Prognostic significance of transient ischemic episodes: response to treatment shows improved prognosis. Results of the Total Ischemic Burden Bisoprolol Study (TIBBs) follow-up

Therapeutic Properties of Highly Selective β-blockers With or Without Additional Vasodilator Properties: Focus on Bisoprolol and Nebivolol in Patients With Cardiovascular Disease

Bisoprolol and nebivolol are highly selective β₁-adrenoceptor antagonists, with clinical indications in many countries within the management of heart failure with reduced left ventricular ejection fraction (HFrEF), ischaemic heart disease (IHD), and hypertension. Nebivolol has additional vasodilator actions, related to enhanced release of NO in the vascular wall. In principle, this additional mechanism compared with bisoprolol might lead to more potent vasodilatation, which in turn might influence the effectiveness of nebivolol in the management of HFrEF, IHD and hypertension. In this article, we review the therapeutic properties of bisoprolol and nebivolol, as representatives of “second generation” and “third generation” β-blockers, respectively. Although head-to-head trials are largely lacking, there is no clear indication from published studies of an additional effect of nebivolol on clinical outcomes in patients with HFrEF or the magnitude of reductions of BP in patients with hypertension.

β-Blockade for Patients with Hypertension, Ischemic Heart Disease or Heart Failure: Where are We Now?

β-blockers are a heterogeneous class of drugs, with varying selectivity/specificity for β₁ vs β₂ receptors, intrinsic sympathomimetic activity (ISA), and vasodilatory properties (through β₂ stimulation, α receptor blockade or nitric oxide release). These drugs are indicated for the management of arterial hypertension, heart failure or ischemic heart disease (IHD; eg angina pectoris or prior myocardial infarction). Most of the benefit of β-blockade in these conditions arises from blockade of the β₁ receptor, and, in practice, the addition of ISA appears to reduce the potential for improved clinical outcomes in people with heart failure or IHD. Aspects of the benefit/risk balance of β-blockers remain controversial, and recent meta-analyses have shed new light on this issue. We have reviewed the current place of cardioselective β-blockade in hypertension, IHD and heart failure, with special reference to the therapeutic profile of a highly selective β₁-adrenoceptor blocker, bisoprolol.

Ambulatory and silent myocardial ischemia in women with coronary microvascular dysfunction: Results from the Cardiac Autonomic Nervous System study (CANS)

BACKGROUND

Up to two-thirds of patients with obstructive coronary artery disease (CAD) have silent ischemia (SI), which predicts an adverse prognosis and can be a treatment target in obstructive CAD. Over 50% of women with ischemia and no obstructive CAD have coronary microvascular dysfunction (CMD), which is associated with adverse cardiovascular outcomes. We aimed to investigate the prevalence of SI in CMD in order to consider it as a potential treatment target.

METHODS

36 women with CMD by coronary reactivity testing and 16 age matched reference subjects underwent 24-h 12-lead ambulatory ECG monitoring (Mortara Instruments) after anti-ischemia medication withdrawal. Ambulatory ECG recordings were reviewed by two-physician consensus masked to subject status for SI measured by evidence of ≥1 minute horizontal or downsloping ST segment depression ≥1.0 mm, measured 80 ms from the J point.

RESULTS

Demographics, resting heart rate, and systolic blood pressure were similar between CMD and reference subjects. Thirty-nine percent of CMD women had a total of 26 SI episodes vs. 0 episodes in the reference group (p = 0.002). Among these women 13/14 (93%) had SI, and few episodes (3/26, 12%) were symptomatic. Mean HR at the onset of SI was 96 ± 13 bpm and increased to 117 ± 16 bpm during the ischemic episodes. 87% reported symptoms that were not associated with ST depressions.

CONCLUSIONS

Ambulatory ischemia is prevalent in women with CMD, with a majority being SI, while most reported symptoms were not accompanied by ambulatory ischemia. Clinical trials evaluating anti-ischemic medications should be considered in the CMD population.

[Evaluation of the antianginal effectiveness of trimetazidine in a new dosage form for a single dose, depending on the region of the Russian Federation. ODA trial results]

The goal evaluation of the effectiveness of treatment with the new TMZ OD dosage form in different regions of the Russian Federation and regional differences in the clinical characteristics of patients with coronary artery disease included in the observation, the nature of their therapy, the presence and degree of correction of modifiable risk factors in real clinical practice.

MATERIAL

Used database research ODA (Evaluation of the effectiveness and therapeutic response to Preductal OD 80 mg in everyday practical use for the treatment of stable angina), which was conducted in 56 cities of the Russian Federation. The analysis was carried out in the Central, North-West, Volga districts and regions united by the territorial principle - Southern + North Caucasian + Crimea + Sevastopol and Ural + Siberian + Far Eastern.

