Spatial QT Dispersion Predicts Nonsustained Ventricular Tachycardia and Correlates with Confined Systodiastolic Dysfunction in Hypertrophic Cardiomyopathy.

OBJECTIVES: An increased dispersion of myocardial repolarization represents one of the mechanisms underlying the arrhythmic risk in hypertrophic cardiomyopathy (HCM). We investigated spatial myocardial repolarization dispersion indices in HCM patients with nonsustained ventricular tachycardia (NSVT) and, contextually, their main clinical determinants. METHODS: Fifty-two well-matched HCM outpatients were categorized into two groups according to the presence or the absence of NSVT at 24-hour Holter electrocardiogram (ECG) monitoring. Each patient underwent a clinical examination, including Doppler echocardiogram integrated with tissue Doppler imaging, cardiac magnetic resonance, and 12-lead surface ECG to calculate the dispersion for the following intervals: QRS, Q-Tend (QTe), Q-Tpeak, Tpeak-Tend (TpTe), J-Tpeak, and J-Tend. RESULTS: The NSVT group showed only QTe dispersion and TpTe dispersion values to be significantly higher than their counterparts. NSVT occurrence was independently predicted by late gadolinium enhancement presence (p=0.021) and QTe Bazett dispersion (p=0.030), the latter strongly associated with the myocardial performance index (MPI) obtained at the basal segment of the interventricular septum (p=0.0004). CONCLUSION: Our data support QTe dispersion as an easy and noninvasive tool for identifying HCM patients with NSVT propensity. The strong relationship between QTe dispersion and MPI allows us to hypothesize an intriguing link between electrical instability and confined myocardial areas of systodiastolic dysfunction.

Synergic effects of renin and aldosterone on right ventricular function in hypertension: a tissue Doppler study.

BACKGROUND: Right ventricular dysfunction (RVD) is associated with poor cardiovascular outcome. The renin-angiotensin-aldosterone system is involved in alterations of the left ventricular geometry and function. Detrimental effects of the renin-angiotensin-aldosterone system on the right ventricular function are being postulated, but data supporting this assumption are still lacking. The aim of the study was to assess the impact of hyperreninemia, hyperaldosteronism or their combination on right ventricular function in hypertensive individuals. METHODS: Plasma renin activity (PRA) and plasma aldosterone concentrations (PACs) were measured in 116 hypertensive patients, divided as follows: normal PRA and PAC (n = 38); high PRA and normal PAC (hypereninemia) (n = 26); normal PRA and high PAC (hyperaldosternism) (n = 27); high PRA and PAC (HRA) (n = 25). Echocardiographic evaluation of the left and right ventricles (RV), including tissue Doppler imaging, was performed. RVD was identified by tissue Doppler Imaging-derived Myocardial Performance Index, calculated with a multisegmental approach. RESULTS: Indices of the right ventricular structure and function, as well as the prevalence of RVD, were higher in hyperreninemia and hyperaldosternism groups as compared with the normal group, and a further increase was observed in the HRA patients. Regression models showed a similar risk of RVD in the hyperreninemia and hyperaldosternism patients, regardless of systemic and pulmonary pressure, as well as left ventricular dysfunction. Notably, patients with both hyperreninemia and hyperaldosternism exhibited the strongest association with RVD as compared with patients with only hyperreninemia or hyperaldosternism. CONCLUSIONS: Isolated hyperreninemia or hyperaldosternism determines a similar impairment of the right ventricular function, whereas their combination is further detrimental. Renin and aldosterone may represent early biomarkers of right ventricular dysfunction in hypertension.

Myocardial repolarization dispersion and late gadolinium enhancement in patients with hypertrophic cardiomyopathy.

BACKGROUND: Growing evidence suggests that late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) is an additive marker of disease severity, and possibly of arrhythmic risk, in hypertrophic cardiomyopathy (HCM). We investigated the possible relationship between LGE and markers of myocardial repolarization dispersion in HCM. METHODS AND RESULTS: Eighty-five HCM outpatients underwent CMR and short-period electrocardiogram analysis to calculate the temporal myocardial repolarization dispersion through the QT variance normalized for QT mean (QTVN) and the QT variability index (QTVI). The QT dispersion in the spatial domain was also obtained. Patients with LGE (62%) had higher left atrial volume, maximum wall thickness, and left ventricular mass (P<0.0001), as well as a greater prevalence of non-sustained ventricular tachycardia (P<0.0001) and hypotensive blood pressure response (P=0.044). Both QTVN and QTVI were higher in the group with LGE (P<0.0001). At multivariate analysis, using QTVI as the dependent variable, %LGE (P<0.0001), age (P<0.0001), left ventricular outflow obstruction (P=0.038), and sudden cardiac death risk factor burden (P=0.020) reached statistical significance. Otherwise, only %LGE (P=0.005) and left ventricular mass index (P=0.015) remained associated with QTVN. CONCLUSIONS: Temporal myocardial repolarization dispersion correlates with LGE extent. Whether these variables could be useful in HCM clinical management warrants confirmation by larger prospective studies.

