Use of Echocardiography in Patients with Hypertrophic Cardiomyopathy: Clinical Implications of Massive Hypertrophy

Midterm Outcome After Septal Myectomy and Medical Therapy in Mildly Symptomatic Patients With Hypertrophic Obstructive Cardiomyopathy

Objective

The purpose of this study was mainly to determine the midterm outcome of septal myectomy (SM) and medical therapy (MT) in mildly symptomatic patients (NYHA class II) with hypertrophic obstructive cardiomyopathy (HOCM).

Methods

The study cohort consisted of 184 mildly symptomatic patients with HOCM evaluated in Beijing Anzhen Hospital, Capital Medical University between March 2001 and December 2017, including 82 patients in the SM group and 102 patients in the MT group. Overall survival and HCM-related survival were mainly observed.

Results

The average follow-up time was 5.0 years. Compared to patients accepting MT, patients treated with SM were associated with comparable overall survival (96.5% and 93.1% vs. 92.9% and 83.0% at 5 and 10 years, respectively; P = 0.197) and HCM-related survival (98.7% and 98.7% vs. 94.2% and 86.1% at 5 and 10 years, respectively; P = 0.063). However, compared to MT, SM was superior at improvement of NYHA class (1.3 ± 0.6 vs. 2.1 ± 0.5, P < 0.001) and mean reduction of resting left ventricular outflow (LVOT) gradient (78.5 ± 18.6% vs. 28.3 ± 18.4%, P < 0.001). Multivariate analysis suggested that resting LVOT gradient in the last clinical examination was an independent predictor of all-cause mortality (HR = 1.017, 95%CI: 1.000–1.034, P = 0.045) and HCM-related mortality (HR = 1.024, 95%CI: 1.005–1.043, P = 0.012) in the entire cohort.

Conclusion

Compared with MT, SM had comparable overall survival and HCM-related survival in mildly symptomatic HOCM patients, but SM had advantages on improving clinical symptoms and reducing resting LVOT gradient. Resting LVOT gradient in the last clinical examination was an independent predictor of all-cause mortality and HCM-related mortality.

Newer risk assessment strategies in hypertrophic cardiomyopathy

PURPOSE OF REVIEW

The present article serves to review current risk assessment guidelines for sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM) and to discuss how these guidelines can be applied to patients with childhood HCM. New diagnostic techniques that could lead to more accurate risk assessment tools are also discussed.

RECENT FINDINGS

Current guidelines for risk assessment in childhood HCM are extrapolated from adult guidelines and lack background research to validate their use. Continuous variables, such as wall thickness, are converted to binary variables, which is particularly concerning in pediatric patients' where weight gain and linear growth is likely to lead to more significant hemodynamic changes in shorter periods of time. Some studies have even shown that risk factors concerning in adults may actually be protective in pediatric patients. Additionally, large gaps still remain between genotype and phenotype expression in HCM.

SUMMARY

A better understanding of the relationship between cause, phenotype, and outcomes is needed to truly be able to determine risk for SCD in childhood HCM. Larger studies, including newer technologies and quantitative models, similar to the European HCM Risk-SCD model, which allows for a quantitative risk diagnosis, are needed as well.

Risk stratification using late gadolinium enhancement on cardiac magnetic resonance imaging in patients with hypertrophic cardiomyopathy: A systematic review and meta-analysis

