Peak oxygen consumption by smartwatches compared with cardiopulmonary exercise test in complex congenital heart disease.

OBJECTIVE: To evaluate for correlation between exercise capacity as assessed by peak oxygen consumption (pVO2) measurement during a cardiopulmonary exercise test (CPET) and smartwatches reporting this parameter in patients with adult congenital heart disease (ACHD) complex lesions. METHODS: A prospective study that included patients with ACHD either a Fontan circulation or a right ventricle supporting the systemic circulation who underwent two separate CPETs at least 1 year apart. Generalised estimating equations linear regression was performed to identify factors associated with correlation between smartwatch and CPET-derived pVO2. RESULTS: 48 patients (71% with a Fontan circulation, 42% females, mean age 33±9 years) underwent two CPETs between May 2018 and May 2022 with echocardiograms performed within 6 months of each CPET. Apple Watch was the predominant smartwatch used (79%). Smartwatch and CPET measured peak heart rate (Pearson correlation=0.932, 95% CI (0.899, 0.954)) and pVO2 (0.8627, 95% CI (0.8007, 0.9064) and 0.8634, 95% CI (0.7676, 0.9215) in the first and second CPET, respectively) correlated well, with smartwatch-measured pVO2 values measuring higher by a mean of 3.146 mL/kg/min (95% CI (2.559, 3.732)). Changes in pVO2 between the first and the second CPET also correlated well (Pearson correlation=0.9165, 95% CI (0.8549, 0.9525)), indicating that for every 1 mL/(min kg) change in CPET-measured pVO2, there was a corresponding 0.896 mL/(min kg) change in the smartwatch-measured pVO2. CONCLUSION: Both absolute values and changes over time in pVO2 as measured by smartwatches and CPETs correlate well in patients with complex ACHD.

Sudden cardiac death as a consequence of Cor triatriatum sinistrum in an adult.

Cor triatriatum sinistrum (CTS) is a rare congenital cardiac malformation in which the left atrium is divided by a fenestrated membrane, which can restrict blood flow and cause symptoms of congestive heart failure. Rarely, the condition can present in adulthood. This case report illustrates a case of sudden cardiac death (SCD) due to the sequelae of untreated CTS. To date, there are no reported cases of SCD attributable to CTS. Learning objectives: Cor triatriatum sinistrum is among the rarest of congenital heart diseases. In this case report, we describe the prevalence, etiology, diagnosis, and management of this disease.

Echocardiographic imaging of temporary percutaneous mechanical circulatory support devices.

Cardiogenic shock is a state of end-organ hypoperfusion due to primary cardiac dysfunction and portends a poor prognosis. Shock refractory to inotropic and vasopressor support is often an indication for mechanical circulatory support. When mechanical support device complications or malfunction arise, echocardiography offers rapid assessment of device position and function. Repositioning can be done under echocardiographic guidance. Despite the widespread use of percutaneous mechanical circulatory support, there is a dearth of information regarding echocardiography as it pertains to these devices. In this review, we discuss the utility of echocardiography with percutaneous mechanical circulatory support devices.

Subendocardial stress in pre-eclampsia.

A primigravida 26-year-old woman who had developed pre-eclampsia with malignant hypertension at 30 weeks of gestation suffered acute myocardial infarction two days postpartum. Electrocardiogram demonstrated diffuse ST-segment depression suggestive of subendocardial ischemia. Echocardiography demonstrated focal asymmetric left ventricular hypertrophy, with a characteristic "basal septal bulge", and a left ventricular mid-cavitary gradient of 51 mmHg. Coronary angiography revealed normal coronary arteries and vascular flow. Peripartum acute myocardial infarction is rare and portends a high mortality. However, to date, only one case of acute myocardial infarction associated with asymmetric left ventricular hypertrophy and pre-eclampsia has been described in the literature.

Right ventricular function and cardiopulmonary performance among patients with heart failure supported by durable mechanical circulatory support devices.

BACKGROUND: Patients with continuous-flow left ventricular assist devices (CF-LVADs) experience limitations in functional capacity and frequently, right ventricular (RV) dysfunction. We sought to characterize RV function in the context of global cardiopulmonary performance during exercise in this population. METHODS: A total of 26 patients with CF-LVAD (aged 58 ± 11 years, 23 males) completed a hemodynamic assessment with either conductance catheters (Group 1, n = 13) inserted into the right ventricle to generate RV pressure‒volume loops or traditional Swan‒Ganz catheters (Group 2, n = 13) during invasive cardiopulmonary exercise testing. Hemodynamics were collected at rest, 2 sub-maximal levels of exercise, and peak effort. Breath-by-breath gas exchange parameters were collected by indirect calorimetry. Group 1 participants also completed an invasive ramp test during supine rest to determine the impact of varying levels of CF-LVAD support on RV function. RESULTS: In Group 1, pump speed modulations minimally influenced RV function. During upright exercise, there were modest increases in RV contractility during sub-maximal exercise, but there were no appreciable increases at peak effort. Ventricular‒arterial coupling was preserved throughout the exercise. In Group 2, there were large increases in pulmonary arterial, left-sided filling, and right-sided filling pressures during sub-maximal and peak exercises. Among all participants, the cardiac output‒oxygen uptake relationship was preserved at 5.8:1. Ventilatory efficiency was severely abnormal at 42.3 ± 11.6. CONCLUSIONS: Patients with CF-LVAD suffer from limited RV contractile reserve; marked elevations in pulmonary, left-sided filling, and right-sided filling pressures during exercise; and severe ventilatory inefficiency. These findings explain mechanisms for persistent reductions in functional capacity in this patient population.

