Progressive left ventricular remodeling in patients with hypertrophic cardiomyopathy and severe left ventricular hypertrophy

Implication of sleep apnea for cardiac remodeling in patients with hypertrophic cardiomyopathy

OBJECTIVES

Cardiac remodeling is a life-long process in hypertrophic cardiomyopathy (HCM), and if uncontrolled, would cause substantial morbidity and mortality. Sleep apnea (SA) is a common comorbidity in HCM. This study aimed to investigate the relationship between SA and cardiac remodeling in a large series of patients with HCM.

METHODS

A total of 606 patients with HCM who underwent sleep evaluations at Fuwai Hospital were included. Parameters of cardiac remodeling were evaluated by echocardiographic studies.

RESULTS

SA was present in 363 (59.9%) patients. Left ventricular (LV) end-diastolic diameter (P < 0.001), left atrial (LA) diameter (P = 0.024), ascending aortic diameter (P < 0.001) all increased and maximal end-diastolic wall thickness (P < 0.001) decreased with the severity of SA. After adjustment for sex, age, body mass index, hypertension, hyperlipidemia, diabetes, coronary artery disease and cigarette use, log (apnea-hypopnea index+1) was independently correlated with increasing LV end-diastolic diameter (β = 0.729, P = 0.003) and deceasing maximal end-diastolic wall thickness (β = -0.503, P = 0.009). Log (percentage of total sleep time spent with oxygen saturation<90% + 1) was independently correlated with increasing LV end-diastolic diameter (β = 0.609, P = 0.004) and LA diameter (β = 0.695, P = 0.006). Severity of SA (severe SA with odds ratio, 2.38; 95% CI, 1.20-4.70; P = 0.013), log (apnea-hypopnea index+1) (OR, 1.28; 95% CI, 1.01-1.63; P = 0.045) and log (percentage of total sleep time spent with oxygen saturation<90% + 1) (OR, 1.31; 95% CI, 1.08-1.59; P = 0.006) were also independently associated with LV enlargement.

CONCLUSIONS

Severity of SA is independently associated with cardiac remodeling indicating a trend toward enlarged chamber size and thinned wall. Clinical trials are required to determine whether treatment of SA improves cardiac remodeling and long-term outcomes in patients with HCM.

Role and Clinical Importance of Progressive Changes in Echocardiographic Parameters in Predicting Outcomes in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

The prognostic utility of follow-up transthoracic echocardiography (FU-TTE) in patients with hypertrophic cardiomyopathy (HCM) is unclear, specifically in terms of whether changes in echocardiographic parameters in routine FU-TTE parameters are associated with cardiovascular outcomes.

METHODS

From 2010 to 2017, 162 patients with HCM were retrospectively enrolled in this study. Using echocardiography, HCM was diagnosed based on morphological criteria. Patients with other diseases that cause cardiac hypertrophy were excluded. TTE parameters at baseline and FU were analyzed. FU-TTE was designated as the last recorded value in patients who did not develop any cardiovascular event or the latest exam before event development. Clinical outcomes were acute heart failure, cardiac death, arrhythmia, ischemic stroke, and cardiogenic syncope.

RESULTS

Median interval between the baseline TTE and FU-TTE was 3.3 years. Median clinical FU duration was 4.7 years. Septal trans-mitral velocity/mitral annular tissue Doppler velocity (E/e'), tricuspid regurgitation velocity, left ventricular ejection fraction (LVEF), and left atrial volume index (LAVI) at baseline were recorded. LVEF, LAVI, and E/e' values were associated with poor outcomes. However, no delta values predicted HCM-related cardiovascular outcomes. Logistic regression models incorporating changes in TTE parameters had no significant findings. Baseline LAVI was the best predictor of a poor prognosis. In survival analysis, an already enlarged or increased size LAVI was associated with poorer clinical outcomes.

CONCLUSIONS

Changes in echocardiographic parameters extracted from TTE did not assist in predicting clinical outcomes. Cross-sectionally evaluated TTE parameters were superior to changes in TTE parameters between baseline and FU at predicting cardiovascular events.

Global Research Trends on Ventricular Remodeling: A Bibliometric Analysis From 2012 to 2022

Ventricular remodeling is the progressive pathologic change of the original substance and morphology of the ventricle caused by various injuries and has attracted increasing attention in the past decade. This study aims to conduct a bibliometric analysis of articles on ventricular remodeling published in the Web of Science Core Collection database from 2012 to 2022 to understand the current research state in the field of ventricular remodeling and provide insights for clinicians and researchers. As a result, a total of 1710 articles on ventricular remodeling were included. Annual publications have been gradually increasing and have remained at a high level over the past 10 years. The United States of America contributed the most publications, followed by China. Circulation was the most mainstream and authoritative journal focusing on ventricular remodeling. Research hotspot analysis suggested that myocardial infarction was the primary risk factor for ventricular remodeling, and emerging risk factor studies have focused on pulmonary hypertension, aortic stenosis, and diabetes. The mechanisms in the pathogenesis of ventricular remodeling were mainly closely associated with inflammation, apoptosis, oxidative stress, and myocardial fibrosis. Intensive investigation of the interactions between different mechanisms might be a future research direction. In terms of treatment, cardiac resynchronization therapy was a hot topic of research. These findings can help researchers grasp the research status of ventricular remodeling and determine future research directions.

Temporal Changes in Cardiac Morphology and Its Relationship with Clinical Characteristics and Outcomes in Patients with Hypertrophic Cardiomyopathy

In this study, we aimed to assess a large cohort of nonapical hypertrophic cardiomyopathy (HC) patients who have undergone 2 serial cardiac magnetic resonance studies to examine morphological dynamics and their correlation to patient characteristics and clinical outcomes. A total of 214 patients with nonapical HC were enrolled in this study, with 2 sequential cardiac magnetic resonance studies separated by a mean interval of 4.8 ± 2.1 years. Progression of indexed left ventricular mass (LVMI) was correlated with lower LVMI at baseline (p <0.00001) and older age >50 years. In terms of maximal wall thickness (MWT), progression was associated with lower baseline MWT and with the presence of LV outflow tract obstruction. No association was demonstrated between the degree of progression of LVMI or MWT and baseline LV volumes, the severity of mitral regurgitation, gender, or the presence of pathogenic HC variants. Progression of left atrial size was significantly associated with the development of atrial fibrillation (p = 0.014; odds ratio 1.18, confidence interval 1.03 to 1.35) and admission for heart failure (p = 0.018; odds ratio 1.18, confidence interval 1.03 to 1.36). No correlation was demonstrated between changes in LV mass or MWT and clinical outcomes of admission for heart failure, progression to New York Heart Association 2/3, progression to end-stage HC, or implantable cardioverter-defibrillator implantation. In conclusion, our study provides novel insights into the natural history of HC from a morphological perspective. It shows that HC is a dynamic disease in which LV morphology and hypertrophy extent change over time, with the presence of risk factors associated with disease progression.

