Insights from Cardiopulmonary Exercise Testing in Pediatric Patients with Hypertrophic Cardiomyopathy.

The usefulness of cardiopulmonary exercise test (CPET) in adult hypertrophic cardiomyopathy (HCM) patients is well-known, whereas its role in pediatric HCM patients has not yet been explored. The present study investigates possible insights from a CPET assessment in a cohort of pediatric HCM outpatients in terms of functional and prognostic assessment. Sixty consecutive pediatric HCM outpatients aged <18 years old were enrolled, each of them undergoing a full clinical assessment including a CPET; a group of 60 healthy subjects served as controls. A unique composite end-point of heart failure (HF) related and sudden cardiac death (SCD) or SCD-equivalent events was also explored. During a median follow-up of 53 months (25th-75th: 13-84 months), a total of 13 HF- and 7 SCD-related first events were collected. Compared to controls, HCM patients showed an impaired functional capacity with most of them showing peak oxygen uptake (pVO2) values of <80% of the predicted, clearly discrepant with functional New York Heart Association class assessment. The composite end-point occurred more frequently in patients with the worst CPETs' profiles. At the univariate analysis, pVO2% was the variable with the strongest association with adverse events at follow-up (C-index = 0.72, p = 0.025) and a cut-off value equal to 60% was the most accurate in identifying those patients at the highest risk. In a pediatric HCM subset, the CPET assessment allows a true functional capacity estimation and it might be helpful in identifying early those patients at high risk of events.

Risk Stratification in Hypertrophic Cardiomyopathy. Insights from Genetic Analysis and Cardiopulmonary Exercise Testing.

The role of genetic testing over the clinical and functional variables, including data from the cardiopulmonary exercise test (CPET), in the hypertrophic cardiomyopathy (HCM) risk stratification remains unclear. A retrospective genotype-phenotype correlation was performed to analyze possible differences between patients with and without likely pathogenic/pathogenic (LP/P) variants. A total of 371 HCM patients were screened at least for the main sarcomeric genes MYBPC3 (myosin binding protein C), MYH7 (ß-myosin heavy chain), TNNI3 (cardiac troponin I) and TNNT2 (cardiac troponin T): 203 patients had at least an LP/P variant, 23 patients had a unique variant of uncertain significance (VUS) and 145 did not show any LP/P variant or VUS. During a median 5.4 years follow-up, 51 and 14 patients developed heart failure (HF) and sudden cardiac death (SCD) or SCD-equivalents events, respectively. The LP/P variant was associated with a more aggressive HCM phenotype. However, left atrial diameter (LAd), circulatory power (peak oxygen uptake*peak systolic blood pressure, CP%) and ventilatory efficiency (C-index = 0.839) were the only independent predictors of HF whereas only LAd and CP% were predictors of the SCD end-point (C-index = 0.738). The present study reaffirms the pivotal role of the clinical variables and, particularly of those CPET-derived, in the HCM risk stratification.

Clinical and prognostic impact of chronotropic incompetence in patients with hypertrophic cardiomyopathy.

BACKGROUND: A blunted heart rate (HR) response is associated with an impaired peak oxygen uptake (pVO2), a powerful outcome predictor in hypertrophic cardiomyopathy (HCM). The present multicenter study sought to determine the prognostic role for exercise-induced HR response in HCM. METHODS: A total of 681 consecutive HCM outpatients on optimized treatment were recruited. The heart failure (HF) end-point was death due to HF, cardiac transplantation, NYHA III-IV class progression, HF worsening leading to hospitalization and severe functional deterioration leading to septal reduction. The sudden cardiac death (SCD) end-point included SCD, aborted SCD and appropriate implantable cardioverter defibrillator discharges. RESULTS: During a median follow-up of 4.2 years (25-75th centile: 3.9-5.2), 81 patients reached the HF and 23 the SCD end-point. Covariates with independent effects on the HF end-point were left atrial diameter, left ventricular ejection fraction, maximal left ventricular outflow tract gradient and exercise cardiac power (ECP = pVO2∗systolic blood pressure) (C-Index = 0.807) whereas the HCM Risk-SCD score and the ECP remained associated with the SCD end-point (C-Index = 0.674). When the VO2-derived variables were not pursued, peak HR (pHR) re-entered in the multivariate HF model (C-Index = 0.777) and, marginally, in the SCD model (C-index = 0.656). A pHR = 70% of the maximum predicted resulted as the best cut-off value in predicting the HF-related events. CONCLUSIONS: The cardiopulmonary exercise test is pivotal in the HCM management, however the pHR remains a meaningful alternative parameter. A pHR < 70% identified a HCM population at high risk of HF-related events, thus calling for a reappraisal of the chronotropic incompetence threshold in HCM.

