in myocardial infarction rate using abciximab bolus-only compared with placebo. A lower bleeding rate in the bolus-only arm compared with bolus plus infusion has been reported. CONCLUSIONS: As stenting and thienopyridine use have become routine, there has been a decrease in the incidence of acute closure and an increasing concern for bleeding complications after percutaneous coronary intervention, which potentially may be addressed by adopting a bolus-only glycoprotein IIb/IIIa inhibitor strategy. The early protective ischemic effect of abciximab bolus-only observed in the EPIC trial may be relevant in this regard.

Prediction of outcome after percutaneous coronary intervention for the acute coronary syndrome.

BACKGROUND: The seven-component Thrombolysis In Myocardial Infarction (TIMI) score has been used to risk stratify, and to guide the medical management of, patients with unstable angina or non-ST-elevation myocardial infarction. We assessed the usefulness of the risk score in predicting in-hospital and 30-day outcomes in such patients who were undergoing percutaneous coronary intervention. METHODS: Using the TIMI score, 2501 patients with unstable angina or non-ST-elevation myocardial infarction were divided into low-risk (zero to two risk factors; n = 974), intermediate-risk (three to four risk factors; n = 1339), and high-risk (five to seven risk factors; n = 188) groups, and outcomes were compared. RESULTS: Angiographic/clinical success and the rate of minor procedural events were similar among the three groups. A higher TIMI risk score was associated with more cardiac comorbid conditions and more complicated angiographic lesions: longer lesions (P = 0.0009), more thrombotic lesions (P = 0.03), more multivessel disease (P <0.0001), and more American College of Cardiology/American Heart Association type B2/C lesions (P = 0.05). Although the risk score did not predict interventional technical success or intraprocedural complications, a high score was associated with prolonged hospital stay, higher postprocedural peak troponin levels, and 30-day major adverse cardiac events. Stepwise logistic regression showed that in conjunction with lesion length and patient sex, a high score was an independent predictor of 30-day major adverse cardiac events (odds ratio = 2.3; 95% confidence interval: 1.1 to 4.1; C statistic = 0.62). CONCLUSION: Although a higher TIMI risk score in patients with unstable angina or non-ST-elevation myocardial infarction who were undergoing percutaneous coronary intervention correlated with adverse clinical outcome, the score alone cannot be used to guide diagnostic or therapeutic strategies.

Postprocedure chest pain after coronary stenting: implications on clinical restenosis.

OBJECTIVES: The goal of this study was to analyze the incidence and predictors of postprocedure chest pain (PPCP) after percutaneous coronary intervention (PCI) and its correlation with clinical restenosis. BACKGROUND: Chest pain after PCI occurs frequently even in the absence of procedural events and is considered to be due to vasospasm or coronary artery stretch. The short- and long-term significance of PPCP after otherwise successful stenting is not clear. METHODS: We analyzed 1,362 patients undergoing coronary stenting for PPCP, procedural and in-hospital events, 30-day major adverse cardiac events, and target vessel revascularization (TVR) at 6 to 9 months. RESULTS: There were 488 patients with PPCP and, of these, 312 patients were excluded due to procedural events. The remaining 176 patients with PPCP were compared with 874 patients without PPCP. Creatine kinase-MB isoenzyme elevation occurred in 25.6% of the PPCP group versus 9.6% of the no PPCP group (p < 0.001). Despite similar reference vessel diameter, the PPCP group had larger postprocedure minimum lumen diameter, higher stent-to-vessel ratio, and higher inflation pressure versus the no PPCP group (p < 0.01). At 30 days, the emergency room visits and repeat catheterization (16% vs. 2.7%; p < 0.001) were higher in the PPCP group versus the no PPCP group, but repeat intervention was similar. At 6- to 9-month follow-up, the TVR was significantly higher in the PPCP group compared with the no PPCP group (29.5% vs. 16.6%; p < 0.01). CONCLUSIONS: Our analysis suggests micromyonecrosis and vessel stretch as causes of PPCP. Postprocedure chest pain is associated with similar short-term outcome as no PPCP, but has higher restenosis, perhaps mediated by deep vessel wall injury. Therefore, PPCP may identify patients at high risk for restenosis.

A protocol for prevention of radiographic contrast nephropathy during percutaneous coronary intervention: effect of selective dopamine receptor agonist fenoldopam.

Radiographic contrast nephropathy (RCN), acute worsening of renal function due to contrast agents, can occur in 15%-40% of patients with baseline renal dysfunction undergoing percutaneous coronary intervention (PCI) and is associated with increased morbidity and in-hospital mortality. The purpose of this study was to evaluate whether the selective dopamine-1 (DA-1) receptor agonist fenoldopam would be beneficial in patients with chronic renal insufficiency (CRI) undergoing PCI and also to design a protocol for prevention of RCN. We analyzed 150 consecutive patients with CRI [baseline serum creatinine (BSCr) +/- 1.5% mg] who underwent PCI and received fenoldopam during and after the procedure, in addition to saline hydration. RCN, defined as > 25% increase of BSCr 48-72 hr after PCI, occurred in 4.7% (n = 7) of 150 PCI patients receiving fenoldopam and 3.5% in diabetics (n = 85) vs. 6.1% in nondiabetics (n = 65; P = NS). No patients required dialysis. The observed 4.7% incidence of RCN with fenoldopam was significantly lower than 18.8% incidence in the historical control group (P < 0.001). Our data suggest that fenoldopam is a useful adjunct in the prevention of RCN during PCI, especially in diabetics.