Age-dependent diagnostic yield of echocardiography as a second-line diagnostic investigation in athletes with abnormalities at preparticipation screening.

AIMS: Systematic pre-participation screening of subjects practicing sports activity has the potential to identify athletes at risk of sudden cardiac death. However, limited evidence are present concerning the yield of echocardiography as a second-line exam in athletes with abnormal pre-participation screening. METHODS: Consecutive athletes were screened (2011-2017) in a community-based sports medicine center in Tuscany, with familial history, physical examination and ECG. Patients with abnormal/>1 borderline ECG findings, symptoms/signs of cardiovascular diseases, cardiovascular risk factors or family history of juvenile/genetic cardiac disease underwent echocardiography. RESULTS: A total of 30109 athletes (age 21 [15;31]) were evaluated. Of these, 6234 (21%) were aged 8-11 years, 18309 (61%) 12-18 years, 4442 (15%) 19-35 years, 1124 (4%) >35 years. A total of 2569 (9%) athletes were addressed to echocardiography. Referral rates increased significantly with age (5% in preadolescents to 38% in master athletes, P< 0.01). Subclinical heart diseases were found in 290/30109 (0.8%) and were common >35 years (135/1124, 11%), but rare at 19-35 years (91/4442, 2%), very rare <18 years (64/24 543, 0.2%; P< 0.01). Seventy-four (0.3%) athletes were disqualified because of the structural alterations identified, 29 (0.1%) with cardiac structural diseases at risk for sudden death. CONCLUSIONS: Italian community-based pre-participation screening showed an age-dependent yield, with a three-fold increase in referral in athletes >35 years. Subclinical structural abnormalities potentially predisposing to sudden death were rare (0.01%), mostly in post-pubertal and senior athletes. Age-specific pre-participation screening protocols may help optimize resources and improve specificity.

Timing and significance of exercise-induced left ventricular outflow tract pressure gradients in hypertrophic cardiomyopathy.

The relation of exercise-induced left ventricular (LV) outflow tract obstruction to functional capacity in hypertrophic cardiomyopathy (HC) is incompletely defined. Thus, we assessed the patterns of onset of physiologically provoked LV outflow gradients and exercise performance in 74 consecutive patients with HC (age 45 ± 16 years; 74% men) without LV outflow obstruction at rest. The subaortic gradients were measured serially using echocardiography in these 74 patients during maximum, symptom-limited, upright bicycle exercise testing. The time course of the provoked gradients and the relation to exercise performance were assessed. Of the 74 patients, 30 (41%) developed a dynamic LV outflow gradient of ≥30 mm Hg (mean 78 ± 37 mm Hg) during upright exercise testing that correlated highly with the gradients measured with the patients supine during the immediate recovery period (R² = 0.97). The 16 patients in whom outflow obstruction developed rapidly at low exercise levels (≤5 METs) had a significantly reduced exercise capacity (6.1 ± 1.3 vs 8.0 ± 1.6 METs; p <0.01) compared to the other 14 patients in whom obstruction appeared later at greater exercise levels of >5 METs. The timing of the gradient onset was not predictable from the baseline clinical and echocardiographic features, peak exercise LV outflow tract gradient, or symptoms. In conclusion, in patients with HC without outflow obstruction at rest, the earlier onset of LV outflow tract gradients during physiologic exercise was associated with impaired exercise performance. These findings have provided insights into the determinants of functional impairment in HC and support the potential value of exercise echocardiography in the clinical assessment of patients with HC.

[Clinical and genetic features of left ventricular noncompaction: a continuum in cardiomyopathies]. / Clinica e genetica del ventricolo sinistro non compatto: conferma di un continuum nelle cardiomiopatie.

Isolated left ventricular non-compaction (LVNC) is a rare genetic form of cardiomyopathy (CM) characterized by prominent left ventricular wall trabeculation and intertrabecular recesses communicating with the ventricular cavity. Clinical signs are variable, ranging from lack of symptoms to severe manifestations including heart failure, sustained ventricular arrhythmias, cardioembolism and sudden death. The diagnosis of LVNC is frequently missed, due to limited awareness in the medical community. Contemporary diagnostic sensitivity has been enhanced by the introduction of specific morphologic criteria by high resolution echocardiography and cardiac magnetic resonance. As a consequence, LVNC has been diagnosed more frequently in association with other disorders such as congenital heart disease or genetic CM. The clinical relevance of regional non-compaction in the context of other cardiac diseases is still uncertain. Recent evidence points to an overlapping genetic background encompassing LVNC, hypertrophic and dilated CM, suggesting a continuum of disease associated with sarcomere protein gene mutations. This concept may prove relevant to the understanding of common pathogenetic mechanisms of CM and offer novel research opportunities.

