Proceed with caution: Standard protocol exercise stress tests fail to replicate the diagnostic utility of supine-stand tests for long QT syndrome.

BACKGROUND: Long QT syndrome (LQTS) is a sudden death predisposing condition characterized by ECG-derived prolongation of the QT interval. Previous studies have demonstrated that the supine-stand test may aid in the diagnosis of LQTS as patients fail to shorten their QT interval in response to standing up. The aim of this study was to evaluate the diagnostic accuracy of ECG data derived from standard protocol, clinically performed treadmill exercise stress tests (TESTs) in their ability to mimic the formal supine-stand test. METHODS: We performed a retrospective review of 478 TESTs from patients evaluated for LQTS. Patients referred for evaluation of LQTS but who were dismissed as normal served as controls. Heart rate & QT values were obtained from standard protocol TESTs. RESULTS: Overall, 243 patients with LQTS (125 LQT1, 63 LQT2, 55 LQT3; 146 [60%] female, mean age at TEST 30 ± 17 years) and 235 controls (142 [60%] female, mean age 24 ± 15 years) were included. The paired ΔQTc (QTcStand -QTcSupine ) was similar between LQTS (-5 ± 26) and controls (-2 ± 25; p = .2). During position change, the QT interval shortened by ≥20 ms in 33% of LQTS patients, remained unchanged in 62%, and increased in 5% of LQTS patients which was similar to controls (shortened in 40%, unchanged in 54%, and increased in 6% of controls; p = .2). Receiver-operator curve analysis to test the diagnostic ability of supine-stand ΔQT performed poorly in differentiating LQTS from controls with an of AUC 0.52 (p = .4). CONCLUSION: TESTs should be used with caution when trying to interpret supine-stand changes for diagnosis of LQTS.

The Role of Cardiopulmonary Exercise Testing in Hypertrophic Cardiomyopathy.

This review emphasizes the importance of cardiopulmonary exercise testing (CPET) in patients diagnosed with hypertrophic cardiomyopathy (HCM). In contrast to standard exercise testing and stress echoes, which are limited due to the ECG changes and wall motion abnormalities that characterize this condition, CPET allows for the assessment of the complex pathophysiology and severity of the disease, its mechanisms of functional limitation, and its risk stratification. It is useful tool to evaluate the risk for sudden cardiac death and select patients for cardiac resynchronization therapy (CRT), cardiac transplantation, or mechanical circulatory support, especially when symptomatology and functional status are uncertain. It may help in differentiating HCM from other forms of cardiac hypertrophy, such as athletes' heart. Finally, it is used to guide and monitor therapy as well as for exercise prescription. It may be considered every 2 years in clinically stable patients or every year in patients with worsening symptoms. Although performed only in specialized centers, CPET combined with echocardiography (i.e., CPET imaging) and invasive CPET are more informative and provide a better assessment of cardiac functional status, left ventricular outflow tract obstruction, and diastolic dysfunction during exercise in patients with HCM.

Atrial fibrillation in the athlete: Case report and a contemporary appraisal.

INTRODUCTION: Atrial fibrillation (AF) is the most prevalent sustained arrhythmia affecting up to 1% of the world's population. The overwhelming majority of patients with AF have concomitant structural heart disease and comorbidities, including hypertension and diabetes mellitus. One out of ten AF patients has no substantial comorbidities and has been traditionally termed "lone AF". Paradoxically, there exists an association of highintensity endurance exercises and AF. CASE: 43-year-old competitive cyclist and cross-country skier with no known cardiac comorbidities who presented with multiple episodes of dyspnea and palpitations. He was found to have exercise-induced AF without structural heart abnormalities. DISCUSSION: This case highlights the clinical diversity of AF in athletes. In this review, we delve into the specifics of the pathophysiology and clinical features of AF in athletes. We then review the key points in managing AF in athletes, including medical therapy and catheter ablation. CONCLUSION: AF in the athletes is incompletely understood due to a lack of prospective study volume. There exist some crucial pathophysiological differences between AF in athletes and AF in older patients with structural heart disease. Treating physicians must be aware of the nuances of management of AF in athletes, including the concepts of detraining, medical therapy options, and ablation.

