Sequence and magnitude of ventricular volume changes in painful and painless myocardial ischemia

Long-Term Preservation of Left Ventricular Systolic Function in Patients With Refractory Angina Pectoris and Inducible Myocardial Ischemia on Optimal Medical Therapy

Refractory angina pectoris (RAP) represents a clinical condition characterized by frequent episodes of chest pain despite therapy optimization. According to myocardial stunning and myocardial hibernation definitions, RAP should represent the ideal condition for systolic dysfunction development. We aim to investigate the evolution of left ventricular (LV) function in patients with RAP. A retrospective study which encompasses 144 patients with RAP referred to our institution from 1999 to December 2014 was performed. Of them, 88 met the inclusion criteria, and LV function was assessed by echocardiography. All of them had persistent angina episodes on top of optimal medical therapy and evidence of significant inducible myocardial ischemia and no further revascularization options. Nitrates consumption rate, time of angina duration, and the number of angina attacks were evaluated. In the whole population, ejection fraction (EF) was 44% ± 2. EF was significantly lower in patients with previous myocardial infarction (41% ± 1.5 vs 51% ± 1.8, p <0.0001). The duration time and the number of angina attacks did not correlate with EF in the whole population and in patients without previous myocardial infarction. In patients with previous myocardial infarction, the number of anginal attacks did not correlate with EF, but EF appeared higher in patients with angina duration >5 years (<5 years EF 37% ± 1 [n = 26]; >5 years 44% ± 2 [n = 44]; p 0.02). Long-term LV function in patients with RAP is generally preserved. A previous history of myocardial infarction is the only determinant in the development of systolic dysfunction. In conclusion, frequent angina attacks and a long-term history of angina are not apparently associated to worse LV function.

A randomized, double-blind comparison of lercanidipine 10 and 20 mg in patients with stable effort angina: clinical evaluation of cardiac function by ambulatory ventricular scintigraphic monitoring

We evaluated the antiischemic action and the effects on left ventricular response to exercise of lercanidipine, a long-acting dihydropyridine calcium antagonist, in 23 patients with stable effort angina in a randomized, double-blind, parallel trial. Left ventricular function was assessed during upright bicycle exercise using an ambulatory radionuclide detector for continuous noninvasive monitoring of cardiac function. Exercise was performed under control conditions before (run-in placebo period) and after 2-week treatment with lercanidipine 10 or 20 mg once daily. During the placebo run-in period and at the study end, patients underwent clinical examination, ECG, exercise tests, ambulatory ventricular scintigraphic monitoring (VEST). Results showed that both drug doses increased time to onset of ST segment depression >/=1 mm and peak ST segment depression, with improvement of total exercise duration. Heart rate, blood pressure, and the rate-pressure product did not significantly change with respect to pretreatment value. The left ventricular ejection fraction, indicating contractility state of myocardium, was unchanged at rest and during exercise after both lercanidipine doses. In conclusion, lercanidipine is safe and effective in reducing ischemia in patients with stable effort angina without any deterioration of cardiac function.

Severe coronary artery disease presenting with a chief complaint of cervical pain

We present the case of a 49-yr-old man with cervical pain of 14 wk of duration. Physical examination and magnetic resonance imaging of the cervical spine demonstrated no neurologic abnormality or corroborative pathology. Cardiac catheterization demonstrated advanced multivessel disease. The patient underwent successful coronary bypass grafting and was symptom free 12 mo later. Spine practitioners are often consulted by the medical community to determine if a patient's limb or chest complaints might be caused by a spinal pain generator. This atypical case reminds us of the overlap between cardiac and cervical symptom referral. A patient with critical cardiac ischemia can present with predominant cervical complaints.

