Hypertrophic cardiomyopathy: a common disease with a good prognosis. Five year experience of a district general hospital

Demographics and Trends of Hypertrophic Cardiomyopathy-Related Mortality in the US, 1999-2020

BACKGROUND

There is limited data on the mortality trends of HCM in the US.

OBJECTIVE

To study the demographics and trends of mortality in patients with HCM.

METHODS

A retrospective cohort analysis was done with mortality data of patients with HCM listed as an underlying cause of death in the US Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research database (CDC-WONDER) from January 1999 to December 2020. The analysis took place in February 2022. First, we measured HCM-related Age-Adjusted Mortality Rate (AAMR) per 100,000 US population stratified by sex, race, ethnicity, and geographic area. We then calculated the Annual Percentage Change (APC) for AAMR for each.

RESULTS

A total of 24,655 HCM-related deaths occurred between 1999 and 2020. The AAMR for HCM-related deaths declined from 0.5/100,000 patients in 1999 to 0.2 in 2020. The APC changes are as follows: -6.8 (95% CI: -11.8 to -1.5) from 2002-2009, -1.23 (95%CI -13.8 to 13.2) from 2009-2014, -6.71 (95%CI -46.2 to 61.7) from 2014-2017 and remained at 2.07 (95%CI -26.1 to 41.1) from 2017-2020. Men had consistently higher AAMR than women. Overall, AAMR in men was 0.4 (95% CI: 0.4-0.5), and in women was 0.3 (95% CI: 0.3-0.3). A similar trend was noticed in men and women over the years, starting from 1999 (AAMR men: 0.7 and women: 0.4) to 2020 (AAMR men: 0.3 and women: 0.2). AAMRs were highest among black or African American patients 0.6 (95% CI: 0.5-0.6), followed by Non-Hispanic and Hispanic white 0.3 (95% CI 0.3-0.3) and Asian or Pacific Islander 0.2 (95% CI 0.2-0.2). There was substantial variation in each region in the US. States such as California, Ohio, Michigan, Oregon, and Wyoming had the highest AAMR. Large metropolitan cities had higher AAMR than non-metropolitan cities.

CONCLUSION

During the study period from 1999 to 2020, HCM-related mortality steadily decreased. The highest AAMR was observed among men, black patients, and residents of metropolitan areas. States such as California, Ohio, Michigan, Oregon, and Wyoming had the highest AAMR.

Risk factors, clinical features, and outcomes of patients with hypertrophic cardiomyopathy complicated by ischemic stroke: A single-center retrospective study

Objective

This study aimed to explore risk factors, clinical features, and prognosis of patients with hypertrophic cardiomyopathy (HCM) complicated by ischemic stroke (IS).

Methods

We conducted a retrospective analysis of all HCM patient data and a 1-year follow-up study.

Results

Totally, 506 patients with HCM, including 71 with IS, were enrolled. Older age (≥63 years) was associated with an increased risk of IS in HCM patients (OR = 1.045, 95% CI: 1.018-1.072, p = 0.001). Among 37 patients complicated by IS, 22 (59.5%, 22/37) manifested as cardioembolism (CE) subtype, and 13 (35.1%, 3/37) small artery occlusion (SAO) subtype, according to TOAST classification. In the acute phase, the IS patients presented with NIHSS 4 (interquartile range: 1, 10). Multi-infarction was more common than single infarction (72.7 vs. 27.3%), while cortical + subcortical infarction (CE group: 50%) or subcortical infarction (SAO group: 53.8%) constituted most IS cases. Additionally, the blood supply areas of anterior circulation (CE group: 45.5%; SAO group: 92.3%) or anterior + posterior circulation (CE group: 50%) were mainly involved. The 1-year survival rate of HCM patients with concomitant IS was 81.8%, and IS was associated with 1-year all-cause death in HCM patients (HR = 5.689, 95% CI: 1.784-18.144, p = 0.003).

Conclusion

Older age is a risk factor for IS occurrence in HCM patients. Patients with HCM complicated by IS had mild or moderate neurologic deficits at disease onset. CE and SAO subtypes predominate in patients with concomitant IS, especially the former. Multiple cortical and subcortical infarctions are their neuroimaging characteristics, mainly involving the anterior circulation or anterior + posterior circulation. Is is a risk factor for all-cause death in HCM patients within 1 year.

Clinical Characteristics and Healthcare Resource Utilization among Patients with Obstructive Hypertrophic Cardiomyopathy Treated in a Range of Settings in the United States

Obstructive hypertrophic cardiomyopathy (oHCM) has been studied primarily in comprehensive centers of excellence. Broadening the understanding of patients with oHCM in the general population may improve identification and treatment in other settings. This retrospective cohort study identified adults with oHCM from a large electronic medical record database comprising data from 39 integrated delivery networks (IBM Explorys; observational period: January 2009–July 2019). Clinical characteristics, healthcare resource utilization (HCRU), and outcomes were reported. Of 8791 patients, 53.0% were female and the mean index age was 61.8 years. Cardiovascular drugs prescribed included beta-blockers (80.5%), calcium channel blockers (46.0%), and disopyramide (2.4%). Over time, heart failure, atrial fibrillation, and ventricular arrhythmias increased. Surgical procedures included septal myectomy (22.0%), alcohol septal ablation (0.6%), and heart transplantation (0.3%). Implantable cardioverter defibrillators were present in 11.2% of patients. After initial septal reduction therapy (SRT), HCRU increased and 550 patients (27.7%) required a reintervention. Of the overall group, 2.7% experienced sudden cardiac arrest by end of study. In conclusion, this cohort of patients with oHCM had guideline-recommended drug therapy and procedures. Despite this, heart failure, atrial fibrillation, and ventricular arrhythmias increased, and more than a quarter of patients undergoing SRT required reintervention. These unresolved issues emphasize the unmet need for new, effective therapies for patients with oHCM.

