Georgios E. Parcharidis

Left Ventricular Outflow Tract Obstruction as a Risk Factor for Sudden Cardiac Death in Hypertrophic Cardiomyopathy

The effect of left ventricular outflow tract obstruction (LVOTO) at rest on the incidence of sudden death (SD) in patients with hypertrophic cardiomyopathy is rather conflicting. The aim of this study was the evaluation of LVOTO at rest as a new potential risk factor for SD in hypertrophic cardiomyopathy. A total of 166 patients (112 men, 51.8 +/- 15.6 years) were studied; 50 patients (30.1%) had peak instantaneous LVOTO gradients of > or = 30 mm Hg at rest. During the follow-up period (median 32.4 months, range 1 to 209), 13 patients either died suddenly, or had cardiac arrest, documented sustained ventricular tachycardia, or implantable cardioverter defibrillator discharge. The cumulative event-free survival rate was 92% in patients with LVOTO, and 92% in patients without obstruction (p = NS). LVOTO at rest was associated with a particularly low positive predictive value for SD (8%), although a high negative predictive value (92%) was recorded. Patients having syncope or presenting with a maximum wall thickness > or =3 cm in echocardiography were more sensitive to SD emergence because they had a 13.07 (95% confidence interval 4.00 to 46.95, p <0.0001) and a 10.07 (95% confidence interval 2.92 to 34.79, p = 0.003) greater relative risk, respectively. In conclusion, our cohort study results do not support LVOTO as an independent risk factor for SD in patients with hypertrophic cardiomyopathy.

Evaluation of left ventricular function and volumes in patients with ischaemic cardiomyopathy: gated single-photon emission computed tomography versus two-dimensional echocardiography

Abstract. The objective of this study was to perform a head-to-head comparison between two-dimensional (2D) echocardiography and gated single-photon emission computed tomography (SPET) for the evaluation of left ventricular (LV) function and volumes in patients with severe ischaemic LV dysfunction. Thirty-two patients with chronic ischaemic LV dysfunction [mean LV ejection fraction (EF) 25%±6%] were studied with gated SPET and 2D echocardiography. Regional wall motion was evaluated by both modalities and scored by two independent observers using a 16-segment model with a 5-point scoring system (1= normokinesia, 2= mild hypokinesia, 3= severe hypokinesia, 4= akinesia and 5= dyskinesia). LVEF and LV end-diastolic and end-systolic volumes were evaluated by 2D echocardiography using the Simpsons biplane discs method. The same parameters were calculated using quantitative gated SPET software (QGS, Cedars-Sinai Medical Center). The overall agreement between the two imaging modalities for assessment of regional wall motion was 69%. The correlations between gated SPET and 2D echocardiography for the assessment of end-diastolic and end-systolic volumes were excellent (r=0.94, P<0.01, and r=0.96, P<0.01, respectively). The correlation for LVEF was also good (r=0.83, P<0.01). In conclusion: in patients with ischaemic cardiomyopathy, close and significant relations between gated SPET and 2D echocardiography were observed for the assessment of regional and global LV function and LV volumes; gated SPET has the advantage that it provides information on both LV function/dimensions and perfusion.

Predicting the Risk of Rupture of Abdominal Aortic Aneurysms by Utilizing Various Geometrical Parameters: Revisiting the Diameter Criterion

