Myocardial strain: a clinical review

BACKGROUND

Myocardial strain-change in myocardial fibre length over the cardiac cycle-is a measure of cardiac muscle function. It is obtained using conventional techniques such as echocardiography and magnetic resonance imaging, adding additional clinical information to augment the current techniques.

METHODS

A narrative review of the current relevant literature with respect to myocardial strain, with a focus on strain measured by echocardiography.

RESULTS

Myocardial strain identifies global and regional abnormalities in myocardial function and differentiates types of cardiomyopathy. It is an earlier marker of myocardial disease than ejection fraction and is predictive of cardiovascular adverse events. Accurate measurement requires high-quality images and experienced practitioners.

CONCLUSION

This review explains advantages and disadvantages of myocardial strain imaging and explains why, through adding increased precision without additional burden, it should be a standard part of cardiac assessment.

Long-term Outcomes for Drug-eluting Balloons versus Drug-eluting Stents in the Treatment of Small Vessel Coronary Artery Disease: A Systematic Review and Meta-analysis

Background: This systematic review and meta-analysis compares long-term outcomes follow-up data comparing drug-eluting balloons (DEBs) and drug-eluting stents (DESs) in interventional treatment of small coronary artery disease (<3 mm). Methods: A systematic review was undertaken along with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome was 1-3-year performance of DEB versus DES in major adverse cardiac events. Secondary outcomes include all-cause mortality, MI, cardiac death, vessel thrombosis, major bleeding, target vessel revascularisation and target lesion revascularisation. Two independent reviewers extracted data. All outcomes used the Mantel-Haenszel and random effects models. ORs are presented with a 95% CI. Results: Of 4,661 articles, four randomised control trials were included (1,414 patients). DEBs demonstrated reduced rates of non-fatal MI at 1 year (OR 0.44; 95% CI [0.2-0.94]), and BASKET-SMALL 2 reported a significant reduction in 2-year bleeding rates (OR 0.3; 95% CI [0.1-0.91]). There was no significant difference in all other outcomes. Conclusion: Long-term follow-up of DEB and DES use in small coronary arteries demonstrates DEBs be comparable with DESs in all outcomes at 1, 2 and 3 years of follow-up. A significant reduction was found in rates of non-fatal MI at 1 year in the DEB arm, and a reduction in major bleeding episodes at 2 years in the BASKET-SMALL 2 trial. These data highlight the potential long-term utility of novel DEBs in small coronary artery disease revascularisation.

Predictive value of high-sensitivity troponin for significant coronary artery disease in new-onset atrial fibrillation with rapid ventricular response

BACKGROUND

High-sensitivity troponin-T (HS-cTnT) levels are often measured in patients presenting with atrial fibrillation (AF), with many subjected to unnecessary invasive assessments. The significance of a normal or mildly raised HS-cTnT in this context is poorly understood. This study aimed to determine the predictive value of HS-cTnT for significant coronary artery disease (CAD) in new AF with rapid ventricular response. We also compared the discriminative ability of HS-cTnT to suspected angina for significant CAD.

METHODS

We examined patients presenting with new AF to two tertiary Irish centers in a defined period. Those included had HS-cTnT taken at presentation and subsequent ischemic evaluation.

RESULTS

Of 5350 cases screened for inclusion, 281 were deemed eligible. Of these, 148 and 133 patients had a positive and negative index HS-cTnT, respectively. Of those with negative HS-cTnT, 13 (9.8%) had significant CAD versus 51 (34.5%) with positive HS-cTnT (P < 0.001). Positive Hs-cTnT status remained significant upon multivariate analysis (OR, 2.9; 95% CI, 1.37-6.14; P = 0.005). A similar model where HS-cTnT was replaced with suspected angina produced an OR of 1.64 (95% CI, 0.75-3.59; P = 0.213). A logistic model determined optimal cutoff value for HS-cTnT to be less than 30 ng/l, producing a negative predictive value of 91.8% and area under the receiver operative curve of 83.36.

CONCLUSION

HS-cTnT exhibits potential as an effective screening biomarker to predict nonsignificant CAD in new rapid AF, allowing more targeted and rationalized ischemic testing. HS-cTnT may also be a more accurate predictor of significant CAD than clinically suspected stable angina.Graphical abstract: http://links.lww.com/MCA/A540.

The use of deformation imaging in the assessment of patients pre and post transcatheter aortic valve implantation

BACKGROUND

Deformation imaging represents a method of measuring myocardial function, including global longitudinal strain (GLS), peak atrial longitudinal strain (PALS) and radial strain. This study aimed to assess subclinical improvements in left ventricular function in patients undergoing transcatheter aortic valve implantation (TAVI) by comparing GLS, PALS and radial strain pre and post procedure.

METHODS

We conducted a single site prospective observational study of 25 patients undergoing TAVI, comparing baseline and post-TAVI echocardiograms. Individual participants were assessed for differences in GLS, PALS and radial strain in addition to changes in left ventricular ejection fraction (LVEF) (%).

RESULTS

Our results revealed a significant improvement in GLS (mean change pre-post of 2.14% [95% CI 1.08, 3.20] p = 0.0003) with no significant change in LVEF (0.96% [95% CI - 2.30, 4.22], p = 0.55). There was a statistically significant improvement in radial strain pre and post TAVI (mean 9.68% [95% CI 3.10, 16.25] p = 0.0058). There was positive trend towards improvements in PALS pre and post TAVI (mean change of 2.30% [95% CI - 0.19, 4.80] p = 0.068).

CONCLUSION

In patients undergoing TAVI, measuring GLS and radial strain provided statistically significant information regarding subclinical improvements in LV function, which may have prognostic implications. The incorporation of deformation imaging in addition to standard echocardiographic measurements may have an important role in guiding future management in patients undergoing TAVI and assessing response.

Feasibility study of computational occupational dosimetry: evaluating a proof-of-concept in an endovascular and interventional cardiology setting

Individual monitoring of radiation workers is essential to ensure compliance with legal dose limits and to ensure that doses are As Low As Reasonably Achievable. However, large uncertainties still exist in personal dosimetry and there are issues with compliance and incorrect wearing of dosimeters. The objective of the PODIUM (Personal Online Dosimetry Using Computational Methods) project was to improve personal dosimetry by an innovative approach: the development of an online dosimetry application based on computer simulations without the use of physical dosimeters. Occupational doses were calculated based on the use of camera tracking devices, flexible individualised phantoms and data from the radiation source. When combined with fast Monte Carlo simulation codes, the aim was to perform personal dosimetry in real-time. A key component of the PODIUM project was to assess and validate the methodology in interventional radiology workplaces where improvements in dosimetry are needed. This paper describes the feasibility of implementing the PODIUM approach in a clinical setting. Validation was carried out using dosimeters worn by Vascular Surgeons and Interventional Cardiologists during patient procedures at a hospital in Ireland. Our preliminary results from this feasibility study show acceptable differences of the order of 40% between calculated and measured staff doses, in terms of the personal dose equivalent quantity H_p(10), however there is a greater deviation for more complex cases and improvements are needed. The challenges of using the system in busy interventional rooms have informed the future needs and applicability of PODIUM. The availability of an online personal dosimetry application has the potential to overcome problems that arise from the use of current dosimeters. In addition, it should increase awareness of radiation protection among staff. Some limitations remain and a second phase of development would be required to bring the PODIUM method into operation in a hospital setting. However, an early prototype system has been tested in a clinical setting and the results from this two-year proof-of-concept PODIUM project are very promising for future development.