Very long-term prognosis in patients with hypertrophic cardiomyopathy: a longitudinal study with a period of 20 years

AIMS

We aim to clarify the prognosis on patients with hypertrophic cardiomyopathy (HCM) for a follow-up period of more than 10 years.

METHODS AND RESULTS

We retrospectively analysed 102 consecutive patients with HCM diagnosed by 31 December 2000. Complete and detailed clinical records were obtained for 93 (91%) of the 102 patients. Sixty-three (68%) of the 93 patients were men, and the mean age of the patients at the initial evaluation was 51.5 ± 13.0 years. During the mean follow-up period of 19.6 ± 8.1 years (median 20.1 years), HCM-related deaths occurred in 20 patients (21% [1.1%/year]). HCM-related adverse events (including HCM-related deaths and nonfatal HCM-related events: hospitalization for heart failure, embolic stroke admission, and sustained ventricular tachycardia with haemodynamic instability or appropriate implantable cardioverter-defibrillator discharge) occurred in 45 patients (48%). The first HCM-related adverse events occurred in approximately 20% of the patients in every decade, the first decade to the third decade, from the initial evaluation. Forty-seven patients (51%) had documentation of atrial fibrillation at the last follow-up. There were seven patients in the end-stage HCM group at the initial evaluation, and 22 patients (24%) had progression to end-stage HCM during the follow-up period.

CONCLUSIONS

In our cohort of patients, HCM-related mortality was relatively favourable. However, approximately half of the patients suffered from HCM-related adverse events during the follow-up period of 20 years. It is important for HCM patients to be carefully followed up over the long-term because HCM is a lifelong disease.

Impact of cibenzoline treatment on left ventricular remodelling and prognosis in hypertrophic obstructive cardiomyopathy

Aims

This study aimed to elucidate the long‐term effect of cibenzoline therapy on cardiovascular complications and prognosis in patients with hypertrophic obstructive cardiomyopathy (HOCM).

Methods and results

Eighty‐eight patients with HOCM were treated with cibenzoline (Group A), and 41 patients did not receive cibenzoline (Group B). The changes in left ventricular (LV) remodelling, incidences of cardiovascular complications and deaths, were examined. The mean follow‐up period was 15.8 ± 5.6 years in Group A and 17.8 ± 7.2 years in Group B. In Group A, the LV pressure gradient (LVPG) decreased immediately after treatment, and the reduction was maintained throughout the study. In Group B, the LVPG decreased gradually according to the deterioration of LV function. LV reverse remodelling was confirmed in Group A, and LV remodelling advanced in Group B. In Group A, the incidence of each cardiovascular complication was <10%. Only one patient experienced LV heart failure (LVHF). LVHF incidence and atrial fibrillation were higher in Group B than those in Group A (P < 0.0001). The incidence of death was 20.5% in Group A and 90.2% in Group B (P < 0.0001). The most frequent cause of death was sudden cardiac death (SCD) (38.9%) in Group A and LVHF (67.6%) in Group B. The incidence of SCD showed no significant difference between the two groups. The cumulative cardiac survival rate was higher in Group A than that in Group B (P < 0.0001).

Conclusions

Cibenzoline treatment significantly reduced all cardiovascular complications and death due to LVHF and may be a promising treatment in patients with HOCM.

Left Ventricular Remodeling in Hypertrophic Cardiomyopathy: An Overview of Current Knowledge

While most patients with hypertrophic cardiomyopathy (HCM) show a relatively stable morphologic and clinical phenotype, in some others, progressive changes in the left ventricular (LV) wall thickness, cavity size, and function, defined, overall, as “LV remodeling”, may occur. The interplay of multiple pathophysiologic mechanisms, from genetic background to myocardial ischemia and fibrosis, is implicated in this process. Different patterns of LV remodeling have been recognized and are associated with a specific impact on the clinical course and management of the disease. These findings underline the need for and the importance of serial multimodal clinical and instrumental evaluations to identify and further characterize the LV remodeling phenomenon. A more complete definition of the stages of the disease may present a chance to improve the management of HCM patients.

Predicting the clinical course in hypertrophic cardiomyopathy using thallium-201 myocardial scintigraphy

Aims

This study aimed to evaluate the changes in left ventricular remodelling with time in patients with hypertrophic cardiomyopathy (HCM) using thallium‐201 myocardial scintigraphy.

Methods and results

Forty‐eight patients with HCM participated in the study. The extent score (ES) and a newly devised index termed the ‘mean count change’ (MCC) were used to evaluate the myocardial perfusion defects. Using the amount of thallium‐201 uptake (TU), MCC (%) was calculated using the following formula: (last TU − initial TU)∕initial TU × 100. To confirm the site of the lesion, the left ventricle was divided into five segments: anterior, septal, inferior, lateral, and apex. Cardiovascular complications and deaths were recorded. The mean follow‐up period was 8.6 ± 2.0 years. ES increased from 17.4 ± 13.7% to 44.0 ± 22.3% (P < 0.0001). MCC increased from 0% to 12.0 ± 9.0% (P < 0.0001). The apex was the most frequent site of lesion. Twenty‐seven patients (56.3%) had experienced left ventricular heart failure (LVHF). Both ES and MCC were greater in patients with LVHF than in those without LVHF. An overlap between the two groups was greater in ES than in MCC. Patients with LVHF had a higher incidence of atrial fibrillation and apoplexy. Nineteen patients (39.6%) died during the study period; 14 died from LVHF, 3 from sudden cardiac death, and 2 from cancer.

Conclusions

Thallium‐201 myocardial scintigraphy is useful for detecting the severity of myocardial damage and for confirming the lesion site in patients with HCM. MCC may be superior to ES in the evaluation of these changes with time.

H3K27ac acetylome signatures reveal the epigenomic reorganization in remodeled non-failing human hearts

BACKGROUND

H3K27ac histone acetylome changes contribute to the phenotypic response in heart diseases, particularly in end-stage heart failure. However, such epigenetic alterations have not been systematically investigated in remodeled non-failing human hearts. Therefore, valuable insight into cardiac dysfunction in early remodeling is lacking. This study aimed to reveal the acetylation changes of chromatin regions in response to myocardial remodeling and their correlations to transcriptional changes of neighboring genes.

