Coronary flow reserve assessment by transthoracic color Doppler echocardiography after primary angioplasty: relationship with recovery of left ventricular function]

BACKGROUND: The aim of this study was to determine the relationship between coronary flow reserve measurement by transthoracic Doppler echocardiography in recent acute myocardial infarction treated with primary coronary angioplasty (PTCA) and recovery of left ventricular function. METHODS: Forty-one consecutive patients (3 patients excluded for not good quality of the Doppler signal) have been studied with: (1) recent first acute myocardial infarction treated with primary PTCA within 6 hours of pain onset; (2) optimal angioplasty result with stent deployment, anti-IIb/IIIa infusion and TIMI 3 flow; (3) lack of type 1 diabetes and/or hypertension; (4) good tolerance to adenosine. Transthoracic Doppler echocardiography was used to record coronary flow velocities in the distal left anterior descending and posterior descending coronary arteries at rest and after infusion of adenosine. Coronary flow reserve was measured after 11 +/- 1 days from the acute event. The wall motion score index (WMSI) was calculated at baseline, 1 month and 3 months from myocardial infarction. RESULTS: Patients of group A (n = 29 with coronary flow reserve > or = 1.6) showed a progressive and significant recovery of left ventricular function at follow-up. Patients of group B (n = 9 with coronary flow reserve < 1.6) had persistent left ventricular dysfunction at 3 months (ANOVA, p < 0.0001). WMSI was 1.64 +/- 0.26 in group A and 1.81 +/- 0.16 in group B (p = 0.09) at baseline; 1.30 +/- 0.26 in group A and 1.75 +/- 0.16 in group B (p < 0.0001) at 1 month; and 1.20 +/- 0.25 in group A and 1.73 +/- 0.17 in group B at 3 months. There was an inverse correlation between coronary flow reserve and WMSI at 1 month (r = -0.564, p < 0.0001), and at 3 months (r = -0.583, p < 0.0001). On multivariate analysis baseline WMSI and coronary flow reserve were the only predictors of 1-month WMSI recovery and of WMSI recovery at 3 months. CONCLUSIONS: Coronary flow reserve by transthoracic color Doppler echocardiography is a useful method for predicting left ventricular function recovery in patients after primary PTCA.     

Relation between neutrophil counts on admission, microvascular injury, and left ventricular functional recovery in patients with an anterior wall first acute myocardial infarction treated with primary coronary angioplasty

Increased neutrophil counts have been associated with an increased risk of adverse clinical events after acute myocardial infarction (AMI). We examined the association of neutrophil counts on admission with degree of microvascular injury and left ventricular functional recovery after primary coronary angioplasty in AMI. We studied 116 patients with a first anterior wall AMI who underwent primary coronary angioplasty within 12 hours of onset. Patients were categorized into 3 groups based on initial neutrophil count: low (<5,000/mm(3)), intermediate (5,000 to 10,000/mm(3)), and high (>10,000/mm(3)). Coronary flow velocity parameters were assessed immediately after reperfusion using a Doppler guidewire. We defined severe microvascular injury as the presence of systolic flow reversal and a diastolic deceleration time <600 ms. Echocardiographic wall motion was analyzed before revascularization and 4 weeks after revascularization. In patients with a high neutrophil count, systolic flow reversal was more frequently observed, diastolic deceleration time was shorter, and coronary flow reserve was lower. By regression analysis, neutrophil count significantly correlated with diastolic deceleration time (r = -0.38, p <0.0001), coronary flow reserve (r = -0.33, p = 0.0004), and score for change in wall motion (r = -0.36, p = 0.0004). Multivariate analysis showed that neutrophil count on admission was an independent predictor of severe microvascular injury (odds ratio 2.94, p = 0.02). In conclusion, neutrophilia on admission is associated with impaired microvascular reperfusion and poor functional recovery after primary coronary angioplasty.     