Background The role of late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (c-MRI) for predicting outcomes of patients with hypertrophic cardiomyopathy (HCM) has been debated. Methods We searched PubMed and Embase and various published bibliographies for prospective studies published in English between January 1990 and February 2019. Two investigators screened 2646 abstracts and full-text articles for inclusion and relevant outcomes. We then performed a systematic review and meta-analysis to calculate pooled odds ratios for LGE on c-MRI and a pooled sensitivity and specificity analysis. Results Our systematic review included 8 prospective studies and 3808 patients. LGE positivity was associated with higher odds of the endpoint of sudden cardiac death (SCD;OR 1.69, 95%CI 1.03-2.78), aborted SCD or appropriate implantable cardioverter- defibrillator (ICD) discharge (OR 3.27 [1.75-6.10]), SCD or aborted SCD or appropriate ICD discharge (OR 2.32 [1.56-3.43]), and all-cause mortality (OR 2.10 [CI 1.00-4.41]). The pooled sensitivity and specificity of positive LGE on c-MRI for SCD were 65% and 42%, respectively; for aborted SCD or appropriate ICD discharge, 79% and 39%; for SCD or aborted SCD or appropriate ICD discharge, 74% and 39%; and for all-cause mortality, 78% and 39%. Conclusion In patients with HCM, LGE on c-MRI is a strong predictor of arrhythmic outcomes including SCD, aborted SCD, and appropriate ICD therapy. These data support the routine use of LGE on c-MRI as a marker of SCD risk in this population.

Prediction and Prevention of Sudden Death in Young Patients (<20 years) With Hypertrophic Cardiomyopathy

Highly reliable identification of adults with hypertrophic cardiomyopathy (HC) at risk for sudden death (SD) has been reported. A significant controversy remains, however, regarding the most reliable risk stratification methodology for children and adolescents with HC. The present study assesses the accuracy of SD prediction and prevention with prophylactic implantable cardioverter-defibrillators (ICDs) in young HC patients. The study group is comprised of 146 HC patients <20 years of age evaluated consecutively over 17 years with prospective risk stratification and ICD decision-making. We relied on ≥1 established individual risk markers considered major within each patient's clinical profile, based on an enhanced American College of Cardiology /American Heart Association (ACC/AHA) guidelines algorithm. Of the 60 largely asymptomatic patients implanted with primary prevention ICDs at age 15 ± 4 years, 9 (15%) experienced device therapy terminating potentially lethal ventricular tachyarrhythmias and restoring sinus rhythm at 19 ± 6 years (range 9 to 29), 5.1 ± 6.0 years after implant; 3 patients had multiple appropriate ICD discharges. The individual risk marker algorithm was associated with 100% sensitivity in predicting SD events (95%CI: 69, 100) and 63% specificity for identifying patients without events (95%CI: 54, 71). Of these patients with device therapy, massive left ventricular hypertrophy (absolute wall thickness ≥30 mm) was the most common predictor, present in 70% of patients either alone or in combination with other risk markers. Each of the 146 study patients have survived to date at 22 ± 5 years, including all 86 without ICD recommendations. In conclusion, an enhanced ACC/AHA risk stratification strategy, based on established individual risk markers, was highly reliable in prospectively predicting SD events in children and adolescents with HC, and preventing arrhythmia-based catastrophes in this susceptible high risk population.

Risk stratification in hypertrophic cardiomyopathy

Sudden cardiac death (SCD) is the most devastating complication of hypertrophic cardiomyopathy (HCM). The greatest challenge in the management of HCM is identifying those at increased risk, since an implantable cardioverter-defibrillator (ICD) is a potentially life-saving therapy. We sought to summarize the available data on SCD in HCM and provide a clinical perspective on the current differing and somewhat conflicting data on risk stratification, with balanced guidance regarding rational clinical decision-making. Additionally, we sought to determine the status of the current implementation of guidelines compiled by HCM experts worldwide. The HCM Risk-SCD model helps improve the risk stratification of HCM patients for primary prevention of SCD by calculating an individual risk estimate that contributes to the clinical decision-making process. Improved risk stratification is important for decision-making before ICD implantation for the primary prevention of SCD.

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.

Sudden Cardiac Death in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a heart disease characterized by hypertrophy of the left ventricular myocardium and is most often caused by mutations in sarcomere genes. The structural and functional abnormalities are not explained by flow-limiting coronary artery disease or loading conditions. The disease affects at least 0.2% of the population worldwide and is the most common cause of sudden cardiac death in young people and competitive athletes because of fatal ventricular arrhythmia. In some patients, however, HCM has a benign course. Therefore, it is of utmost importance to properly evaluate patients and single out those who would benefit from an implanted cardioverter defibrillator. In this article, we review and summarize the sudden cardiac death risk stratification algorithms, methods of preventing death due to HCM, and novel factors that may improve the existing prediction models.

