A clinician's guide to a woman's heart.

Contrary to the perception of most women that breast cancer is the leading cause of death in women, it is heart disease and stroke that claim the most lives of women older than 35 years in the United States. The prevalence of cardiovascular disease is likely to increase as more women-notably the "baby boomers"- enter the menopausal period, a time of increased cardiac vulnerability. Primary care physicians should be on the forefront in taking an inventory of risk factors in their female patients and in educating them about the reality of heart disease in their gender and about the risk factors that these patients can modify to decrease their risk.

Sleep Disordered Breathing in Hypertrophic Cardiomyopathy-Current State and Future Directions.

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and sleep disordered breathing (SDB) is a treatable risk factor that has been seen to occur concurrently, and is known to propagate mortality and morbidity in a number of cardiovascular disease states including heart failure, and indeed hypertrophic cardiomyopathy. In this review, we summarize past studies that explored the simultaneous occurrence of HCM and SDB, and the pathophysiology of SDB in relation to heart failure, arrhythmias, cardiac ischemia and pulmonary hypertension in HCM. The current therapeutic modalities, with the effect of obstructive sleep apnea (OSA) treatment on HCM, are then discussed along with potential future directions.

Tachycardia detection performance of implantable loop recorders: results from a large 'real-life' patient cohort and patients with induced ventricular arrhythmias.

Aims: Implantable loop recorders (ILRs) are valuable for diagnosing arrhythmias. We evaluated tachycardia detection performance of the Medtronic Reveal(®) ILR with FullView™ Software.

Methods And Results: The rate of occurrence of tachycardia detection [supraventricular tachycardia, ventricular tachycardia (VT), and ventricular fibrillation (VF)] and the percentage of appropriately detected tachycardias were determined from all 2190 ILR patients that transmitted to CareLink over a 4-month period (total follow-up = 135.

Glycemic control and weight reduction without causing hypoglycemia: the case for continued safe aggressive care of patients with type 2 diabetes mellitus and avoidance of therapeutic inertia.

Diabetes mellitus (DM) is a major and growing concern in the United States, in large part because of an epidemic of obesity in America and its relation to type 2 DM. In affected patients, postprandial glucose may be an early indicator of glucose intolerance or a prediabetes condition, which may be a better predictor of cardiovascular risk than impaired fasting glucose level. Treating patients who have early signs of hyperglycemia, including elevated postprandial glucose level, with intensive glucose control that does not lead to weight gain, and ideally may be associated with weight reduction, may be vital to preventing or reducing later cardiovascular morbidity and mortality.

Combining shock reduction strategies to enhance ICD therapy: a role for computer modeling.

Objectives: To develop a computer model to test shock reduction strategies such as antitachycardia pacing and shock withholding for supraventricular rhythms, oversensing, and nonsustained ventricular tachycardia.

Background: While the implantable cardioverter defibrillator (ICD) can reduce mortality, inappropriate ICD shocks remain a limitation. Randomized trials provide evidence of efficacy, but they are not always practical.

Pioglitazone for the treatment of type 2 diabetes in patients inadequately controlled on insulin.

Insulin resistance and impaired beta-cell function are primary defects that occur early in the course of development of type 2 diabetes. Insulin resistance leads to hyperinsulinemia in order to maintain normal glucose tolerance. In most cases of type 2 diabetes, beta-cell dysfunction develops subsequent to the development of insulin resistance, and it is not until such beta-cell dysfunction develops that any abnormality in glucose tolerance is seen.

Utility of currently available modes of therapy in reaching lipid goals.

The National Cholesterol Education Program Adult Treatment Panel III lipid management guidelines emphasize the importance of matching the intensity of lipid modification therapy to each patient's risk of coronary heart disease. For many patients who are at low risk, nonpharmacologic interventions such as diet, exercise, and smoking cessation can be effective lipid-lowering strategies. However, many patients require the addition of drug therapy to achieve lipid targets.