Diabetes mellitus and cardiovascular disease

Diabetes is associated with a high incidence and poor prognosis of cardiovascular disease, and with high short- and long-term mortality. Adequate treatment of cardiovascular disorders and aggressive management of coexisting risk factors have proved to be at least as effective in diabetic as in nondiabetic patients in randomized, controlled studies. Indeed, treating diabetic patients with cardiovascular disease results in a larger absolute risk reduction than in nondiabetic subjects. Nevertheless, diabetic patients often receive inadequate therapy, which may, to a certain extent, explain their poor prognosis. Recommendations for the treatment of diabetic patients with acute myocardial infarction should include beta-blockers, aspirin, and ACE-inhibitors in all patients in whom no specific contraindications exist. Fibrinolysis should be administered when indicated, and the benefits of improving glycemic control should not be forgotten either. In patients with multi-vessel disease who need revascularization, when selecting the type of procedure, the superiority of surgical revascularization over angioplasty should be borne in mind. Even heart transplantation should be included as a therapeutic option since there are no data to support the exclusion of patients on account of their diabetes. Finally, coexisting risk factors should be intensively treated through lifestyle intervention, with or without drug therapy, in order to achieve secondary prevention goals.

Mechanisms of cardiac pain

Angina pectoris often results from ischemic episodes that excite chemosensitive and mechanoreceptive receptors in the heart. Ischemic episodes release a collage of chemicals, including adenosine and bradykinin, that excites the receptors of the sympathetic and vagal afferent pathways. Sympathetic afferent fibers from the heart enter the upper thoracic spinal cord and synapse on cells of origin of ascending pathways. This review focuses on the spinothalamic tract, but other pathways are excited as well. Excitation of spinothalamic tract cells in the upper thoracic and lower cervical segments, except C7 and C8 segments, contributes to the anginal pain experienced in the chest and arm. Cardiac vagal afferent fibers synapse in the nucleus tractus solitarius of the medulla and then descend to excite upper cervical spinothalamic tract cells. This innervation contributes to the anginal pain experienced in the neck and jaw. The spinothalamic tract projects to the medial and lateral thalamus and, based on positron emission tomography studies, activates several cortical areas, including the anterior cingulate gyrus (BA 24 and 25), the lateral basal frontal cortex, and the mesiofrontal cortex.

Monitoring of left ventricular ejection fraction with a miniature, nonimaging nuclear detector: accuracy and reliability over time with special reference to blood labeling

BACKGROUND

The purpose of this study was to determine the accuracy of determinations of left ventricular ejection fraction (LVEF) by a nonimaging miniature nuclear detector system (Cardioscint) and to evaluate the feasibility of long-term LVEF monitoring in patients admitted to the coronary care unit, with special reference to the blood-labeling technique.

METHODS AND RESULTS

Cardioscint LVEF values were compared with measurements of LVEF by conventional gamma camera radionuclide ventriculography in 33 patients with a wide range of LVEF values. In 21 of the 33 patients, long-term monitoring was carried out for 1 to 4 hours (mean 186 minutes), with three different kits: one for in vivo and two for in vitro red blood cell labeling. The stability of the labeling was assessed by determination of the activity of blood samples taken during the first 24 hours after blood labeling. The agreement between Cardioscint LVEF and gamma camera LVEF was good with automatic background correction (r = 0.82; regression equation y = 1.04x + 3.88) but poor with manual background correction (r = 0.50; y = 0.88x - 0.55). The agreement was highest in patients without wall motion abnormalities. The long-term monitoring showed no difference between morning and afternoon Cardioscint LVEF values. Short-lasting fluctuations in LVEFs greater than 10 EF units were observed in the majority of the patients. After 24 hours, the mean reduction in the physical decay-corrected count rate of the blood samples was most pronounced for the two in vitro blood-labeling kits (57% +/- 9% and 41% +/- 3%) and less for the in vivo blood-labeling kit (32% +/- 26%). This "biologic decay" had a marked influence on the Cardioscint monitoring results, demanding frequent background correction.

CONCLUSION

A fairly accurate estimate of LVEF can be obtained with the nonimaging Cardioscint system, and continuous bedside LVEF monitoring can proceed for hours with little inconvenience to the patients. Instability of the red blood cell labeling during long-term monitoring necessitates frequent background correction.