RESULTS

We detected chromatin regions with differential acetylation activity (DARs; Padj. < 0.05) between remodeled non-failing patient hearts and healthy donor hearts. The acetylation level of the chromatin region correlated with its RNA polymerase II occupancy level and the mRNA expression level of its adjacent gene per sample. Annotated genes from DARs were enriched in disease-related pathways, including fibrosis and cell metabolism regulation. DARs that change in the same direction have a tendency to cluster together, suggesting the well-reorganized chromatin architecture that facilitates the interactions of regulatory domains in response to myocardial remodeling. We further show the differences between the acetylation level and the mRNA expression level of cell-type-specific markers for cardiomyocytes and 11 non-myocyte cell types. Notably, we identified transcriptome factor (TF) binding motifs that were enriched in DARs and defined TFs that were predicted to bind to these motifs. We further showed 64 genes coding for these TFs that were differentially expressed in remodeled myocardium when compared with controls.

CONCLUSIONS

Our study reveals extensive novel insight on myocardial remodeling at the DNA regulatory level. Differences between the acetylation level and the transcriptional level of cell-type-specific markers suggest additional mechanism(s) between acetylome and transcriptome. By integrating these two layers of epigenetic profiles, we further provide promising TF-encoding genes that could serve as master regulators of myocardial remodeling. Combined, our findings highlight the important role of chromatin regulatory signatures in understanding disease etiology.

Impact of Effective Management Strategies on Patients With the Most Extreme Phenotypic Expression of Hypertrophic Cardiomyopathy

Advances in treatment options for hypertrophic cardiomyopathy (HC) have proven effective in many patients for promoting favorable long-term outcomes. Whether this expectation is similar for patients with the most extreme expression of massive left ventricular (LV) hypertrophy, a particularly aggressive form of the disease is unresolved. Of 1,766 consecutive HC patients presenting to Tufts HC Institute (2004 to 2015), 92 were identified with extreme LV wall thickness (30 to 48 mm), and compared with 1,674 HC patients with less marked hypertrophy (13 to 29 mm). Follow-up assessment was over 5.3 ± 3.4 years. Patients with massive LV hypertrophy (n = 92) had higher sudden death event rates (3.0%/year) than did patients with lesser hypertrophy (0.8%/year; p <0.001). In 16 of the 92 patients (17%), potentially lethal ventricular tachyarrhythmia were successfully aborted by primary prevention implantable cardioverter defibrillator (ICD) therapy at 30 ± 13 years (n = 11), or by resuscitated cardiac arrest with external defibrillation (n = 5) and later by secondary prevention interventions (n = 3); no patient experienced arrhythmic sudden death. Aborted sudden death events (3.0%/year) exceeded HC-related mortality by 7-fold (n = 2; 0.4%/year; p <0.001). European Society of Cardiology risk score would have failed to identify 60% of patients with arrhythmic sudden death events, leaving them exposed to sudden death without ICDs. In addition, 35 patients required surgical myectomy for progressive heart failure due to LV outflow obstruction (improved to NYHA I/II in 30). Eighty-eight (96%) of the 92 patients have survived to age 38 ± 14 years (23% ≥ 50 years). All-cause mortality did not differ from an age and gender-matched general population (p = 0.62). In conclusion, in this referral-based population, patients with the most extreme expression of HC are at increased arrhythmic sudden death risk reliably prevented with prophylactic ICDs. Progressive heart failure secondary to outflow obstruction was reversible with surgical myectomy. Despite extreme phenotypic expression, with contemporary treatment interventions young HC patients have an opportunity to achieve extended survival with good quality of life.

Progression of myocardial fibrosis in hypertrophic cardiomyopathy: mechanisms and clinical implications

Aims

Myocardial fibrosis as detected by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) is a powerful prognostic marker in hypertrophic cardiomyopathy (HCM) and may be progressive. The precise mechanisms underlying fibrosis progression are unclear. We sought to assess the extent of LGE progression in HCM and explore potential causal mechanisms and clinical implications.

Methods and results

Seventy-two HCM patients had two CMR (CMR1-CMR2) at an interval of 5.7 ± 2.8 years with annual clinical follow-up for 6.3 ± 3.6 years from CMR1. A combined endpoint of heart failure progression, cardiac hospitalization, and new onset ventricular tachycardia was assessed. Cine and LGE imaging were performed to assess left ventricular (LV) mass, function, and fibrosis on serial CMR. Stress perfusion imaging and cardiac energetics were undertaken in 38 patients on baseline CMR (CMR1). LGE mass increased from median 4.98 g [interquartile range (IQR) 0.97–13.48 g] to 6.30 g (IQR 1.38–17.51 g) from CMR1 to CMR2. Substantial LGE progression (ΔLGE ≥ 4.75 g) occurred in 26% of patients. LGE increment was significantly higher in those with impaired myocardial perfusion reserve (<MPRI 1.40) and energetics (phosphocreatine/adenosine triphosphate <1.44) on baseline CMR (P ≤ 0.01 for both). Substantial LGE progression was associated with LV thinning, increased cavity size and reduced systolic function, and conferred a five-fold increased risk of subsequent clinical events (hazard ratio 5.04, 95% confidence interval 1.85–13.79; P = 0.002).

Conclusion

Myocardial fibrosis is progressive in some HCM patients. Impaired energetics and perfusion abnormalities are possible mechanistic drivers of the fibrotic process. Fibrosis progression is associated with adverse cardiac remodelling and predicts an increased risk of subsequent clinical events in HCM.

High-Intensity Interval Training is Associated with Improved Long-Term Survival in Heart Failure Patients

This matched-control cohort study explored the effects of high-intensity interval training (HIIT) on left ventricle (LV) dimensions and survival in heart failure (HF) patients between 2009 and 2016. HF patients who underwent the multidisciplinary disease management program (MDP) were enrolled. Non-exercising participants, aged (mean (95% confidence interval)) 62.8 (60.1–65.5) years, were categorized as the MDP group (n = 101). Participants aged 61.5 (58.7–64.2) years who had completed 36 sessions of HIIT were treated as the HIIT group (n = 101). Peak oxygen consumption (VO_2peak) and LV geometry were assessed during the 8-year follow-up period. The 5-year all-cause mortality risk factors and overall survival rates were determined in the longitudinal observation. An increased VO_2peak of 14–20% was observed in the HIIT group after exercise training. Each 1-mL/kg/min increase in VO_2peak conferred a 58% improvement in 5-year mortality. Increased LV end-systolic diameter (LVESD) was significantly (p = 0.0198) associated with increased mortality. The 8-month survival rate was significantly improved (p = 0.044) in HIIT participants compared to non-exercise participants. HF patients with VO_2peak ≥14.0 mL/kg/min and LVESD <44 mm had a significantly better 5-year survival rate (98.2%) than those (57.3%) with lower VO_2peak and greater LVESD. Both HIIT-induced increased VO_2peak and decreased LVESD are associated with improved survival in HF patients.

