The effects of exercise on dynamic sleep morphology in healthy controls and patients with chronic fatigue syndrome

Effects of exercise on dynamic aspects of sleep have not been studied. We hypothesized exercise altered dynamic sleep morphology differently for healthy controls relative to chronic fatigue syndrome (CFS) patients. Sixteen controls (38 ± 9 years) and 17 CFS patients (41 ± 8 years) underwent polysomnography on baseline nights and nights after maximal exercise testing. We calculated transition probabilities and rates (as a measure of relative and temporal transition frequency, respectively) between sleep stages and cumulative duration distributions (as a measure of continuity) of each sleep stage and sleep as a whole. After exercise, controls showed a significantly greater probability of transition from N1 to N2 and a lower rate of transition from N1 to wake than at baseline; CFS showed a significantly greater probability of transition from N2 to N3 and a lower rate of transition from N2 to N1. These findings suggest improved quality of sleep after exercise. After exercise, controls had improved sleep continuity, whereas CFS had less continuous N1 and more continuous rapid eye movement (REM) sleep. However, CFS had a significantly greater probability and rate of transition from REM to wake than controls. Probability of transition from REM to wake correlated significantly with increases in subjective fatigue, pain, and sleepiness overnight in CFS - suggesting these transitions may relate to patient complaints of unrefreshing sleep. Thus, exercise promoted transitions to deeper sleep stages and inhibited transitions to lighter sleep stages for controls and CFS, but CFS also reported increased fatigue and continued to have REM sleep disruption. This dissociation suggests possible mechanistic pathways for the underlying pathology of CFS.

Atypical stress-induced cardiomyopathy: a case series

Stress-induced cardiomyopathy (SIC) is characterized by reversible left ventricular (LV) systolic dysfunction, which appears to be triggered by an intense, stressful event in the absence of significant coronary artery disease. It manifests typically with transient left ventricular wall motion abnormalities (WMA) involving the apical and/or mid-ventricular myocardial segments, associated with minimal troponin rise (<5 ng/ml), and typical EGG changes. Described are 3 cases of stress-induced cardiomyopathy with atypical distribution of wall motion abnormalities. Possible contributing mechanisms to the pathogenesis and the variability in WMA are discussed.

Dual antiplatelet therapy for primary and secondary prevention

The concomitant use of aspirin and an ADP receptor (P2Y12) blocker, also known as dual antiplatelet therapy (DAPT), has been extensively investigated as a primary and secondary prevention strategy in an effort to reduce the risk of cardiovascular events. In this manuscript the authors review the current guideline recommendations for DAPT and discuss the scientific data that supports these recommendations. Reported are also the scientific knowledge gaps and how future studies are likely to delineate these issues. Incremental knowledge is not likely to be an alternative to individualized care provided by the astute clinician to his patient. In consideration for prescribing DAPT (drug, dosage and duration) the clinician will have to weigh the potential benefits (reduction in death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke) and risks (severe or life-threatening bleeding) for each and every patient.

Comparison of efficacy and safety of intracoronary sodium nitroprusside and intravenous adenosine for assessing fractional flow reserve

OBJECTIVES

The purpose of this study was to compare the efficacy and safety of intracoronary (IC) nitroprusside and intravenous adenosine (IVA) for assessing fractional flow reserve (FFR).

BACKGROUND

IV infusion of adenosine is a standard method to achieve a coronary hyperemia for FFR measurement. However, adenosine is expensive, causes multiple side effects, and is contraindicated in patients with reactive airway disease. Sodium nitroprusside (NTP) is a strong coronary vasodilator but its efficacy and safety for assessing FFR is not well established.

METHODS

We compared FFR response and side effects profile of IC NTP and IVA. Bolus of NTP at a dose of 100 μg and IVA (140 μg/kg/min) were used to achieve coronary hyperemia.

RESULTS

We evaluated 75 lesions in 53 patients (60% male) mean age 61.6 ± 13.9 years. Mean FFR after NTP was similar to FFR after adenosine (0.836 ± 0.107 vs. 0.856 ± 0.106; P = 0.26; r = 0.91, P < 0.001). NTP induced maximal stable hyperemia within 10 sec (mean: 6.4 ± 1) which lasted consistently between 38 and 60 sec (mean 51 ± 7.5). NTP caused significant (14%), but asymptomatic decrease in mean blood pressure which returned to baseline within 60 sec. Adenosine caused shortness of breath in 26%, headache and flushing in 19%, and transient second degree heart block in 6% of patients. No adverse symptoms were reported after NTP.