RESULTS

By region, there were no differences in the ratio of men and women included in the observation, the number of smoking patients (about 15%), overweight (about 80% of patients), arterial hypertension (exceeding 85%),dyslipidemia (over 90%), and atrial fibrillation (met at each 8-10 included patient). The proportion of patients older than 65 years was greater in the Central, North-West and Ural regions. Unfavorable heredity in coronary artery disease is more common in the Southern, Central and Ural regions. More than 2/3 of the patients had low physical activity, and in the South - their number reached ¾ of all included in the observation. The largest number of patients with diabetes was in the Central and North-West regions (every fourth patient), in the Ural region every fifth. The lowest frequency of statin prescribing was in the Volga region. The smallest number of those receiving RAS inhibitors was in the North-West, Ural and South regions. Beta blockers took more than 80% of patients. Only 35% of patients had a target systolic blood pressure. The smallest proportion of people with target blood pressure values was in the NorthWest and South regions. Adding TMZ OD to therapy or replacing previous therapy with trimetazidine on TMZ OD in all regions resulted in a significant (p <0.001) decrease in the incidence of angina attacks by as early as 1 month of therapy and the antianginal effect increased by the third month of treatment. By the third month of treatment, the average frequency of angina attacks was the lowest in the North-Western and Ural regions (significantly lower than even in the Central region) and remained higher only in the Volga region compared to the Central, North-Western and Ural regions. During follow-up, treatment compliance increased significantly in all regions.

CONCLUSION

The fight against major risk factors remains insufficient and efforts should be made to change the situation in all regions of the Russian Federation. The inclusion of trimetazidine in therapy in the new TMZ OD dosage form allows to obtain a pronounced antianginal effect and increase adherence to therapy. Low adherence can be overcome by careful observation and closer contact between doctors and patients.

Postoperative Cardiac Ischemia Detection by Continuous 12-Lead Electrocardiographic Monitoring in Vascular Surgery Patients: A Prospective, Observational Study

OBJECTIVES

Elderly patients undergoing vascular surgery are at major risk for perioperative cardiac complications. The authors investigated continuous electrocardiographic Holter monitoring in a postoperative setting to determine the degree of postoperative ischemic load and its possible associations with perioperative myocardial infarction.

DESIGN

A prospective, observational study.

SETTING

One university hospital.

PARTICIPANTS

The study comprised 51 patients aged 65 years or older undergoing peripheral arterial surgery.

INTERVENTIONS

Continuous electrocardiographic monitoring with a Holter device was started postoperatively and continued for 72 hours or until discharge. Postural changes were recorded using a 3-axis accelerometer. Standard 12-lead electrocardiography, high-sensitive troponin T measurements, and an inquiry of ischemic symptoms were performed 4 times perioperatively.

MEASUREMENTS AND MAIN RESULTS

The primary outcomes were ischemic load (area under the function of ischemic ST-segment deviation and ischemic time) and perioperative myocardial infarction. During 3,262.7 patient-hours of monitoring, 17 patients (33.3%) experienced 608 transient ischemic events, all denoted by ST-segment depression. Of these 17 patients, 5 experienced perioperative myocardial infarction. The mean ischemic load in all patients was 913.2±2,797.3 µV×minute. Ischemic load predicted perioperative myocardial infarction, with an area under receiver operating characteristics curve (95% confidence interval) of 0.87 (0.75-0.99). Ischemic changes occurred most frequently during hours 24 to 60 of monitoring. Ischemia was asymptomatic in 14 of 17 patients (82.4%).

CONCLUSION

Postoperative myocardial ischemia was common in peripheral vascular surgery patients and may progress to perioperative myocardial infarction. Ischemic load was a good predictor of perioperative myocardial infarction. Ambulatory electrocardiographic monitoring solutions for continuous postoperative ischemia detection are warranted in the surgical ward.

The Role of Beta-Blockers in the Treatment of Hypertension

IMPORTANCE

Two major guide-line committees (JNC-8 and NICE UK) have dropped beta-blockers as first-line therapy in the treatment of hypertension. Also, recent meta-analyses (that do not take age into account) have concluded that beta-blockers are inappropriate first-line agents in the treatment of hypertension. This review seeks to shed some light on the "rights and wrongs" of such actions and conclusions.

OBJECTIVES

Because the pathophysiology of primary/essential hypertension differs in elderly and younger subjects, the latter being closely linked to obesity and increased sympathetic nerve activity, the author sought to clarify the efficacy of beta-blockers in the younger/middle-aged group in reducing the risk of death, and cardiovascular end-points.