Hypertrophic cardiomyopathy with mild left ventricular remodeling: echocardiographic assessment using left ventricular wall motion score

OBJECTIVES: The present study sought to investigate the echocardiographic features of hypertrophic cardiomyopathy (HCM) with mild left ventricular (LV) remodeling, particularly in relation to wall motion abnormalities. METHODS: Among the 137 consecutive patients with HCM, 13 patients (mean age 52 +/- 13 years) who progressed to mild LV systolic dysfunction (LV ejection fraction (LVEF) of 35-50%) were studied. By reviewing the echocardiograms of these patients, wall motion score index (WMSI) was scored using 16 segments model. RESULTS: HCM patients with mild LV systolic dysfunction exhibited mild LV dilatation, mild left atrial dilatation, septal hypertrophy, and LV wall motion impairment localized in the septal and apical regions (septal WMSI 1.94 +/- 0.33 vs. total WMSI 1.51 +/- 0.25 and posterior WMSI 1.02 +/- 0.07; p < 0.001). During follow-up, further deterioration of LV systolic function (LVEF< 35%) was noted in five patients, who had less severe hypertrophy at the initial echocardiograms. These patients developed progressive LV cavity enlargement and more severe and extensive wall motion abnormalities, accompanied by septal akinesis and wall thinning, although posterolateral wall motion impairment was relatively mild (posterior WMSI 1.80 +/- 0.27 vs. septal WMSI 2.95 +/- 0.11; p < 0.001). CONCLUSIONS: Septal and apical wall motions are reduced in HCM with mild LV remodeling. As LV dysfunction progresses, septal akinesis and wall thinning develop and LV cavity enlargement becomes more prominent, though posterolateral wall motion impairment is relatively mild.     

Assessment of coronary microcirculation in patients with takotsubo-like left ventricular dysfunction.

BACKGROUND: The precise mechanism of takotsubo-like left ventricular (LV) dysfunction remains unclear. METHODS AND RESULTS: Eight consecutive patients with takotsubo-like LV dysfunction were studied. In the acute phase and 3 weeks later, the coronary flow velocity spectrum and coronary flow velocity reserve (CFVR) were recorded by Doppler guidewire. The deceleration time of diastolic velocity (DDT; ms) was measured from the peak diastolic velocity to the point where the extrapolated line intersected the baseline. In all cases, CFVR of the 3 coronary arteries increased during follow-up (1.7+/-0.5 to 2.4+/-0.5 for the left anterior descending artery (p < 0.05), 1.7+/-0.5 to 2.7+/-0.8 for the left circumflex artery (p < 0.05) and 1.7+/-0.3 to 2.5+/-0.4 for the right coronary artery (p < 0.05)). In addition, the DDT of all coronary arteries increased during follow-up. CONCLUSIONS: Decreased CFVR and short DDT were demonstrated in patients with takotsubo-like transient LV dysfunction in the acute phase, and these findings improved 3 weeks later, which suggests that coronary microvascular dysfunction may be a causative mechanism.     

Tako-tsubo-like left ventricular dysfunction in a patient with chronic total occlusion of the left anterior descending artery

This report describes a case of tako-tsubo-like left ventricular dysfunction in a patient with chronically occluded left anterior descending artery. A 74-year-od female, experiencing severe pain due to osteoarthritis, presented with chest pain lasting for 6 h. Electrocardiography revealed ST-segment elevation in the anterior and lateral walls. Left ventriculography in the acute phase displayed an akinetic apex and hyperkinetic basal region. Emergent coronary angiography revealed total occlusion of the left anterior descending artery. Although direct coronary angioplasty to the totally occluded left anterior descending artery was unsuccessful, the left ventricular function returned to normal within three weeks after admission. Thallium scintigraphy showed no significant abnormality, and cardiac enzyme elevation showed only a slight increase. In this case, tako-tsubo-like left ventricular dysfunction was considered to occur in the presence of chronically occluded left anterior descending artery.     