The authors estimated noninvasively the wall stress distribution for actual abdominal aortic aneurysms (AAAs) in vivo on a patient-to-patient basis and correlated the peak wall stress (PWS) with various geometrical parameters. They studied 39 patients (37 men, mean age 73.7 ± 8.2 years) with an intact AAA (mean diameter 6.3 ± 1.7 cm) undergoing preoperative evaluation with spiral computed tomography (CT). Real 3-dimensional AAA geometry was obtained from image processing. Wall stress was determined by using a finite-element analysis. The aorta was considered isotropic with linear material properties and was loaded with a static pressure of 120.0 mm Hg. Various geometrical parameters were used to characterize the AAAs. PWS and each of the geometrical characteristics were correlated by use of Pearsons rank correlation coefficients. PWS varied from 10.2 to 65.8 N/cm2 (mean value 37.1 ± 9.9 N/cm2). Among the geometrical parameters, the PWS was well correlated with the mean centerline curvature, the maximum centerline curvature, and the maximum centerline torsion of the AAAs. The correlation of PWS with maximum diameter was nonsignificant. Multiple regression analysis revealed that the mean centerline curvature of the AAA was the only significant predictor of PWS and subsequent rupture risk. This noninvasive computational approach showed that geometrical parameters other than the maximum diameter are better indicators of AAA rupture.

Impact of autonomic neuropathy on left ventricular function in normotensive type 1 diabetic patients: a tissue Doppler echocardiographic study.

Cardiovascular autonomic neuropathy (CAN) is one of the most serious complications of diabetes and has been weakly linked with left ventricular (LV) diastolic dysfunction. Previous studies that explored this association either suffer from inadequate definition of CAN or have mainly used conventional Doppler or nuclear techniques to investigate LV diastolic function. Tissue Doppler imaging (TDI) has evolved as a new quantitative tool for the assessment of cardiac systolic function, diastolic function, and the hemodynamics of LV filling. We sought to investigate conventional and TDI-derived indexes of LV systolic and diastolic function in type 1 diabetic patients with and without CAN and also in normal control subjects. Our findings suggest that the presence of CAN seems to have an additive effect on LV diastolic dysfunction in type 1 diabetes.

Effects of renin-angiotensin system inhibition on left atrial function of hypertensive patients: an echocardiographic tissue deformation imaging study.

BACKGROUND Although renin-angiotensin system (RAS) inhibitors have beneficial effects on left ventricular myocardium, their effect on left atrial (LA) function remains unknown. The aim of this study was to evaluate the effect of treatment with RAS inhibitors on LA function of patients with essential hypertension. METHODS Forty hypertensive patients (17 males, mean age 47.1 +/- 1.5, mean blood pressure 158.3 +/- 1.8/97.1 +/- 0.7 mm Hg) were studied using LA strain and strain rate (SR) imaging before and after 9 months of treatment with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs). RESULTS Standard echocardiographic parameters of LA function (LA volumes, ejection fraction, active and passive emptying fraction, and ejection force), as well as left ventricular diastolic indexes did not change with RAS-blocking treatment. However, peak systolic LA strain and SR were significantly higher at study end compared to baseline (77.8 +/- 5.2% vs. 63.3 +/- 4.1%, P < 0.001 and 3.9 +/- 0.2 s(-1) vs. 3.1 +/- 0.2 s(-1), P < 0.0001, respectively). No correlation was found between changes in systolic or diastolic blood pressure, and changes in strain or SR change during treatment. CONCLUSIONS LA strain and SR imaging improved after reduction of blood pressure with RAS inhibitors in hypertensive patients, whereas standard LA echocardiographic parameters remained unchanged. LA strain/SR values may have a role in detecting subclinical myocardial involvement in essential hypertension at an early stage; the association between change in these indexes after antihypertensive treatment and clinical outcome merits further evaluation.

Chronotropic incompetence and its relation to exercise intolerance in hypertrophic cardiomyopathy.

