Left Ventricular Outflow Tract Obstruction as a Risk Factor for Sudden Cardiac Death in Hypertrophic Cardiomyopathy

Contemporary Insights and Strategies for Risk Stratification and Prevention of Sudden Death in Hypertrophic Cardiomyopathy

“…2,3,5,[7][8][9][10][12][13][14][43][44][45][46][47][48][49][50][51] In this respect, the strategy differs from that used in patients with CAD; ie, in which primary prevention is based largely on a single predominant risk marker demonstrated by randomized trials and emanating from a major clinical event (myocardial infarction) leading to LV remodeling and impaired function (ejection fraction Յ30% to 35%), often associated with adverse disease progression. 30 -34 The conventional primary prevention risk factors for HCM assume greater weight in patients Ͻ50 years of age ( attenuated blood pressure response to exercise.…”

“…49 In 2 studies, 40,50 obstruction had a modest although statistically significant relation to SD risk in patients without severe heart failure (positive predictive value, only 5% to 10%), but showed no relation in another investigation. 51 Other obstacles to obstruction as a primary risk factor include its dynamic nature and frequency, with 70% of patients capable of generating outflow gradients at rest or with physiological exercise, 52 thus creating the potential for unnecessary ICD implantation in the majority of HCM patients. Reducing the gradient by surgical myectomy (or alcohol ablation) is not a primary strategy for mitigating SD risk.…”

Inverted U-Shaped Relation Between the Risk of Sudden Cardiac Death and Maximal Left Ventricular Wall Thickness in Hypertrophic Cardiomyopathy

“…Since 2003, international guidelines have considered MWT≥30 mm as a risk factor for SCD, 2,3 but the data to support this recommendation are conflicting ( Figure 6). [4][5][6]10,[16][17][18][19][20][21][22][23][24] In this context, our findings suggest that ICD implantation should not be based solely on the severity of left ventricular hypertrophy and that a more global SCD risk assessment, integrating other risk factors, should be used.…”

“…In all studies, the number of patients with maximal wall thickness ≥30 mm is small, and there is no consistent independent association with SCD. [4][5][6]10,[16][17][18][19][20][21][22][23][24] The vertical reference line represents a hazard ratio of 1.…”

Risk Stratification and Role of Implantable Defibrillators for Prevention of Sudden Death in Patients With Hypertrophic Cardiomyopathy

“…In 2 studies, obstruction had a very modest, though statistically significant, relationship to SCD risk (positive predictive value, only 5-10%), 31,32 but another investigation showed no such relationship. 33 Other obstacles to outflow obstruction as a primary risk factor include its dynamic nature, and the high frequency of gradients encountered in the HCM patient population (ie, 70%, at rest or with physiologic exercise). 34 Reduction of obstruction by myectomy (or alcohol ablation) is not considered a primary strategy for mitigating SCD risk.…”