Myocardial perfusion imaging: Lessons learned and work to be done-update.

As the second term of our commitment to Journal begins, we, the editors, would like to reflect on a few topics that have relevance today. These include prognostication and paradigm shifts; Serial testing: How to handle data? Is the change in perfusion predictive of outcome and which one? Ischemia-guided therapy: fractional flow reserve vs perfusion vs myocardial blood flow; positron emission tomography (PET) imaging using Rubidium-82 vs N-13 ammonia vs F-18 Flurpiridaz; How to differentiate microvascular disease from 3-vessel disease by PET? The imaging scene outside the United States, what are the differences and similarities? Radiation exposure; Special issues with the new cameras? Is attenuation correction needed? Are there normal databases and are these specific to each camera system? And finally, hybrid imaging with single-photon emission tomography or PET combined with computed tomography angiography or coronary calcium score. We hope these topics are of interest to our readers.

Defining the distance between the His bundle and first septal perforator: implications for left bundle branch pacing.

BACKGROUND: Left bundle branch pacing (LBBP) is a developing method of native conduction pacing, but cases of injury to the septal perforator arteries during implantation have been reported. Knowing the distance between the His bundle and the first septal perforator artery can help operators implant LBBP leads more safely. METHODS: Using previously performed coronary CT angiography (CCTA) studies, the distance between the His bundle and the first septal perforator was measured. RESULTS: A total of 50 CCTA studies were included. The mean distance from the His bundle to the first septal perforator (His-SP) along the line connecting the His bundle to the RV apex (His-RV apex) was 27.17 ± 7.7 mm with a range of 13.0 to 44.7 mm. The distance was greater than 2.0 cm in 84% of patients. To standardize this distance among patients with varying cardiac structures, the ratio between the His-SP distance and the His-RV Apex distance was also measured. The mean His-SP:His-RV Apex was 0.302 and the median was 0.298. Eighty-six percent of patients had a ratio of greater than 0.20. CONCLUSION: Using this information, operators can aim to implant LBBP leads within 2.0 cm of the His bundle or 20% of the distance between the His bundle and the RV apex with minimal risk of causing vascular injury.

An Anatomic Curiosity: A Sliver of a Liver in an Unusual Location.

A 48-year-old woman underwent preoperative cardiac testing prior to gastric bypass. She was incidentally found to have a right atrial mass on transthoracic echocardiography. Subsequent cardiac magnetic resonance confirmed this finding. She underwent excision of the mass. Tissue pathology revealed ectopic hepatic tissue. (Level of Difficulty: Advanced.).

Development of the Elective Outpatient Percutaneous Coronary Intervention Episode-Based Cost Measure.

BACKGROUND: The Merit-Based Incentive Payment System adjusts clinician payments based on a performance score that includes cost measures. With the Centers for Medicare & Medicaid Services, we developed a novel cost measure that compared interventional cardiologists on a targeted set of costs related to elective percutaneous coronary intervention (PCI). We describe the measure and compare it to a hypothetical version including all expenditures post-PCI. METHODS: Measure development was guided by 39 clinician experts. They identified services within 30 days of PCI that could be potentially affected by the interventional cardiologist. Expenditures for these PCI-related services were included as measure costs in a process termed service assignment. We used 1 year of Medicare claims to calculate clinician scores using the final measure that included only PCI-related costs (with service assignment) and a hypothetical version that included all costs post-PCI (without service assignment). We calculated reliability for both measures. This marker of precision breaks measure variance into signal (difference between clinicians) versus noise (difference between PCI episodes for a clinician). We also determined the change in clinician performance quintile between measures. RESULTS: We identified 100 992 elective outpatient PCI episodes from May 2, 2016, to May 1, 2017. Total Medicare expenditures within 30 days of PCI averaged $13 234. After excluding costs unrelated to PCI, average cost was $10 966. For individual clinicians, mean reliability for the hypothetical measure without service assignment was 0.36. After service assignment, final measure reliability increased to 0.53. When evaluated as clinician groups, reliability increased from 0.43 to 0.73 following service assignment. Approximately 66% (2340 of 3527) of clinicians were reclassified into a different performance quintile after excluding unrelated costs. CONCLUSIONS: The elective outpatient PCI cost measure had increased precision and reclassified clinician performance relative to a hypothetical version that included total expenditures.