BACKGROUND Diminished functional capacity is common in hypertrophic cardiomyopathy (HCM), although the underlying mechanisms are complicated. We studied the prevalence of chronotropic incompetence and its relation to exercise intolerance in patients with HCM. METHODS Cardiopulmonary exercise testing was performed in 68 patients with HCM (age 44.8 ± 14.6 years, 45 males). Chronotropic incompetence was defined by chronotropic index (heart rate reserve)/(220-age-resting heart rate) and exercise capacity was assessed by peak oxygen consumption (peak Vo(2)). RESULTS Chronotropic incompetence was present in 50% of the patients and was associated with higher NYHA class, history of atrial fibrillation, higher fibrosis burden on cardiac MRI, and treatment with β-blockers, amiodarone and warfarin. On univariate analysis, male gender, age, NYHA class, maximal wall thickness, left atrial diameter, peak early diastolic myocardial velocity of the lateral mitral annulus, history of atrial fibrillation, presence of left ventricular outflow tract obstruction (LVOTO) at rest, and treatment with beta-blockers were related to peak Vo(2). Peak heart rate during exercise, heart rate reserve, chronotropic index, and peak systolic blood pressure were also related to peak Vo(2). On multivariate analysis male gender, atrial fibrillation, presence of LVOTO and heart rate reserve were independent predictors of exercise capacity (R(2) = 76.7%). A cutoff of 62 bpm for the heart rate reserve showed a negative predictive value of 100% in predicting patients with a peak Vo(2) <80%. CONCLUSIONS Blunted heart rate response to exercise is common in HCM and represents an important determinant of exercise capacity.

Left ventricular function in elite rowers in relation to training‐induced structural myocardial adaptation

To examine left ventricular (LV) function in elite young athletes in relation to structural adaptation to prolonged intense training. Conventional echocardiography and tissue Doppler imaging (TDI) were performed in 15 elite rowers and 12 sedentary matched controls. Rowers had increased LV mass index, septal (12 vs 10 mm, P<0.005) and posterior wall thicknesses (12 vs 9 mm, P<0.001) and increased relative wall thickness. Septal and lateral systolic velocities were enhanced in rowers (septal Sm=8.5 vs 6.3 cm/s, P<0.001; lateral Sm=11.4 vs 8.0 cm/s, P<0.005), representing a 35% and 42% increase, respectively. Similarly, septal and lateral early diastolic velocities were enhanced (septal Em=12.1 vs 9.5 cm/s, P<0.01; lateral Em=16.6 vs 11.6 cm/s, P<0.001), representing a 27% and 43% increase, respectively. Systolic and early diastolic TDI velocities of the lateral wall showed a positive correlation (r=0.65, P<0.01) in athletes indicating a parallel improvement of systolic and diastolic function, while LV stiffness was decreased [(E/Em)/(LV end‐diastolic diameter)=1.13 vs 1.57, P<0.005). Both systolic and diastolic LV function were improved in elite rowers, despite a pattern of concentric hypertrophy.

Non-diabetic hyperglycaemia correlates with angiographic coronary artery disease prevalence and severity.

AIM The role of glycaemia as a coronary artery disease (CAD) risk factor is controversial, and the optimal glucose level is still a matter of debate. For this reason, we assessed the prevalence and severity of angiographic CAD across hyperglycaemia categories and in relation to haemoglobin A(1c) (HbA(1c)) levels. METHODS We studied 273 consecutive patients without prior revascularization undergoing coronary angiography for suspected ischaemic pain. CAD severity was assessed using three angiographic scores: the Gensinis score; extent score; and arbitrary index. Patients were grouped, according to 2003 American Diabetes Association criteria, into those with normal fasting glucose (NFG), impaired fasting glucose (IFG) and diabetes mellitus (DM). RESULTS CAD prevalence was 2.5-fold higher in both the IFG and DM groups compared with the NFG group. Deterioration of glycaemic profile was a multivariate predictor of angiographic CAD severity (extent score: P=0.027; arbitrary index: P=0.007). HbA(1c) levels were significantly higher among CAD patients (P=0.016) and in those with two or more diseased vessels (P=0.023) compared with the non-CAD group. HbA(1c) levels remained predictive of CAD prevalence even after adjusting for conventional risk factors, including DM (adjusted OR: 1.853; 95% CI: 1.269-2.704). CONCLUSION Non-diabetic hyperglycaemia, assessed either categorically by fasting glucose categories or continuously by HbA(1c) levels, correlates with the poorest angiographic outcomes.