Long-Term Left Ventricular Remodeling of Patients With Hypertrophic Cardiomyopathy

In hypertrophic cardiomyopathy (HC), a process of left ventricular (LV) remodeling carrying an adverse prognosis has been described. Conversely, a gradual and benign LV wall thinning has been suggested but never investigated. Therefore, we studied a HC cohort over a long period of time to evaluate the occurrence of a LV remodeling with a benign clinical course. Data of HC patients aged 18 to 65 years and without any condition known to influence LV remodeling were analyzed over a mean follow-up of 7.6 ± 5.7 years. Of 231 HC patients (65% males, mean age 46 ± 12 years), 47 (20%) developed LV remodeling, of whom 23 (10%) had a thinning ≥15% of LV maximal wall thickness from baseline without systolic dysfunction (MWT thinning); 13 (6%) progressed to a LV ejection fraction <50% (end-stage HC) and 11 (5%) developed an apical aneurysm. Follow-up length (odds ratio 1.07, 95% confidence interval 1.00 to 1.15, p = 0.06) and maximal LV wall thickness at baseline (odds ratio 1.14, 95% confidence interval 1.04 to 1.25, p = 0.004) were the main predictors of MWT thinning. Compared with patients with end-stage HC and apical aneurysm, those with MWT thinning showed lower HC-related morbidity (92% and 36% vs 22%, p = 0.003) and mortality (31% and 27% vs 4%, p = 0.02). Furthermore, they showed a combined HC-related morbidity and mortality similar to patients without LV remodeling (incidence 29/1000 vs 26/1000 patient-year, p = 0.77). In conclusion, a process of LV wall thinning with a benign outcome can occur over the long term in patients with HC. The prognostic importance of LV remodeling varies in relation to the different changes in LV morphology and function.

Long-Term Prognosis after Myectomy in Hypertrophic Obstructive Cardiomyopathy with Severe Left Ventricular Hypertrophy

Objectives: Patients with hypertrophic obstructive cardiomyopathy (HOCM) and severe left ventricular hypertrophy (maximal left ventricular wall thickness ≥30 mm) are at high risk of sudden cardiac death (SCD). In this study, we aimed to determine whether HOCM patients with severe hypertrophy had a lower incidence of SCD after myectomy. Methods: HOCM patients with severe hypertrophy were consecutively enrolled from Fuwai Hospital in China between 2000 and 2013. Long-term outcomes were retrospectively compared between the 2 groups, namely the myectomy group and medical group. Results: A total of 244 patients (118 in the myectomy group and 126 in the medical group) were involved. The mean follow-up durations for the myectomy and medical groups were 5.07 ± 3.73 and 6.23 ± 4.15 years, respectively. During the follow-up period, the annual cardiovascular mortality rate was 0.84% in the myectomy group and 2.04% in the medical group (p = 0.041). The annual SCD rate was 0.33% in the myectomy group and 1.40% in the medical group (p = 0.040). Multivariate Cox regression analysis showed that myectomy was independently associated with lower rates of cardiovascular death and SCD. Conclusions: In HOCM patients with severe hypertrophy, those that underwent myectomy had a lower risk of cardiovascular death and SCD than those treated with medicines only.

The Muscle-Bound Heart

Hypertrophic cardiomyopathy (HCM) is a familial cardiac disease manifested in a wide phenotype and diverse genotype and, thus, presenting unpredictable risks mainly on young adults. Extensive studies are being conducted to categorize patients and link phenotype with genotype for a better management and control of the disease with all its complications. Because the full mechanisms behind HCM are still not revealed, therapeutics are not definitive. Further research is to be conducted for the generation of a complete picture and directed therapy for HCM.

A Novel Founder Mutation in MYBPC3: Phenotypic Comparison With the Most Prevalent MYBPC3 Mutation in Spain

INTRODUCTION AND OBJECTIVES

Mutations in MYBPC3 are the cause of hypertrophic cardiomyopathy (HCM). Although most lead to a truncating protein, the severity of the phenotype differs. We describe the clinical phenotype of a novel MYBPC3 mutation, p.Pro108Alafs*9, present in 13 families from southern Spain and compare it with the most prevalent MYBPC3 mutation in this region (c.2308+1 G>A).

METHODS

We studied 107 relatives of 13 index cases diagnosed as HCM carriers of the p.Pro108Alafs*9 mutation. Pedigree analysis, clinical evaluation, and genotyping were performed.

RESULTS

A total of 54 carriers of p.Pro108Alafs*9 were identified, of whom 39 had HCM. There were 5 cases of sudden death in the 13 families. Disease penetrance was greater as age increased and HCM patients were more frequently male and developed disease earlier than female patients. The phenotype was similar in p.Pro108Alafs*9 and in c.2308+1 G>A, but differences were found in several risk factors and in survival. There was a trend toward a higher left ventricular mass in p.Pro108Alafs*9 vs c.2308+1G>A. Cardiac magnetic resonance revealed a similar extent and pattern of fibrosis.

CONCLUSIONS

The p.Pro108Alafs*9 mutation is associated with HCM, high penetrance, and disease onset in middle age.

Clinical correlates of autonomic response during tilting test in hypertrophic cardiomyopathy

AIMS

The aim is to investigate autonomic nervous system imbalance in hypertrophic cardiomyopathy (HCM) by combining echocardiographic morphological and functional parameters with the analysis of the autonomic responses to orthostatic stress.

METHODS

A 10-min tilting test and a transthoracic echocardiogram focused on ventricular septal systolic (S wave) and diastolic function (isovolumic relaxation time) were performed. Low frequency on high frequency ratio (LF/HF) and RR variation (variation of beat to beat intervals) in response to passive orthostatism were used as measures of sympathetic reflex activation [delta LF/HF (D-LF/HF) and delta RR (DRR), respectively]. Brain natriuretic peptide was measured.

RESULTS

A total of 50 HCM patients were categorized in two groups: D-LF/HF more than 0 (group 1, sympathetic response) and D-LF/HF 0 or less (group 2, parasympathetic response). Patients in group 2 had higher New York Heart Association class, a more frequent history of atrial fibrillation (38 versus 9% P = 0.04) or syncope (46 versus 12% P = 0.01) and an increased septal isovolumic relaxation time (122 versus 82 ms P = 0.02). The same categorization was made according to lowest quartile DRR (DRR at least 23 ms, group 1: sympathetic response; DRR less than 23 ms, group 2: parasympathetic response). In group 2, patients were older, with advanced New York Heart Association class and higher history of atrial fibrillation.

CONCLUSIONS

Autonomic response to passive orthostatism in HCM appears correlated with specific functional features of the hypertrophic heart. Altered neural afferent traffic from the localized area of segmental hypertrophy resulted in autonomic changes with a blunted sympathetic response, and an inappropriate vagal activation, especially in patients with history of atrial fibrillation or syncope.