Women with hypertrophic cardiomyopathy have worse survival

Aims

Sex differences in hypertrophic cardiomyopathy (HCM) remain unclear. We sought to characterize sex differences in a large HCM referral centre population.

Methods and results

Three thousand six hundred and seventy-three adult patients with HCM underwent evaluation between January 1975 and September 2012 with 1661 (45.2%) female. Kaplan-Meier survival curves were assessed via log-rank test. Cox proportional hazard regression analyses evaluated the relation of sex with survival. At index visit, women were older (59 ± 16 vs. 52 ± 15 years, P < 0.0001) had more symptoms [New York Heart Association (NYHA) Class III-IV 45.0% vs. 35.3%, P < 0.0001], more obstructive physiology (77.4% vs. 71.8%, P = 0.0001), more mitral regurgitation (moderate or greater in 56.1% vs. 43.9%, P < 0.0001), higher E/e' ratio (n = 1649, 20.6 vs. 15.6, P < 0.0001), higher estimated pulmonary artery systolic pressure (n = 1783, 40.8 ± 15.4 vs. 34.8 ± 10.8 mmHg, P < 0.0001), worse cardiopulmonary exercise performance (n = 1267; percent VO2 predicted 62.8 ± 20% vs. 65.8 ± 19.2%, P = 0.007), and underwent more frequent alcohol septal ablation (4.9% vs. 3.0%, P = 0.004) but similar frequency of myectomy (28% vs. 30%, P = 0.24). Median follow-up was 10.9 (IQR 7.4-16.2) years. Kaplan-Meier analysis demonstrated lower survival in women compared with men (P < 0.0001). In multivariable modelling, female sex remained independently associated with mortality (HR 1.13 [1.03-1.22], P = 0.01) when adjusted for age, NYHA Class III-IV symptoms, and cardiovascular comorbidities.

Conclusion

Women with HCM present at more advanced age, with more symptoms, worse cardiopulmonary exercise tolerance, and different haemodynamics than men. Sex is an important determinant in HCM management as women with HCM have worse survival. Women may require more aggressive diagnostic and therapeutic approaches.

Prevention of sudden death in hypertrophic cardiomyopathy: bridging the gaps in knowledge

Sudden cardiac death (SCD) is the most devastating complication of hypertrophic cardiomyopathy (HCM). Although the annual rate of SCD in the general HCM population is <1% per year according to contemporary series, there is still a small subset of patients who are at increased risk of SCD. The greatest challenge in the management of HCM is identifying those at increased risk as an implantable cardioverter defibrillator is a potentially life-saving therapy. In this review, we sought to summarize the available data on SCD in HCM and provide a clinical perspective on the current differing and somewhat conflicting European and American recommendations on risk stratification, with balanced guidance with regards to rational clinical decision making. Additionally, we sought to learn more on the actual implementation of the guidelines by HCM experts worldwide.

Sudden Cardiac Death in Genetic Cardiomyopathies

Sudden cardiac death (SCD) caused by ventricular arrhythmias is common in patients with genetic cardiomyopathies (CMs) including dilated CM, hypertrophic CM, and arrhythmogenic right ventricular CM (ARVC). Phenotypic features can identify individuals at high enough risk to warrant placement of an implantable cardioverter-defibrillator, although risk stratification schemes remain imperfect. Genetic testing is valuable for family cascade screening but with few exceptions (eg, LMNA mutations) do not identify higher risk for SCD. Although randomized trials are lacking, observational data suggest that ICDs can be beneficial. Vigorous exercise can exacerbate ARVC disease progression and increase likelihood of ventricular arrhythmias.

Influence of Septal Thickness on the Clinical Outcome After Alcohol Septal Alation in Hypertrophic Cardiomyopathy

BACKGROUND

We assessed the influence of interventricular septal thickness (IVSd) on the clinical outcome and survival after alcohol septal ablation (ASA) in patient with hypertrophic cardiomyopathy.