A case report of ventricular septal defect complicating transcatheter aortic valve implant for aortic regurgitation: novel complication and technical considerations

Background

Transcatheter aortic valve implantation (TAVI) has proven efficacy in the treatment of aortic stenosis (AS). Understandably, there is increasing enthusiasm for its use to treat aortic regurgitation (AR). However, there are significant anatomical differences between AS and AR which make TAVI for AR more complex.

Case summary

We present the case of technically challenging TAVI for severe AR, which was complicated by a traumatic ventricular septal defect (VSD) that required percutaneous closure. To our knowledge, this is the first published case of VSD post-TAVI for AR.

Discussion

This unanticipated complication highlights anatomical differences between TAVI use in AS and AR. Lack of aortic valve calcification and excessive annular compliance made stable deployment of a self-expanding valve extremely challenging. Despite device oversizing, repeated embolization of the prosthesis into the left ventricular outflow tract traumatized the interventricular septum.

Interhospital and interindividual variability in secondary prevention: a comparison of outpatients with a history of chronic coronary syndrome versus outpatients with a history of acute coronary syndrome (the iASPIRE Study)

Background

Studying variability in the care provided to secondary prevention coronary heart disease (CHD) outpatients can identify interventions to improve their outcomes.

Methods

We studied outpatients who had an index CHD event in the preceding 6–24 months. Eligible CHD events included acute coronary syndrome (ACS) and coronary revascularisation for stable chronic coronary syndrome (CCS). Site training was provided by a core team and data were collected using standardised methods.

Results

Between 2017 and 2019, we enrolled 721 outpatients at nine Irish study sites; 81% were men and mean age was 63.9 (SD ±8.9) years. The study examination occurred a median of 1.16 years after the index CHD event, which was ACS in 399 participants (55%) and stable-CCS in 322. On examination, 42.5% had blood pressure (BP) >140/90 mm Hg, 63.7% had low-density lipoprotein cholesterol (LDL-C) >1.8 mmol/L and 44.1% of known diabetics had an HbA1c >7%. There was marked variability in risk factor control, both by study site and, in particular, by index presentation type. For example, 82% of outpatients with prior-ACS had attended cardiac rehabilitation versus 59% outpatients with prior-CCS (p<0.001) and there were also large differences in control of traditional risk factors like LDL-C (p=0.002) and systolic BP (p<0.001) among outpatients with prior-ACS versus prior-CCS as the index presentation.

Conclusions

Despite international secondary prevention guidelines broadly recommending the same risk factor targets for all adults with CHD, we found marked differences in outpatient risk factor control and management on the basis of hospital location and index CHD presentation type (acute vs chronic). These findings highlight the need to reduce hospital-level and patient-level variability in preventive care to improve outcomes; a lesson that should inform CHD prevention programmes in Ireland and around the world.

CT coronary angiography and COVID-19: inpatient use in acute chest pain service

Objectives

CT coronary angiography (CTCA) is a well-validated clinical tool in the evaluation of chest pain. In our institution, CTCA availability was increased in January 2020, and subsequently, expanded further to replace all exercise testing during the COVID-19 pandemic. Our objective was to assess the impact of increased utilisation of CTCA on length of stay in patients presenting with chest pain in the prepandemic era and during the COVID-19 pandemic.

Methods

Study design was retrospective. Patients referred for cardiology review between October 2019 and May 2020 with chest pain and/or dyspnoea were broken into three cohorts: a baseline cohort, a cohort with increased CTCA availability and a cohort with increased CTCA availability, but after the national lockdown due to COVID-19. Coronary angiography and revascularisation, length of stay and 30-day adverse outcomes were assessed.

Results

513 patients (35.3% female) presented over cohorts 1 (n=179), 2 (n=182), and 3 (n=153). CTCA use increased from 7.8% overall in cohort 1% to 20.4% in cohort 3. Overall length of stay for the patients undergoing CTCA decreased from a median of 4.2 days in cohort 1 to 2.5 days in cohort 3, with no increase in 30 days adverse outcomes. Invasive coronary angiogram rates were 45.8%, 39% and 34.2% across the cohorts. 29.6% underwent revascularisation in cohort 1, 15.9% in cohort 2 and to 16.4% in cohort 3.

Conclusions

Increased CTCA availability was associated with a significantly reduced length of stay both pre-COVID-19 and post-COVID-19 lockdown, without any increase in 30-day adverse outcomes.

Early and mid-term outcomes after transcatheter aortic valve implantation (TAVI) in Ireland

BACKGROUND

TAVI is a percutaneous approach to aortic valve replacement in high surgical risk patients deemed inoperable.

AIM

To evaluate the early and mid-term outcomes for an Irish TAVI cohort over a six-year period at St James's Hospital and Blackrock Clinic, Dublin, Ireland.

RESULTS

In total 147 patients, 56% male with an average age of 82 underwent TAVI between December 2008 and December 2014. Thirty day, one year and two year survival was 90.5%, 83% and 71% respectively. Major vascular complications and renal failure were the biggest predictors of mortality at 30 days (p = 0.02). We observed a pacing rate of 13.5%, the majority in patients who had Medtronic Corevalve implants (p < 0.05). With increasing procedural experience there was a reduction in length of stay from 10 days to 7.5 days.

CONCLUSION

This review, the first of its kind in Ireland showed favorable rates of 30 day and one year and two year survival post TAVI with procedural success and complication rates similar to international registry data.

Anti-inflammatory Effects of Statins in Patients with Aortic Stenosis

Background: Aortic stenosis is an inflammatory process, as evidenced by increased tissue expression and serum levels of various endothelial cellular adhesion molecules. Aortic stenosis and atherosclerosis have many risk factors in common, including hypercholesterolemia. In atherosclerosis, statins lower cholesterol and display some anti-inflammatory activity. We hypothesized that statins might also have anti-inflammatory effects in patients with aortic stenosis.

Methods: This observational cross-sectional study measured levels of cellular adhesion molecules in 129 patients (88 male, mean age 68) with aortic stenosis (mean echo gradient 49 mm Hg, range 22 to 112) and compared levels in patients already on statin therapy for primary or secondary prevention of coronary artery disease, to those not on treatment. Concomitant conditions included hypertension (47%), diabetes (10%), and ischemic heart disease (54%). A comparison group consisted of 45 patients with stable ischemic heart disease.

Results: Patients on statins (35) were more likely to have hypertension (62% vs 42%, P = .05), but no significant differences existed in sex, age, concomitant ischemic heart disease, or diabetes. Statin-treated patients had a 20% lower vascular cellular adhesion molecule level than those without (484 ± 143 ng/L vs 604 ± 245 ng/L, P = .006). The reduction in cellular adhesion molecule levels was consistent in patients with aortic stenosis alone, aortic stenosis and ischemic heart disease, or ischemic heart disease alone. There were no differences in the levels of the other adhesion molecules between the three groups, or related to statin therapy.

Conclusion: Statin therapy is associated with reduced serum levels of vascular cellular adhesion molecules in patients with aortic stenosis. Vascular cellular adhesion molecule levels are similar in patients who have aortic stenosis, ischemic heart disease, or both. A prospective study is required to confirm this finding and to determine whether this suppression of endothelial inflammation translates into a slowing of the progression of aortic stenosis.