Elevated Cardiac Enzymes in Hypertrophic Cardiomyopathy Patients With Heart Failure - A 20-Year Prospective Follow-up Study

BACKGROUND

To better understand the evolution of typical hypertrophic cardiomyopathy (HCM) to heart failure (HF), we investigated the relationship between serum biochemical abnormalities and changes in left ventricular (LV) remodeling.

METHODS AND RESULTS

Seventy-seven HCM patients were followed for 20 years. Creatine kinase (CK), CK-MB, lactate dehydrogenase (LDH), LDH-1, troponin T and myosin light chain-1 (MLC-1) were measured. Abnormal CK-MB elevation was observed in 64% of HCM patients. LDH-1 was not significantly different compared with the control subjects. Troponin T elevation was observed in 3 HCM patients and MLC-1 elevation was not observed. According to median CK-MB, HCM patients were divided into 2 groups: group H (CK-MB ≥2.5%, n=33) and group L (CK-MB <2.5%, n=44). During the follow-up period in group H, LV end-diastolic dimension increased (P<0.0001), fractional shortening decreased (P<0.0004), and left atrial dimension increased (P<0.0001). The markers reflecting LV hypertrophy were significantly decreased. In group L, LV end-diastolic dimension increased (P<0.02) and left atrial dimension increased (P<0.0001). HF was observed in 18 patients in group H and in 4 in group L. There were 14 HF deaths in group H and 2 in group L, and 3 sudden cardiac deaths in group H.

CONCLUSIONS

Persistent elevation of cardiac enzymes in HCM patients indicates ongoing myocardial injury, ultimately resulting in death by HF.

The Prevalence and Long-Term Outcomes of Extreme Right versus Extreme Left Ventricular Hypertrophic Cardiomyopathy

OBJECTIVES

Extreme left ventricular hypertrophy (LVH) is a known risk factor for sudden cardiac death in hypertrophic cardiomyopathy (HCM). Extreme right ventricular hypertrophy (RVH) is rare, and whether it is linked to a poor outcome is unknown. This study was designed to investigate differences between HCM patients with extreme RVH and those with extreme LVH.

METHODS

Among 2,413 HCM patients, 31 with extreme RVH (maximum right ventricular wall thickness ≥ 10 mm) and 194 with extreme LVH (maximum left ventricular wall thickness ≥ 30 mm) were investigated. The main clinical features and natural history were compared between the 2 groups.

RESULTS

The prevalence of extreme RVH and extreme LVH was 1.3 and 8.0%, respectively. Patients with extreme RVH tended to be younger and female (p < 0.01). Cardiovascular-related mortality and morbidity within 10 years were significantly greater in the extreme RVH group (p < 0.05). Multivariate analysis demonstrated 3 independent predictors for cardiovascular mortality - extreme RVH, left ventricular end-diastolic dimension ≥ 50 mm, and age ≤ 18 years at baseline - and 2 for morbidity - extreme RVH and presyncope.

CONCLUSIONS

Compared with extreme LVH, extreme RVH was quite uncommon in HCM and had a worse prognosis. A right ventricle examination should be performed in routine HCM evaluation.

MR Imaging in Hypertrophic Cardiomyopathy: From Magnet to Bedside

Hypertrophic cardiomyopathy ( HCM hypertrophic cardiomyopathy ), the most common genetically transmitted cardiac disorder, has been the focus of extensive research over the past 50 years. HCM hypertrophic cardiomyopathy is a multifaceted disease with highly heterogeneous genetic background, phenotypic expression, clinical presentation, and long-term outcome. Though most patients have an indolent course with a life expectancy comparable to that of the general population, early diagnosis and accurate risk profiling are essential to identify the sizeable subset at increased risk of sudden cardiac death or disease progression and heart failure-related complications, requiring aggressive management options. Imaging has a central role in the diagnosis and prognostic assessment of HCM hypertrophic cardiomyopathy patients, as well as screening of potentially affected family members. In this context, magnetic resonance (MR) imaging has recently emerged as an ideal complement to transthoracic echocardiography. Its multiparametric approach, fusing spatial, contrast, and temporal resolution, provides the clinician with detailed characterization of the HCM hypertrophic cardiomyopathy phenotype and assessment of its functional consequences including causes and site of dynamic obstruction, presence and extent of myocardial perfusion abnormalities, and fibrosis. Moreover, MR is key in differentiating HCM hypertrophic cardiomyopathy from "phenocopies"-that is, hearts with similar morphology but profoundly different etiology, such as amyloid or Anderson-Fabry disease. Long term, the incremental information provided by MR is relevant to planning of septal reduction therapies, identification of the early stages of end-stage progression, and stratification of arrhythmic risk. The aim of this review is to depict the increasingly important role of MR imaging in relation to the complexity of HCM hypertrophic cardiomyopathy , highlighting its role in clinical decision making.

TWEAK and NT-proBNP levels predict exercise capacity in hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is characterized by inappropriate hypertrophy, myocyte disarray and increased interstitial fibrosis. The tumour necrosis factor-like weak inducer of apoptosis (TWEAK) is a cell surface cytokine with biological activities including stimulation of cell growth, induction of inflammatory cytokines and stimulation of apoptosis. There are controversial data about the potential role of TWEAK in different cardiovascular pathologies. NT-proBNP is an established biomarker of myocardial wall stress, associated with poor functional class in HCM. We hypothesized that effort capacity in patients with HCM could be related to serum levels of these biomarkers.

MATERIALS AND METHODS

We included 40 haemodynamic stable HCM patients and 53 healthy controls with similar sex and age. We studied exercise capacity by maximal oxygen consumption in a limited treadmill exercise test. TWEAK and NT-proBNP were assayed by ELISA method and automated Elecsys® platform, respectively. We obtained 46 samples of myocardial tissues by septal myectomy in patients with HCM and evaluated myocardial fibrosis, immunoreaction with TWEAK antibody and apoptosis with TUNEL assay.

RESULTS

We found raised TWEAK and NT-proBNP serum levels in patients when compared with control levels (both P < 0.001). In a multivariate analysis, TWEAK and NT-proBNP levels, as well as sex, remained independently associated with the effort capacity (all P < 0.05). We found an association between immunoreaction degree and the degree of myocardial fibrosis (P = 0.021), as well as apoptosis (P = 0.002) in the tissue samples from patients undergoing septal myectomy.

CONCLUSIONS

TWEAK and NT-proBNP levels are biomarkers of disease severity independently associated with the effort capacity in patients with HCM.

