Petros Nihoyannopoulos

Assessing right ventricular function: the role of echocardiography and complementary technologies

The physiological importance of the right ventricle (RV) has been underestimated; the RV was considered mainly as a conduit whereas its contractile performance was thought to be haemodynamically unimportant.1 However, its essential contribution to normal cardiac pump function is well established with the primary RV functions being:nnnnnnRV function may be impaired either by primary right sided heart disease, or secondary to left sided cardiomyopathy or valvar heart disease.2 In addition, it should be considered that RV dysfunction may affect left ventricular (LV) function, not only by limiting LV preload, but also by adverse systolic and diastolic interaction via the intraventricular septum and the pericardium (ventricular interdependence). Moreover, RV function has been shown to be a major determinant of clinical outcome3–9 and consequently should be considered during clinical management and treatment.10 Thus, the need for diagnosis of RV dysfunction is evident. In practice, clinicians largely rely on non-invasive imaging methods for assessment of RV function. Two dimensional echocardiography is the mainstay for analysis of RV function, but recently alternative techniques have been proposed, including tissue Doppler imaging (TDI) techniques,11 three dimensional echocardiography,12 magnetic resonance imaging (MRI), and even invasive assessment of pressure–volume loops.13–17 An overview of these imaging modalities for assessment of RV function is provided in the current manuscript.nnDue to its widespread availability, echocardiography is used as the first line imaging modality for assessment of RV size and RV function. The quantitative assessment of RV size and function is often difficult, because of the complex anatomy. Nevertheless, when used …

Echocardiographic evaluation of cardiac dyssynchrony for predicting a favourable response to cardiac resynchronisation therapy

Cardiac resynchronisation therapy (CRT) is an established therapy for patients with heart failure with wide QRS duration. Recent studies observed that assessment of systolic dyssynchrony is an important diagnostic tool as the treatment involves the re-coordination of regional wall contraction within the left ventricle. Therefore, the effectiveness of CRT depends heavily on whether systolic dyssynchrony is present before the treatment. Echocardiography is a useful tool for quantitative measurement of the severity of dyssynchrony in these patients before and after CRT. A number of echocardiographic tools have been developed during the past three years for such purpose, include M mode measurement of septal-to-posterior wall delay, tissue Doppler imaging for septal-to-lateral wall delay, the measurement of standard deviation of peak contraction time over 12 left ventricular segments, delayed longitudinal contraction, and potentially three dimensional echocardiography. This review discusses the potential role of various echocardiographic techniques in the assessment of systolic dyssynchrony and their clinical applications.

Acquired right ventricular dysfunction

Right ventricular (RV) function may be impaired either by primary right sided heart disease, or secondary to left sided cardiomyopathy or valvar heart disease. Two dimensional echocardiography is the mainstay for analysis of RV function. A detailed description of echocardiographic approaches for assessment of RV function is provided elsewhere.1 This brief review is focused on echocardiographic evaluation of right sided cardiac pathology.nnThe estimation of RV pressure is of great clinical importance since the RV pressure is equal to the pressure in the pulmonary artery, provided that there is no pulmonic stenosis. Typically, in RV pressure overload, the RV wall is thickened (> 4 mm) (often observed in congenital heart disease) or dilated (in acquired heart disease). In both situations, the RV free wall is hypokinetic, and is best appreciated from parasternal long axis projections. If an elevated pulmonary artery pressure is suspected, the shape of the interventricular septum should be evaluated. Normally, the shape of the left ventricular (LV) cavity will be circular because of the higher LV pressure throughout the cardiac cycle. However, in the presence of RV pressure overload, the interventricular septum will shift towards the LV and the septum will appear flattened during systole (D shape), which is best visualised on the parasternal short axis view, just below the mitral valve. The higher the RV pressure, the further the septum will displace into the LV resulting in a D shaped LV cavity (fig 1). Of note, septal flattening in the presence of elevated RV pressure should be distinguished from (isolated) RV volume overload, which leads to a septal flattening during diastole.2,3nnnn Figure 1 nu2003Parasternal short axis view during systole in a patient with severe right ventricle (RV) pressure overload. Note the flattening of the interventricular septum, the D shaped left ventricle (LV) and the enlarged …

