Relaxation in hypertrophic cardiomyopathy and hypertensive heart disease: relations between hypertrophy and diastolic function

NADPH Oxidases and Oxidative Stress in the Pathogenesis of Atrial Fibrillation

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and its prevalence increases with age. The irregular and rapid contraction of the atria can lead to ineffective blood pumping, local blood stasis, blood clots, ischemic stroke, and heart failure. NADPH oxidases (NOX) and mitochondria are the main sources of reactive oxygen species in the heart, and dysregulated activation of NOX and mitochondrial dysfunction are associated with AF pathogenesis. NOX- and mitochondria-derived oxidative stress contribute to the onset of paroxysmal AF by inducing electrophysiological changes in atrial myocytes and structural remodeling in the atria. Because high atrial activity causes cardiac myocytes to expend extremely high energy to maintain excitation-contraction coupling during persistent AF, mitochondria, the primary energy source, undergo metabolic stress, affecting their morphology, Ca2+ handling, and ATP generation. In this review, we discuss the role of oxidative stress in activating AF-triggered activities, regulating intracellular Ca2+ handling, and functional and anatomical reentry mechanisms, all of which are associated with AF initiation, perpetuation, and progression. Changes in the extracellular matrix, inflammation, ion channel expression and function, myofibril structure, and mitochondrial function occur during the early transitional stages of AF, opening a window of opportunity to target NOX and mitochondria-derived oxidative stress using isoform-specific NOX inhibitors and mitochondrial ROS scavengers, as well as drugs that improve mitochondrial dynamics and metabolism to treat persistent AF and its transition to permanent AF.

Mechanisms of pathogenicity in the hypertrophic cardiomyopathy-associated TPM1 variant S215L

Hypertrophic cardiomyopathy (HCM) is an inherited disorder often caused by mutations to sarcomeric genes. Many different HCM-associated TPM1 mutations have been identified but they vary in their degrees of severity, prevalence, and rate of disease progression. The pathogenicity of many TPM1 variants detected in the clinical population remains unknown. Our objective was to employ a computational modeling pipeline to assess pathogenicity of one such variant of unknown significance, TPM1 S215L, and validate predictions using experimental methods. Molecular dynamic simulations of tropomyosin on actin suggest that the S215L significantly destabilizes the blocked regulatory state while increasing flexibility of the tropomyosin chain. These changes were quantitatively represented in a Markov model of thin-filament activation to infer the impacts of S215L on myofilament function. Simulations of in vitro motility and isometric twitch force predicted that the mutation would increase Ca2+ sensitivity and twitch force while slowing twitch relaxation. In vitro motility experiments with thin filaments containing TPM1 S215L revealed higher Ca2+ sensitivity compared with wild type. Three-dimensional genetically engineered heart tissues expressing TPM1 S215L exhibited hypercontractility, upregulation of hypertrophic gene markers, and diastolic dysfunction. These data form a mechanistic description of TPM1 S215L pathogenicity that starts with disruption of the mechanical and regulatory properties of tropomyosin, leading thereafter to hypercontractility and finally induction of a hypertrophic phenotype. These simulations and experiments support the classification of S215L as a pathogenic mutation and support the hypothesis that an inability to adequately inhibit actomyosin interactions is the mechanism whereby thin-filament mutations cause HCM.

Echocardiography E/A Abnormality is Associated with the Development of Primary Left Ventricle Remodeling in Middle-Aged and Elderly Women: A Longitudinal Study

Background

Impaired left ventricular (LV) relaxation is indicative of grade I diastolic dysfunction, which is mainly assessed by late diastolic transmitral flow velocity (E/A ratio). Although the E/A ratio has important diagnostic and prognostic implications with cardiac outcomes, the causal link between abnormal E/A ratio and left ventricle remodeling (LV remodeling) remains unclear.

Methods

A longitudinal analysis of 869 eligible women aged ≥45 years, who had received echocardiography scans as well as 5-year follow-up assessments between 2015 and 2020. Women with pre-existing cardiac abnormalities including grade II/III diastolic dysfunction as diagnosed by echocardiography, or structural heart disease were excluded. E/A abnormality was defined as baseline E/A ratio <0.8. The classification of LV remodeling was based on the measurements of left ventricular mass index (LVMI) and relative wall thickness (RWT). Logistic and linear regression models were used.

Results

Among the 869 women (60.71±10.01 years), 164 (18.9%) had developed LV remodeling after the 5-year follow-up. The proportion of women with E/A abnormality versus non-abnormality was also significantly different (27.13% vs 16.59%, P=0.007). Multivariable-adjusted regression models showed that E/A abnormality (OR: 4.14, 95%Cl:1.80-9.20, P=0.009) was significantly associated with higher risk of concentric hypertrophy (CH) after follow-up. No such association was found in either concentric remodeling (CR) or eccentric hypertrophy (EH). Higher baseline E/A ratio was correlated with lower ΔRWT during the 5-year follow-up (β=-0.006 m/s, 95% CI: -0.012 to -0.002, P=0.025), which was independent of demographics and biological factors.

Conclusion

E/A abnormality is associated with a higher risk of CH. Higher baseline E/A ratio may be associated with decreased relative changes in RWT.