METHODS AND RESULTS

We analyzed 531 patients with hypertrophic cardiomyopathy (age: 56±14 years, men 55%) treated with ASA. Survival status was obtained 7.9±4.0 years after ASA. Baseline IVSd was inversely associated with survival (hazard ratio [HR] for 1 mm increment, 1.13; confidence interval, 1.05-1.21; P<0.001) after adjustment for age, sex, body mass index, and ASA-performing center. Compared with patients with baseline IVSd <20 mm, patients with baseline IVSd ≥25 mm had reduced survival (HR, 5.0; CI, 2.1-12), whereas patients with baseline IVSd 20 to 24 mm had similar survival (HR, 1.4; CI, 0.7-2.8). Baseline IVSd was not correlated with New York Heart Association class, Canadian Cardiology Society class, or syncope. Clinical outcome was assessed 0.6±0.6 years after ASA. IVSd was not related to left ventricular outflow tract gradient reduction at rest (P=0.883) or during Valsalva maneuver (P=0.885). The proportion of patients in New York Heart Association class 3 to 4 was reduced from 86% to 10%; in Canadian Cardiology Society class 3 to 4 from 26% to 2%; and with syncope from 25% to 2%. There were no correlations between baseline IVSd and New York Heart Association class (P=0.067), Canadian Cardiology Society class (P=0.106), or syncope (P=0.426) after ASA.

CONCLUSIONS

ASA had equal effects on left ventricular outflow tract gradients and symptoms throughout the spectrum of septal hypertrophy. Severe septal hypertrophy before ASA remained a marker of reduced survival after ASA with a 5-fold increased risk of all-cause mortality in patients with baseline IVSd >25 mm compared with patients with baseline IVSd <20 mm.

Echocardiographic particle image velocimetry for the evaluation of diastolic function in hypertrophic nonobstructive cardiomyopathy

AIMS

To use particle image velocimetry (PIV) echocardiography for the evaluation of diastolic dysfunction (DD) in patients with hypertrophic nonobstructive cardiomyopathy (HNCM).

METHODS

This study included 50 individuals, thereof 30 patients with DD due to HNCM and 20 healthy individuals who served as controls. HNCM patients were divided into 3 groups according to DD severity. All subjects underwent clinical assessment, exercise testing, and standard as well as PIV echocardiography.

RESULTS

Energy dissipation was higher in DD patients than in the control group. The severity of flow pattern disturbance corresponded to the degree of DD. In a subgroup of 20 HNCM patients we found significant correlations between invasive measured left ventricular end-diastolic pressure and noninvasive PIV parameters for intraventricular pressure differences and filling. Inter-observer variability (mean difference ± 1.96 SD) for all tested PIV measurements was good.

CONCLUSION

According to DD severity, patients with HNCM have disturbed intraventricular flow and reduced intraventricular pressure differences, consistent with a reduced intraventricular suction. PIV echocardiography appears to be feasible for detailed analysis of ventricular vortex flow in DD conditions. Further research using PIV echocardiography in different cardiac pathologies seems warranted.

Heart failure in sub-Saharan Africa

The heart failure syndrome has been recognized as a significant contributor to cardiovascular disease burden in sub-Saharan African for many decades. Seminal knowledge regarding heart failure in the region came from case reports and case series of the early 20th century which identified infectious, nutritional and idiopathic causes as the most common. With increasing urbanization, changes in lifestyle habits, and ageing of the population, the spectrum of causes of HF has also expanded resulting in a significant burden of both communicable and non-communicable etiologies. Heart failure in sub-Saharan Africa is notable for the range of etiologies that concurrently exist as well as the healthcare environment marked by limited resources, weak national healthcare systems and a paucity of national level data on disease trends. With the recent publication of the first and largest multinational prospective registry of acute heart failure in sub-Saharan Africa, it is timely to review the state of knowledge to date and describe the myriad forms of heart failure in the region. This review discusses several forms of heart failure that are common in sub-Saharan Africa (e.g., rheumatic heart disease, hypertensive heart disease, pericardial disease, various dilated cardiomyopathies, HIV cardiomyopathy, hypertrophic cardiomyopathy, endomyocardial fibrosis, ischemic heart disease, cor pulmonale) and presents each form with regard to epidemiology, natural history, clinical characteristics, diagnostic considerations and therapies. Areas and approaches to fill the remaining gaps in knowledge are also offered herein highlighting the need for research that is driven by regional disease burden and needs.

