Diagnostic and prognostic value of Holter-detected ST-segment deviation in unselected patients with chest pain referred for coronary angiography: a long-term follow-up analysis

Ambulatory External Electrocardiography Monitoring: Holter, Extended Holter, Mobile Cardiac Telemetry Monitoring

Ambulatory external electrocardiography (AECG) monitoring is effective as an evidence-based diagnostic tool when suspicion for cardiac arrhythmia is high. Multiple modalities of AECG monitoring exist, with unique advantages and limitations that predict effectiveness in a variety of clinical settings. Knowledge of these characteristics allows appropriate use of AECG, maximizing patient adherence, diagnostic yield, and cost-effectiveness. In addition, new technology has allowed the development of a modern generation of devices that offer increased efficacy and functionality compared with Holter monitors.

Diagnostic value of combined parameters derived from ambulatory electrocardiography for detecting coronary artery disease in non-active chest pain patients

Background and Objective: The diagnostic value of ST-segment deviation detected by ambulatory electrocardiography (AECG) is controversial in identifying coronary artery disease (CAD) referred for coronary angiography (CAG). Recently, many parameters which evaluate CAD can be derived from AECG. Therefore, we aimed to investigate the diagnostic value of AECG in screening CAD referred for CAG when several parameters were combined.

Methods: We studied the 104 chest pain inpatients. All patients received the CAG and AECG. A lumen diameter reduction of ≥ 50% was considered CAD according to CAG. The parameters derived from AECG included ST-segment deviation, apnea hypopnea index (AHI), QT interval dispersion (QTd) and heart rate variability (HRV). The diagnostic value of AECG in screening CAD was evaluated.

Results: Of the 104 patients, 57 (54.8%) had CAD according to CAG. The sensitivity of ST-segment deviation in screening CAD was 64.9%; the specificity was 89.4%; and the Kappa value was 0.528. The sensitivity of at least three combined parameters including ST-segment deviation, AHI, QTd and HRV was 89.5%; the specificity was 87.2%; and the Kappa value was 0.767.

Conclusion: AECG is very useful in screening CAD referred for CAG, especially while several parameters including ST-segment deviation, AHI, HRV and QTd are combined.

Non-invasive cardiac imaging techniques and vascular tools for the assessment of cardiovascular disease in type 2 diabetes mellitus

Cardiovascular disease is the major cause of mortality in type 2 diabetes mellitus. The criteria for the selection of those asymptomatic patients with type 2 diabetes who should undergo cardiac screening and the therapeutic consequences of screening remain controversial. Non-invasive techniques as markers of atherosclerosis and myocardial ischaemia may aid risk stratification and the implementation of tailored therapy for the patient with type 2 diabetes. In the present article we review the literature on the implementation of non-invasive vascular tools and cardiac imaging techniques in this patient group. The value of these techniques as endpoints in clinical trials and as risk estimators in asymptomatic diabetic patients is discussed. Carotid intima-media thickness, arterial stiffness and flow-mediated dilation are abnormal long before the onset of type 2 diabetes. These vascular tools are therefore most likely to be useful for the identification of 'at risk' patients during the early stages of atherosclerotic disease. The additional value of these tools in risk stratification and tailored therapy in type 2 diabetes remains to be proven. Cardiac imaging techniques are more justified in individuals with a strong clinical suspicion of advanced coronary heart disease (CHD). Asymptomatic myocardial ischaemia can be detected by stress echocardiography and myocardial perfusion imaging. The more recently developed non-invasive multi-slice computed tomography angiography is recommended for exclusion of CHD, and can therefore be used to screen asymptomatic patients with type 2 diabetes, but has the associated disadvantages of high radiation exposure and costs. Therefore, we propose an algorithm for the screening of asymptomatic diabetic patients, the first step of which consists of coronary artery calcium score assessment and exercise ECG.

Contemporary management of silent ischemia: the role of ambulatory monitoring

Silent ischemia is highly prevalent among patients with ischemic heart disease and is associated with a poor prognosis in moderate/high risk outpatients who either exhibit exercise- or pharmacological-induced myocardial ischemia, or in those patients who demonstrate silent ischemia following an acute coronary syndrome. Pharmacotherapy, including beta-blockers, angiotensin-converting enzyme inhibitors, statins, calcium channel antagonists and antiplatelet agents, have all demonstrated a reduction in silent ischemia and an improvement in cardiac prognosis. The management of patients with ischemic heart disease is currently based on patients' report of anginal symptoms: documentation of silent ischemia, usually using ambulatory electrocardiography, is not incorporated into the routine management of coronary artery disease. Yet studies comparing ambulatory electrocardiography with exercise testing have shown these tests to be complementary. We review the evidence concerning the prognostic value of ambulatory electrocardiography for monitoring silent ischemia and the prognostic value of attenuating silent ischemia. Mitigation of silent ischemia improves cardiac prognosis and ambulatory electrocardiographic monitoring before and after treatment of silent ischemia can play a valuable role in the management of coronary artery disease.

Gender significance of ST-segment deviation detected by ambulatory (Holter) monitoring

OBJECTIVE

To evaluate the gender influence in diagnostic and prognostic value of Holter-detected ST-segment deviation.

METHODS

Two-hundred seventy-seven consecutive patients (196 men) who underwent coronary angiography for evaluation of chest pain were studied with 24-h Holter monitoring within 72 h of coronary angiography, and were followed up for 65+/-21 months.