The Impact of Mavacamten on the Pathophysiology of Hypertrophic Cardiomyopathy: A Narrative Review

Hypertrophic cardiomyopathy (HCM) is a chronic, progressive disease of the cardiomyocyte with a diverse and heterogeneous clinical presentation and course. This diversity and heterogeneity have added to the complexity of modeling the pathophysiological pathways that contribute to the disease burden. The development of novel therapeutic approaches targeting precise mechanisms within the underlying biology of HCM provides a tool to model and test these pathways. Here, we integrate the results of clinical observations with mavacamten, an allosteric, selective, and reversible inhibitor of cardiac myosin, the motor unit of the sarcomere, to develop an integrated pathophysiological pathway model of HCM, confirming the key role of excess sarcomeric activity. This model may serve as a foundation to understand the role of HCM pathophysiological pathways in the clinical presentation of the disease, and how a targeted therapeutic intervention capable of normalizing sarcomeric activity and repopulating low-energy utilization states may reduce the impact of these pathways in HCM and potentially related disease states.

Management of hypertension in heart failure with preserved ejection fraction: is there a blood pressure goal?

PURPOSE OF REVIEW

Hypertension remains a leading risk factor for heart failure with preserved ejection fraction (HFpEF), and elevated blood pressure (BP) portends an adverse prognosis in patients with established HFpEF. We summarize current evidence for mechanisms linking hypertension to HFpEF and management of hypertension in HFpEF.

RECENT FINDINGS

Data suggest a complex, multifactorial pathophysiology driving the association between hypertension and HFpEF, including left ventricular hypertrophy, diastolic dysfunction, atrial dysfunction, coronary microvascular disease, endothelial dysfunction, myocardial injury and fibrosis. Although intensive BP control may attenuate these processes, this hypothesis has not been tested on clinical outcomes in a dedicated randomized controlled trial (RCT) in HFpEF. Antihypertensive therapies variably improve key surrogate markers in HFpEF, though BP reduction generally does not account for these benefits. Accordingly, BP targets are extrapolated from observational studies and RCTs testing heart failure therapies that affect BP in addition to dedicated RCT data in patients at elevated risk (without heart failure).

SUMMARY

Clinicians should recognize the risk of disease progression and poor outcomes associated with uncontrolled hypertension in HFpEF. Intensive BP control, preferably by therapies known to improve outcomes in heart failure, may slow key pathways in disease progression. Future RCTs testing intensified BP control strategies in HFpEF are warranted.

Early segmental relaxation abnormalities in hypertrophic cardiomyopathy for differential diagnostic of patients with left ventricular hypertrophy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is characterized by asymmetric left ventricular hypertrophy (LVH). However, clinical signs can be subtle and differentiation from other causes of LVH is challenging.

HYPOTHESIS

As diastolic dysfunction (DD) is an early sign in HCM, we aimed to find regional changes in relaxation pattern for differentiation from other entities of LVH.

METHODS

In 148 patients (81 HCM, 55 arterial hypertension (AHT), 12 Fabry disease) and 63 healthy controls, relaxation patterns were assessed using regional tissue Doppler imaging. In 42 HCM patients, myocardial mass and fibrosis were quantified by cardiac magnetic resonance imaging and correlated with relaxation parameters.

RESULTS

In HCM the septal to lateral isovolumic relaxation time (s/l IVRT) ratio was higher (1.5 ± 0.4) compared with AHT (1.1 ± 0.2), Fabry disease (1.0 ± 0.1), and controls (1.1 ± 0.2; P < 0.001), showing 77% sensitivity and 79% specificity to discriminate HCM-related LVH from other entities. The s/l IVRT ratio was independent of global DD in HCM (HCM with DD: 1.5 ± 0.5, n = 52; HCM without DD: 1.5 ± 0.3, n = 29) and remained significantly different from other entities in a subgroup of HCM patients with maximum wall thickness < 20 mm (s/l ratio: 1.5 ± 0.5, n = 28). Regional IVRT did not correlate with the corresponding segmental myocardial mass or amount of fibrosis in cardiac magnetic resonance imaging.

CONCLUSIONS

HCM patients show a prolonged septal IVRT irrespective of the extent of LVH and even before developing global DD. The s/l IVRT ratio is significantly higher in HCM compared with AHT or Fabry disease, thus establishing segmental IVRT analysis as a potential parameter for differential diagnosis in LVH.

Characterization of regional left ventricular function in nonhuman primates using magnetic resonance imaging biomarkers: a test-retest repeatability and inter-subject variability study

Pre-clinical animal models are important to study the fundamental biological and functional mechanisms involved in the longitudinal evolution of heart failure (HF). Particularly, large animal models, like nonhuman primates (NHPs), that possess greater physiological, biochemical, and phylogenetic similarity to humans are gaining interest. To assess the translatability of these models into human diseases, imaging biomarkers play a significant role in non-invasive phenotyping, prediction of downstream remodeling, and evaluation of novel experimental therapeutics. This paper sheds insight into NHP cardiac function through the quantification of magnetic resonance (MR) imaging biomarkers that comprehensively characterize the spatiotemporal dynamics of left ventricular (LV) systolic pumping and LV diastolic relaxation. MR tagging and phase contrast (PC) imaging were used to quantify NHP cardiac strain and flow. Temporal inter-relationships between rotational mechanics, myocardial strain and LV chamber flow are presented, and functional biomarkers are evaluated through test-retest repeatability and inter subject variability analyses. The temporal trends observed in strain and flow was similar to published data in humans. Our results indicate a dominant dimension based pumping during early systole, followed by a torsion dominant pumping action during late systole. Early diastole is characterized by close to 65% of untwist, the remainder of which likely contributes to efficient filling during atrial kick. Our data reveal that moderate to good intra-subject repeatability was observed for peak strain, strain-rates, E/circumferential strain-rate (CSR) ratio, E/longitudinal strain-rate (LSR) ratio, and deceleration time. The inter-subject variability was high for strain dyssynchrony, diastolic strain-rates, peak torsion and peak untwist rate. We have successfully characterized cardiac function in NHPs using MR imaging. Peak strain, average systolic strain-rate, diastolic E/CSR and E/LSR ratios, and deceleration time were identified as robust biomarkers that could potentially be applied to future pre-clinical drug studies.