Epigenetic modulation in the treatment of atherosclerotic disease

Cardiovascular disease is the single largest cause of death in the western world and its incidence is on the rise globally. Atherosclerosis, characterized by the development of atheromatus plaque, can trigger luminal narrowing and upon rupture result in myocardial infarction or ischemic stroke. Epigenetic phenomena are a focus of considerable research interest due to the role they play in gene regulation. Epigenetic mechanisms such as DNA methylation and histone acetylation have been identified as potential drug targets in the treatment of cardiovascular disease. miRNAs are known to play a role in gene silencing, which has been widely investigated in cancer. In comparison, the role they play in cardiovascular disease and plaque rupture is not well understood. Nutritional epigenetic modifiers from dietary components, for instance sulforaphane found in broccoli, have been shown to suppress the pro-inflammatory response through transcription factor activation. This review will discuss current and potential epigenetic therapeutics for the treatment of cardiovascular disease, focusing on the use of miRNAs and dietary supplements such as sulforaphane and protocatechuic aldehyde.

Reduced right ventricular myocardial strain in the elite athlete may not be a consequence of myocardial damage. "Cream masquerades as skimmed milk"

BACKGROUND

Latest research shows that the lower resting values of right ventricular (RV) myocardial % strain may represent a physiologic change rather than subclinical myocardial damage. Therefore, we assessed load-independent changes to the RV as a consequence of high intensity training by measuring the Isovolumic acceleration (IVA) of the free wall of the RV in conjunction with NT pro-BNP measured by an electrochemiluminescence assay.

METHODS

Seventeen controls (mean age 27 ± 4), 24 soccer footballers (mean age 24 ± 4), and 18 elite rowers (mean age 22 ± 4) were studied. Left ventricular (LV) and RV % strain were measured using two-dimensional (2D) speckle based automated functional imaging (AFI) software. RV free wall IVA was measured using pulsed-wave tissue Doppler at the lateral tricuspid annulus. Standard 2D echo were used to measured RV parameters including the Tei index (systolic and diastolic function) and the total annular plane systolic excursion (TAPSE) of the RV annulus. NT pro-BNP was measured by an electrochemiluminescence assay.

RESULTS

The RV diameter was increased in the footballers and elite rowers compared with controls (P < 0.001). RV wall size was greater in the elite rowers compared with controls and footballers (P = 0.002). The peak IVA of the RV was higher in the rowers, compared with the footballers and to controls (P < 0.001). The mean LV and RV % myocardial strain were lower in the elite athletes and the footballers compared with controls (P < 0.001). There was no difference in RV Tei index, levels of BNP, and TAPSE across all subjects.

CONCLUSIONS

This study showed a significant increase in IVA of the RV of athletes despite reduced myocardial % strain and normal levels in NT-proBNP. This suggests that the decrease in % strain is not a consequence of myocardial damage, but may represents a part of the physiological response to endurance exercise. Therefore, a reduced IVA in a remodeled RV could herald a pathological response.

Safety of therapeutic hypothermia in post VF/VT cardiac arrest patients

Therapeutic hypothermia (TH) is a process of cooling a patient post ventricular tachycardia/ventricular fibrillation (VT/VF) cardiac arrest to 32-34 degrees C for 24 hours. This improves neurological outcome and is part of current guidelines. Hypothermia prolongs QT interval, which can precipitate torsades de pointes (TdP). We performed a retrospective review of all patients who received TH in our hospital over a period of 2 years to assess the effect of TH on the corrected OT interval (QTc) and any possible pro-arrhythmia. A total of 13 patients received TH. QTc prolonged in all patients with an average of 80.3 + 57.2 ms., and up to 109.8 + 80.4 ms in patients who received Amiodarone concurrently. No TdP was seen in any patient. We conclude that TH is safe, though careful monitoring of the OTc interval is advisable especially with concurrent use of QT prolonging drugs.

Molecular basis for clinical heterogeneity in inherited cardiomyopathies due to myopalladin mutations

Abnormalities in Z-disc proteins cause hypertrophic (HCM), dilated (DCM) and/or restrictive cardiomyopathy (RCM), but disease-causing mechanisms are not fully understood. Myopalladin (MYPN) is a Z-disc protein expressed in striated muscle and functions as a structural, signaling and gene expression regulating molecule in response to muscle stress. MYPN was genetically screened in 900 patients with HCM, DCM and RCM, and disease-causing mechanisms were investigated using comparative immunohistochemical analysis of the patient myocardium and neonatal rat cardiomyocytes expressing mutant MYPN. Cardiac-restricted transgenic (Tg) mice were generated and protein-protein interactions were evaluated. Two nonsense and 13 missense MYPN variants were identified in subjects with DCM, HCM and RCM with the average cardiomyopathy prevalence of 1.66%. Functional studies were performed on two variants (Q529X and Y20C) associated with variable clinical phenotypes. Humans carrying the Y20C-MYPN variant developed HCM or DCM, whereas Q529X-MYPN was found in familial RCM. Disturbed myofibrillogenesis with disruption of α-actinin2, desmin and cardiac ankyrin repeat protein (CARP) was evident in rat cardiomyocytes expressing MYPN(Q529X). Cardiac-restricted MYPN(Y20C) Tg mice developed HCM and disrupted intercalated discs, with disturbed expression of desmin, desmoplakin, connexin43 and vinculin being evident. Failed nuclear translocation and reduced binding of Y20C-MYPN to CARP were demonstrated using in vitro and in vivo systems. MYPN mutations cause various forms of cardiomyopathy via different protein-protein interactions. Q529X-MYPN causes RCM via disturbed myofibrillogenesis, whereas Y20C-MYPN perturbs MYPN nuclear shuttling and leads to abnormal assembly of terminal Z-disc within the cardiac transitional junction and intercalated disc.

Two-stage percutaneous closure of mitral periprosthetic valvular leak

Periprosthetic valve leak can develop as a complication of valve replacement surgery and may manifest as symptomatic valvular regurgitation, heart failure, or haemolysis. We report a case of severe mitral periprosthetic valve leak requiring a two-stage percutaneous closure technique with multiple Amplatzer® III vascular plugs.

Nebulette mutations are associated with dilated cardiomyopathy and endocardial fibroelastosis

OBJECTIVES

Four variants (K60N, Q128R, G202R, and A592E) in the nebulette gene were identified in patients with dilated cardiomyopathy (DCM) and endocardial fibroelastosis. We sought to determine if these mutations are cardiomyopathy causing.

BACKGROUND

Nebulette aligns thin filaments and connects them with the myocardial Z-disk, playing a role in mechanosensation.

METHODS

We generated transgenic mice with cardiac-restricted overexpression of human wild-type or mutant nebulette. Chimera and transgenic mice were examined at 4, 6, and 12 months of age by echocardiography and cardiac magnetic resonance imaging. The hearts from embryos and adult mice were assessed by histopathologic, immunohistochemical, ultrastructural, and protein analyses. Rat H9C2 cardiomyoblasts with transient expression of nebulette underwent cyclic mechanical strain.

RESULTS

We identified lethal cardiac structural abnormalities in mutant embryonic hearts (K60N and Q128R). Founders of the mutant mouse lines developed DCM with severe heart failure. An irregular localization pattern for nebulette and impaired desmin expression were noted in the proband and chimeric Q128R mice. Mutant G202R and A592E mice exhibited left ventricular dilation and impaired function with specific changes in I-band and Z-disk proteins by 6 months of age. The mutations modulated distribution of nebulette in the sarcomere and Z-disk during stretch of H9C2 cells.

CONCLUSIONS

Nebulette is a new susceptibility gene for endocardial fibroelastosis and DCM. Different mutations in nebulette trigger specific mechanisms, converging to a common pathological cascade leading to endocardial fibroelastosis and DCM.

