The science of uncertainty and the art of probability: syncope and its consequences in hypertrophic cardiomyopathy

Severe right ventricular hypertrophy in hypertrophic cardiomyopathy: Serious symptoms, complex surgical procedures, and poor prognosis in Fuwai Hospital

OBJECTIVE

Severe right ventricular hypertrophy (SRVH) in hypertrophic cardiomyopathy (HCM) is rare. We studied the clinical characteristics and prognosis of 36 patients with HCM and SRVH in a Chinese cohort.

METHODS

Patients with HCM and SRVH were enrolled between 2013 and 2017. The clinical characteristics, treatment therapies, and clinical outcomes of the 36 patients were retrospectively studied and compared with those of 128 patients without SRVH.

RESULTS

Patients in the group with SRVH were younger than those in the group without SRVH (27.58±15.09 years vs 40.34±13.21 years, respectively; p<0.001). Patients with SRVH had more serious clinical symptoms and a higher New York Heart Association functional class than those without SRVH. Most patients in the group with SRVH exhibited diffuse RV hypertrophy, and 13 patients presented with biventricular outflow tract obstruction. Maximal left ventricular (LV) wall thickness (27.29±7.95 mm vs 24.33±5.85 mm, respectively; p=0.027) and LV outflow tract gradient (80.83±24.41 mm Hg vs 42.3±5.7 mm Hg, respectively; p=0.000) were significantly greater in patients with SRVH than in those without SRVH. A total of 30 patients in the group with SRVH underwent surgical correction. During a median follow-up period of 48 months, six patients with SRVH reached primary clinical endpoints (four sudden cardiac deaths, one heart failure-related death, and one heart transplantation), whereas only two deaths occurred in the patients without SRVH.

CONCLUSION

We conclude that patients with HCM and SRVH exhibit serious symptoms and have complex surgical requirements and poor clinical outcomes.

[Syncope in hypertrophic (obstructive) cardiomyopathy]

Hypertrophic cardiomyopathy is the most common genetic cardiac disease. The most important pathophysiological finding is dynamic (outflow tract) obstruction of the left ventricle in about 70% of affected patients. Especially in younger patients, an increased risk of sudden cardiac death has been observed. Syncope and presyncope-in addition to extremely variable cardiac symptoms (dyspnea and angina)-are common. The etiology of syncope is complex. The most important aspect for diagnosis is a detailed history regarding the accompanying circumstances of the syncope. In principle, an attempt must be made to distinguish between rhythmogenic and hemodynamic causes. Diagnostic work-up should be performed under the criteria of a possible prognostic-with implantation of an implantable cardioverter-defibrillator (ICD) in patients at increased risk of sudden cardiac death-and symptomatic therapy. Depending on the underlying morphology and the experience of the surgeon, percutaneous septal ablation and operative myectomy are complementary options for symptomatic treatment if medical therapy with beta-blockers and/or verapamil is inadequate.

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.