Matthew Luckie

Tricuspid regurgitation: contemporary management of a neglected valvular lesion

Right-sided cardiac valvular disease has traditionally been considered less clinically important than mitral or aortic valve pathology. However, detectable tricuspid regurgitation (TR) is common and recent data suggest that significant TR can lead to functional impairment and reduced survival, particularly in patients with concomitant left-sided valvular disease. The tricuspid valve is a complex anatomical structure and advances in three dimensional echocardiography and cardiac MRI have contributed to a greater understanding of tricuspid valve pathology. These imaging techniques are invaluable in determining the aetiology and severity of TR, and provide an assessment of right ventricular function and pulmonary artery pressure. TR is more prevalent in women and those with a history of myocardial infarction and heart failure. It also occurs in about 10% of patients with rheumatic heart disease. Chronic severe TR may have a prolonged clinical course culminating in the development of fatigue and poor exercise tolerance due to a reduced cardiac output. Approximately 90% of cases of TR are secondary to either pulmonary hypertension or intrinsic right ventricular pathology and about 10% are due to primary tricuspid valve disease. Primary causes such as Ebsteins anomaly, rheumatic disease, myxomatous changes, carcinoid syndrome, endomyocardial fibrosis, and degenerative disease have characteristic morphological features readily identifiable by echocardiography. Ascertaining an accurate right ventricular systolic pressure is important in separating primary from secondary causes as significant TR with a pressure <40 mm Hg implies intrinsic valve disease. Cardiac MRI may be indicated in those with inadequate echocardiographic images and is also the gold standard for the evaluation of right ventricular function and morphology. The assessment of leaflet morphology, annular dimensions, and pulmonary artery pressure are particularly important for determining subsequent management. Along with appropriate treatment of the underlying cause of TR and pulmonary hypertension, management guidelines indicate a move towards more aggressive treatment of TR. In those undergoing left-sided valve surgery, tricuspid valve repair is universally recommended in the presence of severe coexistent TR; in those with isolated severe TR, surgery is recommended in the presence of symptoms or progressive right ventricular dilatation or dysfunction.

Left ventricular non-compaction in identical twins with thalassaemia and cardiac iron overload

Cardiac disease in patients with transfusion-dependent beta-thalassaemia major is well described. Cardiac manifestations may include left ventricular wall thickening and both systolic and diastolic dysfunctions. We describe a group of family members, including a pair of identical twins, each of whom suffered from thalassaemia major requiring multiple transfusions. Cardiac magnetic resonance demonstrated myocardial iron overload, and impairment of systolic function. Echocardiography confirmed both significant left ventricular systolic and diastolic impairment, along with features consistent with left ventricular non-compaction. This finding has not been noted in association with thalassaemia-related cardiac disease before. We then review the cardiac manifestations which occur in association with thalassaemia major.

Severe Mitral and Aortic Regurgitation in Association with Ankylosing Spondylitis

Aortic disease and aortic valve regurgitation are well documented in association with ankylosing spondylitis, although involvement of the mitral valve occurs more rarely. We report a case of severe mitral and aortic regurgitation in association with ankylosing spondylitis. We then discuss the characteristic cardiac manifestations that may occur in association with ankylosing spondylitis and the associated echocardiographic features. (ECHOCARDIOGRAPHY, Volume 26, July 2009)

Echocardiographic Detection of Atrial Septal Defects: The Forgotten View

The right parasternal view is conventionally used to assess the aortic valve and the ascending aorta. We describe two cases in which the right parasternal view was helpful in assessment of the interatrial septum and the detection of atrial septal defects (ASD), including one case in which this view confirmed the presence of a defect not seen in any other echocardiographic view. Use of the right parasternal view should be considered for assessment of the interatrial septum, particularly when there is a high index of suspicion for an atrial septal defect but no defect is seen on conventional views. It should also be used to exclude the possibility of multiple defects even when an ASD is visualized using conventional imaging planes. (Echocardiography 2010;27:97‐99)