EVIDENCE ACQUISITION

Four searches were undertaken, utilising PubMed up to 31st Dec 2015. One search was under the terms "hypertension AND obesity AND sympathetic nerve activity". A second was "hypertension AND plasma noradrenaline/norepinephrine AND survival". A third was "beta-blockers or adrenergic beta-antagonists AND hypertension AND age AND stroke or myocardial infarction or death". A fourth was "meta-analysis of beta-blockers AND hypertension AND age AND death, stroke, myocardial infarction" RESULTS: Diastolic (with or without systolic) hypertension, in contrast to isolated systolic hypertension, occurs primarily in younger subjects, and is linked to overweight/obesity and increased sympathetic nerve activity. In younger/middle-aged hypertensive subjects, high plasma norepinephrine levels are linked (independent of blood pressure) to an increased risk of future cardiovascular events and death. High resting heart rates (a surrogate for high sympathetic nerve activity) likewise predict premature all-cause death, coronary heart disease and cardiovascular events in younger hypertensive subjects. In this younger/middle-aged hypertensive group, antihypertensive agents that increase sympathetic nerve activity (diuretics, dihydropyridine calcium blockers, and angiotensin receptor blockers (ARBs)) do not decrease (and may increase) the risk of myocardial infarction, and are therefore inappropriate first-line agents in this age-group. By contrast, in younger/middle-aged hypertensive subjects (less than 60 years old), meta-analysis has shown that beta-blockers are significantly superior to randomised placebo, and at least as effective as randomised comparator agents, in reducing death/stroke/myocardial infarction. In this younger/middle-aged hypertensive group beta-blockers have been shown (vs randomised placebo or diuretics) to reduce the risk of myocardial infarction by 35-50 %, and stroke by 50-55 % (vs placebo), in non-smoker men. Atenolol was at least as effective as ACE-inhibition (captopril) in reducing all 7 cardiovascular endpoints (including stroke which was reduced by 50 %), vs less tight control of blood pressure, in obese hypertensive subjects with type-2 diabetes (UKPDS study); and after 20 years follow-up, atenolol was significantly (23 %) superior to the ACE-inhibitor in reducing the risk of all-cause death (beta-blockers have anti-cancer properties, which maybe relevant).

CONCLUSIONS AND RELEVANCE

Primary/essential hypertension in younger/middle-age is underpinned by high sympathetic nerve activity. In this age-group high resting heart rates and high plasma norepinephrine levels (independent of blood pressure) are linked to premature cardiovascular events and death. Thus, anti-hypertensive agents that increase sympathetic nerve activity ie diuretics, dihydropyridine calcium blockers, and ARBs, are inappropriate first-line choices in this younger age-group. Beta-blockers perform well vs randomised placebo and other antihypertensive agents regarding reduced risk of death/stroke/myocardial infarction in younger (<60 years) hypertensive subjects, and are a reasonable first-line choice of therapy (certainly in men). These facts should be reflected in the recommendations of guideline committees around the world.

TRIMETAZIDINE MR EFFECTS ON THE PARAMETERS OF 24-HOUR ELECTROCARDIOGRAM MONITORING AND HEART RATE VARIABILITY

Aim. To assess the effects of the four-month trimetazidine MR therapy on the parameters of 24-hour electrocardiogram (ECG) monitoring and heart rate variability (HRV) in patients with stable coronary heart disease (CHD).

Material and methods. This prospective, non-randomised study, with the inclusion of 66 consecutive patients who had stable CHD and stable stress test results, investigated the effects of trimetazidine MR therapy on the parameters of 24-hour ECG monitoring and HRV.

Results. Trimetazidine MR did not markedly affect the 24-hour, daytime, or nighttime levels of heart rate. Trimetazidine MR therapy was not associated with any substantial changes in frequency and time-domain HRV parameters or in the incidence of cardiac arrhythmias. However, there was a significant reduction in the number of patients with ST segment depression (from 66,7% to 43,8%; p<0,001) and in the duration of ischemic episodes (from 10 (6,2;21) minutes to 7,42 (5;12,3) minutes (p=0,025)).

Conclusion. Adding trimetazidine MR to the treatment of patients with stable CHD provides an additional beneficial antiischemic effect.

Heart rate as a possible therapeutic guide for the prevention of cardiovascular disease

Epidemiologic evidence indicates that an elevated heart rate (HR) is an independent predictor of all-cause and cardiovascular (CV) mortality. Ivabradine, a pure HR-lowering agent, reduces CV events in patients with coronary artery disease (CAD) and chronic heart failure, and indicate that an HR greater than 70 b.p.m. is hazardous. These findings demonstrate not only that an elevated HR is an epiphenomenon of CV risk status but also that an elevated HR itself should be a therapeutic target. In addition, recent epidemiologic evidence demonstrates that the in-treatment HR or HR change predicts subsequent all-cause and CV mortality, independent of the HR-lowering strategy. Characteristics of the in-treatment HR or HR change are also important as possible therapeutic guides for risk management. However, there have been concerns regarding deleterious effects on CV event prevention owing to β-blocker-derived pharmacologic HR reduction. The potential role of HR and its modulation should be considered in future guidance documents.