Papillary Muscle Rupture Complicating Acute Myocardial Infarction: A Tale of Teamwork.

A 52-year-old man presented with acute onset of chest pain and was found to have an inferolateral ST-segment elevation myocardial infarction and acute mitral regurgitation due to papillary muscle rupture. This case describes a rare, potentially fatal mechanical complication of acute myocardial infarction. (Level of Difficulty: Beginner.).

Basic science curriculums in nuclear cardiology and cardiovascular imaging: evolving and emerging concepts.

The teaching of basic science with regard to physics, instrumentation, and radiation safety has been part of nuclear cardiology training since its inception. Although there are clear educational and quality rationale for such, regulations associated with the Nuclear Regulatory Commission Subpart J of old 10 CFR section 35 (Title 10, Code of Federal Regulations, Part 35) from the 1960s mandated such prescriptive instruction. Cardiovascular fellowship training programs now have a new opportunity to rethink their basic science imaging curriculums with the era of "revised 10 CFR section 35" and the growing implementation of multimodality imaging training and expertise. This review focuses on the history and the why, what, and how of such a curriculum arising in one city and suggests examples of future implementation in other locations.

Right ventricular hemangioma causing right ventricular inflow obstruction and right heart failure.

We report a patient who presented with symptoms of right heart failure. Transesophageal echocardiography revealed a right ventricular mass, causing right ventricular inflow obstruction. Coronary angiography revealed a characteristic tumor blush. After successful surgical resection, histologic findings were consistent with a right ventricular hemangioma.

Risk of thrombogenicity among nonionic radiocontrast agents.

Several contrast agents have been approved in the United States for radiographic imaging purposes. Most of the older ionic, high-osmolar contrast agents are no longer used because of their side effect profile. Therefore, newer nonionic, low or iso-osmolar contrast agents have been widely accepted as an alternative due to their improved tolerability and safety. We investigated the thrombogenicity of the 6 different nonionic radiocontrast media in terms of their platelet reactivity and noted some minor differences among them. In the 50% contrast concentration group, all of the nonionic contrast agents inhibited aggregation, whereas in the 10% contrast concentration group, all agents showed similar aggregation curves in comparison to the normal control. At 50% contrast concentration, the inhibitory effect of aggregation appeared to be related to the inhibition of calcium mobilization, which may be one of the mechanistic effects.

HIV disease in thrombocardiology.

Human immunodeficiency virus (HIV) infection affects multiple organs including the cardiovascular system. Postmortem studies have revealed multiple abnormalities including abnormal coronary artery pathology, arteriopathy/endothelial dysfunction, hyperlipidemia and hypercoagulability prior to the use of protease inhibitors. With the introduction of antiretroviral medications, specifically protease inhibitor therapy, patients with HIV have been further noted to have premature coronary artery disease, hypercoagulability, hyperlipidemia, insulin resistance, fat redistribution syndrome and increased tendency to myocardial infarction. In this article, we report on one patient with HIV disease on protease inhibitor therapy that presented with non-Q-wave myocardial infarction and underwent percutaneous coronary intervention, and was later found to have stent thrombosis. A review of the literature showed no other previous reports of stent thrombosis secondary to acquired hypercoagulability due to protease inhibitor therapy. Possible predictors of stent thrombosis and hypercoagulability are also discussed.

Alveolar hemorrhage associated with platelet glycoprotein IIb/IIIa receptor inhibitors.

Platelet glycoprotein IIb/IIIa receptor inhibitors have been shown to improve outcomes in percutaneous coronary interventions. Their use with multiple anticoagulants has been associated with increased bleeding complications. Among these, alveolar hemorrhage is a rare and potentially fatal complication. Six patients with this complication were identified over a four-year period. Patient characteristics, possible risk factors, pathophysiology, prevention and potential treatment options are discussed.

Serotonin syndrome and other serotonergic disorders.

Serotonin syndrome is an iatrogenic disorder induced by pharmacologic treatment with serotonergic agents that increases serotonin activity. In addition, there is a wide variety of clinical disorders associated with serotonin excess. The frequent concurrent use of serotonergic and neuroleptic drugs and similarities between serotonin syndrome and neuroleptic malignant syndrome can present the clinician with a diagnostic challenge. In this article, we review the pathophysiology, diagnosis, and treatment of serotonin syndrome as well as other serotonergic disorders.