The Effect of Chronic Anabolic-Androgenic Steroid Use on Tp-E Interval, Tp-E/Qt Ratio, and Tp-E/Qtc Ratio in Male Bodybuilders

BACKGROUND

The chronic consumption of androgenic anabolic steroids has shown to cause atrial arrhythmias. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp-e) may correspond to the transmural dispersion of repolarization and that increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate repolarization dispersion measured from the 12-lead surface electrocardiogram (including Tp-e interval, Tp-e/QT ratio, and Tp-e/cQT ratio) in bodybuilders who are using anabolic androgenic steroids (AAS).

METHODS

We selected a population of 33 competitive bodybuilders, including 15 actively using AAS for ≥ 2 years (users) and 18 who had never used AAS (nonusers), all men.

RESULTS

QT, cQT, QTd, cQTd, JT, and cJT were significantly increased in AAS users bodybulders compared to the nonusers (all P < 0.001). Tp-e interval, Tp-e/QT ratio, and Tp-e/cQT ratio were also significantly higher in AAS user group compared to the nonuser group (all P < 0.001). QRS duration was not different between the groups. There were negative correlation between E(m) and Tp-e, Tp-e/QT ratio, Tp-e/cQT ration (r = -0.657, P < 0.01; r = -0.607, P = 0.02; r = -0.583, P = 0.02; respectively).There were also negative correlation between S(m) and Tp-e, Tp-e/QT ratio, Tp-e/cQT ration (r = -0.681, P < 0.01; r = -0.549, P = 0.03; r = -0.544, P = 0.023; respectively).

CONCLUSION

In conclusion, we have presented a strong evidence suggesting that Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio were increased in AAS users, which suggest that there might be a link between AAS use and ventricular arrthymias and sudden death.

Age, left atrial dimension and arterial stiffness after external cardioversion of atrial fibrillation. A vascular component in arrhythmia maintenance? Results from a preliminary study

BACKGROUND AND AIMS

Atrial fibrillation (AF) is the most frequent arrhythmia in elderly patients. Aims of this study were to evaluate the predictors of arterial stiffness after external cardioversion (ECV) of AF and to establish whether a link exists between vascular properties and left atrial diameter (LAD).

METHODS

We studied 33 patients (age 73 ± 12 years). After 5 h from ECV of persistent AF, an echocardiogram was recorded and arterial stiffness was evaluated with cardio-ankle vascular stiffness index (CAVI).

RESULTS

In multivariate analysis (R = 0.538, p = 0.006), CAVI (mean 9.60 ± 1.63) increased with age (p = 0.018) and with an AF length ≤3 months (p = 0.022). LAD was significantly related to CAVI (p = 0.007) even after adjustment for interventricular septum thickness (p = 0.018) (R = 0.574, p = 0.002).

CONCLUSIONS

In patients with AF, immediately after ECV, arterial stiffness is associated with age and AF length, and could represent an important factor for left atrium remodeling and, therefore, for AF maintenance.

Alterations in diastolic function in masked hypertension: findings from the masked hypertension study

BACKGROUND

In a prior study of patients with diabetes, diastolic function was similarly impaired in masked hypertension (MHT) and sustained hypertension (SHT). We evaluated whether MHT is associated with impaired diastolic function compared with SHT and sustained normotension (NT) in the general population.

METHODS

From February 2005 to December 2010, 798 participants without a history of cardiovascular disease or treated hypertension, were enrolled in the Masked Hypertension Study. Participants underwent clinic blood pressure (CBP) and 24-hour ambulatory blood pressure (ABP) measurements. A 2-dimensional Doppler echocardiogram was performed to evaluate diastolic function,s cardiac structure, volume, and systolic function. The 9 CBPs obtained across 3 clinic visits and awake ABP measurements were averaged. Clinic hypertension was defined as systolic/diastolic blood pressure (SBP/DBP) ≥ 140/90 mmHg. Ambulatory hypertension was defined as awake SBP/DBP ≥ 135/85mm Hg. MHT was defined as having ambulatory but not clinic hypertension. White-coat hypertensives (n = 8) were excluded from the analysis.

RESULTS

Of the 790 participants, 116 (14.7%) participants had MHT, 37 (4.7%) participants had SHT, and 637 (80.6%) participants had NT. After age, sex, race/ethnicity, and body mass index adjustment, compared with NT, E'-velocities were significantly lower in MHT (P < 0.01) and SHT (P < 0.05), and E/E' ratios were significantly higher MHT (P < 0.05) and SHT (P < 0.05). These associations were independent of left ventricular mass. Diastolic function parameters did not significantly differ between MHT and SHT.

CONCLUSIONS

Diastolic function was impaired in MHT compared with NT independent of changes in left ventricular mass.