Prevalence and clinical significance of acquired left coronary artery fistulas after surgical myectomy in patients with hypertrophic cardiomyopathy.

OBJECTIVES: The relevance of iatrogenic left coronary artery fistulas complicating surgical myectomy in patients with hypertrophic cardiomyopathy is not known. We prospectively defined the echocardiographic features, prevalence, and clinical significance of left coronary artery fistulas in 40 consecutive patients with hypertrophic cardiomyopathy undergoing extended septal myectomy. METHODS: Echocardiographic analysis was performed preoperatively and 1 and 6 months after surgical intervention. Diagnosis of left coronary artery fistulas required evidence of diastolic flow draining from the left ventricular wall into the left ventricular cavity according to prespecified criteria. RESULTS: Left coronary artery fistulas were detected in 9 (23%) of the 40 study patients as a single occurrence in all except 1 patient, who had multiple fistulas. At 6 months, left coronary artery fistulas could still be detected in only 2 of the 9 patients. Of these, 1 patient remained asymptomatic but continued to show left coronary artery fistula persistence at 37 months postoperatively. The other, a woman with prior alcohol septal ablation, had progressive severe symptoms that required percutaneous closure of the fistula with a covered stent after angiographic identification of a large first septal branch fistula associated with distal left anterior descending coronary artery steal. CONCLUSIONS: In patients with hypertrophic cardiomyopathy, left coronary artery fistulas are common in the early period after surgical myectomy, although their echocardiographic prevalence is dependent on operator awareness. Most left coronary artery fistulas heal spontaneously. Occasionally, however, fistulas can persist and cause symptoms requiring therapeutic intervention.

Clinical features and outcome of hypertrophic cardiomyopathy associated with triple sarcomere protein gene mutations.

OBJECTIVES: The aim of this study was to describe the clinical profile associated with triple sarcomere gene mutations in a large hypertrophic cardiomyopathy (HCM) cohort. BACKGROUND: In patients with HCM, double or compound sarcomere gene mutation heterozygosity might be associated with earlier disease onset and more severe outcome. The occurrence of triple mutations has not been reported. METHODS: A total of 488 unrelated index HCM patients underwent screening for myofilament gene mutations by direct deoxyribonucleic acid sequencing of 8 genes, including myosin binding protein C (MYBPC3), beta-myosin heavy chain (MYH7), regulatory and essential light chains (MYL2, MYL3), troponin-T (TNNT2), troponin-I (TNNI3), alpha-tropomyosin (TPM1), and actin (ACTC). RESULTS: Of the 488 index patients, 4 (0.8%) harbored triple mutations, as follows: MYH7-R869H, MYBPC3-E258K, and TNNI3-A86fs in a 32-year-old woman; MYH7-R723C, MYH7-E1455X, and MYBPC3-E165D in a 46-year old man; MYH7-R869H, MYBPC3-K1065fs, and MYBPC3-P371R in a 45-year old woman; and MYH7-R1079Q, MYBPC3-Q969X, and MYBPC3-R668H in a 50-year old woman. One had a history of resuscitated cardiac arrest, and 3 had significant risk factors for sudden cardiac death, prompting the insertion of an implantable cardioverter-defibrillator in all, with appropriate shocks in 2 patients. Moreover, 3 of 4 patients had a severe phenotype with progression to end-stage HCM by the fourth decade, requiring cardiac transplantation (n=1) or biventricular pacing (n=2). The fourth patient, however, had clinically mild disease. CONCLUSIONS: Hypertrophic cardiomyopathy caused by triple sarcomere gene mutations was rare but conferred a remarkably increased risk of end-stage progression and ventricular arrhythmias, supporting an association between multiple sarcomere defects and adverse outcome. Comprehensive genetic testing might provide important insights to risk stratification and potentially indicate the need for differential surveillance strategies based on genotype.

[Atrial fibrillation in hypertrophic cardiomyopathy: determinants, clinical course and management].

Atrial fibrillation (AF) is the most common sustained arrhythmia in patients with hypertrophic cardiomyopathy (HCM), and represents an important complication in the clinical course of the disease, with adverse consequences on functional status and outcome. Studies on community-based HCM patient populations have shown that AF is associated with long-term clinical deterioration, cardioembolic stroke and increased cardiovascular mortality due to heart failure and stroke. Moreover, acute onset of AF may cause severe hemodynamic impairment and represent a trigger of potentially lethal ventricular arrhythmias. However, the consequences of AF on the long-term prognosis of HCM patients are not uniformly unfavorable, and may be compatible with an uneventful course, when properly managed. Management of AF in HCM is challenging, particularly when onset occurs at a young age. Both paroxysmal and permanent AF represent clear indications for oral anticoagulation. In most patients, maintenance of sinus rhythm is highly desirable but made difficult by the limited long-term efficacy and potentially hazardous side effects of available pharmacological options. In selected patients with HCM and severely symptomatic AF, radiofrequency catheter ablation may represent an effective therapeutic alternative, improving functional status, and reducing or postponing the need for antiarrhythmic drugs. In patients with persistent AF, in whom maintenance of sinus rhythm is not feasible, adequate ventricular rate control should be pursued aggressively by atrio-ventricular node blocking agents.

