ABSTRACT
When analyzing left ventricular wall motion and thickening, two-dimensional echocardiography (2DE) represents a useful non-invasive tool for diagnosing and stratifying ischemic heart disease. New important technical advancements, such as harmonic imaging, allow to overcome limitations due to poor echocardiographic image quality in a large proportion of patients. Combination of exercise or pharmacological stress test with on-line echo images monitoring expands 2DE diagnostic and prognostic value in both ischemia or viability assessment. Study of contrast agents distribution is very promising for clarifying the complex interaction between myocardial perfusion and functional correlates, including myocardial stunning, hibernation and no-reflow phenomena. Direct visualization of epicardial coronary arteries and assessment of coronary artery blood flow has recently been demonstrated to be possible by either transthoracic (TTE) or transesophageal echocardiography (TEE). Acoustic quantification (AQ), automatic border detection (ABD), tissue Doppler imaging (TDI), and color kinesis are other technical modalities which may result to be useful for clinical evaluation of patients with either acute or chronic coronary syndromes.
Subject(s)
Coronary Disease/diagnostic imaging , Echocardiography/methods , Contrast Media , Coronary Circulation/physiology , Coronary Disease/physiopathology , Coronary Vessels/diagnostic imaging , Echocardiography, Doppler , Echocardiography, Doppler, Color , Echocardiography, Transesophageal , Exercise Test , Humans , Image Enhancement , Image Processing, Computer-Assisted , Myocardial Contraction/physiology , Myocardial Ischemia/diagnostic imaging , Myocardial Stunning/diagnostic imaging , Myocardial Stunning/physiopathology , Prognosis , Tissue Survival , Vasodilator Agents , Ventricular Function, Left/physiologyABSTRACT
BACKGROUND: There are limited data about the circadian distribution of ischemic episodes in patients with variant angina. Furthermore, no previous study investigated whether ischemia-related ventricular arrhythmias follow a circadian variation in these patients. METHODS: The circadian variation of transient ischemia and ischemia-induced ventricular arrhythmias was assessed by cosinor methodology on 24-hour Holter recordings of 26 patients with variant angina. RESULTS: On the whole, 301 ischemic episodes were detected in the population, with premature ventricular complexes occurring in 49 of them (16%). Ischemic episodes followed a typical circadian variation (acrophase hr 02:36, p < 0.01) in the total sample. However, a significant circadian variation of ischemic episodes was detectable in the 14 patients without (n = 167, acrophase hr 04:00, p < 0.0001), but not in the 12 patients with (n = 134, p = 0.14) hemodynamically significant coronary stenoses, independently of the location (anterior/inferior) of ischemia. There was no significant circadian variation of ischemia-related ventricular arrhythmias. CONCLUSIONS: Among patients with variant angina, a clearcut circadian variation of ischemia is present in those without, but not in those with, hemodynamically significant coronary artery stenoses, thus suggesting that different pathophysiologic mechanisms may operate, at least in part, in triggering coronary spasm in these two subgroups of patients. There was no significant circadian variation of ischemia-related ventricular arrhythmias in these patients.