Hypertrophic Cardiomyopathy in "Real-World" Community Cardiology Practice

Differences in presentation and natural history of hypertrophic cardiomyopathy (HC) between community cardiology practice and referral centers has been a source of considerable uncertainty. We report here a cross-sectional analysis of 253 consecutive HC patients from a "real-world" clinical cardiology setting. When compared with a highly selected referral center cohort, patients in clinical practice proved to be similar with regard to disease expression such as left ventricular (LV) wall thickness, outflow obstruction, and natural history, including stable and largely benign clinical course with no or mild symptoms (61% in community practice vs. 55% in referred patients, p = 0.23), occurrence of atrial fibrillation (22% vs. 24%, p = 0.75) and nonfatal sudden death (SD) events (3% vs. 4%, p = 0.8). In contrast, progressive heart failure symptoms were most common in the referral cohort (36% vs. 26%, p = 0.04). In clinical practice, SD was prevented by prophylactic implatable cardioverter defibrillators (ICD) in 5 of 44 patients (11%), although risk was overestimated in 6 patients who were implanted with ICDs in the absence of risk markers (14%). In 16 of 61 (26%) severely symptomatic drug-refractory patients with LV outflow obstruction, recommendation for surgical myectomy (or alcohol septal ablation) was delayed. In conclusion, clinical characteristics and course of HC patients in community practice were generally similar to those in HC referral centers. Community cardiologists managed HC patients predominantly in concert with guideline-based strategies, although risk for SD could be overestimated, and the significance of outflow obstruction with timely reversal of refractory heart failure by intervention was underappreciated.

Modes of death and clinical outcomes in adult patients with hypertrophic cardiomyopathy in Thailand

Background

There are limited data about modes of death and major adverse cardiovascular events (MACEs) in patients with hypertrophic cardiomyopathy (HCM) in South East Asian population. The aim of the study was to examine modes of death and clinical outcomes in Thai patients with HCM.

Methods

Between January 1, 2009 and December 31, 2013, 166 consecutive patients with HCM diagnosed in our institution were evaluated. Five patients were excluded because of non-Thai ethnic groups (n = 3) and diagnosis of myocardial infarction at initial presentation documented by coronary angiography (n = 2). The final study population consisted of 161 patients with HCM. HCM-related deaths included: (1) sudden cardiac death (SCD) – death due to sudden cardiac arrest or unexpected sudden death; (2) heart failure – death due to refractory heart failure; or (3) stroke - death due to embolic stroke associated with atrial fibrillation. MACEs included: (1) SCD, sudden unexpected aborted cardiac arrest, fatal, or nonfatal ventricular arrhythmia (ventricular fibrillation or sustained ventricular tachycardia); (2) heart failure (fatal or non-fatal), or heart transplantation; or (3) stroke - fatal or non-fatal embolic stroke associated with atrial fibrillation.

Results

One hundred and sixty-one Thai patients with HCM (age 66 ± 16 years, 58% female) were enrolled. Forty-two patients (26%) died over a median follow-up period of 6.8 years including 25 patients (16%) with HCM-related deaths (2%/year). The HCM-related deaths included: heart failure (52% of HCM-related deaths; n = 13), SCD (44% of HCM-related deaths; n = 11), and stroke (4% of HCM-related deaths, n = 1). The SCDs occurred in 6.8% of patients (1%/year). Eighty-four major MACEs occurred in 65 patients (41, 5%/year). The MACEs included: 40 heart failures in which 2 patients underwent heart transplants; 22 SCDs and nonfatal ventricular arrhythmias; and 22 fatal or nonfatal strokes.

Conclusions

The most common mode of death in adult patients with HCM in Thailand was heart failure followed by SCD. About one-third of the patients experiencing heart failure died during the 6.8 years of follow-up. SCDs occurred in 7% of patients (1%/year), predominantly in the fourth decade or later.

Slowed atrial and atrioventricular conduction and depressed HRV in a murine model of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common heritable cardiac disorder with diverse clinical outcomes including sudden death, heart failure, and stroke. Depressed heart rate variability (HRV), a measure of cardiac autonomic regulation, has been shown to predict mortality in patients with cardiovascular disease. Cardiac autonomic remodelling in animal models of HCM are not well characterised. This study analysed Gly203Ser cardiac troponin-I transgenic (TG) male mice previously demonstrated to develop hallmarks of HCM by age 21 weeks. 33 mice aged 30 and 50 weeks underwent continuous electrocardiogram (ECG) recording for 30 min under anaesthesia. TG mice demonstrated prolonged P-wave duration (P < 0.001) and PR intervals (P < 0.001) compared to controls. Additionally, TG mice demonstrated depressed standard deviation of RR intervals (SDRR; P < 0.01), coefficient of variation of RR intervals (CVRR; P < 0.001) and standard deviation of heart rate (SDHR; P < 0.001) compared to controls. Additionally, total power was significantly reduced in TG mice (P < 0.05). No significant age-related difference in either strain was observed in ECG or HRV parameters. Mice with HCM developed slowed atrial and atrioventricular conduction and depressed HRV. These changes were conserved with increasing age. This finding may be indicative of atrial and ventricular hypertrophy or dysfunction, and perhaps an indication of worse clinical outcome in heart failure progression in HCM patients.

Prognostic role of clinical presentation in symptomatic patients with hypertrophic cardiomyopathy

AIMS

To evaluate the long-term prognostic impact of baseline symptoms in a cohort of hypertrophic cardiomyopathy (HCM) patients.