The Association of Left Ventricular Hypertrophy with Intraventricular Dyssynchrony at Rest and during Exercise in Hypertensive Patients

Background

Impaired exercise tolerance with dyspnea is common in hypertensive patients and this may be due to the exaggeration of nonuniform ventricular activation during exercise. So we want to evaluate the effect of left ventricular hypertrophy (LVH) on systolic intraventricular dyssynchrony during exercise.

Methods

A total of 85 patients with hypertension who having exertional dyspnea and 30 control individuals were enrolled. Exercise stress echocardiography was performed using a symptom limited, multistage supine bicycle test. To evaluate the dyssynchrony of left ventricular (LV), we calculated the standard deviation (SD) of the averaged time-to-peak systolic velocity (TPs-SD, ms) of 12 middle and basal LV segments obtained from the three standard apical views at rest and peak exercise.

Results

There was no significant difference in systolic blood pressure (BP) and heart rate between the two groups. TPs-SD was significantly higher in patients with LVH at rest (31.5 ± 12.1 vs. 22.0 ± 12.6 ms, p = 0.002) with exaggeration of the degree at peak exercise (39.0 ± 11.9 vs. 24.6 ± 13.3 ms, p < 0.001). Multiple regression analysis showed LV mass index was independently associated with LV dyssynchrony at peak exercise (β = 0.515, p = 0.001) when controlled for age, sex, and systolic BP at peak exercise.

Conclusion

Intraventricular systolic dyssynchrony during exercise is significantly associated with the degree of LVH in hypertensive patients.

Myosin cross-bridge dynamics in patients with hypertension and concentric left ventricular remodeling

BACKGROUND

Hypertension (HTN) causes concentric left ventricular remodeling, defined as an increased relative wall thickness or overt left ventricular hypertrophy, and associated diastolic dysfunction. HTN and concentric remodeling are also common precursors to heart failure with a preserved ejection fraction. It is not known whether the myofilament contributes to diastolic dysfunction in patients with concentric remodeling.

METHODS AND RESULTS

Intraoperative myocardial biopsies were obtained in 15 male patients undergoing coronary bypass grafting, all with normal left ventricular ejection fraction and wall motion. Eight patients had a history of HTN and concentric remodeling. Seven without HTN or remodeling served as controls. Myocardial strips were dissected and demembranated with detergent. Isometric tension was measured and sinusoidal length perturbation analysis performed at sarcomere length 2.2 μm and pCa 8 to 4.5. Sinusoidal analysis provides estimates of cross-bridge dynamics, including rate constants of attachment and detachment and cross-bridge attachment time. The normalized isometric tension-pCa relation was similar in HTN and controls. However, cross-bridge attachment time was significantly prolonged at submaximal [Ca(2+)] (pCa ≥6.5) in HTN patients. Analysis of protein phosphorylation revealed ≈25% reduction in phosphorylation of troponin I in HTN patients (P<0.05).

CONCLUSIONS

Compared with controls, patients with HTN and concentric remodeling display prolonged cross-bridge attachment time at submaximal [Ca(2+)] without a change in the tension-pCa relation. Prolonged cross-bridge attachment time implicates altered cross-bridge dynamics as a cause of slowed relaxation in these patients. This finding was associated with reduced phosphorylation of troponin I, suggesting decreased phosphorylation of protein kinase A/G sites as a mechanism.

The diagnosis of hypertrophic cardiomyopathy by cardiovascular magnetic resonance

Hypertrophic cardiomyopathy (HCM) is the most common genetic disease of the heart. HCM is characterized by a wide range of clinical expression, ranging from asymptomatic mutation carriers to sudden cardiac death as the first manifestation of the disease. Over 1000 mutations have been identified, classically in genes encoding sarcomeric proteins. Noninvasive imaging is central to the diagnosis of HCM and cardiovascular magnetic resonance (CMR) is increasingly used to characterize morphologic, functional and tissue abnormalities associated with HCM. The purpose of this review is to provide an overview of the clinical, pathological and imaging features relevant to understanding the diagnosis of HCM. The early and overt phenotypic expression of disease that may be identified by CMR is reviewed. Diastolic dysfunction may be an early marker of the disease, present in mutation carriers prior to the development of left ventricular hypertrophy (LVH). Late gadolinium enhancement by CMR is present in approximately 60% of HCM patients with LVH and may provide novel information regarding risk stratification in HCM. It is likely that integrating genetic advances with enhanced phenotypic characterization of HCM with novel CMR techniques will importantly improve our understanding of this complex disease.

Hypertensive left ventricular hypertrophy risk: beyond adaptive cardiomyocytic hypertrophy

The heart is a remarkably adaptive organ, capable of increasing its minute output and overcoming short-term or prolonged pressure overload. The structural response, in addition to the foregoing functional demands, is that of myocardial hypertrophy. Then, why should an adaptive response increase cardiovascular risk in hypertensive patients with left ventricular hypertrophy (LVH)? Evidence shows that the functional performance of hypertrophied cardiomyocytes is impaired, and that additional alterations develop in cardiomyocytes themselves, the extracellular matrix and the intramyocardial vasculature, leading to myocardial remodelling and providing the basis for the adverse prognosis associated with pathological LVH in hypertensive patients (i.e., hypertensive heart disease, HHD). As molecular information accumulates, the pathophysiological understanding and the clinical approach to HHD are changing. The time has come to develop novel diagnostic and therapeutic strategies aimed at improving the prognosis of HHD on the basis of reversing or even preventing the aforementioned changes in the ventricular myocardium.