The clinical significance of continuous ECG (ambulatory ECG or Holter) monitoring of the ST-segment to evaluate ischemia: a review

Silent ischemia is a common manifestation of coronary artery disease (CAD). Continuous ECG (cECG) monitoring is an effective tool for assessing the frequency and duration of silent ischemic episodes for patients with CAD and for risk stratifying asymptomatic patients or those after an acute coronary syndrome by identifying those at increased risk for future cardiovascular events or death. cECG also allows monitoring of the effectiveness of therapy in patients with CAD. Treatment strategies targeted toward the elimination of silent ischemia have shown that revascularization was better than medical therapy in eliminating silent ischemia, but large scale, prospective studies targeting silent ischemia as a treatment endpoint are still lacking. Future research is warranted to study the effects of newer medical agents or the selected use of revascularization in those patients with persistent silent ischemia despite current medical regiments.

Pharmacokinetics and pharmacodynamics of a β-adrenoblocker bisoprolol: from mechanisms of action to clinical features

The authors discuss the action mechanisms of β-adrenoblockers (β-AB), as well as pharmacokinetics, pharmacodynamics, and drug interaction of a highly selective β-AB bisoprolol. The paper presents the data on bisoprolol effectiveness and safety in arterial hypertension, coronary heart disease, chronic heart failure, and their combination with other diseases.

The role of β-blockers in the management of hypertension: an Asian perspective

Following publication of the National Institute of Clinical Excellence (NICE) Guidelines in 2006, the use of β-blockers as first-line therapy in hypertension has been somewhat controversial. However, a recent reappraisal of the European Society of Hypertension guidelines highlights that these agents exhibit similar BP lowering efficacy to other classes of agents, prompting a re-examination of the utility of these agents in various patient populations. The authors felt that it is important to address this controversy and provide an Asian perspective on the place of β-blockers in current clinical practice and the benefits of β-blockade in selected patient populations. In addition to their use as a potential first-line therapy in uncomplicated hypertension, β-blockers have a particular role in patients with hypertension and comorbidities such as heart failure or coronary artery disease, including those who had a myocardial infarction. One advantage which β-blockers offer is the additional protective effects in patients with prior cardiovascular events. Some of the disadvantages attributed to β-blockers appear more related to the older drugs in this class and further appraisal of the efficacy and safety profile of newer β-blockers will lend support to the current guideline recommendations in Asian countries and encourage increased appropriate use of β-blockade in current clinical practice within Asia.

Elevated heart rate and cardiovascular outcomes in patients with coronary artery disease: clinical evidence and pathophysiological mechanisms

There is an established body of evidence from epidemiological studies which indicates that an elevated resting heart rate is independently associated with atherosclerosis and increased cardiovascular morbidity and mortality, in both the general population and in patients with established cardiovascular disease. Clinical trial data suggest that in patients with coronary artery disease, an elevated heart rate identifies those at increased risk of adverse cardiovascular outcomes, and that lowering of heart rate may reduce major cardiovascular events in patients with an elevated heart rate and symptom-limiting angina. These results suggest that an increased heart rate may have an adverse impact on the atherosclerotic process and increase the risk of a cardiovascular event in patients with coronary artery disease. The precise pathophysiological mechanisms that link heart rate and cardiovascular outcomes have yet to be defined. Possibilities may include indirect mechanisms related to autonomic dysregulation and those due to an increase in heart rate per se, which can increase the ischaemic burden and exert local haemodynamic forces that can adversely impact on the endothelium and arterial wall. For these reasons, heart rate should be considered as a therapeutic target in the treatment of patients with coronary artery disease.

Clinical aspects of silent myocardial ischaemia: with particular reference to diabetes mellitus

Silent ischaemia is a common, under-recognised condition that is associated with an adverse prognosis. It is a marker of significant underlying coronary artery disease and therefore of future cardiovascular events. It is more prevalent in the diabetic population and diagnosis is usually made by a positive exercise tolerance test, positive myocardial perfusion scan or stress echo. The basis of treatment, in diabetic and non-diabetic subjects, is risk factor modification and coronary revascularisation of prognostically important coronary disease. Diabetic patients should receive risk factor modification even in the absence of ischaemia. Detection of silent ischaemia allows patients with prognostically important disease to be offered further treatment. The difficulty lies in deciding who to investigate further for this surreptitious disorder. The following clinical markers are of predictive use in this regard: electrocardiographic changes; erectile dysfunction; peripheral vascular disease and cardiac autonomic neuropathy. Their presence should prompt further investigation for silent ischaemia. Conventional risk factors and breathlessness on exertion may also be helpful. We have proposed an algorithm for the detection, investigation and management of silent myocardial ischaemia in diabetic patients.