Response of left atrial systolic function to handgrip in normal subjects

BASELINE The normal cardiovascular response to isometric exercise includes increases in cardiac output, heart rate, and systolic and diastolic blood pressures, with little or no change in stroke volume and systemic vascular resistance.1 Previous studies of echocardiographic imaging and Doppler display have demonstrated alterations in left ventricular volumes and function during handgrip associated with increased active left atrial contribution to left ventricular filling.2, 3 The present study was undertaken to delineate the changes in left atrial mechanical function leading to increased active left atrial contribution during isometric muscular contraction in normal subjects. Methods. The study population consisted of 10 healthy volunteers (Table I). All were considered normal on the basis of their medical history, physical examination, electrocardiogram, chest radiograph, and M-mode and two-dimensional echocardiogram. Subjects with less than technically optimal baseline echocardiograms and subjects re-

Angiotensin receptor neprilysin inhibitor LCZ696: a novel targeted therapy for arterial hypertension?

The need for novel antihypertensive therapies represents a continuous challenge. LCZ696 is a first-in-class angiotensin receptor neprilysin inhibitor that has been shown to enhance endogenous natriuretic peptide (NP) actions on neurohormonal activation. This effect seems to be additive to that of the renin-angiotensin-aldosterone system (RAAS) suppression, as impressively suggested in the PARADIGM HF study. LCZ696 has been shown to be effective in reducing blood pressure in several small studies; however, its effectiveness and safety remain to be proved in larger studies. This review summarizes the role of RAAS and NP system in the pathophysiology of hypertension and reviews the current data on the antihypertensive effects of LCZ696.

The Role of Statins in Prevention of Preeclampsia: A Promise for the Future?

Preeclampsia has been linked to high morbidity and mortality during pregnancy. However, no efficient pharmacological options for the prevention of this condition are currently available. Preeclampsia is thought to share several pathophysiologic mechanisms with cardiovascular disease, which has led to investigations for the potential role of statins (HMG CoA reductase inhibitors) in its prevention and early management. Pravastatin seems to have a safer pharmacokinetic profile compared to other statins, however, the existing preclinical evidence for its effectiveness in preeclampsia treatment has been mostly restricted to animal models. This review aims to summarize the current data and delineate the potential future role of statins in the prevention and management of preeclampsia.

MicroRNAs in Preeclampsia

Preeclampsia (PE) continues to represent a worldwide problem and challenge for both clinicians and laboratory-based doctors. Despite many efforts, the knowledge acquired regarding its pathogenesis and pathophysiology does not allow us to treat it efficiently. It is not possible to arrest its progressive nature, and the available therapies are limited to symptomatic treatment. Furthermore, both the diagnosis and prognosis are frequently uncertain, whilst the ability to predict its occurrence is very limited. MicroRNAs are small non-coding RNAs discovered two decades ago, and present great interest given their ability to regulate almost every aspect of the cell function. A lot of evidence regarding the role of miRNAs in pre-eclampsia has been accumulated in the last 10 years. Differentially expressed miRNAs are characteristic of both mild and severe PE. In many cases they target signaling pathway-related genes that result in altered processes which are directly involved in PE. Immune system, angiogenesis and trophoblast proliferation and invasion, all fundamental aspects of placentation, are controlled in various degrees by miRNAs which are up- or downregulated. Finally, miRNAs represent a potential therapeutic target and a diagnostic tool.

Atrial fibrillation in pregnancy: a growing challenge

Abstract Background: Atrial fibrillation (AF) constitutes a relatively infrequent pregnancy complication, which may be a therapeutic Gordian knot. Indeed, sparse data exist regarding the prevalence, prognosis, and management of AF during pregnancy. In general, AF occurs as a benign, self-limited arrhythmia, but occasionally may have severe hemodynamic consequences in pregnant patients suffering from heart failure, congenital heart disease, or other comorbidities. Extra-cardiac causes of AF should always be meticulously excluded. Review: Treatment decisions are difficult, since medications may cross the placental barrier and potentially affect fetal growth and organogenesis, or even result in fetal bradyarrhythmias. Treatment goals are not differentiated in comparison to those regarding AF occurring in the general population. Still, while maternal treatment is prioritized, issues regarding fetal health must deliberately be considered. Consequently, hemodynamic instability is to be promptly treated with synchronized electrical cardioversion. In contrast, in stable patients, pharmacologic cardioversion, under appropriate antithrombotic regimen, should be attempted. Selection of appropriate antithrombotic therapy, including novel oral anticoagulants, imposes further difficulties on therapeutic decision-making. Further clinical trials are warranted in order to assess the pathophysiology and prognosis of AF in pregnancy and ameliorate the evidence-based therapeutic strategy in this specific group of the population.