Metoprolol abolishes exercise-induced left ventricular dysfunction in patients with silent ischemia

Left ventricular systolic function is reduced during episodes of silent ischemia in patients with coronary artery disease (CAD). Left ventricular ejection fraction (LVEF) is increased at least 5 absolute percent during exercise in most normal subjects; however, in patients with CAD, LVEF often remains unchanged or decreases. The anti-ischemic effect of beta-adrenergic receptor blockade is well documented, including a reduction of exercise-induced electrocardiographic ST depressions; however, the effect of these drugs on left ventricular volume changes during exercise in patients with silent ischemia is unknown. The aim of this study was to evaluate the effect of a cardio-selective beta-blocking agent, metoprolol, on rest and exercise LVEF in patients with silent ischemia, using radionuclide cardiography. Fifteen patients with silent ischemia completed a double-blind, placebo-controlled crossover study at rest and during submaximal exercise. LVEF remained unchanged during exercise in the placebo phase (56% to 58%; p = NS), but even though LVEF tended to decrease 56% during rest after metoprolol versus 52% after placebo (p = NS), the LVEF increase from rest to exercise resembled a normal LVEF response, 52% to 58% (p = 0.005). Exercise-induced electrocardiographic ST depressions were also reduced during metoprolol treatment. In patients with silent ischemia, the exercise-induced change in LVEF rises significantly during metoprolol treatment. The mechanism may be a reduction in myocardial ischemia as indicated by a reduction in ischemic electrocardiographic findings.

Bedside assessment of myocardial performance in the critically ill

No measurement of myocardial performance currently available in the ICU can be regarded is ideal. Table 2 summarises the main features of the major monitoring techniques. As many of the indices of myocardial performance are interdependent, quantifying the contribution of each component to overall cardiac function is not possible currently, and the clinical utility of monitoring each individually is not therefore established. Bedside measurements of LV dimensions, volumes and ejection fraction, and the other indices of systolic and diastolic function can now be made, but the case for their routine use in influencing clinical practice remains unproven. Transoesophageal echocardiography has an important and established diagnostic role and has been used successfully for continuous monitoring during surgery, but practical considerations seriously limit its potential for routine use. Radionuclide techniques allow the measurement of many of the same parameters and have the potential for continuous use, but practical problems and the additional risk of radiation exposure may limit this application in the critical care environment. Doppler techniques are non-invasive, provide continuous data and are simple to operate, but the data provided has important limitations. Although the pulmonary artery catheter has been in use for over twenty years, questions regarding the information is provides concerning myocardial function remain and the extent to which it should influence therapeutic decisions is still controversial. However with the development of additional facilities, particularly the continuous measurement of cardiac output the pulmonary artery catheter seems likely to remain the mainstay of bedside monitoring of myocardial performance in the critically ill in the immediate future.

Impaired left ventricular filling rate induced by treatment with recombinant interleukin 2 for advanced cancer

BACKGROUND

Immunotherapy with recombinant interleukin 2 (rIL 2) has been extensively used to treat cancer but its use has been hampered by serious side effects including severe hypotension, arrhythmias, and myocardial infarction.

OBJECTIVE

To assess the effects of rIL 2 on human left ventricular function.

METHODS

Left ventricular (LV) function was monitored in 22 patients (9 women, 13 men) (mean (SD) age 53 (10) years) undergoing a 120 h continuous intravenous infusion of rIL 2 (18 x 10(6) IU/m2/day) for melanoma (4), renal cell (16), ovarian (1), and colon cancer (1). Radionuclide ventriculography was performed before and 1 h after the end of treatment. Ejection fraction (EF), peak emptying rate (PER), peak filling rate (PFR), and regional left ventricular wall motion were analysed. Heart rate (HR), central venous pressure (CVP), systolic (SBP) and diastolic blood pressures (DBP), the electrocardiogram, and myocardial enzyme concentrations were monitored throughout the study.

