Crescendo Angina Secondary to Congenital Absence of the Left Circumflex Coronary Artery: A Case Report.

Congenital coronary artery abnormalities (CAAs) are very rare in the general population. Among these congenital anomalies, left circumflex artery (LCx) anomaly is the most common. Although many are asymptomatic, a small percentage of patients with this anomaly present with angina-like symptoms. Usually, a majority of these cases are found incidentally during coronary angiography. We present a 71-year-old male with crescendo angina with a positive chemical stress test. Coronary angiography showed an absent LCx and a superdominant right coronary artery (RCA). Although congenital LCx absence is a benign finding, the coexistence of this abnormality with significant atherosclerotic disease in the coronary artery can lead to significant morbidity and mortality in this population. Understanding the embryological and morphological significance of these anomalies is important in adequately diagnosing and managing these patients.

Exercise acutely increases circulating endothelial progenitor cells and monocyte-/macrophage-derived angiogenic cells.

OBJECTIVES: We investigated whether a single episode of exercise could acutely increase the numbers of endothelial progenitor cells (EPCs) and cultured/circulating angiogenic cells (CACs) in human subjects. BACKGROUND: Endothelial progenitor cells and CACs can be isolated from peripheral blood and have been shown to participate in vascular repair and angiogenesis. We hypothesized that exercise may acutely increase either circulating EPCs or CACs. METHODS: Volunteer subjects (n = 22) underwent exhaustive dynamic exercise. Blood was drawn before and after exercise, and circulating EPC numbers as well as plasma levels of angiogenic growth factors were assessed. The CACs were obtained by culturing mononuclear cells and the secretion of multiple angiogenic growth factors by CACs was determined. RESULTS: Circulating EPCs (AC133+/VE-Cadherin+ cells) increased nearly four-fold in peripheral blood from 66 +/- 27 cells/ml to 236 +/- 34 cells/ml (p < 0.05). The number of isolated CACs increased 2.5-fold from 8,754 +/- 2,048 cells/ml of peripheral blood to 20,759 +/- 4,676 cells/ml (p < 0.005). Cultured angiogenic cells isolated before and after exercise showed similar secretion patterns of angiogenic growth factors. CONCLUSIONS: Our study demonstrates that exercise can acutely increase EPCs and CACs. Given the ability of these cell populations to promote angiogenesis and vascular regeneration, the exercise-induced cell mobilization may serve as a physiologic repair or compensation mechanism.

Body weight is a predictor of biphasic shock success for low energy transthoracic defibrillation.

BACKGROUND: Transthoracic impedance and current flow are determinants of defibrillation success with monophasic shocks. Whether transthoracic impedance, either independently or via its association with body weight, is a determinant of biphasic waveform shock success has not been determined. METHODS AND RESULTS: We studied 22 swine, weighing 18-41 kg. After 15 s of ventricular fibrillation, each pig received transthoracic truncated exponential biphasic shocks (5/5 ms), 70-360 J. Shock success was strongly associated individually with body weight, leading-edge transthoracic impedance and current at low energy levels (70 and 100 J, all P<0.001). Multiple logistic regression analysis showed a significant association of body weight with shock success after adjusting for the effect of leading-edge impedance (odds ratio of success for 1 kg decrease in weight at 70 J was 1.29, 95% CI: 1.05-1.59, P=0.02; and at 100 J was 1.30, 95% CI: 1.14-1.49, P<0.0001). The same result was observed after adjusting for the effect of leading-edge current. At 150 J or higher energy levels, no significant association was observed. CONCLUSIONS: Body weight is a determinant of shock success with biphasic waveforms at low energy levels in this swine model.

Transthoracic biphasic waveform defibrillation at very high and very low energies: a comparison with monophasic waveforms in an animal model of ventricular fibrillation.

The purpose of this study was to compare truncated exponential biphasic waveform versus truncated exponential monophasic waveform shocks for transthoracic defibrillation over a wide range of energies. Biphasic waveforms are more effective than monophasic shocks for defibrillation at energies of 150-200 Joules (J) but there are few data available comparing efficacy and safety of biphasic versus monophasic defibrillation at energies of <150 J or >200 J. Thirteen adult swine (weighing 18-26 kg, mean 20 kg) were deeply anesthetized and intubated. After 15 s of electrically-induced ventricular fibrillation (VF), each pig received truncated exponential monophasic shocks (10 ms) and truncated exponential biphasic shocks (5/5 ms) in random order. Energy doses ranged from 70 to 360 J. Success was defined as termination of VF at 5 s post-shock. For both biphasic and monophasic waveforms success rate rose as energy was increased. Biphasic waveform shocks (5/5 ms) were superior to 10 ms monophasic waveform shocks at the very low energy levels (at 70 J, biphasic: 80+/-9%, monophasic; 32+/-11% and at 100 J, biphasic; 96+/-3% and monophasic 39+/-11%, both P < 0.01). No significant differences in shock success were seen between biphasic and monophasic waveform shocks at 200 J or higher energy levels. Shock success of > 75% was achieved with 200 J (10 J/kg) for both waveforms. Pulseless electrical activity (PEA) or ventricular asystole occurred in 4 animals receiving monophasic shocks and 1 animal receiving biphasic shocks. Biphasic waveform shocks (5/5 ms) for transthoracic defibrillation were superior to monophasic shocks (10 ms) at low energy levels. Percent success increased with increasing energies. PEA occurred infrequently with either waveform.

Increased incidence of stent thrombosis in patients with cocaine use.

INTRODUCTION: Coronary stent thrombosis is a rare occurrence in the era of dual-antiplatelet therapy. It is not known whether patients who use cocaine have a higher risk of thrombosis following coronary stent placement. METHODS: We studied 247 consecutive patients who underwent coronary stent placement at an inner-city hospital. RESULTS: Twelve patients (4.9%) were actively using cocaine at the time of PCI. Of these twelve patients, four patients presented with stent thrombosis (33%) at a mean of 51 +/- 40 days (median 45 days), after the index revascularization procedure. Only 2 of the 235 patients without documented cocaine use (0.85%) had stent thrombosis during the same period (P < 0.0001). CONCLUSION: The patients who actively use cocaine have a markedly higher risk of stent thrombosis when compared with patients without a documented history of cocaine use. We discuss various factors that potentially predispose cocaine users to stent thrombosis.

Detection of early postoperative internal mammary artery atherosclerosis using Tc-99m myocardial perfusion SPECT imaging.

Myocardial perfusion single photon emission computed tomography (SPECT) is a useful noninvasive test to detect the recurrence of myocardial ischemia after coronary artery bypass grafting (CABG). However, the role of myocardial SPECT imaging to detect early recurrence of ischemia after surgery is limited, and its utility in asymptomatic CABG patients remains poorly established.