A associação de esteroide anabolizante ao treinamento físico aeróbio leva a alterações morfológicas cardíacas e perda de função ventricular em ratos

INTRODUÇÃO: O esteroide anabolizante (EA) associado ao treinamento físico induz mudança da hipertrofia cardíaca (HC) fisiológica para patológica. Entretanto, esses trabalhos foram realizados com atletas de força, sendo os efeitos do EA associados ao treinamento aeróbio poucos conhecidos. Com isso, o objetivo do estudo foi avaliar os efeitos do treinamento aeróbio e dos EA sobre a estrutura e função cardíaca. MÉTODOS: Foram utilizados 28 ratos Wistar divididos em quatro grupos: sedentários controle (SC), sedentários anabolizante (SA), treinados controle (TC) e treinado anabolizante (TA). O EA foi administrado duas vezes por semana (10mg/kg/ semana). O treinamento físico de natação foi realizado durante 10 semanas, cinco sessões semanais. Foram avaliadas a pressão arterial e frequência cardíaca por pletismografia de cauda, função ventricular por ecocardiografia, diâmetro dos cardiomiócitos e fração volume de colágeno por métodos histológicos. RESULTADOS: Não foram observadas diferenças na PA. O grupo TC apresentou redução da frequência cardíaca de repouso após o período experimental, o que não ocorreu no grupo TA. Foram observadas HC de 38% no grupo SA, 52% no grupo TC e de 64% no grupo TA em relação ao grupo SC. O grupo TA apresentou diminuição da função diastólica em relação aos outros grupos. Os grupos treinados apresentaram aumentos significantes no diâmetro dos cardiomiócitos. Os grupos SA e TA apresentaram aumento na fração volume de colágeno em relação aos grupos SC e TC. CONCLUSÃO: Os resultados apresentados mostram que o treinamento físico de natação induz a HC, principalmente pelo aumento do colágeno intersticial, o que pode levar a prejuízos da função diastólica.

Heterogeneity of apex-to-base dispersion in diastolic lengthening is related to impaired global left ventricular relaxation in patients with hypertrophic cardiomyopathy

BACKGROUND

The presence of apex-to-base disparity in diastolic left ventricle (LV) endocardial lengthening, based on an electromechanical activation sequence, has been recognized as an important determinant of LV diastolic properties. However, the behavior of LV apical and basal diastolic lengthening and its relationship to LV filling in hypertrophic cardiomyopathy (HCM) are unknown.

METHODS

We obtained basal and apical LV short-axis views in 27 patients with non-obstructive HCM and 25 healthy volunteers. The patients with HCM were subdivided into two groups; those with apical hypertrophy [APH(+)] or those without apical hypertrophy [APH(-)]. Eight equiangular points on the endo-myocardium at end diastole were placed in each view, and the movements of these points were automatically tracked using a two-dimensional echocardiographic tissue tracking system. Time-LV internal diameter curves were obtained and averaged. The time intervals from the aortic valve closure to the point of the first 40% of peak diastolic lengthening (T 40) were measured in each view. The standard deviation of the time to peak systolic circumferential shortening at the base and apex were calculated to assess the heterogeneity of LV contraction.

RESULTS

The time difference in the T 40 between the apex and base (dt-T 40) in the HCM-APH(+) and HCM-APH(-) groups was greater than that in the control group. The heterogeneities in LV apical systolic shortening in the HCM groups were greater than those in the control group. There were good linear correlations between the dt-T 40 and the LV early diastolic echo-parameters and the LV mass index.

CONCLUSIONS

Delayed apical relaxation and filling in patients with HCM is related to LV diastolic dysfunction and systolic dyssynchronous contraction.

Right ventricular diastolic dysfunction in patients with left ventricular hypertrophy: analysis of right ventricular myocardial relaxation using two-dimensional speckle tracking imaging

BACKGROUND

Although several previous studies have suggested the presence of right ventricular (RV) diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM) and those with hypertensive left ventricular hypertrophy (HT-LVH), the mechanisms are still unclear. This study aimed to clarify the relationship between the RV global diastolic dysfunction in these patients and the regional myocardial diastolic function, including synchronicity of the interventricular septum and RV free wall.

METHODS

In 20 age-matched patients with HT-LVH, 20 patients with HCM and 22 control subjects without pulmonary hypertension, RV isovolumic relaxation time (IRTR) was measured using continuous-wave Doppler echocardiography. The early diastolic peak strain rate (E SR) and time from QRS to E SR (T-E SR) were measured in the apical, mid-ventricular and basal segments of the interventricular septum and RV free wall using two-dimensional speckle tracking imaging (2DST).

RESULTS

IRTR was more prolonged both in HT-LVH and in HCM than in the controls. The averaged septal E SR was reduced both in HT-LVH and in HCM (P < 0.0001, respectively), but the averaged RV free wall E SR was decreased only in HCM (P = 0.0007). E SR averaged for six septal and RV free wall segments was correlated with IRTR (r = -0.46, P = 0.0001). Neither intergroup difference nor correlation with IRTR was observed in a coefficient of variation of T-E SR for the six segments.

CONCLUSIONS

RV global diastolic function is impaired in patients with HT-LVH and HCM due to relaxation abnormalities, not an asynchrony, of the myocardium surrounding the RV cavity. The detection of RV free wall relaxation abnormality using 2DST may be useful to differentiate HCM from HT-LVH.