Dose-Response Effect of a Digital Health Intervention During Cardiac Rehabilitation: Subanalysis of Randomized Controlled Trial.

BACKGROUND: Previous data have validated the benefit of digital health interventions (DHIs) on weight loss in patients following acute coronary syndrome entering cardiac rehabilitation (CR). OBJECTIVE: The primary purpose of this study was to test the hypothesis that increased DHI use, as measured by individual log-ins, is associated with improved weight loss. Secondary analyses evaluated the association between log-ins and activity within the platform and exercise, dietary, and medication adherence. METHODS: We obtained DHI data including active days, total log-ins, tasks completed, educational modules reviewed, medication adherence, and nonmonetary incentive points earned in patients undergoing standard CR following acute coronary syndrome. Linear regression followed by multivariable models were used to evaluate associations between DHI log-ins and weight loss or dietary adherence. RESULTS: Participants (n=61) were 79% male (48/61) with mean age of 61.0 (SD 9.7) years. We found a significant positive association of total log-ins during CR with weight loss (r2=.10, P=.03). Educational modules viewed (r2=.11, P=.009) and tasks completed (r2=.10, P=.01) were positively significantly associated with weight loss, yet total log-ins were not significantly associated with differences in dietary adherence (r2=.05, P=.12) or improvements in minutes of exercise per week (r2=.03, P=.36). CONCLUSIONS: These data extend our previous findings and demonstrate increased DHI log-ins portend improved weight loss in patients undergoing CR after acute coronary syndrome. DHI adherence can potentially be monitored and used as a tool to selectively encourage patients to adhere to secondary prevention lifestyle modifications. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01883050); https://clinicaltrials.gov/ct2/show/NCT01883050.

The impact of combined cardiopulmonary exercise testing and SPECT myocardial perfusion imaging on downstream evaluation and management.

OBJECTIVE: The diagnostic yield of combined cardiopulmonary exercise testing (CPET) and myocardial perfusion imaging (MPI) in patients referred for stress testing has received limited study. METHODS: We evaluated consecutive patients who underwent combined CPET-MPI at a single tertiary referral center between 2011 and 2015. An abnormal CPET was defined as any of the following: reduced oxygen consumption, cardiac output impairment, or pulmonary impairment. Normal MPI was defined as the absence of resting or stress perfusion defect. The primary study outcome was change in clinical decision-making after CPET-MPI including management of pulmonary disease, management of deconditioning, heart failure management, and referral for cardiac catheterization. Outcomes of patients with normal and abnormal MPI were presented based on the specific CPET abnormality. RESULTS: 415 patients were included in the study. Of the 269 patients that had normal MPI, 206 (77%) had abnormal CPET. Patients with abnormal CPET and normal MPI, compared with patients that had normal CPET and normal MPI, were more frequently diagnosed with pulmonary disease (11.7% vs 3.2%, P = .04) and deconditioning (33.5% vs 17.4%, P = .01). Of the 146 patients that had abnormal MPI, 128 (88%) had abnormal CPET. Patients with abnormal CPET and abnormal MPI, compared with patients that had normal CPET and abnormal MPI, did not statistically differ with regard to the study outcome. CONCLUSION: An abnormal CPET, if the MPI was normal, prompted further evaluation and led to management of pulmonary disease and deconditioning.

Frequency and characteristics of exercise-induced second-degree atrioventricular block in patients undergoing stress testing.

