ST-Segment Depression in Hyperventilation Indicates a False Positive Exercise Test in Patients with Mitral Valve Prolapse

Comparison of Cardiorespiratory Fitness between Patients with Mitral Valve Prolapse and Healthy Peers: Findings from Serial Cardiopulmonary Exercise Testing

Individuals with mitral valve prolapse (MVP) have exercise intolerance even without mitral valve regurgitation. Mitral valve degeneration may progress with aging. We aimed to evaluate the influence of MVP on the cardiopulmonary function (CPF) of individuals with MVP through serial follow-ups from early to late adolescence. Thirty patients with MVP receiving at least two cardiopulmonary exercise tests (CPETs) using a treadmill (MVP group) were retrospectively analyzed. Age-, sex-, and body mass index-matched healthy peers, who also had serial CPETs, were recruited as the control group. The average time from the first CPET to the last CPET was 4.28 and 4.06 years in the MVP and control groups, respectively. At the first CPET, the MVP group had a significantly lower peak rate pressure product (PRPP) than the control group (p = 0.022). At the final CEPT, the MVP group had lower peak metabolic equivalent (MET, p = 0.032) and PRPP (p = 0.031). Moreover, the MVP group had lower peak MET and PRPP as they aged, whereas healthy peers had higher peak MET (p = 0.034) and PRPP (p = 0.047) as they aged. Individuals with MVP had poorer CPF than healthy individuals as they develop from early to late adolescence. It is important for individuals with MVP to receive regular CPET follow-ups.

Comparison of the Results of Cardiopulmonary Exercise Testing between Healthy Peers and Pediatric Patients with Different Echocardiographic Severity of Mitral Valve Prolapse

Patients with mitral valve prolapse (MVP) have been reported to have exercise intolerance. However, the underlying pathophysiological mechanisms and their physical fitness remain unclear. We aimed to determine the exercise capacity of patients with MVP through the cardiopulmonary exercise test (CPET). We retrospectively collected the data of 45 patients with a diagnosis of MVP. Their CPET and echocardiogram results were compared with 76 healthy individuals as primary outcomes. No significant differences regarding the patient's baseline characteristics and echocardiographic data were found between the two groups, except for the lower body mass index (BMI) of the MVP group. Patients in the MVP group demonstrated a similar peak metabolic equivalent (MET), but a significantly lower peak rate pressure product (PRPP) (p = 0.048). Patients with MVP possessed similar exercise capacity to healthy individuals. The reduced PRPP may indicate compromised coronary perfusion and subtle left ventricular function impairment.

Evaluation of Early Repolarization Pattern in Children with Mitral Valve Prolapse

BACKGROUND

Patients with mitral valve prolapse (MVP) may be prone to ventricular arrhythmias and sudden cardiac death and presence early repolarization pattern (ERP) in electrocardiography may be predict for ventricle arrhythmia. This study aimed to evaluation ERP in Children with MVP.

METHODS

In a cross-sectional study, we enrolled ERP in 70 MVP children with 70 age-and sex-matched healthy individuals. After echocardiography procedure for confirmation MVP, standard 12-lead electrocardiography recordings with sweeping rate of 25mm/s and an amplitude of 10mV/cm, and two cardiologists assessed who were blinded to the both groups.

RESULT

We detected ERP in 17.14% of MVP patient's and seen in 8 case (11.43%) in control group, (P=0.23). the ERP occurred in MVP patient's mild, moderate and severe 4, 6 and 2 cases, (P=0.29). The ERP found in patients with and without chest pain 13 and 7, respectively (P=0.46) and, in patients with and without palpitations 15 and 5 cases, respectively (P=0.24). The ERP occurred 1.6 time more in patient with MVP in comparing with individual without MVP. The ERP occurred more frequently in among patients with moderate MVP in comparing with severe and mild. Chest pain and palpitation occurred more frequently in among patients with severe MVP.

CONCLUSION

The prevalence of ERP in children with MVP has been at a higher-level incidence, especially among patients with complaining from chest pain. We suggested that children with MVP are in need of follow up considering the occurrence of arrhythmias.