Electrocardiogram interpretation in college athletes: Local institution versus sports cardiology center interpretation.

BACKGROUND: Electrocardiogram (ECG) screening in athletes enhances the detection of conditions associated with sudden cardiac death (SCD), but concerns remain for false positive results when conducted outside of specialized centers. This study compared ECG interpretation in college athletes between local physicians and a sports cardiology center (SCC). METHODS: Screening ECGs in athletes from eight Pacific-12 Conference institutions performed between 2010 and 2016 were included. Local interpretation was compared to SCC interpretation using both the Seattle Criteria (SCC-SC) and the International Criteria (SCC-IC). RESULTS: A total of 2445 athlete ECGs (mean age 18.5 years; 57.1% male; 63.2% Caucasian and 15.3% African American) were reviewed. The proportion of ECGs classified as abnormal was similar between local and SCC-SC interpretation (3.5% vs. 3.4%, respectively; p = .94), but was lower by SCC-IC interpretation (1.5%, p < .001). ECG abnormalities interpreted as normal by local physicians but as abnormal by SCC-SC (n = 33) and SCC-IC (n = 16) standards included: pathological Q waves (n = 15 SCC-SC; n = 3 SCC-IC), T-wave inversions (n = 8 both), and ST-depressions (n = 3 both). There was a 97.5% ECG interpretation agreement and substantial interobserver reliability (k = 0.611, p < .001) between local and SCC-SC interpretation in athletes screened starting one year after publication of the Seattle Criteria (n = 1388). Both local and SCC physicians correctly identified six abnormal ECGs associated with conditions at risk of SCD. CONCLUSIONS: ECG interpretation by local physicians at college universities had similar accuracy compared to a specialized SCC with a low overall abnormal rate, similar sensitivity, and substantial interobserver reliability. Uniform application of current ECG interpretation standards is recommended to further improve accuracy.

New insights into resting and exertional right ventricular performance in the healthy heart through real-time pressure-volume analysis.

KEY POINTS: Despite growing interest in right ventricular form and function in diseased states, there is a paucity of data regarding characteristics of right ventricular function - namely contractile and lusitropic reserve, as well as ventricular-arterial coupling, in the healthy heart during rest, as well as submaximal and peak exercise. Pressure-volume analysis of the right ventricle, during invasive cardiopulmonary exercise testing, demonstrates that that the right heart has enormous contractile reserve, with a three- or fourfold increase in all metrics of contractility, as well as myocardial energy production and utilization. The healthy right ventricle also demonstrates marked augmentation in lusitropy, indicating that diastolic filling of the right heart is not passive. Rather, the right ventricle actively contributes to venous return during exercise, along with the muscle pump. Ventricular-arterial coupling is preserved during submaximal and peak exercise in the healthy heart. ABSTRACT: Knowledge of right ventricular (RV) function has lagged behind that of the left ventricle and historically, the RV has even been referred to as a 'passive conduit' of lesser importance than its left-sided counterpart. Pressure-volume (PV) analysis is the gold standard metric of assessing ventricular performance. We recruited nine healthy sedentary individuals free of any cardiopulmonary disease (42 ± 12 years, 78 ± 11 kg), who completed invasive cardiopulmonary exercise testing during upright ergometry, while using conductance catheters inserted into the RV to generate real-time PV loops. Data were obtained at rest, two submaximal levels of exercise below ventilatory threshold, to simulate real-world scenarios/activities of daily living, and maximal effort. Breath-by-breath oxygen uptake was determined by indirect calorimetry. During submaximal and peak exercise, there were significant increases in all metrics of systolic function by three- to fourfold, including cardiac output, preload recruitable stroke work, and maximum rate of pressure change in the ventricle (dP/dtmax ), as well as energy utilization as determined by stroke work and pressure-volume area. Similarly, the RV demonstrated a significant, threefold increase in lusitropic reserve throughout exercise. Ventricular-arterial coupling, defined by the quotient of end-systolic elastance and effective arterial elastance, was preserved throughout all stages of exercise. Maximal pressures increased significantly during exercise, while end-diastolic volumes were essentially unchanged. Overall, these findings demonstrate that the healthy RV is not merely a passive conduit, but actively participates in cardiopulmonary performance during exercise by accessing an enormous amount of contractile and lusitropic reserve, ensuring that VA coupling is preserved throughout all stages of exercise.

Man versus machine? Acquired long QT syndrome in a patient with anorexia nervosa.

Computer-generated Bazett-corrected QT (QTcB) algorithms are common in clinical practice and can rapidly identify repolarization abnormalities, but accuracy is variable. This report highlights marked rate-corrected QT (QTc) interval prolongation not detected by the computer algorithm. A 26-year-old woman with anorexia nervosa was admitted with severe hypokalemia and ventricular ectopy. Computer-generated QTcB was 485 ms, while manual adjudication yielded a QTcB of 657 ms and a Fridericia-corrected QT (QTcF) interval of 626 ms using digital calipers. Computer-generated QTc intervals may aid in clinical decision-making. However, accuracy is variable, particularly in the setting of ectopy, and requires manual verification.