Silent myocardial ischemia

Although much progress has been made in reducing mortality from ischemic cardiovascular disease, this condition remains the leading cause of death throughout the world. This might in part be due to the fact that over half of patients have a catastrophic event (heart attack or sudden death) as their initial manifestation of coronary disease. Contributing to this statistic is the observation that the majority of myocardial ischemic episodes are silent, indicating an inability or failure to sense ischemic damage or stress on the heart. This review examines the clinical characteristics of silent myocardial ischemia, and explores mechanisms involved in the generation of angina pectoris. Possible mechanisms for the more common manifestation of injurious reductions in coronary flow; namely, silent ischemia, are also explored. A new theory for the mechanism of silent ischemia is proposed. Finally, the prognostic importance of silent ischemia and potential future directions for research are discussed.

Clinical and research issues regarding chronic advanced coronary artery disease part II: Trial design, outcomes, and regulatory issues

The population of patients with advanced coronary artery disease (CAD) is growing as a result of the aging of the general population, the extensive use of revascularization, and the efficacy of therapies that have prolonged the survival of patients with severe atherosclerosis. Patients with symptomatic CAD survive to a point where little else can be done to relieve their angina. Despite an anticipated growth in the number of patients with this condition within the next few decades, advanced CAD receives relatively little attention by the medical and research communities. As a result, the scope of the disease is not well defined, its coverage in guidelines from professional associations is limited, and few new medical options are available. In response to this, a group of experts from different fields were brought together at a meeting held December 4 to 5, 2006. This document has been developed as a 2-part article. In the first part, the contemporary and emerging therapies for advanced CAD were reviewed. The present part reviews the current status of understanding of advanced CAD, the limits of contemporary therapies, and the difficulties in and barriers to the development of new treatments.

The electrocardiogram as a prognostic tool for predicting major cardiac events

Among patients with cardiac disease, the identification of those who are at low risk and those who are at high risk for major cardiac events is crucial for a rational clinical management of individual patients. A correct noninvasive risk stratification of cardiac patients, in particular, has relevant clinical implications because it would avoid unnecessary exposure to potentially risky invasive diagnostic or interventional procedures in low-risk patients, whereas it would allow an appropriate aggressive diagnostic and therapeutic approach in high-risk patients. Furthermore, the appropriate identification of low- and high-risk patients would also have social and economic implications by favoring optimization of resource distribution and costs. A large number of studies in previous decades provided evidence that several methods and variables derived from the analysis of the electrocardiogram (ECG) are powerful predictors of major cardiac events in several clinical conditions. Despite that, there has been limited attention about how several of these findings can be used in clinical practice. Furthermore, in recent years, most studies about risk stratification of cardiac patients have mainly been focused on the use of a number of serum/plasma biomarkers with reduced attention to ECG variables. Surprisingly, however, there have been few attempts to establish whether the various proposed risk markers add any significant information to that obtainable from ECG methods. In this article, the evidence for the prognostic value of variables derived from the assessment of the ECG signal by several methods and techniques will be briefly reviewed. Because of the largeness of the topic, this review will be necessarily incomplete. Because most of the clinical research in this field concerned risk stratification of patients with coronary artery disease, the article will be largely focused on this population of patients. The role of ECG methods in specific cardiac diseases and, in particular, in the general population of asymptomatic subjects will be briefly discussed when believed appropriate and helpful. Furthermore, only major clinical events (ie, cardiac death, arrhythmic events, acute myocardial infarction) will be taken into account as end points in this article. Minor clinical events (eg, coronary revascularization procedures, coronary artery restenosis, recurrences of symptoms) are indeed less robust as end points because they are widely biased by subjective judgments.

Are we misunderstanding beta-blockers

In myocardial ischaemia and heart failure, beta-blockers with intrinsic sympathomimetic activity (ISA) e.g. pindolol, xamoterol, bucindolol, nebivolol, have performed poorly in reducing morbidity and mortality. In both indications beta-1 blockade is the vital active ingredient. Beta-1 blockade (bisoprolol) is now an alternative first-line choice to Ace-inhibition in the treatment of heart failure. The therapeutic role of beta-blockers in hypertension is less well understood, particularly since the new recommendations in the UK from the NICE committee stating that: 1. beta-blockers are no longer preferred as a routine initial therapy, 2. the combination with diuretics is discouraged due to the risk of induced diabetes, and 3. in younger patients first-choice initial therapy should be an ACE-inhibitor. Recent data from the Framingham Heart Study and other epidemiological studies have indicated that the development of diastolic hypertension in younger subjects is closely linked to weight-increase and an increase in peripheral resistance; such subjects have a high adrenergic drive and cardiac output. In contrast, elderly systolic hypertension mostly arises de novo via poor vascular compliance. Thus in younger, probably overweight, hypertensives (including diabetics) first-line beta-blockade has performed well in preventing myocardial infarction (a fact hidden by meta-analyses that do not take age into account). Conversely, in elderly hypertensives first-line beta-blockade (atenolol) has performed poorly in reducing cardiovascular risk (due to partial beta-2 blockade atenolol evokes metabolic disturbance and does not improve vascular compliance, or effectively lower central aortic pressure or reverse left ventricular hypertrophy). Thus beta-blockers like atenolol are ill-equipped for first-line therapy in elderly hypertension. Some beta-blockers, e.g. bisoprolol (up to 10 mg/day is highly beta-1 selective) and nebivolol (beta-2/3 intrinsic sympathomimetic activity), do improve vascular compliance and cause no metabolic disturbance. Beta-blockers as second-line to low-dose diuretics (which, by improving vascular compliance and increasing sympathetic nerve activity, create an optimal environment for beta-blockade) in elderly hypertension (including diabetics) have performed well in reducing cardiovascular events (this combination has the added bonus of reducing the risk of bone fracture by about 30%). Meta-analyses which include studies where it is unclear whether a diuretic or beta-blocker was a first-line therapy will dilute the benefit stemming from first-line diuretic/second-line beta-blockade. Hypertensives (of all ages) with ischaemia are well suited to beta-blockade.