BACKGROUND: Spontaneous second-degree atrioventricular block induced by exercise (Ex2AVB) is rare, but it can cause profound exercise intolerance. OBJECTIVE: We sought to determine the frequency of Ex2AVB in our exercise testing practice and to describe characteristics of patients with Ex2AVB. We hypothesized that the number of patients would be small, but they would require invasive treatment. METHODS: We reviewed the Mayo Clinic Integrated Stress Center database for nonimaging tests performed from 2006 through 2010. All exercise tests coded as "second-degree atrioventricular block" were captured and reviewed. Tests were excluded if results showed evidence of second-degree atrioventricular block at rest. RESULTS: From 40,715 tests performed, definite Ex2AVB was found in only 19 patients (0.05%; 5 women and 14 men). Ex2AVB occurred as a Mobitz type II block in 4 patients and as a Mobitz type I block in 15. In 3 patients, Ex2AVB occurred only in recovery. Ex2AVB was intermittent in 11 patients and persistent in 8. Mean peak heart rate was higher with intermittent Ex2AVB than with persistent Ex2AVB (126 ±â€¯39 vs 88 ±â€¯28 bpm, P < .01), as was mean functional aerobic capacity (87% ±â€¯20% vs 59% ±â€¯14%, P < .01). Seven patients with persistent Ex2AVB received a permanent pacemaker; 1 underwent pacemaker adjustment. CONCLUSION: Ex2AVB is uncommon but can cause exercise intolerance that requires pacemaker implantation. Structural or ischemic heart disease and resting conduction abnormalities are common findings in patients with Ex2AVB. Intervention is seldom required for intermittent Ex2AVB.

Digital health intervention during cardiac rehabilitation: A randomized controlled trial.

BACKGROUND: Digital health interventions (DHI) have been shown to improve intermediates of cardiovascular health, but their impact on cardiovascular (CV) outcomes has not been fully explored. The aim of this study was to determine whether DHI administered during cardiac rehabilitation (CR) would reduce CV-related emergency department (ED) visits and rehospitalizations in patients after percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). METHODS: We randomized patients undergoing CR following ACS and PCI to standard CR (n=40) or CR+DHI (n=40) for 3 months with 3 patients withdrawing from CR prior to initiation in the treatment arm and 6 in the control group. The DHI incorporated an online and smartphone-based CR platform asking the patients to report of dietary and exercise habits throughout CR as well as educational information toward patients' healthy lifestyles. We obtained data regarding ED visits and rehospitalizations at 180 days, as well as other metrics of secondary CV prevention at baseline and 90 days. RESULTS: Baseline demographics were similar between the groups. The DHI+CR group had improved weight loss compared to the control group (-5.1±6.5 kg vs. -0.8±3.8 kg, respectively, P=.02). Those in the DHI+CR group also showed a non-significant reduction in CV-related rehospitalizations plus ED visits compared to the control group at 180 days (8.1% vs 26.6%; RR 0.30, 95% CI 0.08-1.10, P=.054). CONCLUSIONS: The current study demonstrated that complementary DHI significantly improves weight loss, and might offer a method to reduce CV-related ED visits plus rehospitalizations in patients after ACS undergoing CR. The study suggests a role for DHI as an adjunct to CR to improve secondary prevention of CV disease. TRIAL REGISTRATION: This trial is registered at clinicaltrials.gov (NCT01883050).

Detailed heart rate variability analysis in athletes.

OBJECTIVE: Heart rate variability (HRV) analysis has been used to evaluate patients with various cardiovascular diseases. While the vast majority of HRV studies have focused on pathological states, our study focuses on the less explored area of HRV analysis across different training intensity and sports. We aimed to measure HRV in healthy elite and masters athletes and compare to healthy, but non-athletic controls. METHODS: Time-domain HRV analysis was applied in 138 athletes (male 110, age 28.4 ± 8.3) and 100 controls (male 56, age 28.3 ± 6.9) during Holter monitoring (21.3 ± 3.0 h). RESULTS: All studied parameters were higher in elite athletes compared to controls [SDNN (CI) 225.3 (216.2-234.5) vs 158.6 (150.2-167.1) ms; SDNN Index (CI) 99.6 (95.6-103.7) vs 72.4 (68.7-76.2) ms; pNN50 (CI) 24.2 (22.2-26.3) vs 14.4 (12.7-16.3) %; RMSSD (CI) 71.8 (67.6-76.2) vs 50.8 (46.9-54.8) ms; p < 0.001]. Masters had higher HRV values than controls, but no significant differences were found between elite athletes and masters athletes. Some parameters were higher in canoeists-kayakers and bicyclists than runners. Lower cut-off values in elite athletes were SDNN: 147.4 ms, SDNN Index: 66.6 ms, pNN50: 9.7 %, RMSSD: 37.9 ms. INTERPRETATION: Autonomic regulation in elite athletes described with HRV is significantly different than in healthy controls. Sports modality and level of performance, but not age- or sex-influenced HRV. Our study provides athletic normal HRV values. Further investigations are needed to determine its role in risk stratification, optimization of training, or identifying overtraining.