RESULTS

All variables (mean (SD)) were normal before rIL 2 was given. After rIL 2 administration HR increased significantly from 84 (11) to 125 (18) beats/min (p < 0.0001), SBP fell from 128 (11) to 100 (9) mmHg (p < 0.001) and DBP from 76 (9) to 65 (7) mmHg (p < 0.0001). CVP decreased from 3.70 (3.2) to 1.30 (0.45) cm H2O (p < 0.001). EF (65 (7) to 64 (8%) and PER (3.56 (0.60) to 3.86 (0.83) EDV/s) did not change significantly. PFR decreased significantly at the end of the rIL 2 infusion from 2.68 (0.46) to 2.37 (0.43) EDV/s (p < 0.01). Left ventricular segmental hypokinesia developed in 6 patients. Myocardial enzyme concentrations remained normal throughout the study.

CONCLUSIONS

The results of this study confirmed that rIL 2 produces important haemodynamic changes, predominantly related to decreased systemic resistance. However, the observed reduction in PFR in most patients suggested that rIL 2 might exert its action at the level of the heart muscle itself. The localised systolic dysfunction in some patients suggested that rIL 2 might also adversely affect myocardial perfusion.

Comparison of painful and painless left ventricular dysfunction recorded during ambulatory ventricular function monitoring in angina pectoris secondary to coronary artery disease

Left ventricular (LV) function and the electrocardiogram of 55 patients with coronary artery disease and angina were monitored for a mean of 3.2 +/- 1.9 hours with an ambulatory LV function monitor. During the monitoring interval, patients performed daily activities such as sitting, walking, climbing stairs, and eating. Sixty episodes of transient reduction in ejection fraction of > 5% lasting > 60 seconds were observed in 24 patients; 13 episodes were associated with typical angina, but 47 were asymptomatic. Asymptomatic episodes had a shorter duration of ventricular dysfunction (116 +/- 49 vs 189 +/- 113 seconds; p < 0.05), and smaller increases in relative end-diastolic and end-systolic volumes (end-diastolic 0.9 +/- 5.4% vs 4.6 +/- 4.9% [p < 0.05], and end-systolic 21 +/- 11% vs 35 +/- 20% [p < 0.05]) than did symptomatic ones. When a subset of patients with both symptomatic and asymptomatic episodes were analyzed, similar results were observed: in asymptomatic episodes, duration was shorter (82 +/- 31 vs 200 +/- 110 seconds; p < 0.005), ejection fraction decrease was smaller (-7.3 +/- 2.6% vs -11.0 +/- 4.7%; p < 0.05), and end-systolic volume increase was smaller (23 +/- 12% vs 37 +/- 19%; p < 0.05). The data suggest that asymptomatic transient LV dysfunction is less severe and of shorter duration in patients with angina pectoris.

The predictive value of silent ischemia at an exercise test before discharge after an episode of unstable coronary artery disease. RISC Study Group

The prognostic value of silent ischemia during a symptom-limited predischarge exercise test (ET) was evaluated in 740 men after an episode of unstable angina or non-Q wave myocardial infarction. The 51% of patients with ST depression at the ET had a higher rate of myocardial infarction or death after 1 year (18%) compared with those without ST depression (9%; p less than 0.01). This increased risk was not influenced by the presence or absence of pain at the ET: 18.3% in patients with painful ischemia compared with 18.1% in patients with silent ischemia. However, ST depression combined with pain at the ET predicted a higher incidence of class III or IV angina at follow-up (43.9% compared with 16.7% in the group with asymptomatic ST depression; p less than 0.001). Because revascularization in addition to alleviating symptoms also enhances the prognosis in certain groups of patients, selections for coronary angiography and possible revascularization should not be made only on the basis of symptoms but also on the presence of myocardial ischemia, whether symptomatic or not.