Current status of vulnerable plaque detection

Critical coronary stenoses have been shown to contribute to only a minority of acute coronary syndromes (ACS) and sudden cardiac death. Autopsy studies have identified a subgroup of high-risk patients with disrupted vulnerable plaque and modest stenosis. Consequently, a clinical need exists to develop methods to identify these plaques prospectively before disruption and clinical expression of disease. Recent advances in invasive and noninvasive imaging techniques have shown the potential to identify these high-risk plaques. The anatomical characteristics of the vulnerable plaque such as thin cap fibroatheroma and lipid pool can be identified with angioscopy, high frequency intravascular ultrasound, intravascular MRI, and optical coherence tomography. Efforts have also been made to recognize active inflammation in high-risk plaques using intravascular thermography. Plaque chemical composition by measuring electromagnetic radiation using spectroscopy is also an emerging technology to detect vulnerable plaques. Noninvasive imaging with MRI, CT, and PET also holds the potential to differentiate between low and high-risk plaques. However, at present none of these imaging modalities are able to detect vulnerable plaque neither has been shown to definitively predict outcome. Nevertheless in contrast, there has been a parallel development in the physiological assessment of advanced atherosclerotic coronary artery disease. Thus recent trials using fractional flow reserve in patients with modest non flow-limiting stenoses have shown that deferral of PCI with optimal medical therapy in these patients is superior to coronary intervention. Further trials are needed to provide more information regarding the natural history of high-risk but non flow-limiting plaque to establish patient-specific targeted therapy and to refine plaque stabilizing strategies in the future.

Mitral valve abnormalities in hypertrophic cardiomyopathy: echocardiographic features and surgical outcomes

BACKGROUND

Functional and intrinsic mitral valve (MV) abnormalities are common in hypertrophic cardiomyopathy (HCM); however, morphologic characteristics constituting indications for surgical intervention are incompletely defined. This study was conducted to define the echocardiographic features of MV pathology in patients with HCM and relate these to repairability of the MV, MV procedures performed, durability of repair, and survival.

METHODS

From 1986 to 2003, 851 patients with HCM underwent operation, and 115 had a concomitant MV procedure. Detailed analysis of their 784 transthoracic and transesophageal echocardiograms, performed intraoperatively and postoperatively, was conducted. Outcomes were assessed by cross-sectional follow-up.

RESULTS

Sixty-seven patients (58%) underwent MV repair, and 48 (42%) had MV replacement. The mean left ventricular outflow tract peak gradient was 70 +/- 50 mm Hg. Systolic anterior motion was present in 95%. Valve abnormalities were degenerative in 36 (31%), myxomatous in 23 (20%), papillary muscle in 23 (20%), restrictive chordal in 22 (19%), restrictive leaflet in 80 (70%), and long leaflet in 64 (56%). Patients undergoing MV repair had higher prevalence of long leaflets and degenerative MV pathology. The anterior mitral leaflet was 3.0 +/- 0.49 cm in the repair group vs 2.5 +/- 0.40 cm in the replacement group (p = 0.0001). MV replacement patients were older, more symptomatic, and had more renal dysfunction and lower hematocrits. By 3 years, 91% of patients with a repair were free of reoperation.

CONCLUSIONS

Intrinsic MV pathology is frequently observed in HCM patients with symptomatic obstruction who undergo myectomy. Echocardiography can identify MV features predictive of successful valve repair. Repair, although durable, is feasible in only about half of patients.

Mutations in PDLIM3 and MYOZ1 encoding myocyte Z line proteins are infrequently found in idiopathic dilated cardiomyopathy

Dilated cardiomyopathy (DCM), characterized by ventricular dilation and decreased systolic function, is estimated to be of genetic origin in up to 50% of cases. In the present study, we investigated the role of two genes, encoding the Z line proteins PDZ and LIM domain protein 3 (PDLIM3) and myozenin-1 (MYOZ1), in the etiology of DCM. The coding regions of PDLIM3 and MYOZ1 were first amplified from the genomic DNA of 185 unrelated DCM patients by polymerase chain reaction (PCR), followed by denaturing high-performance liquid chromatography (DHPLC) analysis. The samples that exhibited abnormal peaks on DHPLC were re-amplified, purified and sequenced using a Big-Dye Terminator cycle sequencing system. Interestingly, a 2-bp insertion (178insCA) in exon 2 of PDLIM3 was identified in one patient who presented with DCM during pregnancy and died a year later awaiting heart transplant. No other significant mutations were found in either PDLIM3 or MYOZ1. The mutation probably resulted in an unstable protein, since no exogenous protein could be detected in transfected murine myoblastoid cells by immunohistochemical or Western blot analyses. We conclude that mutations in PDLIM3 and MYOZ1, encoding myocyte Z line proteins, do not play any significant role in the genetic etiology of idiopathic DCM. The exact mechanism by which the mutation identified in the present study is linked to DCM phenotype remains unknown. The hemodynamic burden of pregnancy and/or other genetic or environmental factors could have precipitated heart failure symptoms in an individual with defective myocardial cytoarchitecture.

Prospective familial assessment in dilated cardiomyopathy: cardiac autoantibodies predict disease development in asymptomatic relatives

BACKGROUND

In autoimmune disorders, circulating autoantibodies identify healthy relatives at risk years before clinical presentation. Healthy relatives of patients with dilated cardiomyopathy (DCM) who have echocardiographic changes, including left ventricular enlargement or depressed fractional shortening at baseline, have increased medium-term risk for DCM development. Approximately one third of relatives have serum anti-heart autoantibodies (AHAs) at baseline; we intended to assess their potential role in predicting DCM development.

METHODS AND RESULTS

Baseline evaluation, including electrocardiography, echocardiography, and AHA, was performed in 592 asymptomatic relatives of 169 consecutive DCM patients (291 males and 301 females; mean age 36+/-16 years). Relatives were classified in accordance with published echocardiographic criteria; those who did not have DCM were followed up (median of 58 months). DCM among relatives was diagnosed by echocardiography at follow-up. Of the 592 individuals evaluated, 77% were assessed as normal, 4.4% as having DCM, and 19% as possibly affected on the basis of depressed fractional shortening without ventricular dilatation in 17 and left ventricular enlargement without systolic dysfunction in 94. Five-year follow-up of 311 relatives revealed that 26 had progressed (13 to DCM, 11 to left ventricular enlargement, and 2 to depressed fractional shortening). Relatives who developed DCM were more frequently AHA-positive than those who did not (69% versus 37%, P=0.02). Five-year probability of progression to DCM, among normal or possibly affected relatives, was higher in AHA-positive cases (P=0.03). By Cox regression, positive AHAs at baseline were independent predictors of progression (RR 2.26, CI 1 to 5.1, P=0.03).

CONCLUSIONS

Among healthy relatives of DCM patients, AHAs are independent predictors of disease development within 5 years.