Coronary vascular reserve in left ventricular hypertrophy secondary to chronic aortic regurgitation

Coronary vascular reserve was studied in 11 patients with severe chronic aortic regurgitation (AR). Nineteen patients with the chest pain syndrome and normal findings on cardiac catheterization served as control subjects. Resting coronary sinus flow and contrast-agent-induced hyperemia were measured by continuous thermodilution. Left ventricular (LV) dimensions and mass were obtained echocardiographically. All patients had normal coronary arteries. Resting coronary flow was increased and coronary reserve was decreased in patients with AR compared with the control subjects: 310 +/- 38 versus 121 +/- 13 ml/min and 56 +/- 9 versus 86 +/- 7.5%, respectively. The decrease in coronary vascular reserve correlated with the increase in LV mass (r = -0.86, p = 0.001) and LV wall thickness (r = -0.83, p = 0.002) and with the decrease in LV volume/mass ratio (r = 0.761, p = 0.007). There was no significant correlation between the decrease in coronary vascular reserve and LV volume (r = 0.255), LV peak wall stress (r = 0.292), LV systolic pressure (r = -0.495), aortic or LV diastolic pressure (r = 0.322 and -0.318, respectively), or aortic-LV diastolic gradient, nor with the voltage on the electrocardiogram (limb leads r = -0.60, precordial leads r = -0.118). Thus, coronary vascular reserve is decreased in proportion to the degree of left ventricular hypertrophy in patients with chronic AR. Patients with angina pectoris tended to have a lower coronary vascular reserve than those without angina (median 26 versus 76%, difference not significant). LV wall thickness and not LV volume is the critical component of left ventricular mass related to coronary reserve. No significant correlation between the decrease in coronary vascular reserve and the presence of angina pectoris was demonstrated.     

Left ventricular dysfunction during dobutamine stress echocardiography in patients with syndrome X and positive myocardial perfusion scintigraphy.

AIMS: A sizeable proportion of patients with angina, angiographically smooth coronary arteries and positive exercise test (syndrome X) have stress/rest myocardial perfusion defects. The aim of the study was to assess whether perfusion defects are dependent upon a reduction in coronary flow reserve causing regional left ventricular dysfunction in syndrome X patients. METHODS AND RESULTS: Twenty-two syndrome X patients underwent dobutamine stress echocardiography (DSE). All had stress-induced perfusion defects documented by 99m-Tc-MIBI scintigraphy. Resting and peak DSE wall motion score index (WMSI) were evaluated. Six patients exhibited resting wall motion abnormalities in 10 segments (WMSI 1.05 +/- 0.11). DSE was positive in 12 patients (53%), in whom 16 myocardial segments were involved: of these, 12 were normokinetic and 4 hypokinetic at rest. Peak WMSI was 1.17 +/- 0.17 (p < 0.05 vs rest). Of the 12 patients with a positive DSE, 9 also showed diagnostic ECG changes and 6 complained of angina. Of the 10 patients with negative DSE, 5 had angina and 5 (one with angina) showed ECG changes. In 7 patients (7 segments) (32%), the location of dobutamine-induced wall motion abnormalities coincided with the area where exercise-induced hypoperfusion was observed with MIBI. CONCLUSIONS: More than a half of syndrome X patients with myocardial perfusion abnormalities also develop regional LV dysfunction during DSE. However, the site of perfusion defects and wall motion abnormalities can be different. Reversible ischemia, defined as a parallel limitation of flow reserve and inducible dysfunction, could be identified as the cause of chest pain in almost one-third of patients.     