CONCLUSIONS

IC NTP is as effective as IVA for measuring FFR. NTP is better tolerated by patients. Since NTP is inexpensive, readily available, well tolerated, and safe, it may be a better choice for FFR assessment.

New index for assessing the chronotropic response in patients with end-stage liver disease who are undergoing dobutamine stress echocardiography

The inability to achieve 85% of the maximum predicted heart rate (MPHR) on dobutamine stress echocardiography (DSE) is defined as chronotropic incompetence and is a predictor of major cardiac events after orthotopic liver transplantation (OLT). The majority of patients with end-stage liver disease (ESLD) receive beta-blockers for the prevention of variceal bleeding. In these patients, it is impossible to determine whether chronotropic incompetence is secondary to cirrhosis-related autonomic dysfunction or is merely a beta-blocker effect. We evaluated the usefulness of the maximum achieved heart rate (MAHR) and the heart rate reserve (HRR) in the detection of chronotropic incompetence in ESLD patients on beta-blocker therapy before DSE. We also evaluated the usefulness of a new index, the modified heart rate reserve (MHRR), in diagnosing chronotropic incompetence and predicting major cardiovascular adverse events after OLT. The study population consisted of 284 ESLD patients. The mean values of MAHR (expressed as a percentage of 85% of MPHR) and HRR were significantly lower for patients on beta-blockers versus patients off beta-blockers [97.1% versus 101.6% (t = 5.01, P < 0.001) and 71.7% versus 77.3% (t = 4.03, P < 0.001), respectively], whereas the values of MHRR were similar in patients on beta-blockers and patients off beta-blockers [102.3% versus 102.1% (t = 0.04, P = 0.97)]. A regression analysis showed a significant association of MAHR (P < 0.001) and HRR (P < 0.001) with beta-blockers, whereas MHRR was not associated with beta-blocker treatment (P = 0.92). MAHR and HRR were found to have no value for diagnosing chronotropic incompetence in ESLD patients. MHRR was not affected by beta-blocker therapy. Patients who developed heart failure (HF) and myocardial infarction (MI) after OLT had significantly lower MHRR values according to pretransplant DSE. MHRR was significantly associated with the subsequent development of HF (P = 0.01) and MI (P = 0.01) after OLT. MHRR may be useful for the determination of the target heart rate for stress testing, the diagnosis of chronotropic incompetence, and the prediction of adverse cardiac events after OLT.

Extensive myocardial iron deposition in a patient with hepatitis C

During a cardiac evaluation prior to liver transplantation, a 51-year-old man with hepatitis C and cirrhosis was found to have nonischemic cardiomyopathy-a condition that would have made him ineligible for liver transplantation. Right ventricular biopsy revealed extensive cardiac hemosiderosis. Despite the elevated levels of serum ferritin, the patient had no history of multiple red blood cell transfusions; moreover, genetic testing for hereditary hemochromatosis was negative for the HFE mutations C282Y and H63D. Chelation therapy was considered for this patient, to reduce the cardiac iron deposits. However, before a course of treatment was established, the patient's clinical condition worsened, and chelation therapy was no longer feasible. He was referred for combined heart and liver transplantation. Cardiac iron deposition can be diagnosed readily using right ventricular biopsy or T2* magnetic resonance imaging. Early detection may allow time for intensive chelation therapy, which might, in turn, reverse the myopathic process. Improved cardiac function should improve cirrhosis patients' chances to be placed on the liver transplant waiting list and ultimately optimize transplantation outcomes.

Routine stress testing after percutaneous coronary interventions

Percutaneous coronary intervention (PCI) is the most frequently performed cardiovascular procedure. Many physicians caring for post-PCI patients have routinely subjected patients to periodic stress testing. In the recent years, due to widespread use of drug eluting stents the combined rates of major adverse cardiac events (MACE) and in-stent restenosis (ISR) dropped <10% in the initial 12 months post-PCI, with only half of these patients bearing symptoms. This has translated into reduced pre-test probability of post-PCI ischemia. Consequently, the beneficial effect of this practice came into question. Moreover, in addition to its financial implications, routine post-PCI stress testing may carry potential harm: medication or exercise induced arrhythmia, infarction and/or death, patient irradiation exposure, false-positive tests resulting in excessive invasive testing or interventions, and the illusion of "wellness" in the face of a somewhat unpredictable disease. This review addresses the role stress testing post-PCI: it is concluded that routine stress testing in clinically stable asymptomatic post-PCI patients should be discouraged. Selective utilization of stress testing in patients with exceptionally high risk of ISR or MACE can be utilized to answer important clinical questions or guide and refine clinical care.