Cardiac tissue Doppler imaging in sports medicine

The differentiation of training-induced cardiac adaptations from pathological conditions is a key issue in sports cardiology. As morphological features do not allow for a clear delineation of early stages of relevant pathologies, the echocardiographic evaluation of left ventricular function is the technique of first choice in this regard. Tissue Doppler imaging (TDI) is a relatively recent method for the assessment of cardiac function that provides direct, local measurements of myocardial velocities throughout the cardiac cycle. Although it has shown a superior sensitivity in the detection of ventricular dysfunction in clinical and experimental studies, its application in sports medicine is still rare. Besides technical factors, this may be due to a lack in consensus on the characteristics of ventricular function in relevant conditions. For more than two decades there has been an ongoing debate on the existence of a supernormal left ventricular function in athlete's heart. While results from traditional echocardiography are conflicting, TDI studies established an improved diastolic function in endurance-trained athletes with athlete's heart compared with controls.The influence of anabolic steroids on cardiac function also has been investigated by standard echocardiographic techniques with inconsistent results. The only TDI study dealing with this topic demonstrated a significantly impaired diastolic function in bodybuilders with long-term abuse of anabolic steroids compared with strength-trained athletes without abuse of anabolic steroids and controls, respectively.Hypertrophic cardiomyopathy is the most frequent cause of sudden death in young athletes. However, in its early stages, it is difficult to distinguish from athlete's heart. By means of TDI, ventricular dysfunction in hypertrophic cardiomyopathy can be disclosed even before the development of left ventricular hypertrophy. Also, a differentiation of left ventricular hypertrophy due to hypertrophic cardiomyopathy or systemic hypertension is possible by TDI. Besides the evaluation of different forms of left ventricular hypertrophy, the diagnosis of myocarditis is also of particular importance in athletes. Today, it still requires myocardial biopsy. The analysis of focal disturbances in myocardial velocities might be a promising non-invasive method; however, systematic validation studies are lacking. An important future issue for the implementation of TDI into routine examination will be the standardisation of procedures and the establishment of significant reference values for the above-mentioned conditions. Innovative TDI parameters also merit further investigation.

Frequency and determinants of early rapid filling abnormality

BACKGROUND

The frequency and determinants of early rapid diastolic filling abnormalities in the community and in cardiac patients are poorly understood.

METHODS AND RESULTS

Early left ventricular (LV) rapid filling was assessed via equilibrium radionuclide angiocardiography in 70 community volunteers (LV ejection fraction [EF] > or = 0.50) and 778 cardiac patients, all aged at least 45 years. The frequency of early rapid filling and the independent clinical, therapeutic, and hemodynamic variables predictive of early rapid filling abnormality were determined. Depending on the parameter assessed, early rapid filling was abnormal in 27% to 54% of the community volunteers, 34% to 53% of cardiac patients with an LVEF of 0.50 or greater, and 42% to 67% of cardiac patients with an LVEF lower than 0.50. On the basis of multivariate analysis, models of clinical, therapeutic, and hemodynamic variables were modestly predictive of early rapid filling abnormality. Age, sex, valvular insufficiency, hypertension, digoxin use, and heart rate were independent determinants of early rapid filling.

CONCLUSIONS

In participants aged older than 44 years, early rapid filling was frequently abnormal in the community volunteers and in patients with an LVEF of 0.50 or greater and was most common in patients with an LVEF lower than 0.50. Clinical, therapeutic, and hemodynamic variables had modest independent predictive value for early rapid filling abnormality.

Role of Left Ventricular Regional Diastolic Abnormalities for Global Diastolic Dysfunction in Patients with Hypertrophic Cardiomyopathy

BACKGROUND

The usefulness of Doppler strain rate imaging for assessment of left ventricular regional diastolic function has not been fully determined.

OBJECTIVE

We aimed to clarify the relationships between diastolic strain rates and global diastolic function and find a useful index for regional diastolic function in patients with hypertrophic cardiomyopathy (HCM).

METHODS

Strain rate curves were obtained using an apical approach at 12 different sites of the left ventricular myocardium in 25 patients with HCM and 20 control subjects, and peak early diastolic strain rate (ESR), peak late diastolic strain rate, and the time from QRS to ESR were measured. The flow propagation velocity was measured using color M-mode Doppler echocardiography as a global diastolic index.

RESULTS

Each of the spatially averaged values of ESR and ESR/peak late diastolic strain rate and the coefficients of variation of time from QRS to ESR was significantly correlated with flow propagation velocity, but the best correlation was observed in ESR. Although both ESR and peak late diastolic strain rate of each myocardial segment of patients with HCM tended to decrease as the wall thickness increased, only ESR significantly decreased even in the segments without apparent hypertrophy.

CONCLUSIONS

In patients with HCM, the reduction of ESR was more closely associated with global diastolic dysfunction than asynchrony, and ESR may be a useful and sensitive index for regional diastolic function.