Relations among impaired coronary flow reserve, left ventricular hypertrophy and thallium perfusion defects in hypertensive patients without obstructive coronary artery disease

Invasive Doppler catheter-derived coronary flow reserve, echocardiographic measurements of left ventricular hypertrophy and intravenous dipyridamole-limited stress thallium-201 scintigraphy were compared in 48 patients (40 were hypertensive or diabetic) with clinical ischemic heart disease and no or minor coronary artery disease. Abnormal vasodilator reserve (ratio less than 3:1) occurred in 50% of the study group and markedly abnormal reserve (less than or equal to 2:1) occurred in 27%. Coronary vasodilator reserve was significantly lower (2.2 +/- 0.8 versus 3.5 +/- 1.3, p = 0.003) and indexed left ventricular mass significantly higher (152.6 +/- 42.2 versus 113.6 +/- 24.0 g, p = 0.0007) in patients with a positive (n = 11) versus a negative (n = 32) thallium perfusion scan. Coronary flow reserve was linearly related in coronary basal flow velocity as follows: y = -0.17x + 4.59; r = -0.57; p = 0.00002. The decrement in flow reserve was not linearly related to the degree of left ventricular hypertrophy. Abnormal vasodilator reserve subsets found in hypertensive patients were defined on the basis of basal flow velocity, indexed left ventricular mass and clinical factors. In this series, diabetes did not cause a detectable additional decrement in flow reserve above that found with hypertension alone. These findings demonstrate that thallium perfusion defects are associated with depressed coronary vasodilator reserve in hypertensive patients without obstructive coronary artery disease. Left ventricular hypertrophy by indexed mass criteria is predictive of which hypertensive patients are likely to have thallium defects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical significance of coronary flow reserve in hypertrophied heart: comparison with Doppler index, hemodynamics and plasma natriuretic peptide concentrations

OBJECTIVES: The relationship was investigated between coronary flow reserve and Doppler echocardiographic parameters, hemodynamic parameters and plasma natriuretic peptide concentrations in the hypertrophied heart. METHODS: The subjects were 19 patients with hypertrophied heart due to various etiologies and no significant coronary artery stenosis. All patients were in sinus rhythm. The left ventricular wall thickness, the E/A ratio in transmitral flow velocity pattern and the Doppler index were determined by Doppler echocardiography, and the plasma atrial and brain natriuretic peptide concentrations were measured. At cardiac catheterization, pulmonary capillary wedge pressure and left ventricular end-diastolic pressure were measured, and the coronary flow reserve was obtained by injecting intracoronary adenosine triphosphate into the left anterior descending artery using a Doppler guidewire. RESULTS: Coronary flow reserve in the patients was significantly lower than in 11 normal control subjects (2.50 +/- 0.76 vs 3.90 +/- 0.64, p < 0.001). There were no significant correlations between coronary flow reserve and the left ventricular wall thickness or the E/A ratio. The mean value of the Doppler index in the patients was 0.48 +/- 0.10 and there was a significant negative correlation between coronary flow reserve and the Doppler index (r = -0.73, p < 0.001). The correlation between coronary flow reserve and left ventricular end-diastolic pressure was not significant, but there was a significant negative correlation between coronary flow reserve and pulmonary capillary wedge pressure (r = -0.64, p < 0.01). There were significant negative correlations between coronary flow reserve and atrial (r = -0.62, p < 0.01), or brain natriuretic peptide concentrations (r = -0.56, p < 0.05). CONCLUSIONS: Coronary flow reserve may reflect overall cardiac performance evaluated by the Doppler index and plasma natriuretic peptide concentrations in the hypertrophied heart, and the measurement of coronary flow reserve may be useful for evaluating disease severity in patients with hypertrophied heart.     

Tako-tsubo-like transient left ventricular dysfunction with apical thrombus formation: a case report

A 76-year-old woman with oppressive chest pain was admitted to our hospital. Initial electrocardiography revealed normal sinus rhythm with ST-segment elevation in leads V2-V5. The patient underwent emergent coronary angiography, which demonstrated no significant coronary stenosis. Left ventriculography revealed marked hypokinesis and akinesis of the mid and distal segments of all ventricular walls, with hyperkinesis of the base. Six days after admission, transthoracic echocardiography revealed immobile apical thrombus. The thrombus disappeared without any embolic episode after 2 weeks of anticoagulant therapy with heparin and warfarin. Left ventricular walls returned to normal 3 months after the attack. Tako-tsubo-like cardiomyopathy with apical thrombus has only been reported in three cases. Left ventricular function normalizes within several days or weeks in most cases of tako-tsubo-like transient left ventricular dysfunction. Therefore, if the thrombus remains within the left ventricle, the risk of embolism might be relatively high. Careful management must be required in patients with tako-tsubo-like transient left ventricular dysfunction.     