Pulmonary hypertension and clinical correlates in hypertrophic cardiomyopathy.

BACKGROUND: Pulmonary hypertension (PH) in patients with hypertrophic cardiomyopathy (HCM) has been investigated in a small number of studies. Purpose of this study was to assess the prevalence and its association with outcome in a population of consecutive HCM outpatients. METHODS: We retrospectively analyzed data of 361 consecutive HCM outpatients in whom echocardiographic measurements of pulmonary artery systolic pressure (PASP) were available at initial and most recent evaluation. Four different clinical groups were specifically investigated: patients without left ventricular outflow tract obstruction (group A, 165), with obstruction (group B, 126), patients diagnosed at the age≥65 (group C, 50) and patients with end stage (ES) HCM (group D, 20). RESULTS: PH was identified in 41 (11.4%) of the 361 patients at initial evaluation while it has been recognized in 25 (7,8% [1.1%/year]) during a median follow-up of 3.4years. Analysis of subgroups showed that prevalence of PH increased from patient group A to D (8%, group A, 19%, group B, 28% group C, 70%, group D, respectively, p<0,01). During follow-up, patients with PH showed a significant higher HCM-related mortality (p=0.01) and morbidity (p<0.001) as compared with those without PH, but in multivariable analysis, PH resulted an independent risk factor only for HCM-related morbidity (HR=2.50, 95% CI 1.08-5.79, p=0.03). CONCLUSION: PH affects a significant proportion of patients with HCM. Its prevalence varies according to different clinical profiles. It is associated with an unfavorable clinical outcome and is an independent predictor of morbidity.

Triple Combination Therapies Based on Olmesartan: A Personalized Therapeutic Approach to Improve Blood Pressure Control.

Recent epidemiological surveys have demonstrated that effective and sustained blood pressure (BP) control is achieved in a relatively small proportion of treated hypertensive patients. Indeed, treatment of hypertension represents a key strategy for preventing coronary artery disease, stroke, congestive heart failure and cardiovascular death. Several interventions have been proposed by international guidelines for ameliorating hypertension management and control, mostly including integrated and multi-dimensional pharmacological and non-pharmacological strategies. In particular, numerous evidence demonstrated that a more extensive use of combination therapy may represent a valid therapeutic option for treating hypertensive patients at different risk profile. This strategy has been definitely strengthened by the availability of single pill fixed-dose combinations. Among potential combination therapies, those based on the association of renin-angiotensin system antagonists, thiazide diuretics and calcium channel blockers are very effective in lowering BP levels and well tolerated. We will provide here an overview of clinical evidence supporting the use of triple combination therapy, with a focus on that based on olmesartan medoxomil, a thiazide diuretic (hydrochlorothiazide) and a calcium channel blocker (amlodipine besylate), which is available in multiple dosages. Finally, in view of the recognised importance of single-pill combination therapy for treating hypertension, we will examine the potential benefits of dual (fixed) combination therapy based on olmesartan medoxomil with either thiazide diuretic hydrochlorothiazide or calcium channel blocker amlodipine in terms of efficacy, safety and tolerability profile.

Monotherapy and Dual Combination Therapies Based on Olmesartan: A Comprehensive Strategy to Improve Blood Pressure Control.

Olmesartan medoxomil is an antihypertensive drug of the class of angiotensin II type 1 (AT1) receptor antagonists (or blockers), characterized by tight and prolonged binding to AT1 receptor compared to other molecules within the same class. These characteristics produce effective and sustained blood pressure reductions in hypertensive patients at different cardiovascular risk profile with a good tolerability profile. After a brief description of the pharmacological characteristics of olmesartan, we will provide a thorough overview of the clinical studies that investigated its efficacy and safety in the clinical management of hypertensive patients both in monotherapy and in dual combination therapies with either thiazide diuretics or calcium channel blockers. These studies demonstrated that olmesartan-based antihypertensive strategy may indeed provide sustained BP control over the 24-h period in a wide proportion of hypertensive patients, thus contributing to a substantial progress in hypertension management. Finally, since growing evidence suggest that olmesartan may also exert potential favourable effects at vascular level, thereby antagonizing the vascular inflammatory process involved in the development and progression of atherosclerosis, the main clinical studies addressing this issue will be also discussed.