Patients with hypertrophic cardiomyopathy at risk for paroxysmal atrial fibrillation: advanced echocardiographic evaluation of the left atrium combined with non-invasive P-wave analysis

AIMS The maintenance of sinus rhythm is crucial for the functional capacity of patients with hypertrophic cardiomyopathy (HCM). Using a multimodality approach, we attempted to identify potential predictors of paroxysmal atrial fibrillation (PAF) in HCM patients. METHODS AND RESULTS Thirty HCM patients (17 males, mean age 57.9 ± 13.6) with at least one documented PAF episode and 32 age- and sex-matched HCM control patients as well as 25 healthy volunteers were studied in sinus rhythm. Study subjects underwent 2D echocardiography including a colour Doppler myocardial imaging evaluation of the left atrium (LA). Additionally, an orthogonal electrocardiogram was acquired; P-wave duration, maximum, and mean energies were calculated for each subject at each orthogonal lead and the composite vector axis using the Morlet wavelet analysis. Compared with HCM controls, in HCM-PAF patients, LA antero-posterior diameter was significantly enlarged (LADAP: 46.1 ± 5.9 vs. 40.0 ± 4.7 mm, P < 0.001), peak strain rate of the LA lateral wall in the reservoir phase was significantly decreased (LAT peak SR-S: 1.93 ± 0.51 vs. 2.55 ± 0.83 s(-1), P < 0.01), and P-wave duration in the Z-lead was significantly prolonged (P-durZ: 106.9 ± 24.6 vs. 86.2 ± 14.3 ms, P < 0.001). Cut-off values and areas under the curve (AUCs) for individual parameters were 42.0 mm, 2.32 s(-1), and 98.8 ms and 0.81, 0.74, and 0.78, respectively. A multivariable model combining LADAP, LAT peak SR-S and P-durZ had an AUC of 0.90, a sensitivity of 0.87, and a specificity of 0.91 for identifying PAF patients. CONCLUSION P-wave duration combined with LA antero-posterior diameter and myocardial deformation indices resulted in a higher power for discriminating HCM-PAF patients, when compared with individual parameters derived from either wavelet analysis or 2D echocardiography.

Identification of high risk patients with hypertrophic cardiomyopathy in a northern Greek population

BackgroundThe percentage of hypertrophic cardiomyopathy (HCM) patients who are in high risk for Sudden Death (SD) constitutes only a minority of all HCM population but the incidence of SD in this subset is high (at least 5% annually). The identification of this small but important proportion of high risk HCM patients has been the clue in the clinical evaluation of these patients.MethodsOur study cohort consisted from 123 patients with HCM who are currently followed up in our Institution. Five clinical risk factors were assessed: a family history of premature SD, unexplained syncope, Non Sustained Ventricular Tachycardia (NSVT) on 24-h ECG monitoring, Abnormal Blood Pressure Response (ABPR) during upright exercise testing and Maximum left ventricular Wall Thickness (MWT) ≥30 mm. The purpose of our study was the identification of high risk HCM patients coming from Northern Greece.ResultsFifteen patients (12.2%) of the whole cohort had MWT ≥ 30 mm, 30 patients (24.4%) had an ABPR to exercise, 17 patients (13.8%) had episodes of NSVT in 24-h Holter monitoring, 17 patients (13.8%) suffered from syncope, and 8 patients (6.5%) had a positive family history of premature SD. Data analysis revealed that 74 patients (60.1%) had none risk factor. Twenty four patients (19.5%) had 1 risk factor, 17 patients (13.8%) had 2 risk factors, 4 patients (3.25%) had 3 risk factors, and 4 patients (3.25%) had 4 risk factors, while none patient had 5 risk factors. Twenty five patients (20.3%) had 2 or more risk factors.ConclusionThis study for the first time confirms that, although a 60% of patients with HCM coming from a regional Greek population are in low risk for SD, a substantial proportion (almost 20%) carries a high risk for SD justifying prophylactic therapy with amiodaron or ICD implantation.