Long-term continuous external electrocardiographic recording: a review

Ambulatory electrocardiographic (AECG) monitoring is an essential tool in the diagnostic evaluation of patients with cardiac arrhythmias. Recent advances in solid-state technology have improved the quality of the ECG signals and new dedicated algorithms have expanded the clinical application of software-based AECG analysis systems. These advances, in addition to the availability of inexpensive large storage capacities, and very long-term continuous high-quality AECG monitoring, have opened new potential uses for AECG. New digital recorders have the capability of multichannel simultaneous recordings (from 3 to 12 leads) and for telemetred signal transduction. These possibilities will expand the traditional uses of AECG for arrhythmia detection, as arrhythmia monitoring to assess drug and device efficacies has been further defined by new studies. The analysis of transient ST-segment deviation still remains controversial, but considerably more data are now available, especially about the prognostic value of detecting asymptomatic ischaemia. Heart rate variability analysis has shown promise for predicting mortality rates in cardiac patients at high risk. We review recent advances in this field of non-invasive cardiac testing.

Silent myocardial ischemia: Recent developments

Silent myocardial ischemia is now in its fourth decade of recognition as a clinical syndrome within the spectrum of coronary artery disease. Prior decades have seen important research into the pathophysiology, detection, prevalence, prognosis, and therapy of this syndrome. More recent developments have continued to add data to each of these areas, with particular emphasis on the comparative value of various diagnostic procedures and the effect of therapy on prognosis. While controversy still exists concerning proper screening guidelines for the asymptomatic population, there is a growing consensus that some form of stress testing in high-risk individuals (ie, those with multiple coronary risk factors) is appropriate.

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.

Canadian Cardiovascular Society classification of effort angina: an angiographic correlation

BACKGROUND

The Canadian Cardiovascular Society classification (CCSC) remains the standard for grading angina in patients with chronic stable angina. The utility value of this angina grading system in predicting the severity of coronary artery disease is not clear.

AIM

We studied the relationship between the clinical angina grade and the angiographic severity of underlying coronary artery disease.

MATERIALS AND METHODS

The participants in the study were 493 patients with stable angina who had undergone coronary angiography from 1998 to 2001. They were grouped according to their anginal grading and the number of vessels diseased. Significant lesions were defined as 50% narrowing for the left main and 70% for the left and right coronaries and their major branches.

STATISTICAL ANALYSIS

The chi2-test was used for statistical analysis and a P-value <0.05 was taken as significant.

RESULTS

There was no significant difference between the four angina class patients and the incidence of single-, double- and triple-vessel involvement. Class 1 patients had less left main trunk disease than class 4 patients. Class 3 and 4 patients had significantly fewer normal coronary angiograms.

CONCLUSIONS

There is generally little correlation between coronary artery disease and the CCSC of effort angina except for left main disease. Presence or absence of angina rather than the CCSC should indicate the need for coronary angiography.

Effects of angiotensin receptor blockade on haemodynamics and gene expression after myocardial infarction

INTRODUCTION

Despite the fact that congestive heart failure (CHF) remains the most common disease in the developed world and has been extensively studied, there is little known about the molecular and cellular mechanisms of cardiac dysfunction. Angiotensin has been implicated as a mediator of cardiac injury; however, the mechanisms of its action have not been delineated. The objective of this study was to examine the relationship between the haemodynamic and molecular events during cardiac dysfunction and the role of the angiotensin system.

STUDY DESIGN

We examined the effects of the angiotensin receptor blocker, valsartan, on changes in the haemodynamic and gene expression patterns in a postmyocardial infarction model in the rat.

METHODS

Myocardial infarction (MI) was induced in rats by coronary artery ligation. Cardiac haemodynamics were monitored using echocardiography. Gene expression profiles after myocardial infarction were identified using Affymetrix Genechip oligonucleotide arrays.