QT spatial dispersion and sudden cardiac death in hypertrophic cardiomyopathy: Time for reappraisal.

BACKGROUND: The 12-lead surface electrocardiographic (ECG) analysis is able to provide independent predictors of prognosis in several cardiovascular settings, including hypertrophic cardiomyopathy (HCM). The present single-center study investigated the possible ability of several ECG-derived variables in stratifying sudden cardiac death (SCD) risk and, possibly, in improving the accuracy of the 2014 European Society of Cardiology guidelines. METHODS: A total of 221 consecutive HCM outpatients were recruited and prospectively followed. All of them underwent a full clinical and instrumental examination, including a 12-lead surface ECG to calculate the dispersion for the following intervals: QRS, Q-Tend (QT), Q-Tpeak (QTp), Tpeak-Tend (TpTe), J-Tpeak (JTp), and J-Tend (JT). The study composite end-point was SCD, aborted SCD, and appropriate implantable cardioverter defibrillator (ICD) interventions. RESULTS: During a median follow-up of 4.4 years (25th-75th interquartile range: 2.4-9.4 years), 23 patients reached the end-point at 5-years (3 SCD, 3 aborted SCD, 17 appropriate ICD interventions). At multivariate analysis, the spatial QT dispersion corrected according to Bazett's formula (QTcd) remains independently associated to the study endpoint over the HCM Risk-SCD score (C-index 0.737). A QTcd cut-off value of 93ms showed the best accuracy in predicting the SCD endpoint within the entire HCM study cohort (sensitivity 56%, specificity 75%, positive predictive value 22%, negative predictive value 97%). CONCLUSION: Our data suggest that the QTcd might be helpful in SCD risk stratification, particularly in those HCM categories classified at low-intermediate SCD risk according to the contemporary guidelines.

Heart Failure Progression in Hypertrophic Cardiomyopathy　- Possible Insights From Cardiopulmonary Exercise Testing.

BACKGROUND: Heart failure (HF) progression and its complications represent major emergent concerns in hypertrophic cardiomyopathy (HCM). We investigated the possible adjunctive role of cardiopulmonary exercise testing (CPET) in predicting HF-related events. An exercise-derived risk model, theHYPertrophicExercise-derivedRiskHF(HYPERHF), has been developed. METHODS AND RESULTS: A multicenter cohort of 620 consecutive HCM outpatients was recruited and followed (2007 to 2015). The endpoint was death from HF, cardiac transplantation, NYHA III-IV class progression, severe functional deterioration leading to hospitalization for septal reduction, and hospitalization for HF worsening. During a median follow-up of 3.8 years (25-75th centile: 2.3-5.3 years), 84 patients reached the endpoint. Peak circulatory power (peak oxygen consumption * peak systolic blood pressure), ventilatory efficiency and left atrial diameter were independently associated with the endpoint and, accordingly, integrated into the HYPERHFmodel (C index: 0.849; best cutoff value equal to 15%). CONCLUSIONS: CPET is useful in the evaluation of HCM patients. In this context, the HYPERHFscore might allow early identification of those patients at high risk of HF progression and its complications. (Circ J 2016; 80: 2204-2211).

Usefulness of Electrocardiographic Patterns at Presentation to Predict Long-term Risk of Cardiac Death in Patients With Hypertrophic Cardiomyopathy.