Use of tissue Doppler imaging to guide tube current modulation in cardiac multidetector computed tomographic angiography

In multidetector computed tomographic coronary angiography, strategies to minimize effective radiation dose (ERD) are urgently needed. Prospective tube current modulation (TCM) allows a decrease in ERD, although it may limit reconstruction options. We sought to determine if tissue Doppler imaging (TDI) by echocardiography could predict an optimal phase for multidetector computed tomography and be used to guide TCM. Echocardiographic studies were performed in 94 patients immediately before multidetector computed tomography (83% men; mean 60 +/- 11 years of age, mean body mass index 27.7+/-4.1 kg/m2) and identified the most quiescent phase of the cardiac cycle within the atrioventricular groove. In 40 patients, prospective TCM was programmed according to TDI (TCM(TDI) group); 54 patients underwent multidetector computed tomography without TCM (no-TCM). In 25 patients assigned to the TCM(TDI) group, multidetector computed tomograms were correlated with invasive quantitative coronary angiograms to ensure maintenance of diagnostic accuracy. Optimal phase determined by TDI was 71 +/- 11%, with a distinct bi-modal distribution. Compared with no-TCM, effective radiation dose was decreased by 42% in the TCM(TDI) group (6.6 +/- 1.2 vs 11.4 +/- 2.2 mSv, p < 0.0001). Only 8 segments (3%) were unevaluable due to motion artifact. In 296 segments, sensitivity, specificity, and positive and negative predictive values to detect lesions > 50% by multidetector computed tomography were 92%, 94%, 65%, and 99%, respectively. There was good correlation between quantitative coronary angiography and multidetector computed tomography for absolute degree of stenosis (r = 0.70, p < 0.0001). In conclusion, TDI is a useful tool to guide prospective TCM in multidetector computed tomography. ERD in multidetector computed tomography may be significantly decreased using this technique while maintaining excellent image quality.

Tissue synchronization imaging and optimal left ventricular pacing site in cardiac resynchronization therapy

The optimal pacing site in cardiac resynchronization therapy (CRT) remains controversial. Tissue synchronization imaging is a novel echocardiographic technique that color-codes for areas of maximal delay in myocardial velocities. This study aimed to identify whether the left ventricular (LV) pacing lead position in CRT should be guided by a patient's area of maximal mechanical delay. Fifty-four patients with advanced heart failure were assessed echocardiographically before and 6 months after CRT. Response was analyzed according to the relation between the LV lead position and the area of maximal delay to peak velocity by tissue synchronization imaging in the first half of the ejection phase: group 1 (n = 22) had lead placement corresponding to the segment of maximal delay; group 2 (n = 13) had lead placement 1 segment adjacent; and group 3 (n = 19) had lead placement remote from this site. Evidence of LV reverse remodeling and improved systolic function was documented in group 1 (mean percentage decrease in end-systolic volume 23%) more than in group 2 (mean decrease 15%), and more than in group 3 (mean increase 8.9%, p <0.0001 compared with groups 1 and 2). In group 1, 16 of 22 patients had reverse remodeling (>15% decrease in end-systolic volume); reverse remodeling was seen in 7 of 13 patients in group 2 and 1 of 19 in group 3. The placing of the lead position proximal to the site of maximal delay by tissue synchronization imaging was correlated with reverse remodeling (r = 0.449, p = 001). Of 7 patients with delay confined to the septum and anterior wall only, none had evidence of reverse remodeling after CRT. In conclusion, pacing at the site of maximal mechanical delay was associated with reverse remodeling. Individually tailored LV lead positioning should be considered before CRT.

Use of percutaneous transluminal septal myocardial ablation for relief of outflow tract obstruction in cardiac amyloidosis: A novel therapeutic target

Cardiac amyloidosis typically presents with diastolic heart failure, but asymmetrical septal hypertrophy with outflow tract obstruction has been described. We illustrate the case of a 71-year-old woman with biopsy-proven cardiac amyloidosis and severe medical comorbidities with refractory severe heart failure who had asymmetric septal hypertrophy, systolic anterior motion (SAM) of the mitral valve, and a resting left ventricular outflow tract gradient of 86 mm Hg, increasing to 102 mm Hg on Valsalva maneuver. She underwent percutaneous transluminal septal myocardial ablation (PTSMA) with a dramatic resolution of her SAM and outflow tract obstruction, confirmed by intracavitary pressure wire measurements. PTSMA is technically feasible in this context, and correction of outflow tract obstruction may represent a new therapeutic target in cardiac amyloidosis.

Reversal of Inappropriate Peripheral Vascular Responses in Hypertrophic Cardiomyopathy

OBJECTIVES

We assessed the frequency of abnormal forearm vasodilator responses during lower body negative pressure (LBNP) in 21 non-obstructive hypertrophic cardiomyopathy (HCM) patients (31 +/- 8 [20 to 43] years) with abnormal blood pressure response (ABPR) to exercise and the effects of three drugs used to treat vasovagal syncope (propranolol, clonidine, and paroxetine) in a double-blind crossover study.

BACKGROUND

Some HCM patients have an ABPR to exercise, which may be due to paradoxical peripheral vasodilatation. A similar proportion has paradoxical forearm vasodilatation during central volume unloading using LBNP. These abnormal reflexes may be caused by left ventricular mechanoreceptor activation. Similar mechanisms may also contribute to some cases of vasovagal syncope.

METHODS

Blood pressure changes were assessed during exercise, and forearm vascular responses and baroreceptor sensitivity were assessed during LBNP using plethysmography.

RESULTS

Nine (43%) patients (group A) had paradoxical vasodilator responses (forearm vascular resistance [FVR] fell by 7.5 +/- 4.6 U), and 12 (57%) patients (group B) had normal vasoconstrictor responses during LBNP (FVR increased by 7.7 +/- 4.9 U). Paroxetine augmented systolic blood pressure (SBP) during exercise in group A (21 +/- 6 mm Hg vs. 14 +/- 11 mm Hg at baseline, p = 0.02); no effect was detected in group B. Paroxetine reversed paradoxical vascular responses during LBNP in seven (78%) patients from group A. Propranolol and clonidine had no significant effect on SBP during exercise but reversed paradoxical vascular responses in some patients from group A (n = 5 and n = 3).

CONCLUSIONS

Paradoxical vasodilatation during LBNP occurs in 40% of patients with ABPR during exercise and is reversed by propranolol, clonidine, and paroxetine. Paroxetine also improved SBP response to exercise.

Prevalence and clinical significance of systolic impairment in hypertrophic cardiomyopathy

OBJECTIVES

To determine the frequency of systolic impairment (SI) and its impact on the natural history of hypertrophic cardiomyopathy (HCM).

METHODS

1080 patients (mean (SD) age 43 (15) years, 660 men) with HCM were evaluated. Initial assessment included history, examination, 48 hour Holter monitoring, cardiopulmonary exercise testing, and echocardiography; SI was defined as a fractional shortening (FS) < or = 25%. Survival data were collected at clinic visits or by direct communication with patients and their general practitioners. The results of serial echocardiography in 462 patients with normal FS at presentation are also reported.

RESULTS

26 (2.4%) patients (49 (14) years, 18 men) had SI at the initial visit. During follow up (58 (49) months), nine (34.6%) died or underwent cardiac transplantation compared with 108 (10.2%) patients with normal FS (p = 0.01). Five year survival from death (any cause) or transplantation was 90.1% (95% confidence interval (CI) 87.8 to 92.4) in patients with normal systolic function versus 52.4% (95% CI 25.2 to 79.6, p < 0.0001) in patients with SI. In patients who underwent serial echocardiography, 22 (4.8%, aged 41 (15) years) developed SI over 66 (40) months; the annual incidence of SI was 0.87% (95% CI 0.54 to 1.31). On initial evaluation patients who developed SI had a higher frequency of syncope (67 (15.2%) v 10 (45.5%) of those who did not develop SI, p = 0.001), non-sustained ventricular tachycardia (91 (20.6%) v 11 (50%), p = 0.002), and an abnormal blood pressure response on exercise (131 (29.7%) v 15 (68.2%), p = 0.001). Patients with SI had greater wall thinning (p = 0.001), left ventricular cavity enlargement (p < 0.0005), and deterioration in New York Heart Association functional class (p = 0.001) during follow up. Thirteen (59.1%) patients who progressed to SI died or underwent transplantation compared with 38 (8.6%) patients who maintained normal systolic function.