Detection of left ventricular regional relaxation abnormalities in patients with hypertrophic cardiomyopathy by quantitative tissue velocity imaging

To assess the left ventricular regional relaxation abnormalities in patients with hypertrophic cardiomyopathy (HCM) by quantitative tissue velocity imaging (QTVI), Doppler echocardiography and QTVI were performed in HCM (n=10) and healthy subjects (n=11) at apical long-axis, two-chamber and four-chamber views. Regional early diastolic velocity (rVe) and regional atrial contraction (rVa) were measured at each segment of ventricular middle, basal and annular levels. Mean rVe and mean rVa at three levels as well as mean rVe/rVa ratio were calculated. Our results showed that transmitral inflow peak velocities during early diastole (E) and atrial contraction (A) were also measured and E/A ratio was calculated. The rVe of all left ventricular segments in HCM were lower than those in healthy subjects (P<0.05), but compared with healthy subjects majority of rVa in HCM were not different except inferior wall and anterior wall. E between HCM and healthy subjects was different (P=0.036), while mean rVe between them was significantly different (P<0.0001). Mean rVa and mean rVe/rVa of three levels were lower in HCM than in healthy subjects (P<0.05), but there were no differences in A and E/A between them (P=0.22, P=0.101). Left ventricular regional myocardial relaxation is reduced in HCM. Transmitral inflow E and A are influenced by preload, relaxation of myocardium and atrial contraction, etc., while rVe and rVa reflect myocardial relaxation function independently. QTVI is more sensitive and more accurate than conventional Doppler imaging for characterizingregional diastolic properties in HCM.

[Characteristics of hypertensive cardiomyopathy in a population of hypertensive patients never treated]

BACKGROUND AND OBJECTIVE

Although impaired diastolic function is frequently found in systemic hypertension, the diagnosis of hypertensive heart disease (HHD) is based on the demonstration of left ventricular (LV) growth. The aim of the current work was to investigate the potential interactions between diastolic function and LV growth in patients with arterial hypertension.

PATIENTS AND METHOD

One hundred and sixteen never-treated asymptomatic hypertensives underwent an echocardiographic evaluation. Classification of diastolic dysfunction (DD) was based on alterations in parameters assessing transmitral inflow, Doppler tissue imaging of mitral annular motion, and color M-mode propagation velocity. Classification of LV growth was based on alterations in left ventricular mass index and/or relative will thickness.

RESULTS

Ninety-four patients (81%) exhibited DD and 22 (19%) exhibited normal diastolic function. Amongst patients with DD, 79 (84%) exhibited a pattern of impaired relaxation and 15 (16%) a pseudonormal pattern. The presence of LV growth was documented in 41% of patients without DD and 75% of patients with DD (p < 0.05). None of the studied patients exhibited echocardiographic signs of systolic dysfunction.

CONCLUSIONS

These findings indicate that DD is an early and highly frequent cardiac alteration in arterial hypertension. In addition, our data show that one fifth of hypertensive patients have DD in the absence of LV growth. It is thus suggested that the diagnosis of HHD can not be further based exclusively on morphologic criteria and should include also the evaluation of alterations in LV filling.

Left ventricular diastolic dysfunction is accompanied by increased aortic stiffness in the early stages of essential hypertension: a TDI approach

OBJECTIVE

To investigate the inter-relationship between aortic stiffness and left ventricular (LV) diastolic function in subjects with newly diagnosed uncomplicated essential hypertension.

METHODS

We studied 106 consecutive newly diagnosed subjects (aged 51 years, 80 males) with stage I-II essential hypertension, and 50 normotensives matched for age, sex and body mass index. LV diastolic function was estimated by pulsed tissue Doppler imaging (TDI) echocardiography, averaging diastolic mitral annular velocity measurements (Emav, Amav, Emav/Amav ratio) from four separate sites (basal septal, lateral, anterior, and inferior LV wall). Moreover, aortic stiffness was evaluated by non-invasive carotid-femoral pulse wave velocity (c-f PWV) measurement.

RESULTS

Hypertensives compared with normotensives exhibited greater LV mass index and Amav (110 versus 95 g/m and 10 versus 8.8 cm/s, respectively, P < 0.001 for both cases), and greater c-f PWV (8.47 versus 7.48 m/s, P < 0.03), as well as lower Emav and Emav/Amav values, (8.4 versus 10 cm/s and 0.82 versus 1.15, respectively, P < 0.001 for both cases). In the group of hypertensives, a univariate analysis revealed that c-f PWV was negatively associated with Emav (r = -0.305, P = 0.005), as well as with Emav/Amav ratio (r = -0.437, P < 0.001). Moreover, a multivariate analysis showed that the TDI-derived Emav/Amav ratio was significantly associated with age (P = 0.001), relative wall thickness (P = 0.006) and c-f PWV (P = 0.03), while the conventional Doppler-derived E/A ratio was significantly associated only with age (P = 0.001).

CONCLUSIONS

TDI-detected LV diastolic dysfunction is accompanied by increased aortic stiffness in newly diagnosed essential hypertension, suggesting that there may be a common pathophysiological pathway linking these two entities.

Differences in regional systolic and diastolic function by Doppler tissue imaging in patients with hypertrophic cardiomyopathy and hypertrophy caused by hypertension

OBJECTIVE

Doppler tissue (DT) velocity abnormalities have been described in patients with pathologic left ventricular hypertrophy (LVH). Impaired myocardial function has been suggested as a primary disorder in hypertrophic cardiomyopathy (HCM) and differences in DT parameters have been reported to be distinguishable from other LVH causes. We evaluated DT differences for patients with LVH caused by hypertension and patients with HCM, assessing regional systolic and diastolic function.

