A 24-hour ambulatory ecg monitoring in assessment of qt interval duration and dispersion in rowers with physiological myocardial hypertrophy

Heart rhythm assessment in elite endurance athletes: A better method?

Introduction

Arrhythmias also occur among elite endurance athletes. Conventional diagnostic tools for assessment of arrhythmias suffer from limited availability and usability challenges, particularly under the demanding training conditions of an elite athlete. Among endurance athletes, there is a need for out-of-hospital monitoring to enhance detection of arrhythmias under conditions that are relevant and potentially provocative of underlying pathology. The Norwegian patch ECG247 Smart Heart Sensor has been developed to simplify the assessment of heart rhythm disorders. The current study aimed to evaluate the ECG247 Smart Heart Sensor function and usability in an elite athlete environment.

Methods

A total of 13 professional cyclists from the UNO-X Pro Cycling Team were examined with the ECG247 Smart Heart Sensor during training camp in Spain, December 2021. All ECG data were analyzed by cardiologists at Sorlandet Hospital Arendal, Norway. The athletes also completed a brief questionnaire registering their training (from on-bike monitoring units) and provided self-assessment of usability parameters after the test.

Results

In 8 of 13 athletes (69% male, age 23 ± 4 years), two test periods were performed with different ECG patches, resulting in a total of 21 tests with continuous ECG monitoring. Average total ECG test duration per athlete was 144 ± 47 h (89 ± 24 h/patch). Athletes performed an average of 15 ± 5 training h during each test. The ECG quality from all tests was considered satisfactory for rhythm analysis—also during exercise. The reported usability of the ECG247 Smart Heart Sensor was high, and no athletes reported trouble sleeping or training with the sensor. The automatic arrhythmia algorithm reported episodes of possible arrhythmias in 5 (24%) tests; 2 atrial flutter, 2 supraventricular tachycardia and 1 bradycardia (heart rate <30/min). Manual assessment by physicians verified the episode of bradycardia but revealed normal sinus rhythm in all other tests. No false negative events were identified in over 1,800 h of ECG collection.

Conclusion

The ECG247 Smart Heart Sensor allowed for high quality ECG monitoring with high usability during intensive exercise in athletes.

QTc interval on 24-hour holter monitor: To trust or not to trust?

Introduction

QT interval represents the ventricular depolarization and repolarization. Its accurate measurement is critical since prolonged QT can lead to sudden cardiac death. QT is affected by heart rate and is corrected to QTc via several formulae. QTc is commonly calculated on the ECG and not the 24‐h Holter.

Methods

100 patients presenting to our institution were evaluated by an ECG followed by a 24‐h Holter. QTc measurement on both platforms using Bazett and Fridericia formulae was recorded and compared.

Results

Mean age was 14.09 years, with the majority being males. Mean heart rate was 125.87. In the ECG, the mean QTc interval via the Bazett formula was 0.40 s compared with 0.38 s using the Fridericia formula. The mean corrected QT via the Bazett formula was 0.45, 0.39, and 0.42 s for the shortest RR, the longest RR, and the average RR, respectively. In contrast to the Fridericia formula, the corrected QT interval was 0.40, 0.39, and 0.40 s for the shortest RR, the longest RR, and the average RR, respectively. Using the Bazett formula, the highest specificity was reached during the longest RR interval (92.2%), while the highest sensitivity was recorded during the shortest RR interval (40%). As for the Fridericiaformula, sensitivity always reached 0%, while the highest specificity was reached during the average RR interval.

Conclusion

QTc measured during Holter ECG reached a high specificity regardless of RR interval using the Fridericia and during the longest and the average RR interval for the Bazett formula. The consistently low sensitivity reveals that Holter ECG should not be used to rule out prolonged QT.

Maximum QTc on Holter electrocardiography in children

BACKGROUND

Corrected QT interval (QTc) on electrocardiography (ECG) at rest and after exercise in a short daytime recording period may be insufficient for the diagnosis and management of long QT syndrome (LQTS), especially for LQTS type 2 and 3. Therefore, examination of QTc on Holter ECG is important. We designed a method of analyzing QTc on Holter ECG that can be performed in daily clinical practice by combining automatic and manual measurements.

METHODS

We reviewed the charts of healthy children (n = 210) and LQTS patients (n = 35) aged <16 years and analyzed QTc at rest and after exercise, and the maximum QTc on Holter ECG.

RESULTS

The QTc (Fridericia's correction) of most controls and LQTS patients reached the maximum at night or early in the morning. QTc differed according to sex and age. In the control group, QTc on ECG of all three types tended to lengthen with age. QTc after exercise was slightly longer than QTc at rest, and the maximum QTc on Holter ECG was much longer than both, reaching >450 ms in boys and 500 ms in girls. In most LQTS type 1 patients, QTc after exercise and that on Holter ECG tended to be long. In most LQTS type 2 and 3 patients, QTc at rest and that after exercise was long, and that on Holter ECG tended to be much longer.

CONCLUSIONS

The present method of analyzing QTc on Holter ECG, in which automatic and manual measurements are combined, is practical and may be useful for diagnosis and risk stratification of LQTS.

Effects of ERK1/2/PPARα/SCAD signal pathways on cardiomyocyte hypertrophy induced by insulin-like growth factor 1 and phenylephrine

AIMS

Short-chain acyl-CoA dehydrogenase (SCAD) is a key enzyme in fatty acid oxidation. In the present study we aim to investigate the changes in SCAD between pathological and physiological cardiomyocyte hypertrophy. We also explore the different signaling pathways of pathological and physiological cardiomyocyte hypertrophy.

MAIN METHODS

After neonatal rat cardiomyocytes were treated as setups, cell surface area, expression of SCAD, PPARα, phospho-ERK1/2, activity of SCAD, free fatty acid content and ATP content in the cardiomyocytes were measured.

KEY FINDINGS

Neonatal rat cardiomyocytes treated by PE showed an increased cell surface area and free fatty acid content, increased ERK1/2 phosphorylation, decreased expression of PPARα, decreased expression and activity of SCAD and decreased levels of ATP. Neonatal rat cardiomyocytes treated by IGF-1 showed the reverse effects except for the cell surface area. PPARα inhibitor GW6471 and PPARα activator Fenofibrate treatments abrogated the effects induced by IGF-1 and PE in cardiomyocytes respectively, as well as ERK1/2 activator EGF and ERK1/2 inhibitor PD98059.

SIGNIFICANCE

SCAD has different changes between pathological and physiological cardiomyocyte hypertrophy. The ERK1/2/PPARα/SCAD signaling pathways play different roles in pathological and physiological cardiomyocyte hypertrophy. SCAD may be used as a new target to prevent the development of pathological cardiac hypertrophy.