Survival After Alcohol Septal Ablation for Obstructive Hypertrophic Cardiomyopathy

Background—

The clinical efficacy of alcohol septal ablation for obstructive hypertrophic cardiomyopathy (HCM) has been demonstrated, but the long-term effects of the procedure remain uncertain. This study examined the survival of patients after septal ablation performed in a tertiary HCM referral center.

Methods and Results—

We examined 177 patients (mean age, 64 years; 68% women) who underwent septal ablation at our institution. Over a follow-up of 5.7 years, survival free of all mortality was no different than the expected survival for a comparable general population, and similar to that of age- and sex-matched patients who underwent isolated surgical myectomy (8-year survival estimate, 79% versus 79%; P =0.64). For the end point of documented sudden cardiac death or unknown cause of death, the incidence per 100 person-year follow-up was 1.31 (95% confidence interval, 0.60–2.38). Residual left ventricular outflow tract gradient after ablation was an independent predictor of long-term survival free of any death.

Conclusions—

In this nonrandomized study of carefully selected patients undergoing septal ablation by experienced operators in a tertiary referral HCM center, long-term survival was favorable and similar to that of an age- and sex-matched general population, and to patients undergoing surgical myectomy, as well, without an increased risk of sudden cardiac death.

Predictors of an optimal clinical outcome with alcohol septal ablation for obstructive hypertrophic cardiomyopathy

BACKGROUND

Alcohol septal ablation has emerged as a therapy for patients with obstructive hypertrophic cardiomyopathy (HCM). However, there are limited data on the predictors of success with the procedure.

METHODS

We examined patient characteristics and cardiac morphology as well as procedural data on 166 HCM patients (mean age, 63 years; 43% men), who underwent ablation at Mayo Clinic. Patients were contacted to determine vital status and symptoms to assess the primary endpoint of survival free of death and severe symptoms (New York Heart Association, class III or IV dyspnea).

RESULTS

The strongest patient characteristics that predicted clinical success were older age, less severe left ventricular outflow tract gradient, lesser ventricular septal hypertrophy, and a smaller left anterior descending (LAD) diameter. Mitral valve geometry or ventricular septal morphology did not predict outcome. Patients with ≥3 characteristics (age ≥65 years, gradient <100 mmHg, septal hypertrophy ≤18 mm, LAD diameter <4.0 mm) had superior 4-year survival free of death and severe symptoms (90.4%) in comparison to those with two characteristics (81.6%) and ≤1 characteristic (57.5%). Case volume with >50 patients was an independent predictor of survival free of severe symptoms. The volume of alcohol injected, number of arteries injected, or size of septal perforator artery were not predictive of clinical success.

CONCLUSIONS

Greater case volume and selection for key patient and anatomic characteristics are associated with superior outcomes with alcohol septal ablation.

Hypertrophic cardiomyopathy in childhood

Hypertrophic cardiomyopathy has important differences in children compared with adults, particularly with regard to the range of causes and the outcomes in infants. Survival is highly dependent on etiology, particularly in the youngest patients, and pursuit of the specific cause is therefore necessary. The clinical utility of defining the genotype in children with familial hypertrophic cardiomyopathy exceeds that at other ages and has a highly favorable cost/benefit ratio. Although most of the available information concerning treatment and prevention of sudden death is derived in adults, management of children requires consideration of the differences in age-specific risk/benefit ratios.

