Kevin A. Bybee

Stress-Related Cardiomyopathy Syndromes

The relationship between the heart and the brain is complex and integral in the maintenance of normal cardiovascular function. Certain pathological conditions can interfere with the normal brain-heart regulatory mechanisms and result in impaired cardiovascular function. The mechanisms through which the central and autonomic nervous systems regulate the heart and the manner in which their impairment adversely affects cardiovascular function have recently been reviewed by Samuels.1 The purpose of this article is to provide an up-to-date review of the clinical presentation of the stress-related cardiomyopathy syndromes, discuss possible causal mechanisms, and highlight the similarities and differences between them.2–16 The stress-related cardiomyopathies appear similar in that they seemingly occur during times of enhanced sympathetic tone and may be precipitated in part or entirely by excessive endogenous or exogenous catecholamine stimulation of the myocardium. Although significant clinical overlap exists in those presenting with stress-associated cardiomyopathy, it is unclear whether myocardial adrenergic hyperstimulation is the only pathophysiological mechanism responsible for these syndromes (Tables 1 and 2⇓). View this table: Table 1. Precipitants of Stress Cardiomyopathy View this table: Table 2. Morphological LV Variants of Stress Cardiomyopathy In the early 1990s, Japanese authors began reporting a unique, reversible cardiomyopathy that appeared to be precipitated by acute emotional stress.2,13,16 They found that these patients were usually postmenopausal women and often developed signs and symptoms of an acute coronary syndrome (ACS) proximate to a strong emotional stressor associated with a transient apical and midventricular wall motion abnormality despite the lack of obstructive coronary artery disease (CAD) at the time of emergent coronary angiography. This syndrome was initially given the name Takotsubo cardiomyopathy (TC) and has subsequently been referred to as the apical ballooning syndrome and broken heart syndrome. It is now recognized that TC can also occur in the setting of acute medical illness and after surgery. TC …

Diagnostic and clinical benefit of combined coronary calcium and perfusion assessment in patients undergoing PET/CT myocardial perfusion stress imaging

BackgroundA limitation of stress myocardial perfusion imaging (MPI) is the inability to detect non-obstructive coronary artery disease (CAD). One advantage of MPI with a hybrid CT device is the ability to obtain same-setting measurement of the coronary artery calcium score (CACS).Methods and ResultsUtilizing our single-center nuclear database, we identified 760 consecutive patients with: (1) no CAD history; (2) a normal clinically indicated Rb-82 PET/CT stress perfusion study; and (3) a same-setting CAC scan. 487 of 760 patients (64.1%) had subclinical CAD based on an abnormal CACS. Of those with CAC, the CACS was >100, >400, and >1000 in 47.0%, 22.4%, and 8.4% of patients, respectively. Less than half of the patients with CAC were receiving aspirin or statin medications prior to PET/CT imaging. Patients with CAC were more likely to be initiated or optimized on proven medical therapy for CAD immediately following PET/CT MPI compared to those without CAC.ConclusionsSubclinical CAD is common in patients without known CAD and normal myocardial perfusion assessed by hybrid PET/CT imaging. Identification of CAC influences subsequent physician prescribing patterns such that those with CAC are more likely to be treated with proven medical therapy for the treatment of CAD.

Cumulative clinical trial data on atorvastatin for reducing cardiovascular events: the clinical impact of atorvastatin.

ABSTRACT Background: Since the 1990s a multitude of statin trials have definitively demonstrated the ability of statin therapy to reduce the risk of adverse coronary heart disease (CHD) events. Among these, the Atorvastatin Landmarks program – a group of 32 major atorvastatin trials – has assessed the efficacy and safety of atorvastatin across its full dose range and has helped illustrate its effectiveness in treatment of cardiovascular disease and its related disorders and also in non-cardiovascular outcomes. Scope: This paper will review the major atorvastatin clinical trials and report the important findings and their clinical significance. Findings: Clinical trials with atorvastatin have established significant reductions in cardiovascular events in patients with and without CHD. Studies show that high-dose atorvastatin will reduce LDL to ≈ 70 mg/dL in many patients and improve cardiac outcomes. Current evidence suggests that high-dose atorvastatin can halt and, in some cases, reverse atherosclerotic progression. A study of diabetic patients showed atorvastatin decreased the occurrence of acute CHD events, coronary revascularizations, and stroke. Atorvastatin has been found to be effective for reducing nonfatal myocardial infarctions and fatal CHD in hypertensive patients with three or more additional risk factors. High-dose atorvastatin was found to be effective in reducing risk of recurrent stroke in patients with prior cerebrovascular events, has been shown to benefit patients suffering a recent acute coronary syndrome, and to slow cognitive decline in preliminary studies of patients with Alzheimers disease. Atorvastatin has been associated with reduced progression of mild chronic kidney disease; however, in a randomized trial of patients with end stage renal disease on hemodialysis, atorvastatin showed no statistically significant benefit. Limitations of this review include lack of generalizablity of the atorvastatin trial data to other statins, lack of head to head outcome trials involving the newer more potent statins, and the relatively short study durations (none exceeded 5 years) when atherosclerosis is typically a decades-long disease. Conclusion: A compelling body of evidence documents that atorvastatin reduces major cardiovascular events in both secondary and primary prevention of CHD and in a broad range of patients and disease conditions. Furthermore, throughout its dose range, atorvastatin is safe and well tolerated.

Statins as anti-arrhythmics: a systematic review part II: effects on risk of ventricular arrhythmias.

Recent studies have demonstrated that statins may possess anti‐arrhythmic properties in addition to their lipid‐lowering effects.

A Longer Course of Varenicline Therapy Improves Smoking Cessation Rates

Smoking exerts strong dose-dependent increases in cardiovascular risk and mortality, and quitting can profoundly decrease these risks. Varenicline attenuates nicotine addiction by reducing withdrawal symptoms and cravings. A meta-analysis performed addressed whether a longer duration of varenicline is associated with better abstinence rates than shorter courses of treatment. For this meta-analysis, a literature search was performed to identify randomized controlled trials investigating the efficacy of the smoking cessation agent varenicline. The association between abstinence and duration of treatment was analyzed using fixed-effect meta-regression. Five randomized controlled trials were identified and included in this meta-analysis. A highly significant relationship (P<.001) was found between the length of exposure to varenicline and abstinence rate. Cessation rates were approximately twice as high with varenicline treatment of 24 weeks compared to 6 weeks. In conclusion, a meta-analysis of randomized controlled trials suggests that longer duration of varenicline therapy improves long-term abstinence rates.

Statins as Antiarrhythmics: A Systematic Review Part I: Effects on Risk of Atrial Fibrillation

Recent studies have demonstrated that statins may possess antiarrhythmic properties in addition to their lipid‐lowering effects.

Reduction of SPECT MPI Radiation Dose Using Contemporary Protocols and Technology

The nuclear cardiology field embarked several years ago on an aggressive effort to reduce radiation exposure for single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) [(1)][1]. Several reports suggest substantial lag in the adoption of radiation-sparing approaches [(2

TIME TO POSITIVITY OF MYOCARDIAL PERFUSION AND OUTCOMES AFTER HEART TRANSPLANT

Cardiac allograft vasculopathy (CAV) is common among orthotopic heart transplant (OHT) recipients and a major factor leading to mortality. We examined to what extent serial myocardial perfusion imaging (MPI) is useful diagnostically and prognostically, in terms of time course and eventual outcomes