Hypertrophic cardiomyopathy: a review

Hypertrophic cardiomyopathy (HCM) is a global disease with cases reported in all continents, affecting people of both genders and of various racial and ethnic origins. Widely accepted as a monogenic disease caused by a mutation in 1 of 13 or more sarcomeric genes, HCM can present catastrophically with sudden cardiac death (SCD) or ventricular arrhythmias or insidiously with symptoms of heart failure. Given the velocity of progress in both the fields of heart failure and HCM, we present a review of the approach to patients with HCM, with particular attention to those with HCM and the clinical syndrome of heart failure.

Comparison of prevalence, clinical course, and pathological findings of left ventricular systolic impairment versus normal systolic function in patients with hypertrophic cardiomyopathy

Impaired left ventricular systolic function (ILVSF) in hypertrophic cardiomyopathy (HC) is a risk factor for sudden death and a determinant of high mortality. We determined its prevalence, clinical parameters, long-term outcome, and pathologic findings of explanted hearts. We retrospectively analyzed 382 patients with HC; ILVSF was characterized by LV ejection fraction <50% at rest and was identified in 24 patients (6.3%). Patients with ILVSF were younger than patients with normal SF (43.5 ± 14.1 vs 55.3 ± 20.4 years, p = 0.001) and had larger LV end-diastolic cavity diameter (53.2 ± 12.2 vs 43.8 ± 6.2 mm, p = 0.001), larger left atrium (51.2 ± 6.5 vs 44.3 ± 8 mm, p <0.001), and lower fractional shortening (30.7 ± 11.1% vs 45.5% ± 10.3%, p <0.001). A combined end point (heart failure death or heart transplantation) was considered. Median follow-up was 3 years (1.2 to 6.3). Fourteen patients with ILVSF (58.3%) had the end point compared to 3 (0.8%) with normal SF (p <0.001). In explanted hearts, fibrosis represented 30.5 ± 12.5% of the left ventricle; we observed a direct correlation between fibrosis and ventricular dilation (r = 0.794, p = 0.001) and an inverse correlation between fibrosis and ejection fraction (r = -0.623, p = 0.023). Number and length density of small arterioles (<50 μm in diameter) were significantly decreased. In conclusion, ILVSF in HC has a poor prognosis and is associated with fibrosis and selective decreased development of small arterioles.

Hypertrophic cardiomyopathy in childhood and adolescence - strategies to prevent sudden death

Clinically overt hypertrophic cardiomyopathy is the most common cause of sudden unexpected death in childhood and has significantly higher sudden death mortality in the 8- to 16-year age range than in the 17- to 30-year age range. A combination of electrocardiographic risk factors (a limb-lead ECG voltage sum >10 mV) and/or a septal wall thickness >190% of upper limit of normal for age (z-score > 3.72) defines a paediatric high-risk patient with great sensitivity. Syncope, blunted blood pressure response to exercise, non-sustained ventricular tachycardia and a malignant family history are additional risk factors. Of the medical treatments used, only beta-blocker therapy with lipophilic beta-blockers (i.e. propranolol, metoprolol or bisoprolol) have been shown to significantly reduce risk of sudden death, with doses ≥ 6 mg/kg BW in propranolol equivalents giving around a tenfold reduction in risk. Disopyramide therapy is a very useful adjunct to beta-blockers to improve prognosis in those patients that have dynamic outflow obstruction in spite of large doses of beta-blocker, and its use in patients with hypertrophic cardiomyopathy is not associated with significant pro-arrhythmia mortality. Calcium-channel blockers increase the risk of heart failure-associated death in hypertrophic cardiomyopathy (HCM) patients with severe generalized hypertrophy and should be avoided in such patients. Amiodarone does not protect against sudden death, and long-term use in children usually has to be terminated because of side effects. Therapy with internal cardioverter defibrillator implantation has high paediatric morbidity, 27% incidence of inappropriate shocks, and does not absolutely protect against mortality but is indicated as secondary prevention or in very high-risk patients.

Does pacemaker implantation provide long-term benefits in severe obstructive hypertrophic cardiomyopathy?

INTRODUCTION AND OBJECTIVES

About 25% of patients with obstructive hypertrophic cardiomyopathy (HCM) remain symptomatic despite optimal medical treatment. Some may benefit from pacemaker implantation. The aim of this study was to determine the effect of pacemaker implantation on the left ventricular outflow tract (LVOT) gradient, the maximum thickness of the left ventricle, and functional capacity.

METHODS

In total, 72 patients with obstructive HCM and incapacitating symptoms underwent pacemaker implantation. Clinical examination, echocardiography (in 61 patients) and treadmill testing (in 34 patients) were performed before and after implantation.

RESULTS

Subjective functional capacity, as assessed using the New York Heart Association (NYHA) classification, improved in 43.1% of patients, but treadmill testing showed no change. There were significant reductions in subaortic gradient, from a median of 87.0 mmHg (interquartile range [IQR] 61.5-115.2 mmHg) to 30.0 mmHg (IQR 18.0-54.5 mmHg; P< .001), and maximum left ventricular thickness, from 22.1+/-4.5 mm to 19.8+/-3.6 mm (P=.001). Univariate analysis identified two factors associated with clinical improvement: female sex (odds ratio [OR]=3.43; P=.020) and functional class III/IV (OR=4.17; P=.009). On multivariate analysis, only functional class III/IV remained a significant predictor (OR=3.12; P=.048).

CONCLUSIONS

In patients with obstructive HCM and incapacitating symptoms, pacemaker implantation reduced the LVOT gradient and the maximum left ventricular thickness, but only 43.1% of patients experienced clinical improvement. The only factor predictive of improvement was advanced NYHA functional class.

Electrocardiographic amplitudes: a new risk factor for sudden death in hypertrophic cardiomyopathy

Aims

Assessment of ECG-features as predictors of sudden death in adults with hypertrophic cardiomyopathy (HCM).

Methods and results

ECG-amplitude sums were measured in 44 normals, 34 athletes, a hospital-cohort of 87 HCM-patients, and 29 HCM-patients with sudden death or cardiac arrest (HCM-CA). HCM-patients with sudden death or cardiac arrest had substantially higher ECG-amplitudes than the HCM-cohort for limb-lead and 12-lead QRS-amplitude sums, and amplitude–duration products (P = 0.00003–P = 0.000002). Separation of HCM-CA from the HCM-cohort is obtained by limb-lead QRS-amplitude sum ≥7.7 mV (odds ratio 18.8, sensitivity 87%, negative predictive value (NPV) 94%, P < 0.0001), 12-lead amplitude–duration product ≥2.2 mV s (odds ratio 31.0, sensitivity 92%, NPV 97%, P < 0.0001), and limb-lead amplitude–duration product ≥0.70 mV s (odds ratio 31.5, sensitivity 93%, NPV 96%, P < 0.0001). Sensitivity in HCM-patients <40 years is 90, 100, and 100% for those ECG-variables, respectively. Qualitative analysis showed correlation with cardiac arrest for pathological T-wave-inversion (P = 0.0003), ST-depression (P = 0.0010), and dominant S-wave in V₄ (P = 0.0048). A risk score is proposed; a score ≥6 gives a sensitivity of 85% but a higher positive predictive value than above measures. Optimal separation between HCM-CA <40 years and athletes is obtained by a risk score ≥6 (odds ratio 345, sensitivity 85%, specificity 100%, P < 0.0001).