Myocardial and Cardiocirculatory Reserve in Asymptomatic Aortic Stenosis and Preserved Ejection Fraction.

BACKGROUND AND AIM OF THE STUDY: Managing patients with asymptomatic severe aortic stenosis (AS) remains a major challenge. Myocardial as well as cardiocirculatory reserve have been hypothesized to predict outcome in patients with asymptomatic AS. METHODS: A total of 48 patients (indexed aortic valve area 0.39 +/- 0.12 cm2/m2; ejection fraction (EF) 67 +/- 7%) underwent spiroergometry and dobutamine stress echocardiography. Death or valve surgery served as a combined endpoint for follow up. RESULTS: Thirty-seven patients reached the endpoint after a mean of 756 days (range: 100-2146 days). Age- and gender-corrected univariate Cox proportional analysis revealed the presence of mild obstructive lung disease, stroke work loss (SWL), end-systolic diameter index, and E/Flow propagation velocity as the best predictive clinical, valvular, cardiostructural, and left ventricular filling pressure parameters, respectively. After inclusion of these parameters into a baseline multivariable Cox proportional hazard model, SWL (HR 1.21 per rise of 1 unit, CI 1.08-1.35, p = 0.0005) and female gender (HR 3.37, CI 1.50-7.59, p = 0.0044) were independently predictive. Similarly, the best-performing myocardial parameter, EF after dobutamine, was independently predictive (HR 0.75 per 5 units, CI 0.57-0.99, p = 0.035) after inclusion. The best-performing exercise capacity parameter, Watt(max), was of borderline significance (HR 0.93 per 5 units, CI 0.86-1.00, p = 0.0505). For each parameter, cut-off values were determined by time-dependent receiver-operator characteristics. The Kaplan-Meier curves of the patients above versus below the cut-offs differed significantly for SWL (p = 0.001), Wattm (p = 0.001), and gender (p = 0.013). CONCLUSION: Besides SWL and female gender, the EF after dobutamine as well as highest exercise stress intensity reached are helpful in determining the prognosis of asymptomatic patients with moderate-severe AS.

Using an online, personalized program reduces cardiovascular risk factor profiles in a motivated, adherent population of participants.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of morbidity, mortality, and cost in Western society. Employer-sponsored work health programs (WHPs) and Web-based portals for monitoring and providing guidance based on participants' health risk assessments are emerging, yet online technologies to improve CVD health in the workplace are relatively unproven. We hypothesized that an online WHP, comprehensively addressing multiple facets of CVD, can be successfully implemented and improve the health of participants. METHODS: A cohort of employees in Tennessee (n = 1,602) was subjected to a health risk assessment at baseline. Those who did not meet all 5 healthy benchmarks (n = 836)-body mass index, blood pressure, glucose, total cholesterol, and smoking status-were prospectively assigned to a Web-based personal health assistant and had repeat measurements taken at 90 days. RESULTS: Of those who both completed the personal health assistant program and underwent baseline plus 90-day assessments (508/836, 61%), 75% were female, mean age was 46.5 ± 11.1 years, and the mean number of risk factors at baseline was 1.1 ± 0.9 with a mean 10-year Framingham Risk Score of 2.9%. This cohort demonstrated a significant reduction in total cholesterol (P < .0001), low-density lipoprotein cholesterol (P < .0001), triglycerides (P < .0001), systolic blood pressure (P = .009), glucose (P = .004), weight (P = .001), and body mass index (P = .001). Most of the participants improved at least 1 risk factor. Framingham Risk 10-year cardiovascular risk percentages were significantly reduced (P = .003). CONCLUSIONS: This study in a prospective cohort of community-dwelling employees suggests that an online WHP can provide a viable means to improve surrogates of CVD risk factors.