Reversible left ventricular hypertrophy after tako-tsubo-like cardiomyopathy

Tako-tsubo-like cardiomyopathy is a newly-recognized enigmatic disease characterized by transient left ventricular dysfunction of a broad area of the apex with a hyperkinetic area around the cardiac base. There is ST-segment elevation with no coronary stenosis. The exact mechanism for this entity remains unknown. Here, we report a case of tako-tsubo-like cardiomyopathy that showed a marked left ventricular hypertrophy (LVH) when the wall motion returned to normal. LVH was normalized at 10 months. The cause of LVH remains unknown.     

Clinical significance of pressure measurement in the infarct-related coronary artery in acute myocardial infarction: evaluation of variables predicting recovery of left ventricular function in the convalescent stage

Early reperfusion and good antegrade flow are essential in restoring better regional left ventricular function in acute myocardial infarction, but they do not always correlate with the extent of recovery. This study evaluated coronary circulation using the new "pressure wire" technique to measure the direct pressure of the coronary circulation including antegrade and collateral flow before and after reperfusion in patients with acute myocardial infarction, and to clarify the influence of these variables on recovery of left ventricular function in the convalescent stage. Fifty six consecutive patients with first acute myocardial infarction underwent percutaneous transluminal coronary angioplasty(PTCA) for totally occluded or severely narrowed infarct-related lesion and evaluation of coronary circulation using pressure wire. Left ventriculography was analyzed at 1 month after the onset in 41 patients. Treatment variables including reperfusion time, reperfusion modality, Thrombolysis in Myocardial Infarction(TIMI) grade after PTCA, and pressure wire variables were compared with parameters of left ventricular function. Reperfusion time was not related to regional wall motion evaluated by the SD chord of left ventriculography in the infarcted zone. Pressure wire measurements showed a correlation between fractional flow reserve measured after PTCA and infarcted regional wall motion(r = 0.558, p < 0.01). Patients with infarct-related lesion in the right coronary artery showed the magnitude of left ventricular regional wall motion was related to fractional collateral flow reserve(maxQc/Qn) during PTCA(r = 0.768, p < 0.05), but no such relationship was observed in patients with infarct-related lesion in the left anterior descending artery. Fractional flow reserve measured after PTCA varied widely in patients with the same TIMI flow grade, so did not vary with it. The pressure wire technique enables assessment of the collateral circulation distal to infarct-related lesion quantitatively before reperfusion in patients with acute myocardial infarction. The fractional flow reserve derived by coronary pressure after reperfusion was significantly related to the recovery of regional wall motion in the infarcted area in the convalescent stage. The fractional flow reserve after reperfusion with PTCA is a better parameter than TIMI flow grade for predicting recovery of regional left ventricular function after myocardial infarction.     

"Chestnut-shaped" transient regional left ventricular hypokinesis with abnormal myocardial fatty acid metabolism, not corresponding to the coronary artery territories: a case report

A 79-year-old female patient, who was initially suspected to have pneumonia, was admitted to the respiratory department of our hospital. She experienced chest pain on the second admission day. Electrocardiography showed ST-segment elevation in leads V3 through V6, and echocardiography revealed hypokinetic left ventricular wall motion. Therefore, myocardial infarction was suspected. She was transferred to the coronary care unit. Heart catheterization was immediately performed. Coronary angiography showed no significant stenotic lesion. Left ventriculography showed regional hypokinesis of the anterior and posterior walls near the base and normokinesis in the apex. Iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid (123-BMIPP)myocardial single photon emission computed tomography(SPECT) revealed inhomogeneous decrease in uptake, especially in the lateral wall, which did not correspond to any of the coronary artery territories. The echocardiographic asynergy was dramatically resolved after 1 week and the 123I-BMIPP SPECT finding was normal at 3 months. Although the clinical course of this patient was similar to that of tako-tsubo-like left ventricular dysfunction, the shape of her left ventricle was not typical. Left ventriculography showed hypokinesis of the anterior and posterior walls near the base and normokinesis in the apex, appearing like a chestnut rather than a tako-tsubo.     