RESULTS

Myocardial contractility, as assessed by cardiac output and left ventricle (LV) fraction of shortening, was reduced in untreated animals by week 3 after MI (p < 0.05 versus baseline), and preserved with valsartan treatment as observed by the nonsignificant changes versus baseline. LV dilatation, as demonstrated by increases in LV systolic and diastolic diameters, developed by week 3 in untreated animals (p < 0.05 versus baseline) while valsartan-treated animals were protected and showed no significant increases in diameter size compared with baseline. LV hypertrophy, as shown by LV posterior wall thickness, was more profound in untreated animals (p < 0.05 versus baseline) than in those treated with valsartan at weeks 3 and 4. Changes in gene expression at 4 weeks after MI included those encoding muscle-specific genes, fibrous tissue proliferation, immune response and various others. Treatment with valsartan reversed these changes in 67% of overexpressed genes and 83% of underexpressed genes.

CONCLUSION

Angiotensin receptor blockade with valsartan was found to protect cardiac function, and this beneficial effect was accompanied by a reversal of changes in gene expression induced by MI.

Cardiovascular drug utilization and its determinants in unselected medical patients with ischemic heart disease

Background: In patients with ischemic heart disease (IHD), secondary preventive drug therapy improves overall prognosis. Therefore, this study evaluated cardiovascular drug utilization in patients suffering from IHD, identified factors influencing drug utilization, and determined the prevalence of shortfalls of antithrombotic, beta-blocker, and lipid-lowering drug use. Methods: This study is based on data recorded prospectively between 1996 and 1998 in two Swiss teaching hospitals for the SAS/CHDM pharmacoepidemiologic database project. Drug utilization was evaluated in all 987 monitored medical inpatients with IHD. Results: At discharge, only 64% of patients with IHD received platelet aggregation inhibitors, 42% beta-blockers, and 26% lipid-lowering drugs. Secondary preventive drugs were more frequently administered to patients with acute myocardial infarction and less frequently in the elderly. After including other co-factors, no gender difference could be detected. Shortfalls of antithrombotic therapy occurred in 6.5--8.3% of patients and shortfalls in beta-blocker use in 9.9--23.3%. Only about half of all patients with IHD and elevated cholesterol received lipid-lowering drugs. Conclusions: Drugs for secondary prevention are prescribed to the majority of patients with IHD. However, their use could be further increased, especially in the elderly and in patients with IHD who are admitted to the hospital for reasons other than acute myocardial infarction. Lipid-lowering drugs should also be prescribed more often for patients with hypercholesterolemia.

Cost estimates for treatment of cardiac ischemia (from the Asymptomatic Cardiac Ischemia Pilot [ACIP] study)

Costs for management of myocardial ischemia are enormous, yet comparison cost and outcome data for various ischemia treatment strategies from randomized trials are lacking and will require cost and resource utilization data from a large prospective trial. The Asymptomatic Cardiac Ischemia Pilot provided feasibility data for planning such a trial and an opportunity to estimate the long-term costs of different treatment strategies. Economic implications for ischemia management were compared in 558 patients with stable coronary artery disease and myocardial ischemia during both stress testing and daily life. Participants were randomized to 3 different initial treatment strategies and followed for 2 years. Based on cost trends over follow-up, costs for subsequent care were estimated. As expected, due to initial procedural costs, at 3 months, estimated costs for revascularization were approximately 10 times greater than costs for a medical care strategy. Extrapolated costs for anticipated resource consumption for care beyond 2 years, however, were approximately 2 times greater for an initial medical care strategy than for initial revascularization. This was due to increased need for drugs and hospitalizations for both late revascularizations and other ischemia-related events. Estimated costs for anticipated care in the medical strategies reached the anticipated cost of the revascularization strategy within 10 years. Because this cost-equal time period is well within the median life expectancy for such a patient population, these findings could have important public health implications and require testing in a full-scale prognosis trial. We anticipate that over the patients' life expectancy, early revascularization is likely to become either cost-neutral or cost-effective.

Prognostic implications of ambulatory myocardial ischemia and arrhythmias and relations to ischemia on exercise in chronic stable angina pectoris (the Angina Prognosis Study in Stockholm [APSIS])