Abnormal regulation of renin angiotensin aldosterone system is associated with right ventricular dysfunction in hypertension.

BACKGROUND: Right ventricular dysfunction (RVD) is a major predictor of cardiovascular mortality. Inadequate suppression of the renin-angiotensin-aldosterone system (RAAS) after postural manoeuvres favours alterations of left ventricular (LV) function. The effects of RAAS dysregulation on RV performance remain elusive. The present study investigated RV function in hypertensive patients with or without altered RAAS activation. METHODS: Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured in 104 newly diagnosed hypertensive patients after both supine and upright positioning to assess dynamic changes of RAAS induced by antigravitational stress. Twenty-four-hour ambulatory blood pressure monitoring and echocardiographic evaluation of the right ventricle including tissue Doppler imaging (TDI) were performed. Patients were divided as follows: (1) normal PRA and PAC (N group [n = 58]), (2) suppressible RAAS after supine positioning (SR group [n = 24]), and (3), nonsuppressible RAAS (NSR group [n = 22]). RVD was identified by the TDI-derived myocardial performance index (MPI) calculated with a multisegmental approach. RESULTS: Patients in the NSR group had reduced indices of RV function compared with patients in the N and SR groups. MPI of the right ventricle as well as prevalence of RVD were also significantly higher in the NSR group. Regression models showed that inadequate RAAS suppression was independently associated with RVD, regardless of blood pressure values and LV dysfunction (LVD). CONCLUSIONS: Patients without supine normalization of RAAS display a significant impairment of RV function. Our findings suggest that a dynamic RAAS evaluation may help to identify hypertensive patients at higher risk of RVD.

Inadequate RAAS suppression is associated with excessive left ventricular mass and systo-diastolic dysfunction.

BACKGROUND: Inadequate suppression of renin-angiotensin-aldosterone system (RAAS) following postural maneuvers may have detrimental effects on cardiac structure and function. In this study, we aimed to appraise the clinical significance of this phenomenon by assessing its relation with inappropriate ventricular mass (ILVM), an adverse phenotype of LV remodeling and dysfunction. METHODS: Both supine and upright plasma renin activity (PRA) and aldosterone concentrations (PAC) were measured in 115 young newly diagnosed hypertensive subjects. 24-h ambulatory blood pressure monitoring and echocardiographic evaluation including tissue Doppler imaging (TDI) were also performed. Patients were divided as follows: (1) normal PRA and PAC (N) (n = 63); (2) suppressible RAAS (SR) in supine position (n = 27); (3) not suppressible RAAS (NSR) (n = 25). ILVM was expressed as the observed/predicted LV mass ratio ×100 (%PLVM), while LV dysfunction (LVD) was identified by TDI-derived myocardial performance index (MPI). RESULTS: NSR showed a higher prevalence of ILVM than SR and N. As compared with N and SR, NSR patients had reduced indices of systolic and diastolic function. MPI of the LV as well as prevalence of LVD was also significantly higher in the NSR group. Regression models showed that lack of RAAS suppression was independently associated with ILVM and LVD. CONCLUSIONS: Prevalence of ILVM and LVD is higher in patients without clinostatic RAAS suppression. Our findings encourage the assessment of RAAS deregulation to better estimate individual cardiovascular risk in patients with arterial hypertension.

Do diabetes, metabolic syndrome or their association equally affect biventricular function? A tissue Doppler study.

Metabolic syndrome (MetS) and type 2 diabetes (T2DM) have been associated with an impairment of left (LV) and right ventricular (RV) function as well as an increased risk of heart failure (HF). However, it remains unclear whether these clinical entities or their associations promote a similar derangement of biventricular function. Overall, 345 patients without overt cardiovascular disease consecutively underwent routine blood chemistry including high-sensitivity C reactive protein (hs-CRP) and echocardiographical examination with conventional and tissue Doppler imaging (TDI) of both ventricles. According to the ATP III criteria and fasting glucose levels, the study population was stratified into four groups: (1) healthy controls (n=120); (2) MetS without T2DM (n=84); (3) T2DM without MetS (n=49); and (4) MetS+T2DM (n=92). The Myocardial performance index (MPI) of the RV and LV was obtained with a multi-segmental approach using TDI. Patients with MetS and T2DM exhibited a similar impairment of biventricular function compared with healthy controls, whereas a further decline was observed in patients having both MetS and T2DM. In addition to MetS markers, hs-CRP exhibited the strongest association with the MPI of both ventricles. Regression analyses indicated that individual MetS markers were inferior to MetS in identifying subtle cardiac dysfunction. Independent associations of MetS and T2DM with biventricular dysfunction were comparable, and the coexistence of MetS and T2DM exhibited the highest risk for biventricular dysfunction. Our findings emphasize the importance of MetS as an equivalent of T2DM and support a synergic effect of these clinical conditions on cardiac organ damage requiring more aggressive therapeutic strategies to prevent HF.

