ABC | Volume 115, Nº2, August 2020

Original Article Mattos BP et al. Sudden death in hypertrophic cardiomyopathy Arq Bras Cardiol. 2020; 115(2):197-204 6±3 years, 15 (17%) patients received an ICD for SCD primary prevention. Two (2%) patients experienced appropriate shock, 6 (7%) experienced SCD and 6 (7%) had death unrelated to HCM (Table 2). Five and ten-year SCD or ICD appropriate shock free survival rates were 93% and 92%, respectively, in the period. Five and ten-year all-cause death-free survival in five and ten years was 80%. ESC HCM risk-SCD score for sudden cardiac death risk stratification The mean calculated ESC HCM risk-SCD was 3.2±2.5% in the sample and it was estimated as low (<4%) in 67 (75%) patients, intermediate (≥4%–<6%) in 11 (12%) and high (>6%) in 12 (13%). The comparative analysis of SCD markers adopted in the two guidelines between the three risk ranges showed that NSVT [3 (4%) vs. 6 (54%) vs. 8 (67%), p=0.0001], syncope [6 (9%) vs. 3 (27%) vs. 7 (58%), p=0.0001] and increased MLVWT (17±3mm vs. 21±2mm vs. 21±8 mm, p=0.002) were predominant in higher risk. The other predictors do not differ between the groups (Table 3). SCD or appropriate ICD shock rates were similar between low, medium and high-risk patients [6 (8.8%) vs. 2 (18.2%) vs. 0 (0%), p=0.22]. Table 4 presents the percentages achieved by each of the variables included in the ESC HCM Risk-SCD score in the three risk categories. The risk factors that have mainly contributed to the score calculation in the low, intermediate and high-risk levels were MLVWT, left atrial diameter and age. LVOT obstruction, family history of SCD, NSVT and syncope reached lower weights. Comparison between the 2011 American College of Cardiology Foundation/American Heart Association and the 2014 European Society of Cardiology guidelines According to the 2011 ACCF/AHA criteria, 43 (48%) patients received class IIa recommendation for ICD, 3 (3%) class IIb and 44 (49%) class III. In the 2014 ESC guideline, 12 (14%) patients received class IIa recommendation for ICD therapy, 11 (12%) class IIb, and 67 (74%) class III. Comparison of the classes of ICD recommendations showed low agreement (Kappa=0.355, p=0.0001) between the two guidelines. The ESC HCM risk-SCD score decreased the ICD recommendations in 32 (36%) patients, maintained in 57 (63%) and provided an additional recommendation in only one (1%). Of the 43 (48%) individuals with class IIa recommendation under the 2011 ACCF/AHA guideline, the ESC risk score decreased the class of recommendation for ICD therapy in 32 (74%) patients, 8 (18%) for class IIb and 24 (56%) for class III. Only 11 (26%) remained in class IIa recommendation. Of the 44 (49%) patients in class III with the 2011 ACCF/ AHA guideline, the European model determined an ICD unwarranted in 43 (98%) (Table 5). Figure 1 shows the study summary and its main findings. The mean calculated ESC risk score was 3±1.7% in the 8 (9%) patients experiencing SCD or appropriate shock. Four (50%) had class IIa recommendation for device implantation with the 2011 ACCF/AHA guideline, but none achieved this Table 1 – Clinical characteristics of 90 patients with hypertrophic cardiomyopathy Age (years) 62±12 Age >40 years (n, %) 85 (94%) Female sex (n, %) 56 (62%) NYHA functional class I/II (n, %) 75 (83%) III/IV (n, %) 15 (17%) Coronary artery disease (n, %) 11 (12%) Treatment Betablockers (n, %) 70 (78%) Amiodarone (n, %) 20 (22%) Verapamil/diltiazem (n, %) 24 (27%) Echocardiogram LA diameter (mm) 44±7 LV diastolic diameter (mm) 43±6 LV systolic diameter (mm) 34±5 Septal diastolic thickness (mm) 19±4 LV posterior wall diastolic thickness (mm) 11±2 Ejection fraction (%) 71±9 E/E´ 16±8 LVOT gradient at rest (mmHg) 28±31 LVOT gradient with Valsalva maneuver (mmHg) 36±38 SCD risk factors Family history of SCD* 23 (26%) NSVT* 17 (19%) Syncope* 16 (18%) Abnormal BP response to exercise * 9 (10%) MLVWT >30 mm* 1 (1%) LVOT gradient ≥30 mmHg † 44 (49%) LGE on CMR † 11 (12%) LV apical aneurysm † 0 Malignant mutation † 0 Number of SCD risk factors 0 42 (47%) 1 32 (35%) ≥2 16 (18%) *Independent predictors † Modifying factors; NYHA: New York Heart Association; LA: left atrium; LV: left ventricle; LVOT: left ventricular outflow tract; SCD: sudden cardiac death; NSVT: non-sustained ventricular tachycardia; BP: blood pressure; MLVWT: left ventricle maximal wall thickness; LGE: late gadolinium enhancement; CMR; cardiac magnetic resonance. class of recommendation with the 2014 ESC model, although 2 (25%) remained in class IIb. The combination of risk factors that received class IIa recommendation with the 2011 ACCF/AHA strategy was associated with a downgrade in ICD recommendation with 199