Sudden death in hypertrophic cardiomyopathy: old risk factors re-assessed in a new model of maximalized follow-up

AIMS

in hypertrophic cardiomyopathy (HCM), the following five risk factors have a major role in the primary prevention of sudden death (SD): family history of SD (FHSD), syncope, massive wall thickness (MWTh) >30 mm, non-sustained ventricular tachycardia (nsVT) in Holter monitoring of electrocardiography, and abnormal blood pressure response to exercise (aBPRE). In HCM, as a genetic cardiac disease, the risk for SD may also exist from birth. The aim of the study was to compare the survival curves constructed for each of the five risk factors in a traditional follow-up model (started at the first presentation of a patient at the institution) and in a novel follow-up model (started at the date of birth). In an additional analysis, we compared the survival rate in three subgroups (without FHSD, with one SD, and with two or more SDs in a family).

METHODS AND RESULTS

a total of 1306 consecutive HCM patients (705 males, 601 females, mean age of 47 years, and 193 patients were <18 years) evaluated at 15 referral centres in Poland were enrolled in the study. In a novel method of follow-up, all the five risk factors confirmed its prognostic power (FHSD: P = 0.0007; nsVT: P < 0.0001; aBPRE: P = 0.0081; syncope: P < 0.0001; MWTh P> 0.0001), whereas in a traditional method, only four factors predicted SD (except aBPRE). In a novel model of follow-up, FHSD in a single episode starts to influence the prognosis with a delay to the fifth decade of life (P = 0.0007). Multiple FHSD appears to be a very powerful risk factor (P < 0.0001), predicting frequent SDs in childhood and adolescence.

CONCLUSION

the proposed concept of a lifelong calculated follow-up is a useful strategy in the risk stratification of SD. Multiple FHSD is a very ominous risk factor with strong impact, predicting frequent SD episodes in the early period of life.

Left ventricular outflow tract gradient variability in hypertrophic cardiomyopathy

BACKGROUND

The presence and magnitude of left ventricular outflow tract (LVOT) obstruction directs the management algorithm in symptomatic patients with hypertrophic cardiomyopathy (HCM). Although it is well known that the degree of LVOT obstruction is dynamic and dependent upon ventricular load and contractility, the magnitude and potential impact of the day-to-day variability seen in practice has not been well appreciated.

HYPOTHESES

We hypothesized that LVOT gradient variability in HCM has an impact on clinical decision-making.

METHODS

A total of 100 HCM patients (mean age, 58 +/- 13 years; 47% male) underwent comprehensive 2-dimensional Doppler transthoracic echocardiography and cardiac catheterization with transseptal measurement of left-sided pressures. All studies were performed within 48 hours of one another.

RESULTS

The correlation of LVOT gradients from both methods performed at different times had a wide scatter with the 95% confidence limits of agreement being +/- 84 mm Hg. For classifying patients as having severe LVOT obstruction on the basis of either method (<30 vs > or = 30 mm Hg), discrepant results occurred in 21% of patients. To confirm the accuracy of Doppler measurements, 15 studies were performed with simultaneous measurement of LVOT gradient, which revealed a very strong correlation (r = 0.98, p < 0.0001) with 95% confidence limits of agreement +/- 12 mm Hg.

CONCLUSIONS

In patients with HCM, LVOT gradient measurements are routinely obtained to characterize the severity of obstruction. However, these data demonstrate the marked variability of the LVOT obstruction, which must be considered when determining appropriate therapy in symptomatic patients.

Role of cardiac magnetic resonance imaging in assessment of nonischemic cardiomyopathies

Diagnosis of nonischemic cardiomyopathy is a challenging process that influences patient morbidity and mortality. Currently, the well known World Health Organization classification has been revisited by an American Heart Association expert consensus panel. The contemporary classification is compatible with the rapid evolution in molecular genetics and evolving diagnostic tools such as cardiac magnetic resonance imaging (MRI). Magnetic resonance imaging is a robust diagnostic tool that offers various techniques to assess the function, morphology, perfusion, and scarring of myocardial tissue thus providing better understanding of the underlying causes of nonischemic cardiomyopathies. In this review, we discuss the current role of cardiac MRI in the evaluation of nonischemic cardiomyopathy, in the context of the current American Heart Association classification of these disorders.