METHODS AND RESULTS

We considered 84 HCM patients symptomatic at diagnosis: 26 (31%) with heart failure (group 1), 34 (40%) with syncope/palpitations (group 2) and 24 (29%) with chest pain (group 3). During a median follow-up of 102 (53-187) months, 25 (30%) patients died/underwent heart transplant (HTx), 14 of 26 (54%) in group 1, 10 of 34 (29%) in group 2 and one of 24 (4%) in group 3. At 12, 60 and 120 months, HTx-free survival rates were 100, 79 and 52% in group 1, vs. 100, 97 and 69% in group 2, vs. 96, 96 and 96% in group 3, respectively (P = 0.008). At multivariate analysis, heart failure [hazard ratio (HR) 2.59, confidence interval (CI) 95% 1.09-6.17, P = 0.032] and left atrium diameter (HR 1.83, CI 95% 1.16-2.89, P = 0.009) emerged as independent predictors of death/HTx, with incremental prognostic power with respect to echo Doppler variables of left ventricular systolic and diastolic dysfunction [area under the curve (AUC) of receiver operating characteristics (ROC) curves at 5 years: 0.90 vs. 0.78, respectively, P = 0.03].

CONCLUSION

Clinical presentation emerged as a relevant prognostic tool in HCM patients symptomatic at onset, as heart failure was associated with a particularly poor outcome. Heart failure and left atrium diameter at diagnosis showed incremental prognostic power compared with echo Doppler assessment of left ventricular systolic and diastolic dysfunction.

Prevalence of isolated atrial amyloidosis in young patients affected by congestive heart failure

Atrial natriuretic peptide (ANP), whose amyloid is responsible of isolated atrial amyloidosis (IAA), is known to play an important role in the pathophysiology of congestive heart failure (CHF). We provide here the microscopic examination of atrial biopsies from 36 young (mean 40 years) CHF patients distinguished in idiopathic dilated cardiomyopathy (DC) affected and hypertrophic Cardiomyopathy (HC) affected, endorsing the presumptive association of early CHF with IAA. We utilized a multiple method, using Congo red (CR) staining, CR fluorescence (CRF), and immunohistochemistry to assess the presence of IAA in CHF. Immunostaining showed a moderate deposition of IAA in the atrium surrounding working myocardium with small intracellular deposits. Our findings suggest a monitoring of young CHF cases for the development of IAA. Our study also demonstrated how the concurrent use of immunohistochemistry, CR, and CRF may greatly enhance the detection of low-grade amyloid deposits.

Historical trends in reported survival rates in patients with hypertrophic cardiomyopathy

OBJECTIVE

To determine the range of survival rates of patients with hypertrophic cardiomyopathy (HCM) by comparing and contrasting the natural history of a cohort of patients seen between 1988 and 2002 with that of other published series.

METHODS

956 adult (> or = 16 years old) patients with HCM (572 men, mean (SD) age 42 (15) years, range 16-88) were evaluated by ECG, Holter, exercise testing, and echocardiography. Patient characteristics and survival data were compared with those in natural history studies from referral and non-referral centres published between 1960 and January 2003.

RESULTS

The duration of follow up was 69 (45) months. 120 (12.6%) patients died or underwent cardiac transplantation. Sudden cardiac death (n = 48) was the most common mode of death. The annual rate of sudden death or implantable cardioverter-defibrillator discharge was 1.02 (95% confidence interval (CI) 0.76 to 1.26). Annual rates for heart failure death or transplantation and stroke related death were 0.55% (95% CI 0.37% to 0.78%) and 0.07% (95% CI 0.02% to 0.19%), respectively. When studies published within the last 10 years of the study period were compared with earlier reports, the size of individual study cohorts was larger (309 (240.6) v 136.5 (98.8), p = 0.058) and the proportion with severe functional limitation NYHA class III/IV lower (12.4% v 24.8%, p < 0.0001), and fewer patients underwent septal myotomy-myectomy (5.2% v 18.7%, p < 0.0001). Published sudden death rates over the last 10 years were lower than previously published figures (median 1.0% (range 0.1-1.7) v 2.0% (0-3.5)).

CONCLUSION

Published survival rates in HCM cohorts have improved progressively over the past 40 years. In the modern era the prevalence of disease related complications is similar in all reporting centres.

Benign outcome in a long-term follow-up of patients with hypertrophic cardiomyopathy in Brazil

BACKGROUND

Selected patients with hypertrophic cardiomyopathy (HCM) have 3% to 4% annual mortality as compared to only 0.5% to 1.5% in nonselected patients. Our aim was to evaluate survival and prognostic factors in HCM in patients in a tertiary care center.

METHODS

From 1980 to 1997, 214 patients were prospectively studied, with a mean follow-up of 7 years (range 1-25 years); there were 102 male and 112 female patients, aged 37 +/- 16 years (range 3-76 years). All patients had 12-lead electrocardiogram, 24-hour Holter monitor, and surface echocardiography. Univariate analysis was performed for known adverse factors such as young age, family history, syncope, functional class, atrial fibrillation, ventricular hypertrophy, left ventricular outflow tract obstruction, and nonsustained ventricular tachycardia.

RESULTS

There were 22 deaths (10%), 15 directly related to HCM (sudden in 11). The cumulative survival rates were 94.5% at 5 years, 91% at 10 years, and 87.9% at 15 years. The annual mortality rate was 1%. Only New York Heart Association functional class III/IV and maximal ventricular wall thickness >30 mm were associated with HCM-related cardiac death.

CONCLUSIONS

We concluded that even a referred population of HCM patients may have a relatively benign outcome. Prognosis is related to advanced functional class and degree of left ventricular hypertrophy.

Hypertrophic cardiomyopathy in a large community-based population: clinical outcome and identification of risk factors for sudden cardiac death and clinical deterioration

OBJECTIVES

This study evaluates the clinical course and identifies risk factors for sudden cardiac death (SCD) and clinical deterioration in hypertrophic cardiomyopathy (HCM) in a large community-based population. Comparison was made with data from six tertiary referral and six nonreferral institutions.

BACKGROUND

Hypertrophic cardiomyopathy is a disease with marked heterogeneity in clinical presentation and prognosis. Risk factors for SCD are not well defined in patients free of referral bias.

METHODS

Between 1970 and 1999, 225 consecutive patients (mean age [+/-SD] 41+/-16 years) were examined and followed at yearly intervals.