The objective of this study was to investigate the prognostic significance of 12-lead electrocardiogram (ECG) patterns in a large multicenter cohort of patients with hypertrophic cardiomyopathy; 1,004 consecutive patients with hypertrophic cardiomyopathy and a recorded standard ECG (64% men, mean age 50 ± 16 years) were evaluated at 4 Italian centers. The study end points were sudden cardiac death (SCD) or surrogates, including appropriate implanted cardiac defibrillator discharge and resuscitated cardiac arrest and major cardiovascular events (including SCD or surrogates and death due to heart failure, cardioembolic stroke, or heart transplantation). Prevalence of baseline electrocardiographic characteristics was: normal ECG 4%, ST-segment depression 56%, pseudonecrosis waves 33%, "pseudo-ST-segment elevation myocardial infarction (STEMI)" pattern 17%, QRS duration ≥120 ms 17%, giant inverted T waves 6%, and low QRS voltages 3%. During a mean follow-up of 7.4 ± 6.8 years, 77 patients experienced SCD or surrogates and 154 patients experienced major cardiovascular events. Independent predictors of SCD or surrogates were unexplained syncope (hazard ratio [HR] 2.5, 95% confidence interval [CI] 1.4 to 4.5, p = 0.003), left ventricular ejection fraction <50% (HR 3.5, 95% CI 1.9 to 6.7, p = 0.0001), nonsustained ventricular tachycardia (HR 1.7, 95% CI 1.1 to 2.6, p = 0.027), pseudo-STEMI pattern (HR 2.3, 95% CI 1.4 to 3.8, p = 0.001), QRS duration ≥120 ms (HR 1.8, 95% CI 1.1 to 3.0, p = 0.033), and low QRS voltages (HR 2.3, 95% CI 1.01 to 5.1, p = 0.048). Independent predictors of major cardiovascular events were age (HR 1.02, 95% CI 1.01 to 1.03, p = 0.0001), LV ejection fraction <50% (HR 3.73, 95% CI 2.39 to 5.83, p = 0.0001), pseudo-STEMI pattern (HR 1.66, 95% CI 1.13 to 2.45, p = 0.010), QRS duration ≥120 ms (HR 1.69, 95% CI 1.16 to 2.47, p = 0.007), and prolonged QTc interval (HR 1.68, 95% CI 1.21 to 2.34, p = 0.002). In conclusion, a detailed qualitative and quantitative electrocardiographic analyses provide independent predictors of prognosis that could be integrated with the available score systems to improve the power of the current model.

Cardiopulmonary exercise test and sudden cardiac death risk in hypertrophic cardiomyopathy.

BACKGROUND: In hypertrophic cardiomyopathy (HCM), most of the factors associated with the risk of sudden cardiac death (SCD) are also involved in the pathophysiology of exercise limitation. The present multicentre study investigated possible ability of cardiopulmonary exercise test in improving contemporary strategies for SCD risk stratification. METHODS: A total of 623 consecutive outpatients with HCM, from five tertiary Italian HCM centres, were recruited and prospectively followed, between September 2007 and April 2015. The study composite end point was SCD, aborted SCD and appropriate implantable cardioverter defibrillator (ICD) interventions. RESULTS: During a median follow-up of 3.7 years (25th-75th centile: 2.2-5.1 years), 25 patients reached the end point at 5 years (3 SCD, 4 aborted SCD, 18 appropriate ICD interventions). At multivariate analysis, ventilation versus carbon dioxide relation during exercise (VE/VCO2 slope) remains independently associated to the study end point either when challenged with the 2011 American College of Cardiology Foundation/American Heart Association guidelines-derived score (C index 0.748) or with the 2014 European Society of Cardiology guidelines-derived score (C index 0.750). A VE/VCO2 slope cut-off value of 31 showed the best accuracy in predicting the SCD end point within the entire HCM study cohort (sensitivity 64%, specificity 72%, area under the curve 0.72). CONCLUSIONS: Our data suggest that the VE/VCO2 slope might improve SCD risk stratification, particularly in those HCM categories classified at low-intermediate SCD risk according to contemporary guidelines. There is a need for further larger studies, possibly on independent cohorts, to confirm our preliminary findings.

The natriuretic peptides system in the pathophysiology of heart failure: from molecular basis to treatment.

After its discovery in the early 1980s, the natriuretic peptide (NP) system has been extensively characterized and its potential influence in the development and progression of heart failure (HF) has been investigated. HF is a syndrome characterized by the activation of different neurohormonal systems, predominantly the renin-angiotensin (Ang)-aldosterone system (RAAS) and the sympathetic nervous system (SNS), but also the NP system. Pharmacological interventions have been developed to counteract the neuroendocrine dysregulation, through the down modulation of RAAS with ACE (Ang-converting enzyme) inhibitors, ARBs (Ang receptor blockers) and mineralcorticoid antagonists and of SNS with ß-blockers. In the last years, growing attention has been paid to the NP system. In the present review, we have summarized the current knowledge on the NP system, focusing on its role in HF and we provide an overview of the pharmacological attempts to modulate NP in HF: from the negative results of the study with neprilysin (NEP) inhibitors, alone or associated with an ACE inhibitor and vasopeptidase inhibitors, to the most recently and extremely encouraging results obtained with the new pharmacological class of Ang receptor and NEP inhibitor, currently defined ARNI (Ang receptor NEP inhibitor). Indeed, this new class of drugs to manage HF, supported by the recent results and a vast clinical development programme, may prompt a conceptual shift in the treatment of HF, moving from the inhibition of RAAS and SNS to a more integrated target to rebalance neurohormonal dysregulation in HF.