ABNORMAL REMODELING OF SUBCUTANEOUS SMALL ARTERIES IS ASSOCIATED WITH EARLY DIASTOLIC IMPAIRMENT IN METABOLIC SYNDROME

Background Small artery pathophysiology is frequently invoked as a cause of obesity‐related diastolic heart failure. However, evidence to support this hypothesis is scant, particularly in humans. Methods and Results To address this, we studied human small artery structure and function in obesity and looked for correlations between vascular parameters and diastolic function. Seventeen obese patients with metabolic syndrome and 5 control participants underwent echocardiography and subcutaneous gluteal fat biopsy. Small arteries were isolated from the biopsy and pressure myography was used to study endothelial function and wall structure. In comparison with the control group, small arteries from obese participants exhibited significant endothelial dysfunction, assessed as the vasodilatory response to acetylcholine and also pathological growth of the wall. For the obese participants, multiple regression analysis revealed an association between left atrial volume and both the small artery wall thickness (β=0.718, P=0.02) and wall‐to‐lumen ratio (β=0.605, P=0.02). Furthermore, the E:E′ ratio was associated with wall‐to‐lumen ratio (β=0.596, P=0.02) and inversely associated with interleukin‐6 (β=−0.868, P=0.03). By contrast, endothelial function did not correlate with any of the echocardiographic parameters studied. Conclusions Although the small arteries studied were not cardiac in origin, our results support a role for small artery remodeling in the development of diastolic dysfunction in humans. Further direct examination of the structure and function of the myocardial resistance vasculature is now warranted, to elucidate the temporal association between metabolic risk factors, small artery injury, and diastolic impairment.

Resolution of echocardiographic features of left ventricular non-compaction and systolic dysfunction following treatment for heart failure.

Isolated left ventricular non-compaction (IVNC) is a myocardial disease, thought to be related to abnormal embryological development of the myocardium. The condition may be associated with left ventricular dysfunction and heart failure, as well as arrhythmias and thrombo-embolism. The left ventricular dysfunction is generally regarded to be progressive in nature, leading to worsening heart failure and death. We report a case in which initial investigations fulfilled the diagnostic criteria for IVNC. However, follow-up investigation demonstrated recovery of left ventricular systolic function as well as resolution of the features of non-compaction, making a retrospective diagnosis of myocarditis more likely.

One-month global longitudinal strain identifies patients who will develop pacing-induced left ventricular dysfunction over time: The pacing and ventricular dysfunction (PAVD) Study

Background Predicting which individuals will have a decline in left ventricular (LV) function after pacemaker implantation remains an important challenge. We investigated whether LV global longitudinal strain (GLS), measured by 2D speckle tracking strain echocardiography, can identify patients at risk of pacing-induced left ventricular dysfunction (PIVD) or pacing-induced cardiomyopathy (PICMP). Methods Fifty-five patients with atrioventricular block and preserved LV function underwent dual-chamber pacemaker implantation and were followed with serial transthoracic echocardiography for 12 months for the development of PIVD (defined as a reduction in LV ejection fraction (LVEF) ≥5 percentage points at 12 months) or PICMP (reduction in LVEF to <45%). Results At 12 months, 15 (27%) patients developed PIVD; of these, 4 patients developed PICMP. At one month, GLS was significantly lower in the 15 patients who subsequently developed PIVD, compared to those who did not (n = 40) (GLS -12.6 vs. -16.4 respectively; p = 0.022). When patients with PICMP were excluded, one month GLS was significantly reduced compared to baseline whereas LVEF was not. One-month GLS had high predictive accuracy for determining subsequent development of PIVD or PICMP (AUC = 0.80, optimal GLS threshold: <−14.5, sensitivity 82%, specificity 75%); and particularly PICMP (AUC = 0.86, optimal GLS threshold: <−13.5, sensitivity 100%, specificity 71%). Conclusions GLS is a novel predictor of decline in LV systolic function following pacemaker implantation, with the potential to identify patients at risk of PIVD before measurable changes in LVEF are apparent. GLS measured one month after implantation has high predictive accuracy for identifying patients who later develop PIVD or PICMP.

Emergency percutaneous aortic balloon valvuloplasty in a nonagenarian

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Cardiac resynchronisation therapy reduces mortality in patients with heart failure but questions remain

Commentary on: WellsGParkashRHealeyJS. Cardiac resynchronization therapy: a meta-analysis of randomized controlled trials. CMAJ 2011;183:421–9.

Ventricular oversensing in an implantable defibrillator during lead impedance testing

Ventricular oversensing in an implantable defibrillator may be associated with inappropriate shocks. We report a case of oversensing during implantable cardioverter-defibrillator (ICD) implantation, which occurred recurrently during manual lead impedance testing. The oversensing is determined to be normal device function, explained by the programmed parameters, and algorithms determining the related aspects of device function.