Clinical evaluation of cardiac function by ambulatory ventricular scintigraphic monitoring (VEST): validation and study of the effects of nitroglycerin and nifedipine in patients with and without coronary artery disease

Global left ventricular function and ECGs were continuously monitored by radionuclide ambulatory ventricular function monitoring (VEST) and validated against multigated blood pool analysis (MUGA) and left ventriculography in 26 subjects (study 1). Ejection fraction by VEST (Y) showed good correlation with Y = 5.5 +/- 0.79 X (r = 0.91), Y = 1.7 +/- 0.86 X' (r = 0.91), and Y = 11.6 + 0.68 X" (r = 0.82) to sitting and supine MUGA and left ventriculography, respectively. In study 2 left ventricular function and ECGs were evaluated at rest and during exercise without any drug (control), with nitroglycerin, and with nifedipine in 21 patients with coronary disease (group I) and six normal subjects (group II). In group I abnormal ejection fraction responses (exercise increase less than or equal to 6%) during the control exercise period were found in 15 patients (71%), ST segment abnormalities in seven (33%), and chest pain in four (18%). Control exercise increased end-diastolic volume (100 to 112 +/- 8%) and end-systolic volume (53 +/- 15% to 63 +/- 22%) and decreased the ejection fraction (47 +/- 15% to 43 +/- 21%). The ejection fraction during exercise increased after nitroglycerin (50 +/- 22%) or nifedipine (54 +/- 21%) (p less than 0.05). In group II the ejection fraction was unchanged between rest and exercise with or without nitroglycerin or nifedipine. Thus combined radionuclide and ECG monitoring by VEST could detect changes in left ventricular function at rest and during exercise over a prolonged period and demonstrated that nitroglycerin and nifedipine improved cardiac function in the ischemic setting with an increased ejection fraction in the upright position.

Silent ischaemia in the 1990s

Silent myocardial ischaemia (significant ST depression without chest pain) is a common occurrence in most forms of coronary heart disease and can be associated with permanent changes in myocardial structure. The haemodynamic and ECG manifestations of silent episodes are similar to those observed in painful ischaemia. Exercise testing is the most appropriate method for assessing the severity of coronary artery disease; increased sensitivity can be obtained by combining it with radionuclide scintigraphy or ventriculography. Ambulatory ECG monitoring may fail to detect ischaemic changes revealed by exercise provocation. The treatment approach should depend on the degree of ischaemia. Numerous clinical investigations in stable and unstable angina and in patients with a previous myocardial infarction indicate that the prognosis of patients with myocardial ischaemia does not depend on whether the ischaemia is silent or symptomatic. Silent and symptomatic episodes alone represent the same degree of coronary disease. Moreover, it appears that ischaemic episodes are a more powerful adverse prognostic influence than left ventricular function or the extent of coronary artery disease. All anti-ischaemic agents, such as beta-blockers, calcium antagonists and nitrates, and interventions such as coronary balloon angioplasty or coronary bypass surgery, are very effective treatments for myocardial ischaemia. All efforts should be made to prevent ischaemic episodes, whether silent or symptomatic, since the severity of disease rather than the presence or absence of symptoms more accurately reflects the need for intervention.

Painful versus silent myocardial ischemia during leg and arm exercise testing in stable angina pectoris

When 51 patients with proven coronary heart disease and stable angina pectoris underwent exercise testing, 22 experienced painful myocardial ischemia during both leg and arm exercise testing (group L + A), whereas 29 patients had such episodes only during the leg testing (group L). Upright bicycle exercise was performed with the legs first, followed 2 days later by arm testing. Exercise was stopped when typical anginal pain and greater than 1-mm ST horizontal depression occurred during leg testing, and when greater than 1-mm ST horizontal depression was noted during arm testing. Heart rate, systolic blood pressure and rate-pressure product for leg and arm testing, either at the beginning of anginal pain or at the time when 1-mm ST depression was noted, were similar. Two-dimensional echocardiography showed that the L group had higher (p less than 0.01) end-systolic volume at rest and decreased (p less than 0.05) ejection fraction during exercise. Coronary angiography showed that the L group had a greater (p less than 0.001) number of patients with 3-vessel disease, a decreased (p less than 0.001) ejection fraction and less patients with 1-vessel disease. In these patients, absence of anginal pain during arm exercise suggests defective segmental transmission of pain sensation related to severe coronary artery disease. Thus, arm testing, in addition to leg testing, seems to be a simple and useful tool for the detection of severe coronary disease.