Dynamic detection and reversal of myocardial ischemia using an artificially intelligent bioelectronic medicine

Myocardial ischemia is spontaneous, frequently asymptomatic, and contributes to fatal cardiovascular consequences. Importantly, myocardial sensory networks cannot reliably detect and correct myocardial ischemia on their own. Here, we demonstrate an artificially intelligent and responsive bioelectronic medicine, where an artificial neural network (ANN) supplements myocardial sensory networks, enabling reliable detection and correction of myocardial ischemia. ANNs were first trained to decode spontaneous cardiovascular stress and myocardial ischemia with an overall accuracy of ~92%. ANN-controlled vagus nerve stimulation (VNS) significantly mitigated major physiological features of myocardial ischemia, including ST depression and arrhythmias. In contrast, open-loop VNS or ANN-controlled VNS following a caudal vagotomy essentially failed to reverse cardiovascular pathophysiology. Last, variants of ANNs were used to meet clinically relevant needs, including interpretable visualizations and unsupervised detection of emerging cardiovascular stress. Overall, these preclinical results suggest that ANNs can potentially supplement deficient myocardial sensory networks via an artificially intelligent bioelectronic medicine system.

Does chest shape influence exercise stress echocardiographic results in patients with suspected coronary artery disease?

Despite the good specificity of exercise stress echocardiography (ESE) for the detection of coronary artery disease (CAD), false positive (FP) results may occur. We have previously reported that chest abnormalities may affect parameters of cardiac contractility. The influence of chest shape on ESE results has never been previously investigated. We retrospectively analyzed 160 consecutive patients (64.4 ± 13.0-year old, 91 women) who had undergone coronary angiography at our Institution because of positive ESE, between June 2014 and May 2020. Modified Haller index (MHI; chest transverse diameter over the distance between sternum and spine) was assessed in all patients. Obstructive CAD was diagnosed by ≥ 70% stenosis in any epicardial coronary artery. Outcome was false-positivity at ESE. 80.6% of patients were diagnosed with obstructive CAD, while 19.4% had no CAD (FP). We separately analyzed patients with normal chest shape (MHI ≤ 2.5) and those with concave-shaped chest wall (MHI > 2.5). These latter were mostly women with small cardiac chambers, mitral valve prolapse (MVP) and exercise-induced ST-segment changes. Likelihood of false-positivity was significantly higher in subjects with MHI > 2.5 than those with MHI ≤ 2.5 (30.7% vs 9.4%, p = 0.001). By multivariate logistic regression analysis, MHI > 2.5 (OR 4.04, 95%CI 1.45-11.2, p = 0.007), MVP (OR 3.47, 95%CI 1.32-9-12, p = 0.01) and dyssynergy in the left circumflex territory (OR = 3.35, 95%CI 1.26-8.93, p = 0.01) were independently associated with false-positivity. Concave-shaped chest wall (MHI > 2.5) may be associated with false-positive stress echocardiographic result. Mechanisms underpinning this finding need to be further explored.

False-positive electrocardiographic changes during exercise test in a patient with pectus excavatum

Exercise-induced ST-segment changes simulating myocardial ischemia have been described in otherwise normal subjects during hyperventilation. We present the case of a 60-year-old man with pectus excavatum showing significant exercise-induced "pseudo-ischaemic" ST-segment changes with neither coronary artery disease nor anxiety-induced hyperventilation. We found no report of the possible causative role of a narrow antero-posterior chest diameter in inducing "pseudo-ischaemic" ST-segment changes during exercise stress test in the literature.

Electrocardiographic changes in mitral valve prolapse syndrome

Introduction: Mitral valve prolapse syndrome (MVP) is the most common valvular abnormalityin the young and is correlated with increased frequency of cardiac dysrhythmias and sudden death.The aim of this study was to compare frequency of “early repolarization” in electrocardiogram(ECG) between MVP patients and healthy adults.

Methods: In this cross-sectional study, we compared ECG presentations of early repolarizationincluding notch in descending arm of QRS and J-point and/or ST segment changes in 100 patientswith MVP with 100 healthy individuals. MVP patients were referred to cardiology clinic withsymptoms of palpitation, chest pain or anxiety.

Results: The mean age in patients with MVP was significantly less than healthy subjects (29.5 ±9.3 years versus 31.0 ± 6.9 years in control group, P= 0.1967). We detected early repolarizationas a prevalent sign in ECG of patients which was a notch in descending arm of QRS and/or STsegment or J-point elevation seen in 74% of patients ( 51% in inferior leads and 23% in I and aVLleads) , whilst the same findings were seen in 8 men (8%) in control group (P= 0.0001).

Conclusion: Early repolarization in ECG presented as a notch in descending arm of QRS and/or ST segment or J-point elevation is more frequent in in young patients with MVP syndrome.