Reducing the risk of coronary heart disease via lipid reduction.

Elevated low-density lipoprotein cholesterol (LDL-C) is closely associated with an increased risk of cardiovascular morbidity and mortality. Results from numerous well-designed clinical trials indicate that interventions designed to modify lipid levels significantly reduce the risk of coronary heart disease (CHD), particularly in patients at highest risk. The National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) guidelines recommend matching the intensity of lipid-lowering therapy to the patient's risk of CHD.

Identification and management of vascular risk: beyond low density lipoprotein cholesterol.

Vascular disease is basically an inherited metabolic disease. Eighty percent of individuals who develop disease have the same blood cholesterol levels as individuals who do not develop disease. With vascular disease pervasive throughout the world and current assessment techniques insufficient to identify those at risk, use of a multifactorial approach to vascular assessment is prudent.

Treatment of intermittent claudication with beraprost sodium, an orally active prostaglandin I2 analogue: a double-blinded, randomized, controlled trial.

Objectives: In the current study, we hypothesized that beraprost would: 1) improve treadmill exercise performance and quality of life; and 2) decrease rates of ischemic events in patients with intermittent claudication.

Background: Previous trials with beraprost sodium, an orally active prostaglandin I(2) analogue, in the treatment of claudication in patients with peripheral arterial disease (PAD) have been inconsistent.

Methods: Patients with intermittent claudication (n = 897) were randomized to receive either 40 microg three times a day of beraprost with meals (n = 385) or placebo (n = 377) in a double-blinded manner for one year.

Echocardiographic transponder-guided catheter ablation feasibility and accuracy.

Background: The utility of echocardiography for catheter guidance during percutaneous endocardial ablation is increasingly apparent. However, the technique is currently imperfect due to limitations in discerning the ablation electrode from other parts of the catheter shaft.

Purpose: To examine the feasibility and accuracy of echocardiography-guided ablation using commercial ablation catheters fitted with a transponder to improve localization of the ablation electrode.

Using intracardiac catheter recordings from the His and proximal coronary sinus to distinguish isthmus conduction block during catheter ablation of type I atrial flutter.

Isthmus conduction block, demonstrated with the use of multipolar catheter recordings, is considered the preferred endpoint for ablation of type I atrial flutter. This study investigated the feasibility of using recordings from the His and coronary sinus (CS) to document isthmus conduction block. Isthmus conduction block was produced with linear radiofrequency (RF) ablation in 27 patients with type I atrial flutter.

Electrical impedance properties of normal and chronically infarcted left ventricular myocardium.

Background: Previous reports have disclosed that a significant difference exists between the electrical impedance properties of healthy and chronically infarcted ventricular myocardium.

Purpose: To assess the potential utility of electrical impedance as the basis for mapping in chronically infarcted left ventricular myocardium. Specifically: (1) to delineate electrical impedance properties of healthy and chronically infarcted ventricular myocardium, with special emphasis on the infarction border zone; (2) to correlate impedance properties with tissue histology; (3) to correlate impedance properties with electrogram amplitude and duration; (4) To demonstrate that endocardial impedance can be measured effectively in vivo using an electrode mounted on a catheter inserted percutaneously.

Efficacy of radiofrequency catheter ablation for ventricular tachycardia in healed myocardial infarction.

Radiofrequency catheter ablation has been useful in the treatment of ventricular tachycardia (VT) in selected patients with healed myocardial infarction. Previous studies have demonstrated success rates of 60% to 96% for targeted VT morphologies; however, these studies included patients only after they have had successful mapping procedures and have received radiofrequency lesions. All patients referred for VT ablation from July 1992 to November 1996 were included in this analysis on an intention-to-treat basis.

Implantable defibrillator diagnostic storage capabilities: evolution, current status, and future utilization.