Blood Pressure Levels at the Time of Percutaneous Coronary Revascularization and Risk of Coronary In-Stent Restenosis.

BACKGROUND: High blood pressure (BP) levels expose patients treated with percutaneous coronary interventions (PCI) to very high risk of 10-year cardiovascular morbidity and mortality. OBJECTIVE: To investigate the role of BP levels at the time of PCI on the risk of in-stent restenosis (ISR). METHODS: We retrospectively included 796 patients previously treated with PCI, who underwent repeated angiography for recurrent angina or reversible myocardial ischemia. Patients were stratified into either case (n = 354) and control (n = 442) groups in the presence or absence of ISR (defined as in-stent diameter stenosis ≥50%). BP levels were measured at the time of first and second procedures. Normal BP levels were defined for <140/90 mm Hg. RESULTS: Patients with normal BP showed significantly higher ISR-free survival (Log-rank: 5.937; P = 0.015). Both systolic (HR (95% CI): 0.731 (0.590-0.906)) and systolic/diastolic BP (HR (95% CI): 0.757 (0.611-0.939)) were significantly and independently associated with lower risk of ISR at Cox-regression analysis, adjusted for potential confounding factors, including stent type and concomitant medications. Patients with ISR showed lower rates of normal systolic/diastolic BP values (166 (47%) vs. 254 (57%); P = 0.003) compared to controls. They also received higher stent number (1.40±0.74 vs. 1.24±0.51; P < 0.001) with higher stent length (24.3±15.6 vs. 21.7±13.9 mm; P = 0.012), and lower rate of drug-eluting stents (DESs) (210 (48%) vs. 139 (40%); P = 0.025) compared to controls. CONCLUSIONS: Normal BP at the time of PCI is associated with nearly 24% risk reduction of ISR as evaluated in a new angiography in patients with coronary artery disease.

Restrictive cardiomyopathy and pseudoxanthoma elasticum skin lesions.

: We report a rare case of a patient with AL amyloidosis and pseudoxanthoma elasticum skin lesions. An association between these two diseases has been previously described as amyloid elastosis in only six cases, but cardiac findings were not fully elucidated. The peculiarity of our case is that a severe cardiac involvement influenced the prognosis negatively. Furthermore, the electron microscopic examination did not show all the peculiar histopathological findings of amyloid elastosis, precluding a final diagnosis of this disease.

Spatial QT Dispersion Predicts Nonsustained Ventricular Tachycardia and Correlates with Confined Systodiastolic Dysfunction in Hypertrophic Cardiomyopathy.

OBJECTIVES: An increased dispersion of myocardial repolarization represents one of the mechanisms underlying the arrhythmic risk in hypertrophic cardiomyopathy (HCM). We investigated spatial myocardial repolarization dispersion indices in HCM patients with nonsustained ventricular tachycardia (NSVT) and, contextually, their main clinical determinants. METHODS: Fifty-two well-matched HCM outpatients were categorized into two groups according to the presence or the absence of NSVT at 24-hour Holter electrocardiogram (ECG) monitoring. Each patient underwent a clinical examination, including Doppler echocardiogram integrated with tissue Doppler imaging, cardiac magnetic resonance, and 12-lead surface ECG to calculate the dispersion for the following intervals: QRS, Q-Tend (QTe), Q-Tpeak, Tpeak-Tend (TpTe), J-Tpeak, and J-Tend. RESULTS: The NSVT group showed only QTe dispersion and TpTe dispersion values to be significantly higher than their counterparts. NSVT occurrence was independently predicted by late gadolinium enhancement presence (p=0.021) and QTe Bazett dispersion (p=0.030), the latter strongly associated with the myocardial performance index (MPI) obtained at the basal segment of the interventricular septum (p=0.0004). CONCLUSION: Our data support QTe dispersion as an easy and noninvasive tool for identifying HCM patients with NSVT propensity. The strong relationship between QTe dispersion and MPI allows us to hypothesize an intriguing link between electrical instability and confined myocardial areas of systodiastolic dysfunction.