RESULTS

Forty-four deaths were recorded of which 27 cases were cardiovascular. Fourteen patients died suddenly, six were successfully resuscitated, and seven patients died of congestive heart failure. The annual mortality, annual cardiac mortality, and annual mortality due to sudden death were 1.3%, 0.8%, and 0.6%, respectively. At least one New York Heart Association (NYHA) functional class deterioration was reported in 33% of the patients with a significant (> or =50 mm Hg) left ventricular outflow tract (LVOT) gradient in contrast to 7% without obstruction. The presence of syncope was related to SCD (p < 0.05). Younger age and more severe functional limitation distinguishes patients from in hospital-based centers from the ones in community-based centers.

CONCLUSIONS

Hypertrophic cardiomyopathy is a benign disease in an unselected population with a low incidence of cardiac death. Syncope was associated with a higher incidence of SCD and patients with a significant LVOT obstruction were more susceptible to clinical deterioration.

The role of pharmacologic treatment to prevent sudden death in the implantable cardioverter defibrillator era

The prevention of sudden death remains a key aspect of clinical management in patients with hypertrophic cardiomyopathy (HCM). For many years, amiodarone has been widely used to treat and prevent symptomatic atrial arrhythmias in patients with HCM, but its role in the prevention of potentially fatal ventricular arrhythmia has remained controversial. The publication of several observational studies examining the efficacy of implantable cardioverter defibrillators (ICDs) in patients with the disease has stimulated a re-evaluation of the drug's place in the management of HCM. This article reviews the literature on amiodarone therapy in HCM and discusses the indications for its use in the ICD era.

Current management of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is a familial cardiac disorder with heterogeneous expression and a diversity of morphological, functional and clinical features. Some individuals with hypertrophic cardiomyopathy may be asymptomatic while others are disabled by symptoms of angina and breathlessness. This article summarizes the genetics, pathophysiology and present management of this important condition.

Heart rate variability in hypertrophic obstructive cardiomyopathy: association with functional classification and left ventricular outflow gradients

BACKGROUND

The aim of this study was to investigate cardiac autonomic control in patients with hypertrophic obstructive cardiomyopathy (HOCM) and to assess the indexes of heart rate variability (HRV) in relation to the clinical and echocardiographic features.

METHODS AND RESULTS

Twenty-three patients (17 male, six female: mean age 43+/-11) with HOCM and 18 healthy volunteers were included. M-mode and two-dimensional echocardiography, pulsed and continuous-wave Doppler studies were obtained. All patients and volunteers underwent continuous 24-h ambulatory ECG monitoring. Time domain variables considered in this study were standard deviation of mean R-R intervals (SDNN), root mean-squared successive difference (RMSSD) and percentage of cycles differing from the preceding one by more than 50 ms (PNN 50%). Patients were compared to detect associations between indices of heart rate variability, left ventricular outflow tract obstruction and clinical status. Heart rate variability parameters were also correlated with the echocardiographic and clinical characteristics of the patients. Both New York Heart Association (NYHA) functional class I-II patients (group I) and NYHA III-IV patients (group II) had lower values of SDNN, RMSSD and PNN 50% when compared with the control group (P<0.001, P<0.05 and P<0.01, respectively, for group I and P<0.001, P<0.001 and P<0.001, respectively, for group II). Time domain heart rate variability parameters were found to be significantly correlated with the subaortic dynamic obstruction.

CONCLUSION

Heart rate variability is reduced in HOCM and well correlated with the degree of subaortic obstruction. Heart rate variability indices are also sensitive markers of the functional status.

Sudden death in hypertrophic cardiomyopathy: identification of high risk patients

OBJECTIVES

We sought to identify patients with hypertrophic cardiomyopathy (HCM) at high risk of sudden death (SD).

BACKGROUND

Relatively low mortality rates in HCM make conventional analysis of multiple clinical risk markers for SD problematic. This study used a referral center registry to investigate a smaller number of generally accepted noninvasive risk markers.

METHODS

We studied 368 patients (14 to 65 years old, 239 males) with HCM. There were five variables: nonsustained ventricular tachycardia (NSVT), syncope, exercise blood pressure response (BPR), family history of sudden death (FHSD) and left ventricular wall thickness (LVWT).

RESULTS

During follow-up (3.6+/-2.5 years [range 2 days to 9.6 years]), 36 patients (9.8%) died, 22 of them suddenly. Two patients received heart transplants. The six-year SD-free survival rate was 91% (95% confidence interval [CI] 87% to 95%). In the Cox model, there was a significant pairwise interaction between FHSD and syncope (p = 0.01), and these were subsequently considered together. The multivariate SD risk ratios (with 95% CIs) were 1.8 for BPR (0.7 to 4.4) (p = 0.22); 5.3 for FHSD and syncope (1.9 to 14.9) (p = 0.002); 1.9 for NSVT (0.7 to 5.0) (p = 0.18) and 2.9 for LVWT (1.1 to 7.1) (p = 0.03). Patients with no risk factors (n = 203) had an estimated six-year SD-free survival rate of 95% (95% CI 91% to 99%). The corresponding six-year estimates (with 95% CIs) for one (n = 122), two (n = 36) and three (n = 7) risk factors were 93% (87% to 99%), 82% (67% to 96%) and 36% (0% to 75%), respectively. Patients with two or more risk factors had a lower six-year SD survival rate (95% CI) compared with patients with one or no risk factors (72% [56% to 88%] vs. 94% [91% to 98%]) (p = 0.0001).

CONCLUSIONS

This study demonstrates that patients with multiple risk factors have a substantially increased risk of SD sufficient to warrant consideration for prophylactic therapy.

Natural history of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is a disease of the cardiac sarcomere and is the most common inherited cardiovascular disorder affecting up to 1 in 500 people in the general population. The disease is typified by variable clinical penetrance and heterogeneous clinical expression, resulting in a wide range of clinical manifestations. Most patients have few if any symptoms and a relatively benign clinical course. A minority are at risk of serious complications including ventricular arrhythmia, sudden death, thromboembolism, congestive cardiac failure, heart block, and infective endocarditis. This article reviews the natural history of the disease, with particular emphasis on lessons learned from recent genetic studies.

