Reversible ischaemia in hypertrophic cardiomyopathy

Role of multimodality cardiac imaging in the management of patients with hypertrophic cardiomyopathy: an expert consensus of the European Association of Cardiovascular Imaging Endorsed by the Saudi Heart Association

Taking into account the complexity and limitations of clinical assessment in hypertrophic cardiomyopathy (HCM), imaging techniques play an essential role in the evaluation of patients with this disease. Thus, in HCM patients, imaging provides solutions for most clinical needs, from diagnosis to prognosis and risk stratification, from anatomical and functional assessment to ischaemia detection, from metabolic evaluation to monitoring of treatment modalities, from staging and clinical profiles to follow-up, and from family screening and preclinical diagnosis to differential diagnosis. Accordingly, a multimodality imaging (MMI) approach (including echocardiography, cardiac magnetic resonance, cardiac computed tomography, and cardiac nuclear imaging) is encouraged in the assessment of these patients. The choice of which technique to use should be based on a broad perspective and expert knowledge of what each technique has to offer, including its specific advantages and disadvantages. Experts in different imaging techniques should collaborate and the different methods should be seen as complementary, not as competitors. Each test must be selected in an integrated and rational way in order to provide clear answers to specific clinical questions and problems, trying to avoid redundant and duplicated information, taking into account its availability, benefits, risks, and cost.

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.

Systolic dysfunction and blood pressure responses to supine exercise in patients with hypertrophic cardiomyopathy

Left ventricular function and blood pressure responses were evaluated in 56 patients with non-obstructive hypertrophic cardiomyopathy (HCM) and 12 control subjects by using a radionuclide ventricular function monitor during supine ergometer exercise. Patients with HCM were divided into 2 groups: (i) group A had no decrease in ejection fraction (EF) during exercise; and (ii) group B had a decrease in EF during exercise. During exercise, the change in end-diastolic volume did not differ between the 3 groups. In contrast, the change in end-systolic volume differed between the 3 groups (p<0.0001). The change in systolic blood pressure (SBP) also differed significantly between the 3 groups. The change in SBP in group B was smaller than that in the control group and group A, and changes in the EF and changes in the SBP between rest and peak exercise showed a significant correlation (p<0.005). These results suggest that exercise-induced systolic dysfunction in patients with non-obstructive HCM may contribute to abnormal blood pressure response in those patients.

Mid-Term Results of Dual-Chamber Pacing in Children with Hypertrophic Obstructive Cardiomyopathy

BACKGROUND: Permanent dual-chambered pacing (DDD) is an alternative to surgical treatment in patients with severe hypertrophic obstructive cardiomyopathy (HOCM) who do not have a satisfactory response to medical treatment. METHODS: Five children with severe HOCM still symptomatic despite medical treatment underwent permanent DDD pacing and were followed for 21 +/- 9.7 months. RESULTS: All patients improved their functional class. Doppler echocardiographic studies showed an early reduction of the left ventricular outflow tract gradient from 66 +/- 40 to 40 +/- 20 mmHg (P < 0.05) and to 30 +/- 11 mmHg (P < 0.05 and NS for comparison with the baseline and the early post-DDD pacing gradients, respectively) at mid-term follow-up. There was no evidence of left ventricular systolic dysfunction, and the results of left ventricular filling studies ruled out deleterious effects on diastolic function. Doppler echocardiography played a key role in the initial and subsequent assessment of these patients. CONCLUSIONS: Permanent DDD pacing is a reasonable alternative to surgery in children with HOCM who are still symptomatic despite medical therapy.

Effects of permanent dual chamber pacing on myocardial perfusion in symptomatic hypertrophic cardiomyopathy

OBJECTIVE

Angina and the presence of myocardial ischaemia are common in hypertrophic cardiomyopathy. Dual chamber pacing results in clinical improvement in these patients. This study evaluates the effects of permanent dual chamber pacing on absolute regional myocardial perfusion and perfusion reserve.

SETTING

University hospital.

PATIENTS AND DESIGN

Six patients with hypertrophic cardiomyopathy and severe symptoms of angina received a dual chamber pacemaker. Absolute myocardial regional perfusion and perfusion reserve (dipyridamole 0.56 mg/kg) were measured by dynamic positron emission tomography with 13N-ammonia both during sinus rhythm and 3 months after pacemaker insertion. Results were compared with those from 28 healthy volunteers.

RESULTS

Pacing resulted in a reduction of anginal complaints and a reduction in intraventricular pressure gradient from 65 (SD 30) mm Hg to 19 (10) mm Hg. During sinus rhythm, baseline perfusion was higher in patients with hypertrophic cardiomyopathy than controls (184 (31) v 106 (26) ml/min/100 g, P < 0.01), and perfusion reserve was lower (1.6 (0.4) v 2.8 (1.0), P < 0.05). During pacing myocardial perfusion decreased to 130 (27) ml/min/100 g (P < 0.05), with variable responses in terms of perfusion reserve. Pacing caused a redistribution of myocardial stress perfusion and perfusion reserve. The coefficient of regional variation of myocardial stress perfusion decreased from 19.7 (7.0)% to 14.6 (3.9)% during pacing (12.9 (3.8)% in controls, P < 0.01). The coefficient of regional variation of perfusion reserve decreased from 16.7 (6.6)% to 11.4 (2.6)% during pacing (9.8 (4.1)% in controls, P < 0.01).

CONCLUSIONS

Pacing caused a decrease of resting left ventricular myocardial blood flow and blood flow during pharmacologically induced coronary vasodilatation. Although global perfusion reserve remained unchanged, myocardial perfusion reserve became more homogeneously distributed.