Integrated preclinical cardiovascular prevention: a new paradigm to face growing challenges of cardiovascular disease.

Cardiovascular disease (CVD) still represents the leading cause of mortality and morbidity worldwide. Despite considerable improvements in the prognosis of CVD and the significant reduction of CVD mortality obtained during the past half century, patients developing CVD, even though satisfactorily treated, still carry coronary artery disease and remain at risk for advanced CVD. Thus, the healthcare and socioeconomic burden linked to CVD remains high. As a result, more effective CVD prevention strategies remain crucial. 'Population strategies' and 'high-risk' approaches both have limitations and have often been viewed as alternative solutions. This persistent dualism could be overcome with the promotion of integrated prevention strategies based on a systematic evaluation of the total risk of disease, at both a population and an individual level. New approaches are also needed to reach people earlier in the course of the vascular disease and, possibly, to prevent risk factors and reduce CVD clinical manifestation.

Reducing Cardiovascular and Cancer Risk: How to Address Global Primary Prevention in Clinical Practice.

Emerging evidence suggesting the possibility that interventions able to prevent cardiovascular disease (CVD) may also be effective in the prevention of cancer have recently stimulated great interest in the medical community. In particular, data from both experimental and observational studies have demonstrated that aspirin may play a role in preventing different types of cancer. Although the use of aspirin in the secondary prevention of CVD is well established, aspirin in primary prevention is not systematically recommended because the absolute cardiovascular event reduction is similar to the absolute excess in major bleedings. By adding to its cardiovascular prevention benefits, the potential beneficial effect of aspirin in reducing the incidence of mortality and cancer could tip the balance between risks and benefits of aspirin therapy in primary prevention in favor of the latter and broaden the indication for treatment with aspirin in populations at average risk. Prospective and randomized studies are currently investigating the effect of aspirin in prevention of both cancer and CVD; however, clinical efforts at the individual level to promote the use of aspirin in global (or total) primary prevention already could be made on the basis of a balanced evaluation of the benefit/risk ratio.

[Role of adherence to long-term drug therapy in patients with cardiovascular disease: an Italian intersocietary consensus document]. / Il ruolo dell'aderenza al trattamento farmacologico nella terapia cronica delle malattie cardiovascolari: documento intersocietario di consenso.

Chronic therapy with statins, antihypertensive and antiplatelet drugs is one of the most important interventions for primary and secondary prevention of cardiovascular disease. Adherence to drug treatment is key to successful therapeutic intervention, especially in chronic conditions. This holds particularly true in the setting of cardiovascular diseases, because poor adherence may have serious adverse effects in terms of morbidity and mortality. Many factors may contribute to poor adherence, which can be either patient-related or dependent on the healthcare system, the physician and the environment. The identification and appropriate correction of these factors may result in both clinical and economic benefits. In this setting it is also important to assess the implications of the increasing use of generic or equivalent drugs on adherence to pharmacological therapy.

Myocardial repolarization dispersion and late gadolinium enhancement in patients with hypertrophic cardiomyopathy.

BACKGROUND: Growing evidence suggests that late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) is an additive marker of disease severity, and possibly of arrhythmic risk, in hypertrophic cardiomyopathy (HCM). We investigated the possible relationship between LGE and markers of myocardial repolarization dispersion in HCM. METHODS AND RESULTS: Eighty-five HCM outpatients underwent CMR and short-period electrocardiogram analysis to calculate the temporal myocardial repolarization dispersion through the QT variance normalized for QT mean (QTVN) and the QT variability index (QTVI). The QT dispersion in the spatial domain was also obtained. Patients with LGE (62%) had higher left atrial volume, maximum wall thickness, and left ventricular mass (P<0.0001), as well as a greater prevalence of non-sustained ventricular tachycardia (P<0.0001) and hypotensive blood pressure response (P=0.044). Both QTVN and QTVI were higher in the group with LGE (P<0.0001). At multivariate analysis, using QTVI as the dependent variable, %LGE (P<0.0001), age (P<0.0001), left ventricular outflow obstruction (P=0.038), and sudden cardiac death risk factor burden (P=0.020) reached statistical significance. Otherwise, only %LGE (P=0.005) and left ventricular mass index (P=0.015) remained associated with QTVN. CONCLUSIONS: Temporal myocardial repolarization dispersion correlates with LGE extent. Whether these variables could be useful in HCM clinical management warrants confirmation by larger prospective studies.