Outcome of alcohol septal ablation for obstructive hypertrophic cardiomyopathy

BACKGROUND

The clinical efficacy of alcohol septal ablation for drug-refractory hypertrophic cardiomyopathy remains unclear. This study examines the outcome of alcohol septal ablation performed at a tertiary hypertrophic cardiomyopathy referral center.

METHODS AND RESULTS

Among 601 patients with severely symptomatic obstructive hypertrophic cardiomyopathy referred for alcohol septal ablation or myectomy from 1998 to 2006, 138 patients (median age, 64 years; 39% men) chose to undergo ablation. Procedural complications included death in 1.4%, sustained ventricular arrhythmias in 3%, tamponade in 3%, and pacemaker implantation in 20%. This rate was higher than a combined complication rate of 5% in age- and gender-matched patients who had undergone septal myectomy at Mayo Clinic (P<0.0001). Four-year survival free of all mortality was 88.0% (95% confidence interval, 79.4 to 97.5%), which was similar to that of the age- and gender-matched patients who had undergone myectomy (P=0.18). Six patients had documented ventricular arrhythmias after ablation, 4 of whom had successful intervention. Four-year survival free of death and severe New York Heart Association class III/IV symptoms after septal ablation was 76.4%, and 71 patients (51%) became asymptomatic. Myectomy patients <or=65 years of age had significantly better survival free of death and severe symptoms (P=0.01).

CONCLUSIONS

Alcohol septal ablation is an efficacious procedure if performed in an experienced institution and may resolve symptoms in a subset of patients with obstructive hypertrophic cardiomyopathy. However, the procedural complication rate exceeds that of myectomy. Patients 65 years of age have better symptom resolution with myectomy. No impairment in short-term survival was noted in this nonrandomized study, but the long-term outcome remains unknown.

RAAS gene polymorphisms influence progression of pediatric hypertrophic cardiomyopathy

Hypertrophic Cardiomyopathy (HCM) is a disease with variable rate of progression. Young age is an independent risk factor for poor outcome in HCM. The influence of renin-angiotensin-aldosterone (RAAS) genotype on the progression of HCM in children is unknown. Children with HCM (n = 65) were enrolled prospectively across two centers (2001-2005). All subjects were genotyped for five RAAS gene polymorphisms previously associated with LV hypertrophy (pro-LVH): AGT M235T, ACE DD, CMA-1903 A/G, AGTR1 1666 A/C and CYP11B2-344 C/T. Linear regression models, based on maximum likelihood estimates, were created to assess the independent effect of RAAS genotype on LV hypertrophy (LVH). Forty-six subjects were homozygous for <2 and 19 were homozygous for > or =2 pro-LVH RAAS polymorphisms. Mean age at presentation was 9.6 +/- 6 years. Forty children had follow-up echocardiograms after a median of 1.5 years. Indexed LV mass (LVMI) and LV mass z-scores were higher at presentation and follow-up in subjects with > or =2 pro-LVH genotypes compared to those with <2 (P < 0.05). Subjects with > or =2 pro-LVH genotypes also demonstrated a greater increase in septal thickness (IVST) and in LV outflow tract (LVOT) obstruction on follow-up (P < 0.05). On multivariate analysis, a higher number of pro-LVH genotypes was associated with a larger effect size (P < 0.05). Pro-LVH RAAS gene polymorphisms are associated with progressive septal hypertrophy and LVOT obstruction in children with HCM. Identification of RAAS modifier genes may help to risk-stratify patients with HCM.

The Role of Cardiovascular MRI in Heart Failure and the Cardiomyopathies

Heart failure (HF) is a common syndrome related to varied pathophysiologic processes. Individualization of care according to the patient's pathologic and modifiable substrate is of increasing importance. The use of modern cardiovascular MRI (CMR) provides for the centralization of diagnostic testing with the ability to assess cardiac morphology, function, flow, perfusion, acute tissue injury, and fibrosis in a single setting. This offers the potential for a paradigm shift in the noninvasive diagnosis and monitoring of patients with HF. This article outlines a diagnostic approach for the primary use of CMR in the phenotypic characterization, risk stratification, and therapeutic management of patients with HF.