Conclusion

Twelve-lead ECG is a powerful instrument for risk-stratification in HCM.

Left atrial remodelling in hypertrophic cardiomyopathy: relation with exercise capacity and biochemical markers of tissue strain and remodelling

BACKGROUND

Left atrial remodelling, assessed as left atrial volume (LAV), has been proposed as a good marker of left ventricular diastolic dysfunction. The aim of this study was to analyse the influence of LAV on exercise performance in hypertrophic cardiomyopathy (HCM), and in a subset of subjects, assess the relation of LAV and exercise performance to four biomarkers of disease pathophysiology: matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) (as indices of tissue remodelling), N-terminal portion of pro B-type natriuretic peptide (NT-pro-BNP) (associated with ventricular dysfunction) and C-reactive protein (CRP, an index of inflammation).

METHODS

We studied 75 consecutive HCM patients (aged 46 +/- 14 years, 56 men) where LAV was calculated assuming the ellipsoid model with two orthogonal planes. LAV was indexed to body surface area. Exercise capacity was evaluated by treadmill exercise test (symptom limited) and assessed with metabolic equivalent units (MET). Basal NT-pro-BNP and CRP levels were measured in 70 patients, whereas MMP-2 and TIMP-1 in 43 patients.

RESULTS

Enlarged LAV was observed in those patients with previous atrial fibrillation (p = 0.016). Mean LAV was greater in patients with impaired functional New York Heart Association (NYHA) class (p < 0.001). LAV correlated with age (Spearman, r: 0.28), higher maximal left ventricular wall thickness (r: 0.32) and raised E/A ratio (r: 0.37) (all p < 0.01). LAV was significantly correlated with NT-pro-BNP values (r: 0.34; p = 0.04), MMP-2 (r: 0.32; p = 0.034), CRP (r: 0.33; p = 0.005) and correlated inversely with MET units (r: -0.39; p < 0.01). In multivariate analysis, MET units were only associated with NT-pro-BNP (p = 0.002) and LAV (p = 0.010).

CONCLUSIONS

Enlarged LAV is associated with impaired functional NYHA class and inversely with treadmill exercise capacity. Enlarged LAV is also associated with NT-pro-BNP, MMP-2 and CRP, perhaps as markers of disease severity and tissue remodelling. Age, LAV and NT-pro-BNP are independent predictors of exercise performance.

Matrix metalloproteinases and tissue remodeling in hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is defined by the presence of unexplained left ventricular hypertrophy, myocyte disarray, and interstitial fibrosis. An increase in extracellular matrix produces interstitial fibrosis, by raised amounts of collagen type I/III. Regions of myocardial late gadolinium enhancement by cardiac magnetic resonance (CMR) represented increased myocardial collagen. Regarding the role of matrix metalloproteinases (MMPs) in myocardial remodeling and subsequent fibrosis, the aim of our study was to explore the relation between MMP system and myocardial late gadolinium enhancement by CMR (as expression of image-documented fibrosis) and N-terminal pro-brain natriuretic peptide (NT-proBNP) (as a marker of cardiac overload) in HCM.

METHODS

We included 67 HCM patients (44 men aged 49 +/- 14 years) and were compared to 58 controls with similar age and sex. Risk factors for sudden death were recorded. A blinded CMR was performed with gadolinium. Matrix metalloproteinase 1, MMP-2, and MMP-9 plasma levels were assayed by enzyme-linked immunosorbent assay. Serum samples were used for measurement of NT-proBNP.

RESULTS

In patients, >50% of MMP-1 values were below the lowest limit of detection of the technique. Raised levels of MMP-2, MMP-9, and NT-proBNP were observed in HCM patients (all P < .01). Matrix metalloproteinase 2 was associated with dyspnea (P = .049) and correlated with MMP-9 (r = 0.28, P = .025) and NT-proBNP (r = 0.39, P = .001). Matrix metalloproteinase 9 was associated with the presence of gadolinium enhancement in CMR (P = .001) and correlated with NT-proBNP (r = 0.52, P < .001). NT-proBNP was also associated with gadolinium enhancement (P = .006). Both MMP-2 and MMP-9 correlated negatively with exercise capacity (metabolic equivalent units), (r = -0.36 and r = -0.42 respectively, both P < .01). On multivariate analysis (adjusted by sudden death risk factors and echocardiographic markers), only MMP-9 was associated with fibrosis (P = .011).

CONCLUSIONS

Matrix metalloproteinase 9 is independently associated with gadolinium enhancement on CMR in patients with hypertrophic cardiomyopathy, suggesting that the MMP system has an important role in cardiac remodeling and fibrosis in this condition.

Increased Brain Natriuretic Peptide Secretion is a Marker of Disease Progression in Nonobstructive Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is associated with increased plasma brain natriuretic peptide (BNP), but sequential plasma and myocardial BNP assessment in stable and dilated HCM has never been performed.

METHODS AND RESULTS

Forty consecutive HCM patients (42 +/- 8 years, 25 males) underwent cardiac catheterization, angiography, and left ventricular (LV) endomyocardial biopsy. During follow-up (70.5 +/- 6.7 months), 30 patients (Group 1) remained stable whereas 10 patients (Group 2) progressed to dilated phase. Group 2 patients underwent a second invasive study with LV biopsy. BNP plasma levels were measured at baseline and at follow-up in all patients. All biopsies were processed for histology and immunohistochemistry with anti-BNP antibodies. BNP plasma levels remained unchanged in Group 1, whereas it significantly increased in all Group 2 patients who exhibited an elevation of LV and right ventricular end-diastolic pressure. Immunohistochemistry showed an increase of BNP-positive myocytes in follow-up biopsies when compared with baseline (75.0 +/- 15.0 % versus 29.8 +/- 10.0 %; P = .005) with a significant correlation with LV end-diastolic pressure (r = 0.78, P < .001) and plasma BNP (r = 0.83, P < .001).

CONCLUSIONS

Progression to end-stage of HCM is characterized by further increase of myocardial and plasma BNP. Serial assessment of plasma BNP may provide noninvasive recognition of hemodynamic deterioration, allowing prompt institution of heart failure therapy.