There has been a rapid and significant evolution in the stored diagnostic information available from implantable cardioverter defibrillators (ICDs). The diagnostic information available in current generation ICDs has greatly enhanced the clinicians' ability to determine the rhythm triggering device therapy as well as to identify potential problems with the ICD system. Furthermore, this information may be useful in identifying triggers of ventricular arrhythmias in patients at high risk for sudden death.

Characterization of the excitable gap in human type I atrial flutter.

Objectives: We sought to characterize the excitable gap of the reentrant circuit in atrial flutter.

Background: The electrophysiologic substrate of typical atrial flutter has not been well characterized. Specifically, it is not known whether the properties of the tricuspid valve isthmus differ from those of the remainder of the circuit.

Right ventricular radiofrequency ablation of ventricular tachycardia after myocardial infarction.

Radiofrequency transcatheter ablation of ventricular tachycardia in the setting of a prior myocardial infarction is typically performed with application of energy to the left ventricular endocardium. In this article, two cases are described in which successful radiofrequency transcatheter ablation of ventricular tachycardia occurred with energy delivery to the right ventricular septum after failed ablation attempts from the left ventricle. Both patients had tachycardias with a left bundle branch block morphology and markedly presystolic activity recorded from the right ventricular septum.

Repetitive monomorphic tachycardia from the left ventricular outflow tract: electrocardiographic patterns consistent with a left ventricular site of origin.

Objectives: This study sought to characterize the electrocardiographic patterns predictive of left ventricular sites of origin of repetitive monomorphic ventricular tachycardia (RMVT).

Background: RMVT typically arises from the right ventricular outflow tract (RVOT) in patients without structural heart disease. The incidence of left ventricular sites of origin in this syndrome is unknown.

Does the initial presentation of patients with implantable defibrillator influence the outcome?

The influence of the clinical presentation on the long-term outcome in 213 consecutive patients with ICDs, ECG storage capability, and nonthoracotomy leads, was analyzed. Sixty-six patients presented with cardiac arrest (CA), 81 patients with hemodynamically stable VT, and 66 patients with syncope (SY). Patient characteristics were: mean age CA 62, VT 61, SY 61 years; mean ejection fraction CA 31%, VT 29%, SY 30%; coronary artery disease CA 71%, VT 71%, SY 64% (all P > 0.

Effect of coronary perfusion of heptanol on conduction and ventricular arrhythmias in infarcted canine myocardium.

Introduction: Abnormal cellular coupling is a major constituent of the slow, dissociated conduction that supports ventricular tachycardia (VT) following myocardial infarction. Agents that modulate cellular coupling may exert either proarrhythmic or antiarrhythmic effects.

Methods And Results: The effects of modulating cellular coupling on conduction and susceptibility to inducible VT were studied in 11 dogs with healed left anterior descending (LAD) infarction.

Myocardial viability: methods of assessment and clinical relevance.

Myocardial hibernation is hypoperfused dysfunctional myocardium that has the potential to recover function after coronary revascularization. Although recovery of regional function after revascularization is the gold standard for assessing the diagnostic accuracy of various techniques, improvements of EF, symptoms, and survival are fundamental end points. Despite important differences in the markers of viability by positron-emission tomography, single-photon emission tomography, two-dimensional echocardiography, and magnetic resonance imaging, their positive and negative predictive values in nonrandomized studies are fairly comparable.

Conduction block in the inferior vena caval-tricuspid valve isthmus: association with outcome of radiofrequency ablation of type I atrial flutter.

Objectives: We sought to 1) correlate conduction block in the isthmus of the right atrium between the inferior vena cava and the tricuspid annulus with the efficacy of catheter ablation of type I atrial flutter, and 2) characterize the effects of ablative lesions on the properties of isthmus conduction.

Background: There are few data on the mechanism of persistent suppression of recurrence of atrial flutter by catheter ablation.

Methods: Thirty-five patients with type I atrial flutter underwent catheter mapping and ablation.