The prognostic significance of ambulatory ischemia, alone and in relation to ischemia during exercise was assessed in 686 patients (475 men) with chronic stable angina pectoris taking part in the Angina Prognosis Study In Stockholm (APSIS), who had 24-hour ambulatory electrocardiographic registrations and exercise tests at baseline (n = 678) and after 1 month (n = 607) of double-blind treatment with metoprolol or verapamil. Ambulatory electrocardiograms were analyzed for ventricular premature complexes and ST-segment depression. During a median follow-up of 40 months, 29 patients died of cardiovascular (CV) causes, 27 had a nonfatal myocardial infarction, and 89 underwent revascularization. Patients with CV death had more episodes (median 5 vs. 1; p<0.01) and longer median duration (24 vs. 3 minutes; p<0.01) of ST-segment depression than patients without events. For those who had undergone revascularization, the duration was also longer (12 vs. 3 minutes; p<0.05). In a multivariate Cox model including sex, history of previous myocardial infarction, hypertension, and diabetes, the duration of ST-segment depression independently predicted CV death. When exercise testing was included, ambulatory ischemia carried additional prognostic information only among patients with ST-segment depression > or =2 mm during exercise. When the treatment given and treatment effects on ambulatory ischemia were added to the Cox model, no significant impact on prognosis was found. Ventricular premature complexes carried no prognostic information. Thus, in patients with stable angina pectoris, ischemia during ambulatory monitoring showed independent prognostic importance regarding CV death. Ambulatory electrocardiographic monitoring and exercise testing provide complementary information, but only among patients with marked ischemia during exercise. Treatment reduced ambulatory ischemia, but the short-term treatment effects did not significantly influence prognosis.

Visceral chest pain in unstable angina pectoris and effects of transcutaneous electrical nerve stimulation. (TENS). A review

A substantial proportion of patients with chest pain referred to hospital, show signs of coronary artery disease. Anginal pain could be conceptualized as a warning signal for coronary artery disease and impending death. But, for many reasons this theory is partly disputed. Firstly, not all ischemic episodes are accompanied by anginal pain (silent ischemia). Secondly, chest pain indistinguishable from true angina pectoris may be the result of other abnormalities of thoracic viscera. Nevertheless acute severe cardiac ischemia often gives rise to anginal chest pain. Unstable angina pectoris is carrying a higher risk for future events in spite of intensive medical treatment. A special problem are patients awaiting coronary intervention because of severe ischemia and maximum medical treatment, who experience ischemic pain. New treatment regimens are needed for these patients. This review discusses the symptom of visceral pain from the heart, angina pectoris, its relation to ischemia and unstable angina pectoris. It also addresses the role of afferent nerve stimulation (transcutaneous electrical nerve stimulation, TENS) in the treatment of severe angina pectoris as well as recent findings of TENS applicability in unstable angina.

Role of beta blockade in the treatment of myocardial ischemia

A number of antianginal drugs and therapeutic strategies are now available for the treatment of patients with coronary artery disease (CAD) and myocardial ischemia. Of the available antianginal drugs, beta blockers appear to be most effective in suppressing myocardial ischemia. The superior anti-ischemic efficacy of beta blockers can be explained by their beneficial actions on hemodynamic parameters, vasomotion, and platelet function. Compared with other anti-ischemic drugs, beta blockers appear to be more efficacious in reducing the magnitude of myocardial ischemia during routine daily activities. In addition, the results of recent studies indicate that treatment with beta blockers not only suppresses myocardial ischemia, but also improves the clinical outcome in patients with CAD. These beneficial effects, along with the well-demonstrated cardioprotective effects of beta blockade in the postinfarction period, clearly suggest that this class of anti-ischemic drugs is an ideal therapeutic choice in most patients with CAD.

Relation between clinical, angiographic and ischemic findings at baseline and ischemia-related adverse outcomes at 1 year in the Asymptomatic Cardiac Ischemia Pilot study. ACIP Study Group

OBJECTIVES

We attempted to investigate the relation between patient characteristics and adverse outcome in patients with ischemia and clinically stable coronary artery disease (CAD).

BACKGROUND

Evidence suggests that cardiac ischemia, detected by exercise stress testing (ETT) and ambulatory electrocardiographic (AECG) monitoring during daily living, identifies a subgroup of patients at increased risk for adverse outcome, but the relation between these ischemia findings and clinical and angiographic characteristics is largely unknown.

METHODS

We examined the relation between clinical, angiographic and ischemia characteristics at entry with adverse outcome observed at 1 year in the 558 patients enrolled in the Asymptomatic Cardiac Ischemia Pilot (ACIP) study.

RESULTS

By the 12-month visit 13.1% of patients had an ischemia-related adverse clinical outcome that included death, nonfatal myocardial infarction or an ischemia-related hospital admission. Multivariate analysis identified only the number of AECG ischemic episodes at entry (odds ratio [OR] 1.06, 99% confidence interval [CI] 1.01 to 1.12, p = 0.002) as an independent predictor of outcome. Assignment to revascularization (as opposed to an initial medical treatment strategy) showed a trend (OR 0.56, 99% CI 0.26 to 1.2, p = 0.05). None of the other baseline clinical, exercise or angiographic variables examined provided additional information relative to adverse outcome.

CONCLUSIONS

Determinants of adverse outcome, among clinically stable patients with CAD and ischemia induced by stress and daily life were magnitude of AECG ischemia before treatment and, possibly, initial treatment assignment. Among the many other characteristics examined, including age, symptom status and angiographic and exercise variables, none contributed additional independent prognostic information. These two simple variables, which may be modifiable, need further study in a larger trial.