Prevalence of systolic impairment in an unselected regional population with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HC) may transition to a phase characterized by systolic impairment resembling dilated cardiomyopathy. This study retrospectively assessed the incidence of left ventricular (LV) systolic impairment at initial clinical evaluation in 248 consecutive patients with HC (mean age 53 +/- 16 years). HC with systolic impairment was diagnosed if the LV ejection fraction was <50%, calculated by echocardiography. Twenty patients (8%) had HC with LV systolic impairment at initial evaluation. Patients with systolic impairment had a greater incidence of family histories of sudden cardiac death (SCD) than patients with preserved systolic function (25% vs 5.3%, p = 0.006) and more severe functional limitations (New York Heart Association class >or=III, p <0.001). All-cause mortality and cardiovascular mortality did not differ between the 2 groups. The incidence of SCD was 1.7% in patients with normal LV ejection fractions, and no SCD was observed in patients with systolic impairment. The latter group had more frequent major cardiac events (SCD, ventricular fibrillation, aborted cardiac arrest, and first implantable cardioverter-defibrillator discharge; p = 0.03). During follow-up, 2 patients progressed to HC with systolic impairment (annual incidence 0.85%). In conclusion, systolic impairment is not exceptional in patients with HC at initial evaluation and is associated with functional deterioration and major cardiac events.

New non-invasive approaches for the diagnosis of cardiomyopathy: magnetic resonance imaging

Cardiac magnetic resonance imaging (CMR) permits a detailed look at the myocardium in patients with recent onset heart failure. Late-enhancement CMR provides information that is similar to that obtained by the naked eye of a pathologist. Myocardial scarring is endocardial in myocardial infarction, but it is epicardial in myocarditis and intramyocardial in hypertrophic cardiomyopathy. Thus, the distinction between these entities is possible by depicting scar via late-enhancement CMR and observing myocardial function by cine magnetic resonance imaging. Moreover, non-invasive follow-up--and hence observation of the healing or remodelling process--can be achieved using CMR. New CMR pulse sequences also permit depiction of myocardial oedema, which may occur early in patients with myocarditis and may be the only sign of the disease in the absence of necrosis. It is anticipated that cardiac MRI will become a standard diagnostic technique in patients with new onset of heart failure, left-ventricular hypertrophy or clinical symptoms suggestive of myocarditis.

Age-Related Hemodynamic and Morphologic Differences in Patients Undergoing Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

Alcohol septal ablation (ASA) decreases the left ventricular (LV) outflow gradient and relieves symptoms in patients with highly symptomatic hypertrophic obstructive cardiomyopathy (HOCM). The aim of this study was to evaluate the early course of hemodynamic, morphologic and clinical changes in younger and elderly patients.

METHODS AND RESULTS

Forty-four consecutive patients (age, 24-81 years) underwent the ASA procedure for HOCM. Clinical and echocardiographic data were obtained at baseline and periodically up to 12 months after ASA. There was a significant correlation between septum thickness and age at baseline and in the early post procedural period (p = 0.004 at baseline, p = 0.0033 days postoperative, p = 0.0193 weeks pos operative). The dependence of septal thickness on the duration of follow-up (p < 0.001) was significantly influenced by age (p = 0.026), which retained statistical significance after multivariate adjustment (p = 0.031). A decrease in the gradient of the LV outflow was identified in all age-related groups of patients (p < 0.001). After multivariate adjustment, there was a significant influence of age (p = 0.003) and creatine kinase-MB peak (p = 0.016) on the course of outflow gradient reduction.

CONCLUSIONS

ASA is an effective treatment option for patients with HOCM, irrespective of their age. Younger patients are characterized by a thicker basal septum at baseline and a slower hemodynamic improvement within the early post procedural period.

Lifelong Left Ventricular Remodeling of Hypertrophic Cardiomyopathy Caused by a Founder Frameshift Deletion Mutation in the Cardiac Myosin-Binding Protein C Gene Among Japanese

OBJECTIVES

We studied the longitudinal evolution of hypertrophic cardiomyopathy (HCM) caused by a founder frameshift mutation in the cardiac myosin-binding protein C (MyBPC) gene.

BACKGROUND

Mutations in the MyBPC gene have been associated with delayed expression of HCM and a good prognosis. Few studies, however, demonstrated the phenotype-genotype correlations in the longitudinal study.

METHODS

We studied long-term evolution of clinical features of 15 unrelated families who were found to have an identical frameshift mutation in the MyBPC gene: a one-base deletion of a thymidine at nucleotide 11645 (V592fs/8).

RESULTS

Thirty-nine individuals in 15 families were genotype-positive. Thirty of the 39 individuals with the mutation were phenotype-positive. The disease penetrance was 100% in subjects > or =50 years and 65% in those <50 years. "End-stage" HCM (ejection fraction <50%) was observed in 7 (18%) of the 39 genotype-positive individuals (7 [23%] of the 30 phenotype-positive patients); 6 of them were 60 years or older. Seven patients were hospitalized for treatment of repeated congestive heart failure, and four patients died or had implantable cardioverter-defibrillator discharge (13%; incidence, 1.4%/year) during a mean follow-up period of 9.2 +/- 5.5 years.

CONCLUSIONS

Elderly patients with a V592fs/8 mutation in the MyBPC gene may evolve into the "end-stage" HCM, characterized by left ventricular systolic dysfunction, cavity dilation, and irreversible heart failure. The clinical course in patients with this mutation is not benign in the long run, with progressive left ventricular remodeling with advancing age.

Functional Assessment by Myocardial Performance Index (Tei Index) Correlates With Plasma Brain Natriuretic Peptide Concentration in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) might exhibit not only diastolic, but also latent systolic dysfunction. Therefore combined assessment of both systolic and diastolic function using myocardial performance index (Tei index) can be useful in HCM. Plasma brain natriuretic peptide (BNP) level is reported to be elevated in HCM, but the mechanism of BNP elevation in HCM remains to be established.

METHODS AND RESULTS

The value of Tei index in 45 HCM patients was compared with that of 20 normal control subjects. The HCM patients showed a higher value of Tei index (0.55+/-0.12 vs 0.36+/-0.08, p < 0.0001) and longer isovolumic relaxation and contraction times than control subjects. The plasma BNP level correlated with Tei index in non-obstructive HCM (n = 35, r = 0.61, p < 0.0001), although the correlation was mild when overall HCM patients were included (r = 0.34, p = 0.02). The correlation was still significant after adjusting for age, or the extent and severity of left ventricular hypertrophy. Multiple stepwise regression analysis identified mitral E/A ratio (r = 0.49, F = 13.1) and Tei index (r = 0.37, F = 7.6) as independent predictors of higher plasma BNP level in non-obstructive HCM.

CONCLUSIONS

Myocardial performance index was abnormal in HCM, reflecting both systolic and diastolic dysfunction in this disorder. Plasma BNP level correlated with functional assessment by Tei index in non-obstructive HCM.