Prognostic value of systemic blood pressure response during exercise in a community-based patient population with hypertrophic cardiomyopathy

OBJECTIVES

The present study was designed to prospectively evaluate the prognostic relevance of abnormal blood pressure response to exercise (ABPR), defined as hypotension or failed blood pressure increase (<20 mm Hg) with exercise, in a community-based hypertrophic cardiomyopathy (HCM) population representative of the overall disease spectrum.

BACKGROUND

Abnormal blood pressure response to exercise has been proposed as a marker for hemodynamic instability and increased risk for disease-related mortality in highly selected patient populations with HCM.

METHODS

The study population comprised 126 patients (aged 42+/-14 years) who underwent maximal symptom-limited cycloergometer exercise testing as part of the standard evaluation at our institution, and who were followed systematically for 4.7+/-3.7 years after testing.

RESULTS

Of the 126 study patients, 98 (78%) had a normal blood pressure response during exercise, whereas the other 28 (22%) had ABPR, including nine with hypotension and 19 with failed blood pressure rise. During the follow-up period, nine patients (7%) died of HCM-related causes (three suddenly and six heart failure-related), of whom four had ABPR. In those patients aged < or =50 years, survival analysis after exercise testing showed a significantly increased risk for cardiovascular mortality associated with ABPR compared with a normal exercise response (p = 0.04), with an odds ratio of 4.5 (95% confidence interval: 1.1, 20.1). However, ABPR showed low positive predictive accuracy for cardiovascular mortality (i.e., 14%), whereas negative predictive accuracy was high (i.e., 95%).

CONCLUSIONS

A hypotensive blood pressure response during exercise occurred in over 20% of a community-based patient cohort with HCM, and was associated with adverse long-term prognosis in patients <50 years old. However, the positive predictive accuracy of this blood pressure response is too low to justify modifications of clinical management or to allow identification of the high-risk patient based solely on an abnormal test result. By virtue of its high negative predictive accuracy for HCM-related mortality, the blood pressure response to exercise appears to be most valuable (in conjunction with the absence of other well recognized risk factors) as a screening test for the identification of low-risk subsets of patients.

Prognosis of completely asymptomatic adult patients with hypertrophic cardiomyopathy

OBJECTIVES

We investigated the long-term prognosis of completely asymptomatic adult patients with hypertrophic cardiomyopathy (HC). Diagnosis of HC was suspected because of an abnormal electrocardiogram and/or cardiac murmur and confirmed by echocardiography and/or left ventricular angiography, and hemodynamic investigation.

BACKGROUND

Hypertrophic cardiomyopathy shows marked heterogeneity in clinical expression and prognosis. The prognosis of asymptomatic patients with HC has not been fully defined.

METHODS

Of 128 consecutive adult patients with HC, 58 asymptomatic patients (Group 1, mean age 42.8 years) and 70 symptomatic patients (Group 2, mean age 50.4 years) were studied to assess cardiac mortality. Mean follow-up periods were 11.0 years for Group 1 and 9.1 years for Group 2.

RESULTS

At presentation, Group 1 patients were younger and had smaller left atrial dimensions than did Group 2 patients. The annual cardiac mortality rate and the rate for sudden death alone in Group 1 were significantly lower than in Group 2 (0.9% vs. 1.9%, p < 0.05, 0.1% vs. 1.4%, p < 0.05, respectively). Although about one-third of the survivors in Group 1 had cardiac symptoms at their most recent evaluation, only one patient died suddenly compared with eight in Group 2. The annual mortality rate due to heart failure was similar in each group. Only a syncopal episode was associated with both cardiac death and sudden death for both groups combined.

CONCLUSIONS

The cardiac mortality rate for completely asymptomatic adult patients with HC was very low, significantly lower than that of symptomatic patients, and there was a disproportionately low incidence of sudden death.

Prognostic value of non-sustained ventricular tachycardia and the potential role of amiodarone treatment in hypertrophic cardiomyopathy: assessment in an unselected non-referral based patient population

BACKGROUND

Amiodarone has been reported to reduce the likelihood of sudden death in patients with hypertrophic cardiomyopathy (HCM). However, data regarding the clinical course in HCM have traditionally come from selected referral populations biased toward assessment of high risk patients.

AIMS

To evaluate antiarrhythmic treatment for sudden death in an HCM population not subject to tertiary referral bias, closely resembling the true disease state present in the community.

METHODS

Cardiovascular mortality was assessed in relation to the occurrence of non-sustained ventricular tachycardia (NSVT) on 24 or 48 hour ambulatory Holter recording, a finding previously regarded as a marker for sudden death, particularly when the arrhythmia was frequent, repetitive or prolonged. 167 consecutive patients were analysed by multiple Holter ECG recordings (mean (SD) 157 (129) hours) and followed for a mean of 10 (5) years. Only patients with multiple repetitive NSVT were treated with amiodarone, and in relatively low. doses (220 (44) mg/day).

RESULTS

Nine HCM related deaths occurred: 8 were the consequence of congestive heart failure, but only 1 was sudden and unexpected. Three groups of patients were segregated based on their NSVT profile: group 1 (n = 39), multiple (> or = 2 runs) and repetitive bursts (on > or = 2 Holters) of NSVT, or prolonged runs of ventricular tachycardia, included 4 deaths due to heart failure; group 2 (n = 38), isolated infrequent bursts of NSVT, included 1 sudden death; group 3 (n = 90), without NSVT, included 4 heart failure deaths. Kaplan-Meier survival analysis showed no significant differences in survival between the three groups throughout follow up.

CONCLUSIONS

In an unselected patient population with HCM, isolated, non-repetitive bursts of NSVT were not associated with adverse prognosis and so this arrhythmia does not appear to justify chronic antiarrhythmic treatment. Amiodarone, administered in relatively low doses, did not carry an independent and additive risk for cardiac mortality. Amiodarone may have contributed to the absence of sudden cardiac death in patients believed to be at higher risk because of multiple repetitive NSVT.