CONCLUSIONS

SI is an infrequent complication of HCM but, when present, is associated with a poor prognosis.

Echocardiographic evaluation in asymptomatic relatives of patients with dilated cardiomyopathy reveals preclinical disease

BACKGROUND

Idiopathic dilated cardiomyopathy is often familial, and apparently healthy relatives may have latent, early, or undiagnosed established disease.

OBJECTIVE

To determine the prevalence and natural history of asymptomatic cardiac abnormalities among sampled relatives of unselected patients referred for management of dilated cardio-myopathy.

DESIGN

Prospective cohort study.

PATIENTS

767 asymptomatic relatives of 189 consecutive unselected patients with dilated cardiomyopathy.

MEASUREMENTS

Clinical evaluation, including history, physical examination, electrocardiography, and echocardiography, was performed. Participants were classified in accordance with published echocardiographic criteria. Sampled relatives who did not have evidence of dilated cardiomyopathy at the initial evaluation were followed for a median of 57 months (range, 1 to 133 months).

RESULTS

Of the 767 patients evaluated, 592 (77.2%) were assessed as healthy, 35 (4.6% [95% CI, 3.7% to 7.6%]) had dilated cardiomyopathy, 119 (15.5% [CI, 12.5% to 18.8%]) had left ventricular enlargement without systolic dysfunction, and 21 (2.7% [CI, 1.9% to 4.9%]) had depressed fractional shortening without ventricular dilatation. At follow-up, progression to dilated cardiomyopathy occurred in 13 (10%) relatives with left ventricular enlargement or depressed fractional shortening versus 3 (1.3%) healthy relatives. In a multivariate model, only left ventricular enlargement or depressed fractional shortening independently predicted progression to dilated cardiomyopathy (hazard ratio, 10.0 [CI, 2.8 to 35.5]; P < 0.001).

LIMITATIONS

Because relatives had to be willing to participate and be available geographically, selection bias may have occurred.

CONCLUSION

Treatable asymptomatic dilated cardiomyopathy was identified in 4.6% of asymptomatic relatives. In addition, left ventricular enlargement and depressed fractional shortening were common in asymptomatic relatives of patients with dilated cardiomyopathy and were associated with a statistically significant medium-term risk for disease progression. Evaluation of relatives of patients with cardiomyopathy is recommended.

Adenosine monophosphate-activated protein kinase disease mimicks hypertrophic cardiomyopathy and Wolff-Parkinson-White syndrome: natural history

OBJECTIVES

The aim of this study was to investigate the clinical expression of adenosine monophosphate-activated protein kinase (AMPK) gene mutations (PRKAG2) in adenosine monophosphate (AMP) kinase disease based on 12 years follow-up of known mutation carriers and to define the prevalence of PRKAG2 mutations in hypertrophic cardiomyopathy (HCM).

BACKGROUND

Adenosine monophosphate-activated protein kinase gene mutations cause HCM with Wolff-Parkinson-White syndrome and conduction disease.

METHODS

Clinical evaluation of 44 patients with known AMP kinase disease was analyzed. Mutation analysis of PRKAG2 was performed by fluorescent single-strand confirmation polymorphism analysis and direct sequencing of abnormal conformers in 200 patients with HCM.

RESULTS

Only one additional mutation was identified. The mean age at clinical diagnosis in the 45 gene carriers was 24 years (median 20 years, range 9 to 55 years). Symptoms of palpitation, dypspnea, chest pain, or syncope were present in 31 (69%) gene carriers; 7 (15%) complained of myalgia and had clinical evidence of proximal myopathy. Skeletal muscle biopsy showed excess mitochondria and ragged red fibers with minimal glycogen accumulation. Disease penetrance defined by typical electrocardiogram abnormalities was 100% by age 18 years. Thirty-two of 41 adults (78%) had left ventricular hypertrophy (LVH) on echocardiography, and progressive LVH was documented during follow-up. Survival was 91% at a mean follow-up of 12.2 years. Progressive conduction disease required pacemaker implantation in 17 of 45 (38%) at a mean age of 38 years.

CONCLUSIONS

The AMP kinase disease is uncommon in HCM and is characterized by progressive conduction disease and cardiac hypertrophy and includes extracardiac manifestations such as a skeletal myopathy, consistent with a systemic metabolic storage disease. Defects in adenosine triphosphate utilization or in specific cellular substrates, rather than mere passive deposition of amylopectin, may account for these clinical features.

Role of Echocardiography in Diagnosis and Management of Endocarditis

Echocardiography plays an increasingly important role in diagnosis and management of patients with infective and noninfective endocarditis. Significant changes to diagnostic criteria for endocarditis have occurred, and there are evolving trends associated with an older population presenting with endocarditis, greater numbers of patients with prosthetic heart valves and complex congenital heart disease, and an exponential increase in the numbers of patients eligible for pacing and defibrillator implants. The diagnostic accuracy of echocardiography has been enhanced by developments such as multiplanar transesophageal probes, real-time three-dimensional echocardiography, and intracardiac echocardiography. Standard echocardiography techniques now define the need for and timing of surgical intervention in endocarditis and may help determine the duration of treatment and follow-up after diagnosis.

Genetics and cardiomyopathy: where are we now?

Many cases of cardiomyopathy have a genetic component: 90% of cases of hypertrophic cardiomyopathy are familial, and genetic factors may be responsible for 30% to 50% of cases of dilated cardiomyopathy. Clinical genetic testing for hypertrophic cardiomyopathy is becoming available, with significant implications for the clinician. This article gives an overview of how these genetic discoveries were made and how these new insights from genetics will affect clinical practice.

Frequency and clinical expression of cardiac troponin I mutations in 748 consecutive families with hypertrophic cardiomyopathy

OBJECTIVES

The aim of this study was to evaluate the potential utility of genetic diagnosis in clinical management of families with hypertrophic cardiomyopathy (HCM) caused by mutations in the gene for cardiac troponin I (TNNI3).

BACKGROUND

Knowledge about the clinical disease expression of sarcomeric gene mutations in HCM has predominantly been obtained by investigations of single individuals (probands) or selected families. To establish the role of genetic diagnosis in HCM families, systematic investigations of probands and their relatives are needed.

METHODS

Cardiac troponin I was investigated by direct sequencing and fluorescent (F)-SSCP analysis in 748 consecutive HCM families. Relatives of HCM probands with TNNI3 mutations were invited for cardiovascular and genetic assessment.

RESULTS

The prevalence of TNNI3 mutations was 3.1%. Mutations appeared to cluster in exons 7 and 8. A total of 100 mutation carriers were identified in 23 families with 13 different mutations (6 novel). Disease penetrance was 48%. Patients were diagnosed from the second to eighth decade of life. The morphologic spectrum observed represented a wide range of HCM. Two offspring of clinically unaffected mutation carriers were resuscitated from cardiac arrest, and an additional four individuals died suddenly as their initial presentation. Six individuals experienced other disease-related deaths.

CONCLUSIONS

The clinical expression of TNNI3 mutations was very heterogeneous and varied both within and between families with no apparent mutation- or gene-specific disease pattern. The data suggest that disease development may be monitored by regular assessment of cardiac symptoms and electrocardiographic abnormalities. Genetic diagnosis of TNNI3 is valuable in identifying clinically unaffected mutation carriers at risk of disease development and facilitates accurate management and counseling.