Changes in cardiopulmonary exercise testing parameters following continuous flow left ventricular assist device implantation and heart transplantation.

BACKGROUND: Reduced exercise tolerance from impaired cardiac output is an important criterion for left ventricular assist device (LVAD) implantation. However, little is known about how exercise capacity changes after LVAD and how changes compare with patients undergoing heart transplantation. METHODS AND RESULTS: We compared changes in cardiopulmonary exercise testing performed pre- and postoperatively in patients who underwent HeartMate II LVAD implantation (n = 25) and heart transplantation (n = 74) at the Mayo Clinic in Rochester, Minnesota, between 2007 and 2012. Preoperatively, patients undergoing LVAD and transplant had markedly reduced exercise time (mean 5.1 minutes [45% predicted] and 5.0 minutes [44% predicted], respectively), low peak oxygen consumption (VO2; mean 11.5 mL · kg · min [43% predicted] and 11.9 mL · kg · min [38% predicted]), and abnormal ventilatory gas exchange (ratio of minute ventilation to carbon dioxide production [VE/VCO2] nadir 39.4 and 37.4). After LVAD and transplant, there were similar improvements in exercise time (mean Δ +1.2 vs. 1.7 minutes, respectively, P = .27) and VE/VCO2 nadir (mean Δ -3.7 vs. -4.2, P = .74). However, peak VO2 increased posttransplant but did not change post-LVAD (mean Δ +5.4 vs. +0.9 mL · kg · min, respectively, P < .001). Most patients (72%) had a peak VO2 < 14 mL · kg · min post-LVAD. CONCLUSIONS: Although improvements in exercise capacity and gas exchange are seen after LVAD and heart transplant, peak VO2 doesn't improve post-LVAD and remains markedly abnormal in most patients.

Incidence of Severe Adverse Drug Reactions to Ultrasound Enhancement Agents in a Contemporary Echocardiography Practice.

OBJECTIVES: Prior data indicate a very rare risk of serious adverse drug reaction (ADR) to ultrasound enhancement agents (UEAs). We sought to evaluate the frequency of ADR to UEA administration in contemporary practice. METHODS: We retrospectively reviewed 4 US health systems to characterize the frequency and severity of ADR to UEA. Adverse drug reactions were considered severe when cardiopulmonary involvement was present and critical when there was loss of consciousness, loss of pulse, or ST-segment elevation. Rates of isolated back pain and headache were derived from the Mayo Clinic Rochester stress echocardiography database where systematic prospective reporting of ADR was performed. RESULTS: Among 26,539 Definity and 11,579 Lumason administrations in the Mayo Clinic Rochester stress echocardiography database, isolated back pain or headache was more frequent with Definity (0.49% vs 0.04%, P < .0001) but less common with Definity infusion versus bolus (0.08% vs 0.53%, P = .007). Among all sites there were 201,834 Definity and 84,943 Lumason administrations. Severe and critical ADR were more frequent with Lumason than with Definity (0.0848% vs 0.0114% and 0.0330% vs 0.0010%, respectively; P < .001 for each). Among the 3 health systems with >2,000 Lumason administrations, the frequency of severe ADR with Lumason ranged from 0.0755% to 0.1093% and the frequency of critical ADR ranged from 0.0293% to 0.0525%. Severe ADR rates with Definity were stable over time but increased in more recent years with Lumason (P = .02). Patients with an ADR to Lumason since the beginning of 2021 were more likely to have received a COVID-19 vaccination compared with matched controls (88% vs 75%; P = .05) and more likely to have received Moderna than Pfizer-Biotech (71% vs 26%, P < .001). CONCLUSION: Severe and critical ADR, while rare, were more frequent with Lumason, and the frequency has increased in more recent years. Additional work is needed to better understand factors, including associations with recently developed mRNA vaccines, which may be contributing to the increased rates of ADR to UEA since 2021.