Diagnostic accuracy of extended-length electrocardiogram in differentiating between athlete's heart and hypertrophic cardiomyopathy.

BACKGROUND: Standard 12-lead electrocardiogram (ECG) has several limitations in solving the differential diagnosis between physiologic left ventricular hypertrophy (PLVH) and hypertrophic cardiomyopathy (HCM), given the high rate of false-positive results in athletes. The aim of this study was to assess the usefulness of several arrhythmic risk indexes in differentiating PLVH from HCM. METHODS: A multiparametric ECG analysis (extended-length ECG) was performed on 30 male athletes with PLVH and 30 male patients with HCM, with homogeneous age distribution. RESULTS: The combination of 4 extended-length ECG variables, namely, corrected QT interval (Bazett), QT dispersion, mean resting heart rate, and low-amplitude signal duration at 25 Hz (low-amplitude signal duration at the end of filtered QRS) displayed remarkable diagnostic accuracy (area under receiver operating characteristic curve, 94%). The same accuracy was obtained replacing QT dispersion with T-wave complexity index. CONCLUSIONS: Extended-length ECG can be considered an effective, low-cost, and low time-consuming clinical tool for distinguishing between PLVH and HCM.

[Myocardial hypoperfusion due to microvascular dysfunction in hypertrophic cardiomyopathy: role of positron emission tomography].

Hypertrophic cardiomyopathy (HCM) is characterized by extreme clinical heterogeneity, ranging from sudden cardiac death to long-term disease progression and heart failure-related complications. Myocardial ischemia, occurring at the microvascular level, is a major determinant of clinical expression and outcome. Accordingly, the severity of this microvascular dysfunction has been shown to represent an early and powerful predictor of unfavorable outcome in HCM. The assessment of microvascular function in vivo is technically challenging, although critical to a truly comprehensive evaluation and risk stratification of HCM patients. Available technologies include positron emission tomography and cardiac magnetic resonance (CMR). Studies of regional myocardial blood flow using positron emission tomography have demonstrated that the vasodilator response to dipyridamole is impaired in most HCM patients, not only in the hypertrophied ventricular septum but also in the less hypertrophied or non-thickened left ventricular free wall. CMR also allows measurement of myocardial flow, although the technique is currently time-consuming and largely limited to research situations. CMR provides further insight into the effects of ischemia in HCM patients, by visualizing the distribution and extent of fibrosis at the intramyocardial level. Late gadolinium enhancement (LGE) is a potential predictor of risk in HCM patients, and is believed to largely reflect replacement fibrosis resulting from recurrent microvascular ischemia. LGE is associated with increased prevalence of ventricular arrhythmias, and associated with microvascular dysfunction. The present review is to provide a concise overview for the available evidence of microvascular ischemia and its consequences in HCM.

Microvascular dysfunction, myocardial ischemia, and progression to heart failure in patients with hypertrophic cardiomyopathy.

Microvascular dysfunction can be demonstrated in most patients with hypertrophic cardiomyopathy (HCM), both in the hypertrophied and nonhypertrophied myocardial walls, mostly due to intimal and medial hyperplasia of the intramural coronary arteries and subsequent lumen reduction. As a consequence, regional myocardial ischemia may be triggered by exercise, increased heart rate, or arrhythmias, in areas which are unable to increase myocardial blood flow. In patients with HCM, microvascular dysfunction leading to severe myocardial hypoperfusion during maximal hyperemia represents a strong predictor of unfavorable outcome, left ventricular remodeling with progressive wall thinning, left ventricular dysfunction, and heart failure. Accurate quantitative assessment of microvascular dysfunction and myocardial ischemia is not easily feasible in clinical practice. Although signs of inducible myocardial ischemia may be detected by electrocardiogram, echocardiography, or myocardial scintigraphy, the vasodilator response to dipyridamole by positron emission tomography is considered the method of choice for the assessment of maximal regional and global flow. Cardiac magnetic resonance provides further information, by late gadolinium enhancement (LGE), which may show areas where replacement fibrosis has occurred following microvascular ischemia and focal necrosis. LGE areas colocalize with severe regional microvascular dysfunction, are associated with increased prevalence of ventricular arrhythmias, and show more extensive distribution in the late stages of the disease, when heart failure is the dominant feature. The present review aims to provide a concise overview of the available evidence of microvascular dysfunction and ischemia eventually leading to disease progression and heart failure in HCM patients.