Myocardial blood flow and metabolism in patients with hypertrophic cardiomyopathy--a study with carbon-11 acetate and positron emission tomography

The underlying pathophysiology of hypertrophic cardiomyopathy (HCM) is still unclear. positron emission tomography is a suitable and promising technique for the detection of possible metabolic consequences of the disease. To assess regional myocardial blood flow and metabolism, 19 asymptomatic or only mildly symptomatic patients with HCM and 10 normal control subjects were studied using carbon-11 acetate and fluorine-18-labelled deoxyglucose (FDG) as tracers of myocardial blood flow (Ao), oxygen consumption (k), and exogenous glucose utilization. In the patients, regional Ao in the hypertrophied septum and apex (H) was similar to that in the nonhypertrophied free wall (N) (91.3 +/- 3.9% vs 92.9 +/- 3.1%; p = NS). However, the k values were significantly lower in H than in N (0.044 +/- 0.012 vs 0.060 +/- 0.016/min, p < 0.0001). The k value in N and normal control subjects (0.062 +/- 0.013) was similar. Postprandial FDG uptake was lower in H than in N (70 +/- 16 vs 91 +/- 7%; p < 0.0001) in 16 patients and slightly higher in 3 patients. Fasting FDG study showed increased FDG uptake in H in 3 out of 13 patients, suggesting a disorder of the myocardial microvascular circulation. A relative decrease in hypertrophied septal and apical oxidative metabolism and glucose utilization without any corresponding perfusion defect could reflect abnormal regional aerobic metabolism in the disproportionately thickened myocardium in patients with HCM. This suggests that a primary myocardial metabolic defect might be present in patients with HCM.

Hypertrophic cardiomyopathy in Tuscany: clinical course and outcome in an unselected regional population

OBJECTIVES

Our aim was to study a population of patients with hypertrophic cardiomyopathy from the well defined geographic region of Tuscany in central Italy, a group virtually free of selective referral bias and therefore probably closely representative of the true patient population with this disease.

BACKGROUND

Most available information on clinical course, natural history and prognosis of hypertrophic cardiomyopathy is based on data generated from tertiary referral centers and therefore constitutes a potentially biased perspective of the disease process in this complex and diverse condition.

METHODS

The study group comprised 202 patients aged 1 to 74 years (mean +/- SD 41 +/- 17) at initial diagnosis and followed up for 1 to 30 years (mean 10 +/- 5).

RESULTS

Largely with the use of single or multiple drug therapy, the vast majority of patients (n = 154 [76%]) were asymptomatic or mildly symptomatic and in stable or improved condition over the period of follow-up, whereas the remaining patients (n = 48 [24%]) experienced deterioration, had substantial functional impairment or died. Of the 13 patients (6%) who died of cardiovascular causes related to hypertrophic cardiomyopathy, 11 had progressive congestive heart failure (including 6 in the end-stage phase) and only 2 died suddenly. The annual mortality rate for cardiovascular disease was 0.6% and that due to sudden cardiac death was only 0.1%; the cumulative survival rate was 97%, 95% and 92%, respectively, at 5, 10 and 15 years of follow-up. Atrial fibrillation proved to be a relatively common (n = 57 [28%]) and particularly unfavorable clinical feature, with premature death occurring in 9 of the 57 patients. The cumulative survival rate after 15 years was 76% for patients with atrial fibrillation versus 97% for patients with sinus rhythm. Syncope occurred in 33 patients (16%) but did not appear to be of prognostic significance.

CONCLUSIONS

In an unselected regional population, hypertrophic cardiomyopathy had a relatively benign prognosis inconsistent with its prior characterization as a generally progressive disorder, based primarily on the experience of selected referral institutions. Sudden unexpected cardiac death was distinctly uncommon, although a sizable proportion of patients (particularly the subset prone to atrial fibrillation), did experience clinical deterioration.

Natural history of hypertrophic cardiomyopathy. A population-based study, 1976 through 1990

BACKGROUND

Hypertrophic cardiomyopathy is a disease entity characterized by marked heterogeneity in morphology and natural history. Most of our knowledge of the natural history of this disorder derives from the study of hospital-based populations and is influenced by referral bias. Therefore, this population-based study was undertaken to examine the natural history of hypertrophic cardiomyopathy among unselected residents of Olmsted County, Minnesota.

METHODS AND RESULTS

Patients with hypertrophic cardiomyopathy, confirmed by echocardiography, were identified by use of the resources of the Rochester Epidemiology Project. Patients with the echocardiographic features of hypertrophic cardiomyopathy but with long-standing hypertension requiring drug therapy were categorized as having hypertensive hypertrophic cardiomyopathy. Baseline clinical details and follow-up events were obtained by retrospective chart review. Thirty-seven patients were diagnosed with hypertrophic cardiomyopathy and 24 with hypertensive hypertrophic cardiomyopathy. Eight additional patients were first diagnosed at autopsy. The mean age of the 37 patients with hypertrophic cardiomyopathy was 59 +/- 20 years (range, 1 week to 92 years); the mean ventricular septal thickness was 17.5 +/- 3 mm. Follow-up was obtained for a median of 7.7 years (range, 45 days to 17.2 years). The 1- and 5-year survival rates were 95% and 92%, respectively; these rates did not differ from those of an age- and sex-matched population (P = NS). The annual risk of cardiac death was 0.7%. The mean age of patients with hypertensive hypertrophic cardiomyopathy was 79 +/- 8 years (range, 62 to 91 years), and the mean ventricular septal thickness was 19 +/- 2.5 mm. Follow-up was obtained for a median of 2.8 years (range, 4 days to 16.7 years). The 1- and 5-year survival rates were 75% and 43%, respectively, which differed sharply from the expected rates of 94% and 70% (P = .0028). The annual risk of cardiac death was 5%. Atrial fibrillation and evidence for myocardial infarction on ECG, use of digoxin and diuretics, and a high New York Heart Association functional class at presentation were all associated with decreased survival by multivariate analysis for both groups combined. A history of myocardial infarction, atrial fibrillation, and mitral annual calcification at presentation were associated with cardiac death.