Relation between right and left ventricular function in patients undergoing chronic dialysis.

AIMS: Occurrence of heart failure during dialysis treatment is associated with high mortality. However, mechanisms underlying left ventricular dysfunction (LVD) in these patients are still elusive. In patients undergoing haemodialysis, arteriovenous fistula (AVF) is associated with right ventricular dysfunction (RVD) and a further impairment is observed when AVF is brachial rather than radial. However, it is not known whether AVF-induced RVD is associated with an impaired left ventricular function. We studied the relation between right and left ventricular function in 120 patients undergoing either haemodialysis or peritoneal dialysis and 100 healthy age-matched controls. METHODS: Echocardiography including tissue Doppler imaging (TDI) was performed for both ventricles. Average myocardial performance index (MPI) of the right ventricle (RV MPI) was obtained with a multisegmental approach by using TDI. RESULTS: RVD was higher in haemodialysis than peritoneal dialysis patients and a further increase was observed in haemodialysis patients with brachial access. Interestingly, RV MPI inversely correlated with indices of both left ventricular contraction and relaxation and the association was even stronger in haemodialysis patients, particularly in those with brachial AVF. Of note, dialysis patients in the upper tertile of RV MPI showed the larger impairment of left ventricular function. Regression analyses showed that RV MPI was independently associated with reduced left ventricular function. By contrast, LVD did not significantly affect right ventricular performance in this setting. CONCLUSION: AVF-induced RVD may contribute to LVD in dialysis patients. AVF plays a pivotal role in triggering LVD via right-to-left ventricular interdependence.

High blood pressure, ventricular tachycardia and transient left ventricular dysfunction: do not forget pheocromocytoma.

Pheochromocytoma is a neuroendocrine tumour of the adrenal gland that secretes an excessive amount of catecholamines, leading to a rapid rise and fall in blood pressure, headache, sweating and palpitations. The clinical scenario of pheochromocytoma, however, may be extremely variable and may include atypical cardiovascular manifestations, eventually leading to delays or mistakes in diagnosis. This issue is crucial since a missed diagnosis of pheochromocytoma may imply fatal consequences. This article reports a case of pheochromocytoma presenting with quite atypical cardiovascular manifestations such as transient left ventricular dysfunction and ventricular tachycardia. The pathophysiological determinants underlying uncommon clinical presentations of pheochromocytoma are also discussed. Received for publication 19 May 2011; accepted for publication 10 June 2011.

Right ventricular dysfunction in patients with end-stage renal disease.

BACKGROUND: While chronic dialysis treatment has been suggested to increase pulmonary pressure values, right ventricular dysfunction (RVD) is a major cause of death in patients with end-stage renal disease. We investigated the impact of different dialysis treatments on right ventricular function. METHODS: We examined 220 subjects grouped as follows: healthy controls (n = 100), peritoneal dialysis (PD; n = 26), hemodialysis (HD) with radial arteriovenous fistula (AVF; n = 62), and HD with brachial AVF (n = 32). Echocardiography including tissue Doppler imaging (TDI) of the right ventricle was performed in all patients. RESULTS: Pulmonary pressure values progressively rose from controls across the 3 dialysis groups (21.7 ± 6.8, 29.7 ± 6.7, 37.9 ± 6.7 and 40.8 ± 6.6 mm Hg, respectively; p < 0.001). TDI indices of right ventricular function were more impaired in HD patients, particularly in those with brachial AVF. RVD, assessed by TDI myocardial performance index, was higher in HD patients compared with PD patients (71.3 vs. 34.6%, p < 0.001). Moreover, the prevalence of RVD further increased in patients with brachial AVF compared with the radial access (90.6 vs. 61.3%, p < 0.001). CONCLUSIONS: Compared to DP, HD increases the risk of RVD, particularly in the presence of brachial AVF. TDI may detect early functional failure of the right ventricle in HD patients.