"Tako-tsubo-like left ventricular dysfunction": a clinical entity mimicking acute myocardial infarction with a favorable prognosis

An emotionally-distressed, elderly Caucasian woman presented with chest pain and hypertension. Electrocardiogram showed inferior ST-segment elevation, and an urgent cardiac catheterization was performed. Coronary angiography revealed normal appearing coronary arteries; however, left ventriculography showed extensive left ventricular apical akinesis. The patient had a mild rise in cardiac enzyme levels indicative of myocardial injury. She was discharged after an uncomplicated in-hospital course. One month later, the left ventricular wall motion abnormality had improved. In this report, the authors discuss this compilation of findings known as tako-tsubo-like left ventricular dysfunction.     

Coronary flow velocity reserve in hypertensive patients with left ventricular systolic dysfunction

BACKGROUND: Hypertensive microvascular disease is speculated to be a limiting factor for the ability of left ventricular (LV) hypertrophy to maintain LV systolic function in systemic hypertension. The role of coronary reserve, which may be affected by microvascular disease, remains uncertain in the pathophysiology of hypertensive heart disease. HYPOTHESIS: A progressive impairment of coronary flow velocity reserve (CFVR) according to the presence and severity of LV systolic dysfunction is anticipated to occur in hypertension. METHODS: According to the absence or presence of LV dysfunction (LV fractional shortening - FS% < 30), two groups of hypertensive patients were investigated: HP1 (n = 9, FS% = 36+/-6) and HP2 (n = 13, FS% = 18+/-6). Eight normal subjects (NL) served as controls (LVFS% = 35+/-3). Doppler blood flow velocity was obtained from the left anterior descending coronary artery using transesophageal echocardiography before, and during 6-min continuous adenosine infusion (140 microg x kg(-1) x min(-1) intravenous). The CFVR was calculated as the ratio of maximal to baseline peak diastolic flow velocities. RESULTS: The comparison among NL, HP1, and HP2 groups showed statistically different (p < 0.05) mass index (101+/-18, 172+/-46, and 257+/-54 g x m(-2)), end-systolic wall stress (76.9+/-14.4, 78.4+/-23.9, and 174.5+/-43.0 10(3) x dyn x cm(-2)), and CFVR (3.5+/-0.6, 3.2+/-0.4, and 2.6+/-0.8), respectively. The CFVR correlated significantly and directly with LVFS% (r = 0.40) and correlated inversely with both mass index (r = -0.54) and end-systolic stress (r = -0.40). CONCLUSIONS: These results indicate that CFVR impairment is weakly related to LV dysfunction in hypertension.     

The natural history of myocardium awaiting revascularisation in patients with impaired left ventricular function.