The safety of cardiopulmonary exercise testing in a population with high-risk cardiovascular diseases.

BACKGROUND: Cardiopulmonary exercise testing (CPX) with measurement of peak oxygen uptake (Vo(2)) is a powerful test for assessment and quantification of functional impairment resulting from cardiovascular disease. The safety of CPX has been established in patients with coronary artery disease and congestive heart failure, but clinical use of CPX in other cardiac diseases has been limited, in part because of a paucity of safety data. This study investigates the safety of CPX in a heterogeneous cohort of patients with a wide variety of underlying high-risk cardiac diagnoses. METHODS AND RESULTS: This single-center retrospective review examined 5060 CPX studies performed in 4250 unique patients, including 1748 (35%) female subjects and 686 (14%) subjects aged ≥75 years. The primary end point was major adverse event during stress testing. The study population included patients with a variety of high-risk cardiac diseases, including congestive heart failure (n=1289, 25.5%), hypertrophic cardiomyopathy (n=598, 11.8%), pulmonary hypertension (n=194, 3.8%), and aortic stenosis (n=212, 4.2%). This patient population generally had severe functional impairment, including 1192 (24%) patients with peak Vo(2)<14 mL/kg/min. Eight adverse events occurred during CPX, for an adverse event rate of 0.16%. The most common adverse event (n=6) was sustained ventricular tachycardia. There were no fatal events. CONCLUSIONS: CPX is generally a safe procedure, even in a population with underlying high-risk cardiovascular diagnoses.

Orthostatic intolerance without postural tachycardia: how much dysautonomia?

BACKGROUND: Chronic symptoms of orthostatic intolerance occur in postural tachycardia syndrome (POTS) and patients with orthostatic intolerance (OI) without tachycardia. We recently reported that deconditioning is almost universal in both patient groups. In this study, we focussed on the question of how much dysautonomia, besides orthostatic tachycardia, is there in POTS vs. OI, and how the two groups compare in regards to clinical, autonomic, laboratory, and exercise variables. METHODS: We retrospectively studied all patients referred for orthostatic intolerance at Mayo Clinic between January 2006 and June 2011, who underwent standardized autonomic and exercise testing. RESULTS: Eighty-four POTS and 100 OI fulfilled inclusion criteria, 89 % were females. The mean age was 25 and 32 years, respectively. Clinical presentation, autonomic parameters, laboratory findings, and degree of deconditioning were overall similar between the two groups, except for the excessive orthostatic heart rate (HR) rise and mild vasomotor findings observed in POTS but not in OI (slightly larger Valsalva ratio and incomplete blood pressure recovery during Valsalva). Both groups responded poorly to various medications. Severely deconditioned patients were similar to non-deconditioned patients, except for 24 h urine volume (1,555 vs. 2,417 ml), sweat loss on thermoregulatory sweat test (1.5 vs. 0.5 %), and few respiratory parameters during exercise, which are likely clinically insignificant. CONCLUSION: Though similar in clinical presentation, POTS and OI are different entities with greater, albeit still mild, dysautonomia in POTS. The clinical and pathophysiological relevance of minimal dysautonomia in the absence of orthostatic tachycardia as seen in OI remain uncertain.

Cardiac Complications of COVID-19 Infection and the Role of Physical Activity.

Since December 2019, the newly emerging coronavirus has become a global pandemic with >250 million people infected and >5 million deaths worldwide. Infection with coronavirus disease-2019 (COVID-19) causes a severe immune response and hypercoagulable state leading to tissue injury, organ damage, and thrombotic events. It is well known that COVID-19 infection predominately affects the lungs; however, the cardiovascular complications of the disease have been a major cause of morbidity and mortality. In addition, patients with cardiovascular disease are vulnerable to contract a severe form of the illness and increased mortality. A significant number of patients who survived the disease may experience post-COVID-19 syndrome with a variety of symptoms and physical limitations. Here, we review the cardiac complications of COVID-19 infection and the results of cardiopulmonary exercise testing and guidelines for exercise training after infection.