Natural history and familial characteristics of isolated left ventricular non-compaction

AIMS

Non-compaction of the left ventricle (LVNC) is a disorder of endomyocardial morphogenesis that results in multiple trabeculations in the left ventricular myocardium. The current literature suggests that LVNC in adults is rare and associated with a poor prognosis. Given that the disorder is present at birth and that several studies have reported asymptomatic familial disease in some patients, we hypothesized that there is a long pre-clinical phase of the disease. The aim of this study was to define the prognosis and familial incidence of LVNC.

METHODS AND RESULTS

This study cohort comprised 45 patients (mean age at diagnosis 37 years) consecutively identified at a referral centre for cardiomyopathy over a 10-year period. Twenty-eight patients (62%) had dyspnoea at presentation; 41 (91%) an abnormal ECG; and 30 (66%) left ventricular dilatation and impaired systolic function. Nine patients (20%) had non-sustained ventricular tachycardia on 24 h Holter monitoring. Mean survival from death or transplantation was 97% at 46 months. There were three thromboembolic events in two patients (4%). On systematic family screening, 8 of 32 (25%) asymptomatic relatives had a range of echocardiographic abnormalities, including LVNC, LVNC with impaired systolic function, and left ventricular enlargement without LVNC.

CONCLUSION

This study demonstrates that LVNC is associated with a better prognosis than previously reported. In patients with familial disease, relatives may have features consistent with dilated cardiomyopathy rather than LVNC.

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

OBJECTIVES

The aim of this study was to determine the natural history of patients with hypertrophic cardiomyopathy (HCM) and severe left ventricular hypertrophy (LVH) (i.e., maximal left ventricular wall thickness [MLVWT] >/=30 mm) and whether changes in cardiac morphology influence the course of the disease.

BACKGROUND

Severe LVH is common in young and rare among elderly patients with HCM. This has been explained by a high incidence of sudden death. We hypothesized that this age-related difference might be explained by left ventricular wall thinning.

METHODS

A total of 106 (age 33 +/- 15 years; 71 males) consecutive patients with severe LVH underwent history taking, examination, electrocardiography, echocardiography, cardiopulmonary exercise testing, and Holter analysis. Survival data were collected at subsequent clinic visits or by communication with patients and their general practioners. In order to assess morphologic and functional changes, 71 (67.0%) patients (mean age 31 +/- 15 years; 47 males) followed at our institution underwent serial (>/=1 year) assessment.

RESULTS

Of the 106 patients, the majority (78 [71.6%]) were <40 years of age. During follow-up (92 +/- 50 months [range 1 to 169]), 18 (17.0%) patients died or underwent heart transplantation (13 sudden cardiac deaths, 2 heart failure deaths, 1 heart transplantation, 1 stroke, 1 postoperative death). Five-year survival from sudden death was 90.1% (95% confidence interval [CI] 84.0% to 96.3%), and that from heart failure death or transplantation was 97.7% (95% CI 94.5 to 100). In patients serially evaluated over 85 +/- 51 months, there was an overall reduction in MLVWT of 0.6 mm/year (95% CI 0.31 to 0.81, p = 0.00004). Wall thinning >/=5 mm was observed in 41 patients (57.7%; age 35 +/- 13 years; 28 males). On multivariate analysis, the follow-up duration only predicted wall thinning (0.6 mm/year, 95% CI 0.38 to 0.85, p < 0.00001).

CONCLUSIONS

Left ventricular remodeling is common in patients with severe LVH and contributes to the low prevalence of severe LVH seen in middle age and beyond.

Isolated left ventricular noncompaction is rarely caused by mutations in G4.5, alpha-dystrobrevin and FK Binding Protein-12

Isolated left ventricular noncompaction (LVNC) is a form of cardiomyopathy that most commonly presents in infancy with a hypertrophic and dilated left ventricle characterized by deep trabeculations and intertrabecular recesses. Our goal was to determine the frequency of mutations in G4.5, alpha-dystrobrevin, and FK Binding protein-12 in isolated LVNC patients. No mutations were identified in 47 of the 48 patients studied, while a splice site acceptor site mutation of intron 10 of G4.5 was identified in one patient, resulting in the deletion of exon 10 from the mRNA.

Vitamin E modulation of C-reactive protein in smokers with acute coronary syndromes

Acute coronary syndromes are characterized by the expression of proinflammatory cytokines such as C-reactive protein (CRP). Sustained upregulation of inflammatory markers is associated with an adverse prognosis. Vitamin E is known to have significant anti-inflammatory properties and has been associated with a reduction in cardiovascular events in some studies of high-risk patients. The mechanism of benefit remains controversial. We conducted a randomized, double-blind placebo controlled trial of vitamin E 400 IU daily for 6 months in 110 patients with acute coronary syndromes. Serum samples were collected at enrollment and at 2, 4, and 6 months. CRP, interleukin-6 and the soluble cell adhesion molecules were measured. Vitamin E levels increased significantly in the treatment group (from 31 micromol/l at baseline to 51 micromol/l, p <.0001) and were unchanged in the placebo group (32 micromol/l at baseline to 34 micromol/l, p = NS). CRP levels fell in both the vitamin E group and the placebo group over the treatment period (from 17.2 +/- 2.9 to 6.1 +/- 0.8 mg/l and from 21.5 +/- 4.9 to 5.9 +/- 0.9 mg/l, p = NS for the difference between active and placebo groups). However, vitamin E treatment was associated with significantly lower 6 month CRP levels in smokers versus smokers on placebo (4.7 +/- 0.71 mg/l vs. 8.26 +/- 1.5 mg/l, p =.02). Vitamin E reduces CRP levels in smokers with acute coronary syndromes for up to 6 months after hospitalization.

Novel mutation in cardiac troponin I in recessive idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy is a common cause of heart failure. Half of cases are believed to be hereditary, and mutations in cardiac sarcomeric contractile protein genes have been reported with autosomal dominant inheritance. We used mutation analysis suitable for identification of both dominant and recessive mutations to investigate the sarcomeric gene for cardiac troponin I (TNNI3) in 235 patients with dilated cardiomyopathy. We identified a novel TNNI3 mutation in a family with recessive disease. Functional studies showed impairment of troponin interactions that could lead to diminished myocardial contractility. TNNI3 is the first recessive gene identified for this condition, and we suggest that other such genes could be pinpointed by mutation analyses designed to identify homozygous mutations.

Mutations in Cypher/ZASPin patients with dilated cardiomyopathy and left ventricular non-compaction

OBJECTIVES

We evaluated the role of Cypher/ZASP in the pathogenesis of dilated cardiomyopathy (DCM) with or without isolated non-compaction of the left ventricular myocardium (INLVM).

BACKGROUND

Dilated cardiomyopathy, characterized by left ventricular dilation and systolic dysfunction with signs of heart failure, is genetically transmitted in 30% to 40% of cases. Genetic heterogeneity has been identified with mutations in multiple cytoskeletal and sarcomeric genes causing the phenotype. In addition, INLVM with a hypertrophic dilated left ventricle, ventricular dysfunction, and deep trabeculations, is also inherited, and the genes identified to date differ from those causing DCM. Cypher/ZASP is a newly identified gene encoding a protein that is a component of the Z-line in both skeletal and cardiac muscle.

METHODS

Diagnosis of DCM was performed by echocardiogram, electrocardiogram, and physical examination. In addition, levels of the muscular isoform of creatine kinase were measured to evaluate for skeletal muscle involvement. Cypher/ZASP was screened by denaturing high performance liquid chromatography (DHPLC) and direct deoxyribonucleic acid sequencing.

RESULTS

We identified and screened 100 probands with left ventricular dysfunction. Five mutations in six probands (6% of cases) were identified in patients with familial or sporadic DCM or INLVM. In vitro studies showed cytoskeleton disarray in cells transfected with mutated Cypher/ZASP.