AIMS: Our aim was to follow changes in myocardial function and physiology in patients awaiting coronary artery bypass surgery (CABG) and relate changes to post-revascularisation functional response. METHODS AND RESULTS: In 21 patients with CAD and LV dysfunction, myocardial glucose utilisation (MGU) and blood flow (MBF) were measured with positron emission tomography using F-18-fluorodeoxyglucose and oxygen-15-labelled water. Left ventricular function, MGU, and MBF were re-assessed after one year, immediately prior to CABG. At baseline, dysfunctional myocardium displayed a reduction in MGU, hyperaemic MBF, and coronary vasodilator reserve (CVR) compared to normally functioning muscle. In the year preceding CABG, the overall wall motion score index increased (2.09 +/- 0.65 vs. 2.3 +/- 0.7, p=0.0001) and the LV ejection fraction decreased (30.6 +/- 11.1% vs. 27.3 +/- 11.5%, p<0.001). LVEF fell in 14 patients (28.7 +/- 9.4 vs. 23.8, p<0.0001). Aggregate regional wall motion worsened in 15 patients. In contrast to myocardium displaying stable function at echocardiography, myocardium with evidence of deterioration showed a parallel decrease in hyperaemic MBF and CVR (1.57 +/- 0.67 vs. 1.19 +/- 0.7 ml/min/g, [p=0.004] and 1.9 +/- 0.75 vs. 1.33 +/- 0.6, [p=0.005], respectively). Such myocardium displayed attenuated recovery postoperatively (21/68 [31%] LV segments) versus 'waiting-time' stable myocardium (98/169 [58%], p=0.0002). CONCLUSION: Delayed revascularisation in ischaemic left ventricular impairment results in declining function and a reduced likelihood of contractile improvement.     

Stunned left ventricular myocardium after exercise treadmill testing in coronary artery disease

Myocardial stunning (postischemic ventricular dysfunction) occurs in dogs after coronary stenosis following treadmill exercise. Less data are available in humans regarding development of stunned myocardium after exercise. Regional wall motion changes were evaluated in 22 patients with known coronary artery disease using 2-dimensional echocardiography and exercise treadmill testing. Wall motion was scored as 1 = normal, 2 = hypokinetic, 3 = akinetic, 4 = dyskinetic. At least 1 left ventricular segment with normal resting function developed an increase in wall motion score at 15 or 30 minutes compared with values at rest. The wall motion score in the midportion of the ventricular septum increased from 1.0 at rest to 1.6 (p less than 0.004) at 30 minutes after exercise; the basal inferior wall score worsened from 1.0 at rest to 1.9 (p less than 0.01) at 30 minutes after exercise. Coronary angiographic data in these patients revealed that left anterior descending narrowing correlated best with left ventricular septal wall motion abnormalities, whereas right coronary artery and circumflex narrowing best correlated with inferior and posterior wall motion abnormalities. Eight normal adult volunteers with no history of myocardial ischemia also underwent 2-dimensional echocardiography and exercise testing. No wall motion abnormalities were observed at any time after exercise. The present study suggests that in patients with coronary artery disease, exercise treadmill testing may induce regional wall motion abnormalities of the left ventricle that persist greater than or equal to 30 minutes after exercise, an observation consistent with the phenomenon of stunned myocardium.     

Prognostic importance of wall motion abnormalities in patients with ischemic cardiomyopathy and an implantable cardioverter-defibrillator

Patients with extensive regional wall motion abnormalities are predisposed to development of ventricular tachyarrhythmia. The prognostic effect of this in patients with an implantable cardioverter-defibrillator (ICD) and coronary artery disease (CAD) is not known. Echocardiographic left ventricular systolic indexes, wall motion score index (WMSI), and extent of regional akinesia in 140 patients (65 +/- 10 years old; 92% men) with an ICD and CAD were studied. Arrhythmic events requiring ICD therapy and causing death (n = 41, 29%) were recorded over a mean follow-up of 1.4 +/- 0.8 years. Left ventricular basal fractional shortening, ejection fraction, global WMSI, and extent of akinesia, especially in the inferoposterior regions of a right coronary artery territory, were univariate predictors (all p values <0.05). Global WMSI (hazard ratio 2.18, 95% confidence interval 1.03 to 4.65, p = 0.04) and fractional shortening (hazard ratio 0.93, 95% confidence interval 0.88 to 1.00, p = 0.04) were multivariate predictors. Global WMSI (p = 0.04) and > or =2 right coronary region akinetic segments (p = 0.05) provided incremental risk prediction to left ventricular ejection fraction in a global risk-assessment model (chi-square p = 0.001). Presence of right coronary region akinesia better identified those at increased risk of events (p = 0.02) compared with the presence of left anterior descending region akinesia (p = 0.2), independent of systolic function. In conclusion, global WMSI and left ventricular basal fractional shortening were important additional risk predictors of ICD events in CAD. Global WMSI and right coronary region inferoposterior akinesia provided independent and incremental risk assessment to left ventricular ejection fraction and improved identification of those at increased risk of ICD-related events in patients with ischemic cardiomyopathy.     