RESULTS

Men had a higher prevalence of coronary artery disease (169 of 196, 86%) compared to that of women (54 of 81, 67%), p<0.00025. Thirty-three (17%) men and 15 (19%) women had ST-segment deviation during 24-h recording. The sensitivity, specificity and positive predictive values of ST-segment deviation (elevation, depression, or both) for the detection of significant coronary artery disease were similar in men and women. The negative predictive values were significantly higher in women than men for ST-segment deviation (36% vs. 15%, p<0.001), ST-segment elevation (35% vs. 14%, p<0.001), and ST-segment depression (34% vs. 15%, p<0.001). Similarly, the diagnostic accuracies were significantly higher in women than men for ST-segment deviation (44% vs. 29%, p<0.025), ST-segment elevation (38% vs. 19%, p<0.001), and ST-segment depression (40% vs. 24%, p<0.025). There was no significant difference in composite end-point of events (mortality, nonfatal myocardial infarction, unstable angina, and coronary revascularization) in men versus women with ST-segment deviation (elevation, depression, or both).

CONCLUSION

Holter-detected ST-segment deviation has a higher negative predictive value and diagnostic accuracy for detection of significant coronary artery disease in women than in men, although the prognostic values are not significantly different between men and women.

Association of hypoglycemia and cardiac ischemia: a study based on continuous monitoring

OBJECTIVE

In some studies intensive diabetes treatment in patients with type 2 diabetes may be associated with increased cardiovascular events. It is not clear whether these events are related to hypoglycemic episodes. To determine whether episodes of hypoglycemia were more likely to be associated with cardiac ischemia than normoglycemia or hyperglycemia, we carried out a study in 21 patients with coronary artery disease (CAD) and type 2 diabetes treated with insulin who had good glycemic control.

RESEARCH DESIGN AND METHODS

We carried out 72-h continuous glucose monitoring along with simultaneous cardiac Holter monitoring for ischemia. Patients also recorded symptoms of cardiac ischemia (chest pain) and symptoms of hypoglycemia.

RESULTS

Satisfactory continuous glucose monitoring system recordings were obtained in 19 patients. We recorded 54 episodes of hypoglycemia (blood glucose <70 mg/dl; 26 of these were symptomatic) and 59 episodes of hyperglycemia (blood glucose >200 mg/dl; none symptomatic). Of the 54 episodes of hypoglycemia, 10 were associated with symptoms of chest pain, during 4 of which electrocardiographic abnormalities were documented. In contrast, only 1 episode of chest pain occurred during 59 episodes of hyperglycemia. No chest pain or electrocardiographic abnormalities occurred when the blood glucose was within the normal range. The difference between the frequency of ischemia during hypoglycemia and the frequency during both hyperglycemia and normoglycemia was statistically significant (P < 0.01). There were 50 episodes during which the blood glucose changed by >100 mg over a 60-min period, and ischemic symptoms occurred during 9 of these episodes (P < 0.01 compared with stable normoglycemia or hyperglycemia).

CONCLUSIONS

Hypoglycemia is more likely to be associated with cardiac ischemia and symptoms than normoglycemia and hyperglycemia, and it is particularly common in patients who experience considerable swings in blood glucose. These data may be important in the institution of insulin treatment and attempting near-normal glycemia in patients with known CAD. Further research is needed to determine strategies to prevent ischemia associated with hypoglycemia.

Continuous 12-lead electrocardiographic monitoring in an emergency department chest pain unit: an assessment of potential clinical effect

STUDY OBJECTIVES

Continuous 12-lead serial ECG monitoring has been proposed to assist in the evaluation of patients with acute coronary syndrome and nondiagnostic ECG in an emergency department chest pain unit. However, the ability of serial ECG to detect acute coronary syndrome and its benefit in addition to a standard protocol has not been established. We evaluate the ability of continuous 12-lead ECG to detect acute coronary syndrome, assess the incremental benefit of the serial ECG in association with a set protocol in an ED chest pain unit, and evaluate whether serial ECG changes could be considered as prognostic factors.

METHODS

Patients who met Agency for Health Care Policy and Research guidelines for intermediate risk for short-term cardiovascular event unstable angina were prospectively studied in the chest pain unit. Patients were monitored with the Mortara Instruments ELI 100 STM continuous 12-lead ECG system with ST-segment analysis. ST-segment changes of greater than 100 microV in 2 or more contiguous leads or greater than 200 microV in 1 lead were considered positive. Data were compared with serial serum cardiac markers, cardiac function study results, angiographic results, and 30-day outcome results.

RESULTS

One hundred nineteen patients had serial ECG applied. The median duration of monitoring was 4.2 hours. Forty patients were given a diagnosis of acute coronary syndrome. Chest pain unit protocol detected 52 patients, and 23 were given a diagnosis of acute coronary syndrome (sensitivity 58%; specificity 63%). Sixteen patients had ST-segment changes of greater than 100 microV or greater than 200 microV, and 9 were given a diagnosis of acute coronary syndrome. The addition of the serial ECG to the chest pain unit protocol increased the sensitivity to 65% and decreased the specificity to 58%. Two patients with ST-segment changes but none without ST-segment changes had an adverse cardiac event, yielding a sensitivity of 100% and a specificity of 88%.

CONCLUSION

Serial ECG is of limited value in the diagnostic evaluation of intermediate-risk patients managed in the chest pain unit with a standard protocol. However, when ST-segment changes are present, they indicate an increased likelihood for an adverse cardiac event.