Cardiopulmonary Exercise Testing in Athletes With Hypertrophic Cardiomyopathy.

Patients with hypertrophic cardiomyopathy (HCM) have historically been restricted from athletic participation because of the perceived risk of sudden cardiac death. More contemporary research has highlighted the relative safety of competitive athletics with HCM. However, lack of published data on reference values for cardiopulmonary exercise testing (CPET) complicates clinical management and counseling on sports participation in the individual athlete. We conducted a single-center, retrospective cohort study to investigate CPET in athletes with HCM and clinical characteristics associated with objective measures of aerobic capacity. We identified 58 athletes with HCM (74% male, mean age 18 ± 3 years, mean left ventricular (LV) wall thickness 20 ± 7 mm). LV outflow tract obstruction was present in 22 (38%). A total of 15 (26%) athletes were taking a ß blocker (BB), but only 4 (7%) reported exertional symptoms. Overall, exercise capacity was mildly reduced, with a peak myocardial oxygen consumption (peak VO2) of 37.9 ml/min/kg (83% of predicted peak VO2). Both LV outflow tract obstruction and BB use were associated with reduced exercise capacity. Limited peak heart rate was more common in athletes taking BB (47% vs 9%, p = 0.002). At a mean 5.6 years follow-up, 5 patients underwent myectomy (9%), and 8 (14%) received an implantable cardioverter defibrillator (ICD) for primary prevention. One individual with massive LV hypertrophy experienced recurrent ICD shocks for ventricular fibrillation and underwent myectomy 7 years after initial evaluation and was no longer participating in sports. There were no deaths over the follow-up period. In conclusion, the prognostic role of CPET remains unclear in athletes with HCM. Mildly reduced exercise capacity was common; however, reduced peak VO2 did not correlate with symptom status or clinical outcomes. A significant proportion went on to require myectomy and/or ICD, thus highlighting the need for close follow-up. These data provide some initial insight into the clinical evaluation of "real world" athletes with HCM; however, further study is warranted to help guide shared decision-making, return-to-play discussions, and the potential long-term safety of competitive athletic participation.

Cardiopulmonary testing in long COVID-19 versus non-COVID-19 patients with undifferentiated Dyspnea on exertion.

BACKGROUND: Dyspnea and fatigue are characteristics of long SARS-CoV-2 (COVID)-19. Cardiopulmonary exercise testing (CPET) can be used to better evaluate such patients. RESEARCH QUESTION: How significantly and by what mechanisms is exercise capacity impaired in patients with long COVID who are coming to a specialized clinic for evaluation? STUDY DESIGN AND METHODS: We performed a cohort study using the Mayo Clinic exercise testing database. Subjects included consecutive long COVID patients without prior history of heart or lung disease sent from the Post-COVID Care Clinic for CPET. They were compared to a historical group of non-COVID patients with undifferentiated dyspnea also without known cardiac or pulmonary disease. Statistical comparisons were performed by t-test or Pearson's chi2 test controlling for age, sex, and beta blocker use where appropriate. RESULTS: We found 77 patients with long COVID and 766 control patients. Long COVID patients were younger (47 ± 15 vs 50 ± 10 years, P < .01) and more likely female (70% vs 58%, P < .01). The most prominent difference on CPETs was lower percent predicted peak V̇O2 (73 ± 18 vs 85 ± 23%, p < .0001). Autonomic abnormalities (resting tachycardia, CNS changes, low systolic blood pressure) were seen during CPET more commonly in long COVID patients (34 vs 23%, P < .04), while mild pulmonary abnormalities (mild desaturation, limited breathing reserve, elevated V̇E/V̇CO2) during CPET were similar (19% in both groups) with only 1 long COVID patient showing severe impairment. INTERPRETATION: We identified severe exercise limitation among long COVID patients. Young women may be at higher risk for these complications. Though mild pulmonary and autonomic impairment were common in long COVID patients, marked limitations were uncommon. We hope our observations help to untangle the physiologic abnormalities responsible for the symptomatology of long COVID.