The STAT-MI (ST-Segment Analysis Using Wireless Technology in Acute Myocardial Infarction) trial improves outcomes

OBJECTIVES

The goal of this study was to evaluate the impact of the STAT-MI (ST-Segment Analysis Using Wireless Technology in Acute Myocardial Infarction) network on outcomes in the treatment of patients presenting with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Shortening door-to-balloon (D2B) time remains a national priority for the treatment of STEMI. We previously reported a fully automated wireless network (STAT-MI) for transmission of electrocardiograms (ECGs) for suspected STEMI from the field to offsite cardiologists, allowing early triage with shortening of subsequent D2B times. We now report the impact of the STAT-MI wireless network on infarct size, length of hospital stay (LOS), and mortality.

METHODS

A fully automated wireless network (STAT-MI) was developed to enable automatic 12-lead ECG transmission and direct communication between emergency medical services personnel and offsite cardiologists that facilitated direct triage of patients to the cardiac catheterization laboratory. Demographic, laboratory, and time interval data of STAT-MI network patients were prospectively collected over a 33-month period and compared with concurrent control patients who presented with STEMI through non-STAT-MI pathways.

RESULTS

From June 2006 through February 2009, 92 patients presented via the STAT-MI network, and 50 patients presented through non-STAT-MI pathways (control group). Baseline clinical and demographic variables were similar in both groups. Overall, compared with control subjects, STAT-MI patients had significantly shorter D2B times (63 [42 to 87] min vs. 119 [96 to 178] min, U = 779.5, p < 0.00004), significantly lower peak troponin I (39.5 [11 to 120.5] ng/ml vs. 87.6 [38.4 to 227] ng/ml, U = 889.5, p = 0.005) and creatine phosphokinase-MB (126.1 [37.2 to 280.5] ng/ml vs. 290.3 [102.4 to 484] ng/ml, U = 883, p = 0.001), higher left ventricular ejection fractions (50% [35 to 55] vs. 35% [25 to 52], U = 1,075, p = 0.004), and shorter LOS (3 [2 to 4] days vs. 5.5 [3.5 to 10.5] days, U = 378, p < 0.001).

CONCLUSIONS

A fully automated, field-based, wireless network that transmits ECGs automatically to offsite cardiologists for the early evaluation and triage of patients with STEMI shortens D2B times, reduces infarct size, limits ejection fraction reduction, and shortens LOS.

Treatment of anemia with darbepoetin alfa in heart failure

Anemia is common in heart failure (HF) patients. A prespecified pooled analysis of 2 randomized, double-blind, placebo-controlled studies evaluated darbepoetin alfa (DA) in 475 anemic patients with HF (hemoglobin [Hb], 9.0-12.5 g/dL). DA was administered subcutaneously every 2 weeks and titrated to achieve and maintain a target Hb level of 14.0+/-1.0 g/dL. By week 27, mean (SD) Hb concentrations did not increase with placebo but increased with DA from 11.5 (0.7) to 13.3 (1.3) g/dL. Hazard ratios (HRs) for DA compared with placebo for all-cause death or first HF hospitalization (composite end point), all-cause death, and HF hospitalization by month 12 were 0.67 (95% confidence interval [CI], 0.44-1.03; P=.067), 0.76 (95% CI, 0.39-1.48; P=.419), and 0.66 (95% CI, 0.40-1.07; P=.093), respectively. Incidence of adverse events was similar in both groups. In post hoc analyses, improvement in the composite end point was significantly associated with the mean Hb change from baseline (adjusted HR, 0.40; P=.017) with DA treatment. There was no increased risk of all-cause mortality or first HF hospitalization with DA in patients with reduced renal function or elevated baseline B-type natriuretic peptide, a biomarker of worse HF. These results suggest that DA is well tolerated, corrects HF-associated anemia, and may have favorable effects on clinical outcomes.