The effect of collateral circulation on left ventricular systolic function

BACKGROUND: Conflicting reports exist on the influence of coronary collateral circulation on preservation of left ventricular systolic function. The aim of this study was to assess the effect of coronary collateral circulation on left ventricular systolic function in coronary artery disease. METHODS: Seventy-one consecutive patients having left anterior descending arteries with proximal or near-proximal stenosis of at least 95% (excluding 100%) were included in the study. The coronary collateral circulation to left anterior descending artery was evaluated with regard to its effects on left ventricular systolic function. RESULTS: Among the 71 patients, 46 patients were found to have a coronary collateral circulation grade of >or=1 (group 1), whereas the remaining 25 patients had coronary collateral circulation grade of 0 (group 2). The mean value of left ventricular function score in group 1 was higher than that of group 2 (3.69+/-2.34 vs. 2.00+/-1.55, P=0.002), whereas the mean value of left ventricular ejection fraction in group 1 was lower than that of group 2 (44.67+/-12.05 vs. 54.32+/-10.22, P=0.001). The value of coronary collateral circulation grade was found to be positively correlated with the value of left ventricular function score (P=0.01, r=0.3), and negatively correlated with the value of left ventricular ejection fraction (P=0.01, r=-0.3). CONCLUSION: Coronary collateral circulation to the severely stenotic left anterior descending artery was not found to have an improving effect on left ventricular systolic function. In contrast with the previous studies demonstrating the coronary collateral circulation-associated preservation of left ventricular systolic function, presence of coronary collateral circulation was found to accompany or be associated with impairment of left ventricular systolic function. The grade of coronary collateral circulation was also found to be positively correlated with the severity of left ventricular systolic dysfunction. Further research on larger patient populations based on a long-term follow-up is warranted to investigate this issue.     

Regional coronary flow and contractile reserve in patients with idiopathic dilated cardiomyopathy

OBJECTIVES: The purpose of this study was to assess regional coronary flow and contractile reserve in patients with idiopathic dilated cardiomyopathy (IDCM). BACKGROUND: Although IDCM has been associated with alterations in coronary blood flow and contractile reserve, little is known about their regional distribution and correlation. METHODS: Fourteen patients with IDCM and 11 control subjects underwent coronary flow velocity (APV) measurements in the left anterior descending (LAD), left circumflex (LCx), and right coronary (RCA) arteries at baseline (b) and at maximal hyperemia (h). Coronary flow reserve (CFR) was defined as h-APV/b-APV. Wall thickening was assessed in 16 segments (7 assigned to LAD, 5 to LCx, and 4 to RCA) both at rest and under peak stress during low-dose dobutamine echocardiography. Regional contractile reserve was defined as the percentage difference in wall motion score index between rest and stress in each vascular territory. RESULTS: Although there were no significant differences in b-APV, patients with IDCM had significantly lower h-APV than controls in all three vascular territories and reduced CFR (LAD: 2.79 +/- 0.43 vs. 3.48 +/- 0.51, p < 0.05; LCx: 2.71 +/- 0.39 vs. 3.36 +/- 0.65, p < 0.05; and RCA: 3.43 +/- 0.55 vs. 4.02 +/- 0.73, p < 0.05). There was also a significant correlation between CFR and the corresponding contractile reserve in the vascular territory of the LAD (r = 0.75, p = 0.002) and the LCx (r = 0.64, p = 0.014). CONCLUSIONS: Patients with IDCM have alterations in regional coronary flow and reduced CFR. Furthermore, the correlation between regional CFR and the corresponding contractile reserve indicates that microvascular dysfunction may have a pathophysiologic role in the evolution of the disease.