CONCLUSIONS

These data suggest that mutated Cypher/ZASP can cause DCM and INLVM and identify a mechanistic basis.

Mutations in the muscle LIM protein and alpha-actinin-2 genes in dilated cardiomyopathy and endocardial fibroelastosis

Dilated cardiomyopathy (DCM) is a major cause of morbidity and mortality. Two genes have been identified for the X-linked forms (dystrophin and tafazzin), while mutations in multiple genes cause autosomal dominant DCM. Muscle LIM protein (MLP) is a member of the cysteine-rich protein (CRP) family and has been implicated in both myogenesis and sarcomere assembly. In the latter role, it binds zyxin and alpha-actinin, both of which are involved in actin organization. An MLP-deficient mouse has been described; these mice develop dilated cardiomyopathy and heart failure. Based upon these data, and the recent descriptions of mutations in MLP in patients with DCM or hypertrophic cardiomyopathy, we screened patients for mutations in the MLP and alpha-actinin-2 genes. We identified a patient with DCM and EFE, having a mutation in MLP with the residue lysine 69 substituted by arginine (K69R). This is within a highly conserved region adjacent to the first LIM domain involved in alpha-actinin binding. Analysis in cell culture systems demonstrated that the mutation abolishes the interaction between MLP and alpha-actinin-2 and the cellular localization of MLP was altered. In another individual with DCM, a W4R mutation was identified. However, this mutation did not segregate with disease in this family. In another patient with DCM, a Q9R mutation was identified in alpha-actinin-2. This mutation also disrupted the interaction with MLP and appeared to inhibit alpha-actinin function in cultured cells, in respect to the nuclear localization of actinin and the initiation of cellular differentiation.

Reciprocal activation of leukocyte-endothelial adhesion molecules in acute coronary syndromes

BACKGROUND

The acute coronary syndromes are associated with an intense inflammatory response and sustained leukocyte activation. This inflammatory state has been correlated with an adverse prognosis, but the source of this inflammation remains controversial, with evidence that it may arise either from the coronary vasculature or from the systemic endothelium.

METHODS

Levels of soluble cell adhesion molecules, and of their respective monocyte cell surface ligands, were measured in the peripheral serum of 21 patients presenting with acute coronary syndromes. Soluble intercellular adhesion molecule-1 and soluble vascular cell adhesion molecule-1 were measured by enzyme linked immunosorbent assay and expression of the monocyte integrins CD11b (Mac-1) and CD49d (VLA-4) was measured by direct immunofluorescence using flow cytometry.

RESULTS

High levels of the monocyte receptor CD11b (531 vs. 345 MFI, P<0.01), and its soluble intercellular adhesion molecule-1 (329 vs. 232 ng/ml, P<0.01), were noted in patients with acute coronary syndromes compared to healthy controls.

CONCLUSIONS

Reciprocal activation of monocyte receptor ligands and endothelial adhesion molecules was found in the peripheral blood of patients with acute coronary syndromes. This may indicate a coordinated state of pro-inflammatory upregulation with widespread activation of both leukocytes and endothelium and suggests a systemic rather than local source for inflammation in acute coronary disease.

Audit of acute myocardial infarctions at Saint James's Hospital, Dublin, from 1996 to 1999

Saint James' Hospital is a 650-bed tertiary referral hospital. An audit was performed of acute transmural myocardial infarctions for the years 1996 to 1999 inclusive. On average there were 2043 cardiology admissions annually, 9.8% of all hospital admissions. Acute transmural myocardial infarction was diagnosed in 178 patients annually, and was less common during the summer. The figure of 72% receiving revascularisation therapy (thrombolysis 67%, primary angioplasty 5%) compares favourably with 35% in 1992. The main reason for not receiving thrombolysis was late presentation (15%) with contraindications present in only 5%. The case fatality rate was 16% confirming the higher mortality in clinical practice than that of thrombolytic trials. The prescription of aspirin or warfarin (99%) and betablockers (67%) was in line with international trials. The use of angiotensin converting enzyme inhibitors (34%) and statins (28%) is similar to other studies but less than would be expected according to trial evidence.

Endothelial inflammation and thrombolysis resistance in acute myocardial infarction

BACKGROUND

Despite recent refinements to thrombolysis for acute myocardial infarction, a significant minority of patients still fail to reperfuse. There is no reliable predictor of this state of "thrombolysis resistance", but platelet and endothelial factors are believed to be important. Cell adhesion molecules are expressed by the endothelium when activated and their shed or soluble portion can be quantified in the peripheral serum, where they may be taken as a measure of endothelial activation. We sought to find a link between markers of endothelial inflammation at time of infarction and failure to reperfuse as measured by vessel occlusion at angiography.

METHODS

Patients presenting with their first acute myocardial infarction had levels of soluble adhesion molecules, C-reactive protein and monocyte chemotactic protein-1 measured prior to thrombolysis. An angiogram on day five after admission was performed to establish patency of the index vessel.

RESULTS

Levels of soluble vascular adhesion molecule-1 (sVCAM-1) taken prethrombolysis were significantly elevated compared to those with a patent vessel (620+/-90 vs. 418+/-28 ng/ml, P<0.03. The positive predictive value of sVCAM-1 for vessel patency was 88%.

CONCLUSIONS

We found elevated serum levels of the adhesion molecule soluble vascular adhesion molecule-1 (sVCAM-1) at presentation in patients with acute myocardial infarction who did not respond to thrombolysis. Endothelial activation may be important in thrombolysis resistance.

Enhanced endothelial activation in diabetic patients with unstable angina and non-Q-wave myocardial infarction

AIMS

Diabetes mellitus (DM) is associated with chronic endothelial dysfunction. Diabetic patients presenting with acute coronary syndromes have a worse prognosis than non-diabetics. An acute inflammatory reaction at the site of coronary plaque rupture and increased expression of surface and soluble cellular adhesion molecules (CAMs) are pathological features of acute coronary syndromes. We set out to characterize the expression of soluble CAMs in patients with and without diabetes presenting with unstable angina (UA) and non Q-wave myocardial infarction (NQMI).

METHODS

Patients presenting with UA and NQMI had serum samples taken on presentation, after 72 h and then 3, 6 and 12 months after discharge. Levels of soluble intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin and P-selectin were measured using an ELISA technique.

RESULTS

We studied 15 diabetic patients and 15 age- and sex-matched non-diabetic patients presenting with either UA or NQMI. Levels of soluble E-selectin were elevated in the diabetic patients in comparison with the non-diabetic patients at all measured time points: 74 +/- 10 ng/ml vs. 47 +/- 3 ng/ml, P < 0.03 at t = 0 h, 55 +/- 5 ng/ml vs. 38 +/- 2 ng/ml, P < 0.02 at t = 72 h. However, levels of soluble P-selectin were lower in the diabetic cohort during follow-up: 134 +/- 15 ng/ml vs. 225 +/- 32 ng/ml, P < 0.02 at t = 3/12 and 112 +/- 8 ng/ml vs. 197 +/- 23 ng/ml, P < 0.02 at t = 6/12. There was no significant difference in levels of soluble ICAM-1 and VCAM-1 between diabetic and non-diabetic patients.

CONCLUSIONS

Levels of soluble E-selectin are significantly elevated in diabetic patients presenting with UA and NQMI in comparison with non-diabetics. This finding may reflect enhanced endothelial activation which may contribute to the adverse prognosis of diabetic patients with acute coronary syndromes.