Clinical applicability of coronary atherosclerotic lesion characterization

Native coronary atherosclerosis (CAS) is a diffuse and progressive disease process that is occasionally associated with either clinical atherothrombosis and/or major adverse cardiac events (MACE) including: ST elevation myocardial infarction (STEMI), acute coronary syndromes without ST elevation (ACSWSTE), heart failure, cardiac arrest and sudden cardiac death. Both, the timing and coronary site responsible for the MACE are currently unpredictable. Cardiovascular investigators have engaged in the task of characterizing CAS lesions in order to enhance our knowledge of CAS pathophysiology. It was expected that the knowledge acquired will allow scientists and clinicians to develop effective strategies to detect and treat "vulnerable plaque" (VP) prior to the evolution of MACE. This review discusses the emerging data regarding the pathology and natural history of the VP and vulnerable patient and the progress made in characterizing atherosclerotic plaque instability and vulnerability. Future directions in the field of plaque characterization and their potential clinical and research applications are discussed.

Intra-aortic balloon pump prior to noncardiac surgery: a forgotten remedy?

High-risk cardiac patients, especially those with severe coronary artery disease, are prone to ischemic, arrhythmic and heart failure complications during urgent or emergent noncardiac surgery. The American and European guidelines endorse selective revascularization by either coronary artery bypass grafting or percutaneous coronary intervention in symptomatic ischemic patients prior to major elective surgery. However, conventional revascularization may not be suitable for certain patients requiring emergent or urgent surgery. Reported are two representative cases in which severely ischemic patients were bridged uneventfully through moderate-risk surgery by using prophylactic intra-aortic balloon pump (IABP). Prophylactic IABP should be considered for the support of ischemic patients who are severely symptomatic or hemodynamically unstable undergoing moderate-high risk surgery, who are not suitable for preoperative revascularization. This therapeutic option should be acknowledged in the relevant guidelines.

HFSA 2010 Comprehensive Heart Failure Practice Guideline

Heart failure (HF) is a syndrome characterized by high mortality, frequent hospitalization, reduced quality of life, and a complex therapeutic regimen. Knowledge about HF is accumulating so rapidly that individual clinicians may be unable to readily and adequately synthesize new information into effective strategies of care for patients with this syndrome. Trial data, though valuable, often do not give direction for individual patient management. These characteristics make HF an ideal candidate for practice guidelines. The 2010 Heart Failure Society of America comprehensive practice guideline addresses the full range of evaluation, care, and management of patients with HF.

Massive coronary perforation and shock: From appropriate labeling to appropriate calls

Coronary perforation is a rare, unpredictable and dreaded complication of percutaneous coronary Intervention. With Ellis Grade 3 perforations the only effective treatment includes temporary balloon occlusion of the perforated coronary artery and placement of JOSTENT GraftMaster stent to cover the perforation. The authors describe coronary perforation during proximal right coronary artery (RCA) stenting, resulting in immediate cardiogenic shock. The patient was treated with temporary balloon occlusion of the RCA, reversal of anti-coagulation, sealing of the perforation with a GraftMaster stent, inotropes, intra-aortic balloon counterpulsation (IABC) and surgical drainage the pericardial space. The authors describe the rational of their therapeutic strategy. The methodology and pitfalls of GraftMaster deployment, in patients with massive coronary perforation are discussed. This report also emphasizes, that as opposed to manufactures instructions and all previous manuscripts, GraftMaster can be easily deployed via conventional 6F guiding catheters with internal diameter 0.070 inch (1.8 mm).

Aspirin for the prevention of cardiovascular morbidity

Aspirin (ASA) use for secondary prevention in patients with cardiovascular (CV) disease is well established through its beneficial effects on the reduction of myocardial infarction, ischemic stroke and CV mortality. This beneficial effect of ASA seems to consistently outweigh the risk in most patient subsets. Current guidelines endorse ASA for primary prevention of CV events in adults who are at moderate-high risk of CV morbidity. Recent emerging data on the efficacy and safety of ASA conflicts with former randomized clinical trials and raises concerns regarding the validity of these recommendations. The following manuscript describes the data emerging from contemporary trials regarding the efficacy and safety of ASA in various patient subsets. The authors propose certain strategies to enhance safety and efficacy in order to augment the beneficial effects of ASA along with other modalities of primary prevention for suitable candidates. When contemplating ASA prescription for primary prevention of CV events, physicians should carefully weigh the potential benefits of risk reduction versus likelihood of harm, mostly related to bleeding complications.