CONCLUSIONS

Hypertrophic cardiomyopathy is a more benign disease than previously reported from tertiary referral centers. Patients assessed as having hypertensive hypertrophic cardiomyopathy represent a subset at higher risk for cardiac and noncardiac death, with an overall decreased survival rate.

Prevalence of hypertrophic cardiomyopathy in an outpatient population referred for echocardiographic study

Although hypertrophic cardiomyopathy (HC) is believed to be a relatively uncommon cardiac disease, the frequency with which it occurs in the general or cardiac population has not been defined. To address this issue, the patient population of a community-based echocardiography laboratory was used to assess the prevalence of HC in 714 consecutively studied outpatients with (or suspected of having) heart disease. The most common cardiac disease identified was mitral valve prolapse (73 patients [10%]), and HC was present in 4 patients (0.5%). Ages were 50 to 69 years. Maximal left ventricular wall thicknessess were 15 to 22 mm (mean 19); only 1 had evidence of obstruction to left ventricular outflow by virtue of marked mitral valve systolic anterior motion. Before echocardiographic study, each of the 4 patients with HC had signs or symptoms of cardiac disease, but the correct diagnosis had not been suspected. Of 11 other patients who were referred for echocardiographic study because of a clinical suspicion of HC, none proved to have this disease. The present study demonstrates that HC is a particularly uncommon disease entity occurring in about 0.5% of an unselected outpatient population referred for echocardiographic study.

Natural history of idiopathic dilated cardiomyopathy: effect of referral bias and secular trend

OBJECTIVES

The current study was designed to determine the effect of secular trend and referral bias on the natural history of idiopathic dilated cardiomyopathy.

BACKGROUND

In a previous study of 104 patients with idiopathic dilated cardiomyopathy conducted in a referral population at the Mayo Clinic between 1960 and 1973, the 1- and 5-year mortality rates were 31% and 64%, respectively. A recent study of 40 patients with idiopathic dilated cardiomyopathy conducted in a population-based cohort at the Mayo Clinic between 1975 and 1984 reported 1- and 5-year mortality rates of 5% and 20%, respectively. We hypothesized that improvements in diagnosis and therapy have occurred since the original referral cohort was described and that these improvements have altered the apparent natural history of the disease. We refer to this effect as secular trend. Alternatively, the presence of more advanced disease in the referral population (referral bias) may also contribute to the differences in survival.

METHODS

Two sequential referral populations with idiopathic dilated cardiomyopathy seen at the Mayo Clinic between 1976 and 81 (n = 85) and 1982 and 1987 (n = 137) were identified. Outcome was compared between these cohorts and the 1960-1973 referral cohort to examine the effect of secular trend. Outcomes were compared with that of the population-based cohort to examine the effect of referral bias.

RESULTS

Survival in the 1976-1981 referral cohort did not differ from that in the 1960-1973 referral cohort, suggesting little impact of secular trend during these time periods. Survival in the more recent 1982-1987 referral cohort was significantly better than that in the earlier referral cohorts, suggesting that improvements in diagnosis and treatment in the 1980s altered the natural history of idiopathic dilated cardiomyopathy. Survival in the 1982-1987 referral cohort was still worse than that of the population-based cohort, suggesting an effect of referral bias on studies of the natural history of idiopathic dilated cardiomyopathy.

CONCLUSIONS

The current study demonstrates that secular trend and referral bias affect the apparent natural history of idiopathic dilated cardiomyopathy. Survival in referral patients with this disease is significantly better than previously described.

The prevalence of hypertrophic cardiomyopathy in men: an echocardiographic population screening study with a review of death records

The purpose of this study was to estimate the prevalence of hypertrophic cardiomyopathy (HCM) in 3607 men from the Reykjavik study of 1979-81. Of these, 452 men had an abnormal (group A) and 3155 a normal electrocardiogram. An echocardiographic control group of 128 men was selected from cohorts with a normal electrocardiogram (group B). Until 1987, 189 deaths had occurred, 59 from group A and 130 from cohorts with a normal ECG including 4 from group B. To identify subjects with HCM, survivors of groups A and B were examined by echocardiography and by review of all autopsy data and death certificates. HCM was found in 14 subjects from group A but none in group B. Two additional cases were found at autopsy in cohorts with a normal ECG. The prevalence of HCM in men with an abnormal and normal ECG was 3.6% and 0.8%, respectively. The overall prevalence was calculated to be 1.1% with a 95% confidence interval of 0.3-3.2%. Men with HCM reported more symptoms than others in groups A and B (P < 0.05-0.001). 25% were without symptoms. Asymptomatic ventricular arrhythmias were detected by Holter monitoring in 45% of men with HCM. The total annual mortality was 1.6% compared with 0.5% in the group with a normal ECG (P < 0.001).