Exercise Test Predicts Both Noncardiovascular and Cardiovascular Death in a Primary Prevention Population.

OBJECTIVE: To identify specific causes of death and determine the prevalence of noncardiovascular (non-CV) deaths in an exercise test referral population while testing whether exercise test parameters predict non-CV as well as CV deaths. PATIENTS AND METHODS: Non-imaging exercise tests on patients 30 to 79 years of age from September 1993 to December 2010 were reviewed. Patients with baseline CV diseases and non-Minnesota residents were excluded. Mortality through January 2016 was obtained through Mayo Clinic Records and the Minnesota Death Index. Exercise test abnormalities included low functional aerobic capacity (ie, less than 80%), heart rate recovery (ie, less than 13 beats/min), low chronotropic index (ie, less than 0.8), and abnormal exercise electrocardiogram (ECG) of greater than or equal to 1.0 mm ST depression or elevation. We also combined these four abnormalities into a composite exercise test score (EX_SCORE). Statistical analyses consisted of Cox regression adjusted for age, sex, diabetes, hypertension, obesity, current and past smoking, and heart rate-lowering drug. RESULTS: The study identified 13,382 patients (females: n=4736, 35.4%, 50.5±10.5 years of age). During 12.7±5.0 years of follow-up, there were 849 deaths (6.3%); of these 162 (19.1%) were from CV; 687 (80.9%) were non-CV. Hazard ratios for non-CV death were significant for low functional aerobic capacity (HR, 1.42; 95% CI, 1.19 to 1.69; P<.0001), abnormal heart rate recovery (HR, 1.36; 95% CI, 1.15 to 1.61; P<.0033), and low chronotropic index (HR, 1.49; 95% CI, 1.26 to 1.77; P<.0001), whereas abnormal exercise ECG was not significant. All exercise test abnormalities including EX_SCORE were more strongly associated with CV death versus non-CV death except abnormal exercise ECG. CONCLUSION: Non-CV deaths predominated in this primary prevention cohort. Exercise test abnormalities not only predicted CV death but also non-CV death.

Relationship between BMI and prognosis of chronic heart failure outpatients in Vietnam: a single-center study.

Background: Insufficient data exists regarding the relationship between body mass index (BMI) and the prognosis of chronic heart failure (CHF) specifically within low- and middle-income Asian countries. The objective of this study was to evaluate the impact of BMI on adverse outcomes of ambulatory patients with CHF in Vietnam. Methods: Between 2018 and 2020, we prospectively enrolled consecutive outpatients with clinically stable CHF in an observational cohort, single-center study. The participants were stratified according to Asian-specific BMI thresholds. The relationships between BMI and adverse outcomes (all-cause death and all-cause hospitalization) were analyzed by Kaplan-Meier survival curves and Cox proportional-hazards model. Results: Among 320 participants (age 63.5 ± 13.3 years, 57.9% male), the median BMI was 21.4 kg/m2 (IQR 19.5-23.6), and 10.9% were underweight (BMI <18.50 kg/m2). Over a median follow-up time of 32 months, the cumulative incidence of all-cause mortality and hospitalization were 5.6% and 19.1%, respectively. After multivariable adjustment, underweight patients had a significantly higher risk of all-cause mortality than patients with normal BMI (adjusted hazard ratios = 3.03 [95% CI: 1.07-8.55]). Lower BMI remained significantly associated with a worse prognosis when analyzed as a continuous variable (adjusted hazard ratios = 1.27 [95% CI: 1.03-1.55] per 1 kg/m2 decrease for all-cause mortality). However, BMI was not found to be significantly associated with the risk of all-cause hospitalization (p > 0.05). Conclusion: In ambulatory patients with CHF in Vietnam, lower BMI, especially underweight status (BMI < 18.5 kg/m2), was associated with a higher risk of all-cause mortality. These findings suggest that BMI should be considered for use in risk classification, and underweight patients should be managed by a team consisting of cardiologists, nutritionists, and geriatricians.