Chatla V. R. Reddy

Radionuclide simultaneous dual-isotope stress myocardial perfusion study using the three window technique

Several methods are available for performing radionuclide stress myocardial perfusion studies. All of these methods require two separate acquisition and processing iterations, which is time-consuming and inconvenient for the patient. The authors introduce a new method using the “three window technique” that they developed to perform simultaneous dual-isotope imaging for stress myocardial perfusion studies. In addition to TI-201 and Tc-99m windows centered at 70 KeV and 140 KeV, respectively, a third window centered at 105 KeV, representing scattered radioactivity from Tc-99m, is established. By subtracting the radioactivity in the third window from the radioactivity in the TI-201 window, “crosstalk” interference is significantly reduced. The simultaneous dual-isotope imaging method acquires and processes resting and stress myocardial perfusion images simultaneously. It halves imaging time and doubles patient throughput, improves scheduling flexibility, and reduces patient waiting time and discomfort.

Profound thrombocytopenia associated with tirofiban : Case report and review of literature

Platelet glycoprotein (GP) IIb/IIIa inhibitors prevent fibrinogen binding and platelet aggregation. Inhibition of platelet activity at the injured coronary plaque is a target for novel therapeutic strategies. They decrease ischemic complications associated with non-ST-segment elevation acute coronary syndromes and percutaneous coronary intervention. Thrombocytopenia is a serious complication well described with the use of the prototype GP IIb/IIIa inhibitor abciximab. Its association with other agents of this class has been underemphasized. It is important to monitor platelet counts closely after initiation of GP IIb/IIIa inhibitor therapy, not only for abciximab, but also for small molecule inhibitors such as eptifibatide and tirofiban. Monitoring of platelet counts at 2 to 6 hours and 24 hours will detect most cases of acute thrombocytopenia. Adverse events may be prevented by prompt discontinuation of GP IIb/IIIa inhibitor therapy. The authors present a case of profound thrombocytopenia after the administration of tirofiban in the treatment of a patient with an acute coronary syndrome.

Clinical significance of variability of ventricular late potentials detected before discharge in patients after myocardial infarction.

BACKGROUND Signal-averaged electrocardiography (SAECG) in patients after myocardial infarction (MI) is widely used to identify patients at risk for ventricular tachycardia (VT) and sudden cardiac death (SCD). It is believed that ventricular late potentials when detected after day 5 after MI are relatively stable and carry the most significant relation to subsequent arrhythmic events. This study sought to determine if ventricular late potentials in patients after MI exhibit variability when recordings were made 10 to 12 hours apart on day 7 and to assess the clinical significance of this variability. METHODS AND RESULTS SAECG was recorded in 261 patients on the 7th day after MI at 7 to 10 AM (morning) and 6 to 8 PM (evening). Forty of these patients also had recordings 30 to 40 minutes apart to determine the 95% confidence interval of variability of each parameter of SAECG. The data were analyzed with the criteria of the American College of Cardiology policy statement. A prospective analysis for the clinical end points of VT and SCD was carried out for a period of 1 year. We identified 3 groups of patients. Group 1 (54, 20.7%) had consistently positive SAECG by at least 2 abnormal parameters in both morning and evening. Group 2 (37, 14.2%) had positive SAECG at 1 time only, either morning or evening. Group 3 (170, 65.1%) had negative SAECG on both occasions. Diabetes mellitus was an independent predictor of the variability of late potentials (P <.0001). A prospective analysis for the clinical end points of VT and SCD showed that the event rate was significantly higher in group 1 than in group 2 (P <.019). CONCLUSIONS To improve the positive predictive value of SAECG in patients after MI, we advise that all positive tests be repeated 10 to 12 hours later, especially in patients with diabetes mellitus. Such testing will identify patients with consistently positive SAECG who appear to be at the highest risk for VT and SCD.

An unusual case of multiple right atrial thrombi in a patient with a dual-chamber pacemaker--a case report.

The authors present an unusual case of multiple large atrial thrombi attached to perma nent pacemaker leads identified by transesophageal echocardiography. Pathogenesis, clinical implications, and therapeutic options of pacemaker thrombi are discussed.

Clinical Science Review: Current Aspects of Thrombolytic Therapy in Women with Acute Myocardial Infarction

Acute myocardial infarction (AMI) remains the greatest threat to health in our society and is the most common cause of death in the United States and in many other Western industrialized countries. Recent data demonstrate that mortality from MI is continuing to decline. In these days of more aggressive management of acute MI (AMI) there has been a resurgence of interest in advances in thrombolytic therapy. However, observational studies of patients with AMI have shown that women sustaining an AMI have a worse prognosis than men. AMI is the number-one killer of women in the United States; approximately 247,000 of more than 520,000 deaths due to AMI that occur each year are among women, and almost one-third of the women are younger than forty-five years old. While there have been great advances in thrombolytic therapy, these advances have benefited men to a more significant degree than they have benefited women. The purpose of this paper is to critically review the efficacy of thrombolytic therapy in women with AMI with consideration of some of the key components of its effectiveness: mortality, bleeding risk, infarct-artery patency, ventricular function, and cardiac arrhythmia.

New-onset congestive heart failure secondary to a "huge" right atrial mass--a case report.

Transesophageal echocardiography is a useful adjunct to other diagnostic modalities in uncov ering the etiology of congestive heart failure. The authors describe the case of a 75-year-old woman with a 4-week history of progressive congestive heart failure, in whom trans esophageal echocardiography played a critical role in the diagnosis of a right atrial mass, accounting for this patients constellation of symptoms.

Asymptomatic left ventricular permanent pacemaker malposition detected on routine follow-up--a case report.

The authors present an asymptomatic left ventricular pacemaker lead malposition that was detected upon routine 2-D Echocardiography. Clinical implication diagnosis and therapeutic options on left ventricular pacemaker lead malposition are discussed.