Clinical course of middle-aged asymptomatic patients with hypertrophic cardiomyopathy

Patients with hypertrophic cardiomyopathy (HC) may present a wide spectrum of clinical and morphologic manifestations. Although many aspects of the natural history of HC are understood, the initial presentation and subsequent clinical course of certain subgroups are not yet well defined. To further our understanding in this regard, 241 middle-aged patients with HC (aged 35 to 55 years) were analyzed. The vast majority of patients (210) had already experienced symptoms, whereas the remaining 31 initially presented with no or minimal symptoms and are the focus of this investigation; 29 of these were followed for greater than or equal to 2 years (range to 11.5 years, mean 8). A separate group of 30 moderately symptomatic age- and gender-matched patients with HC were selected as control subjects for morphologic comparisons. Of the 29 study patients with follow-up, 22 (76%) are presently free of important cardiac symptoms, but 3 showed progression of symptoms, and 4 have died suddenly. Annual mortality rate was 1.7%. Eighteen of the middle-aged asymptomatic patients with HC (58%) had localized left ventricular hypertrophy, usually involving only the anterior ventricular septum; in contrast, only 9 of the 30 symptomatic control subjects (30%) had such localized hypertrophy (p = 0.02). In conclusion, of those patients with HC who achieved middle-age without developing important cardiac symptoms, approximately 75% remained asymptomatic during the ensuing average 8-year follow-up. However, such patients are not protected in absolute terms from unfavorable clinical events (despite relatively mild left ventricular hypertrophy and in most cases absence of outflow obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Severity of arrhythmias and extent of hypertrophy in hypertrophic cardiomyopathy

To evaluate the relationship between the extent of left ventricular hypertrophy and ventricular or atrial arrhythmias, 77 patients with hypertrophic cardiomyopathy underwent two-dimensional echocardiography and 24-hour Holter monitoring. Antiarrhythmic treatment was discontinued before the study. Hypertrophy was septal in 33 patients, "extensive" (i.e., involving the septum and free wall) in 38 patients, and predominantly apical in six patients. Lown grade I and II ventricular arrhythmias were detected in 37% of patients, grade III in 21%, and grade IV in 29%. Atrial extrasystoles were seen in 52% of patients and chronic atrial fibrillation in 13%. More serious ventricular arrhythmias (Lown grades III and IV) occurred significantly more frequently in patients with extensive than in those with only septal hypertrophy (22/38 vs 11/33; p less than 0.001); similarly, chronic atrial fibrillation occurred more commonly in those with extensive hypertrophy (9/38 vs 1/33; p less than 0.01). During a mean follow-up period of 2.6 years, three patients died. All had a pattern of extensive hypertrophy. Two of them had ventricular tachycardia and the third had chronic atrial fibrillation. Results of this study suggest that an echocardiographic finding of extensive hypertrophy represents a useful marker for detecting patients at increased risk for serious ventricular and atrial arrhythmias.

The significance of increased left ventricular outflow tract velocities in the elderly measured by continuous wave Doppler

Forty-four elderly patients (mean age 80 +/- 7 years) with elevated left ventricular outflow tract velocities and corresponding outflow tract gradients documented by continuous wave Doppler are reported (mean peak gradient 50 +/- 28). They had severe left ventricular hypertrophy, small left ventricular end-diastolic dimensions, and supernormal ejection fractions. Thirty-nine percent had a history of hypertension. They were predominantly female, had uniform concentric left ventricular hypertrophy, and had a high incidence of congestive heart failure. Diastolic function was found to be reduced in the elderly group compared to young patients with hypertrophic cardiomyopathy and to age- and sex-matched normal controls. It is concluded that most elderly patients with increased left ventricular outflow tract velocities are etiologically distinct from young patients with hypertrophic cardiomyopathy.

The course of idiopathic dilated cardiomyopathy in New Zealand

The course of dilated cardiomyopathy in New Zealand was studied in 72 cases that were followed up for less than or equal to 10 years after cardiac catheterisation and coronary angiography. Eighty one per cent were male and 86% were white; the remainder were Maori. The mean age of patients at the time of investigation was 50 X 15 years. Most patients were unskilled labourers. The commonest presenting symptom was dyspnoea and the commonest physical sign was cardiomegaly. Mean survival time from first hospital presentation was 85 months; half the deaths were sudden. Factors predicting a poor survival included cardiomegaly, age, arrhythmias, cigarette smoking, and subclinical thiamine deficiency. The syndrome of dilated cardiomyopathy in New Zealand appears to be identical with that seen in other European populations.

Development of severe left ventricular outflow tract obstruction over the course of 14 years: an unusual natural history of hypertrophic obstructive cardiomyopathy

A patient with hypertrophic obstructive cardiomyopathy who when first seen had a normal physial examination, chest x-ray, and electrocardiogram, and no provokable gradient with isoproterenol at cardiac catheterization, was re-evaluated after 14 years. At the time of re-evaluation, she was found to have a typical systolic ejection murmur, cardiomegaly, left ventricular hypertrophy, a pseudoinfarction pattern on electrocardiography, and a significant subaortic gradient both by catheterization and by doppler. This case demonstrates that hypertrophic obstructive cardiomyopathy can be a progressive disease and that patients with this condition warrant careful follow-up. Echocardiography with doppler may provide an excellent noninvasive method of following these patients.

Chronic haemolytic anaemia in hypertrophic cardiomyopathy

A patient with hypertrophic cardiomyopathy was found to have a chronic intravascular haemolytic anaemia. After investigation this was attributed to the abnormal haemodynamics of the cardiac disease. Treatment with propranolol was associated with an improvement in the anaemia. No further cases of haemolytic anaemia were found in 37 other patients with hypertrophic cardiomyopathy. It is concluded that haemolytic anaemia is a very rare feature of the condition.

Cardiomyopathy in western Denmark

A retrospective study was carried out to assess the incidence of cardiomyopathy in western Denmark (Jutland and Funen) (population 2 798 000) during a two year period (1980-81). The WHO/ISCF classification was strictly followed, and rigid criteria for exclusion and inclusion of patients were adopted. Thus cases in which specific heart muscle disorders (myocarditis, alcoholic heart disease, hypertension etc) were merely suspected were excluded. Forty one patients had dilated cardiomyopathy (overall incidence 7.3/10(6) population/year) and 20 hypertrophic cardiomyopathy (overall incidence 3.6/10(6) population/year). In men aged 40-59 years the occurrence of dilated cardiomyopathy was 23.4/10(6) population/year. Only one case of Löffler's endomyocardial disease was diagnosed during the study period. Since the investigation was retrospective and was a study of diseased persons and not a population, and since a specific set of criteria for exclusion and inclusion was rigidly applied, the results represent the minimum frequency of these diseases.