METHODS

A total of 62 participants were studied: 21 with HCM; 22 with LVH secondary to hypertension; and 19 control subjects. DT was used to record mitral annulobasal segment motion in the longitudinal axis. Systolic and diastolic velocities were measured at lateral and septal sites, and well-known ratios were obtained for diastolic assessment. A new global function index (GFI) that evaluates both systole and diastole was also calculated (GFI = [Emi/E(DT)]/S(DT) [s x cm(-1)], where mi is mitral inflow, E is E wave, and S is systolic wave).

RESULTS

Comparison showed significant differences in all parameters evaluated at the septal-basal segment and a GFI value of 1.77 showed 85% sensitivity and 75% specificity for detecting HCM when interventricular septum thickness was increased.

CONCLUSIONS

In the presence of unexplained LVH, markedly decreased DT velocities at basal septum efficiently detect myocardial dysfunction at this segment, and a calculated GFI > 1.77 strongly supports the diagnosis of HCM.

Doppler tissue imaging: regional myocardial function in hypertrophic cardiomyopathy and in athlete's heart

BACKGROUND

The distinction between hypertrophic cardiomyopathy (HCM) and the athlete's (AT) heart is an important clinical problem, and the analysis of regional myocardial function with Doppler tissue imaging may be useful in the differential diagnosis.

OBJECTIVE

Our aim was to compare regional function assessed by Doppler tissue imaging in rowers and in a group of patients with HCM.

METHODS

In 24 patients with nonobstructive HCM and in 20 competitive rowers with similar age, blood pressure, and heart rate, we analyzed with pulsed Doppler tissue imaging left ventricular (LV) regional function (velocities, time intervals, heterogeneity and asynchrony indices, and meridional gradient) in the longitudinal (8 segments, apical views) and in the radial (2 segments, short-axis view) axis.

RESULTS

Compared with AT, patients with HCM showed: (1). systolic function; (a). longitudinal: lower velocities and meridional gradient; longer precontraction period (PCP); and higher PCP/LV contraction time; (b). radial: lower velocities and gradient; longer PCP; and higher PCP/LV contraction time; (2.diastolic function; (a). logitudinal: lower e (early diastolic), a (late diastolic), and e/a velocities; and longer prerelaxation time and time to peak e. The percentage of segments with e/a < 1 was 25% in the HCM group and 0% in the AT heart group; (b). radial: lower e velocity and gradient; lower e/a gradient; and longer medial prerelaxation and basal time to peak e. Most of these differences also occurred in the nonhypertrophied inferior wall of patients with HCM.

CONCLUSIONS

There are significant differences between regional LV function of competitive rowers and patients with HCM. These differences (1). occur in systole and diastole; (2). affect velocities and time intervals; (3). are more striking in the long axis, but are also seen in the short axis, and (4). also occur in nonhypertrophied segments, suggesting the usefulness of the technique in the differential diagnosis between the 2 situations, namely in individuals that fall in Maron's "grey zone."

Regional left ventricular function during transient coronary occlusion: relation with coronary collateral flow

OBJECTIVE

To test the hypothesis that regional left ventricular (LV) function during balloon angioplasty is related to the amount of collateral flow to the ischaemic region.

DESIGN

Prospective study.

SETTING

Tertiary referral centre.

METHODS

In 50 patients with coronary artery disease and without myocardial infarction, regional systolic and diastolic LV function was determined using tissue Doppler ultrasound (TD) before and at the end of a 60 second occlusion of a stenotic lesion undergoing percutaneous transluminal coronary angioplasty (PTCA) through a pressure guidewire. The study population was subdivided into a group with collaterals insufficient (n = 33) and one with collaterals sufficient (n = 17) to prevent ECG ST shifts suggestive of myocardial ischaemia during PTCA. Pulsed TD was performed from an apical window in the myocardial region supplied by the vessel being treated by PTCA. Pressure derived collateral flow index (CFI) was determined by simultaneous measurement of mean aortic (P(ao)) and distal intracoronary occlusive pressures (P(occl)), where CFI = (P(occl) - 8)/(P(ao) - 8).

RESULTS

At 60 seconds of occlusion, several parameters of systolic and diastolic TD derived LV long axis function were significantly different between the groups. Also, there was a significant correlation between regional systolic excursion velocity, early diastolic excursion velocity, regional isovolumetric relaxation time, and CFI.

CONCLUSION

During brief coronary artery occlusions, regional systolic and diastolic LV function is directly related to the amount of collateral flow to this territory.

Diastolic dysfunction in hypertension

Heart failure is one of the most common causes of cardiovascular morbidity and mortality, and hypertension is the most common cause of cardiac failure. Recent studies have shown that isolated diastolic dysfunction very often accompanies hypertensive heart disease. Ventricular diastolic function may be divided into an active relaxation phase and a passive compliance period. These two components have been investigated invasively, and they remain the gold standards for the study of diastolic function. However, in the routine clinical setting, echocardiographic and Doppler techniques are most useful for evaluating ventricular filling. Thus, analysis of E and A waves of mitral flow have provided important and useful information. Unfortunately, these indices depend on too many factors. Newer indices obtained from ventricular time intervals, tissue Doppler imaging, and color M-mode echocardiography have enhanced the means to assess diastolic function. In addition, new methods including MRI and cine CT have also provided better understanding of left ventricular filling in hypertension. Using these techniques, diastolic dysfunction has been found to be common in patients with hypertension, even before left ventricular hypertrophy is demonstrable and before hypertension in young, normotensive male offspring of hypertensive parents has developed. Furthermore, it has been made clear recently that myocardial ischemia and fibrosis are two important factors associated with diastolic dysfunction in hypertension.