Doppler-derived left ventricular filling pressures and the regulation of heart rate recovery after exercise in patients with suspected coronary artery disease

Heart Rate Recovery: Up to Date in Heart Failure-A Literature Review

The rising prevalence of cardiovascular disease underscores the growing significance of heart failure (HF). Pathophysiological insights into HF highlight the dysregulation of the autonomic nervous system (ANS), characterized by sympathetic overactivity and diminished vagal tone, impacting cardiovascular function. Heart rate recovery (HRR), a metric measuring the heart's ability to return to its baseline rate post-exertion, plays a crucial role in assessing cardiovascular health. Widely applied across various cardiovascular conditions including HF, coronary artery disease (CAD), and arterial hypertension (HTN), HRR quantifies the difference between peak and recovery heart rates. Given its association with elevated sympathetic tone and exercise, HRR provides valuable insights into the perspective of HF, beyond effort tolerance, reaching toward prognostic and mortality indicators. Incorporating HRR into cardiovascular evaluations enhances our understanding of autonomic regulation in HF, offering potential implications for prognostication and patient management. This review addresses the significance of HRR in HF assessment, analyzing recently conducted studies, and providing a foundation for further research and clinical application.

Effects of COVID-19 on the Autonomic Cardiovascular System: Heart Rate Variability and Turbulence in Recovered Patients

BACKGROUND

COVID-19 may be a risk factor for developing cardiovascular autonomic dysfunction. Data are limited, however, on the association between heart rate variability, heart rate turbulence, and COVID-19. The aims of this study were to evaluate the effect of COVID-19 on the cardiovascular autonomic system in patients with persistent symptoms after recovering from COVID-19 and to determine whether these patients showed changes in ambulatory electrocardiography monitoring.

METHODS

Fifty-one adults who had confirmed SARS-CoV-2 infection and presented with persistent symptoms to the cardiology outpatient clinic after clinical recovery between April and June 2021 were included. Patients were prospectively followed for 6 months. The patients were evaluated at the time of first application to the cardiology outpatient clinic and at 6 months after presentation. Ambulatory electrocardiography monitoring and echocardiographic findings were compared with a control group of 95 patients.

RESULTS

Patients in the post-COVID-19 group had significantly higher mean (SD) turbulence onset (0.39% [1.82%] vs -1.37% [2.93%]; P < .001) and lower heart rate variability than those in the control group at both initial and 6-month evaluations. The post-COVID-19 group had no significant differences in echocardiographic findings compared with the control group at 6 months, except for right ventricle late diastolic mitral annular velocity (P = .034). Furthermore, turbulence onset was significantly correlated with turbulence slope (r = -0.232; P = .004), heart rate variability, and the parameters of left (r = -0.194; P=.049) and right (r = 0.225; P = .02) ventricular diastolic function.

CONCLUSIONS

COVID-19 may cause cardiovascular autonomic dysfunction. Heart rate variability and turbulence parameters can be used to recognize cardiovascular autonomic dysfunction in patients who have recovered from COVID-19 but have persistent symptoms.

Heart rate recovery: a practical clinical indicator of abnormal cardiac autonomic function

The autonomic nervous system (ANS) and cardiovascular function are intricately and closely related. One of the most frequently used diagnostic and prognostic tools for evaluating cardiovascular function is the exercise stress test. Exercise is associated with increased sympathetic and decreased parasympathetic activity and the period of recovery after maximum exercise is characterized by a combination of sympathetic withdrawal and parasympathetic reactivation, which are the two main arms of the ANS. Heart rate recovery after graded exercise is one of the commonly used techniques that reflects autonomic activity and predicts cardiovascular events and mortality, not only in cardiovascular system disorders, but also in various systemic disorders. In this article, the definition, applications and protocols of heart rate recovery and its value in various diseases, in addition to exercise physiology, the ANS and their relationship, will be discussed.

The diastolic stress test: a new approach to an old problem

The evaluation of ischemic heart disease is the cornerstone of clinical Cardiology. Although there are many means of ischemic evaluation, all are with their own limitations. While perfusion-based studies are highly sensitive, they lack specificity. Conversely, systolic wall motion analysis with echocardiography tends to have high specificity; however, the sensitivity may be limited by short duration of systolic abnormalities when present. With the advent of Doppler echocardiography, and more specifically tissue Doppler imaging, and strain and strain rate imaging, a more comprehensive evaluation of the left ventricular function is available, including diastole. Diastolic abnormalities in the setting of ischemia are now being studied using these new parameters and have been suggested as a reliable marker of ischemia. Exercise-induced abnormalities in diastolic parameters have improved sensitivities and specificities over traditional stress testing and persist longer than systolic abnormalities. A review of the medical literature regarding the subject will be discussed here.

Exercise-induced changes in E/E' ratio in patients with suspected coronary artery disease

OBJECTIVES

Ischemia affects the left ventricular (LV) diastolic function earlier than the systolic function. The ratio of the early diastolic transmitral velocity to the early diastolic tissue velocity (E/E') measured by tissue Doppler echocardiography allows a reliable assessment of the diastolic function. We investigated whether exercise-induced changes in E/E' ratio may help in the detection of coronary artery disease (CAD).

METHODS

The study population consisted of 114 patients undergoing coronary angiography. Patients with impaired LV ejection fraction, earlier myocardial infarction, arterial hypertension greater than stage I, or LV hypertrophy were excluded. Patients underwent a treadmill exercise test combined with an echocardiogram at baseline and within the first minute after exercise.

RESULTS

Coronary angiography showed a stenosis more than 70% in 72 (63%) patients (CAD group), the remaining 42 formed the non-CAD group. The two groups did not differ regarding age, sex, LV dimensions, and function. At baseline, the E/E' lateral and septal ratios and their average did not differ between the two groups. The exercise-induced changes of the E/E' ratios were higher in the CAD group (change of E/E' average: 1.9+/-3.3 vs. -1.1+/-2.3, P<0.001). In the CAD group, 78% showed an exercise-induced increase of E/E' average compared with 24% in the non-CAD group (P<0.001). In multivariate analysis, the association between an increase of E/E' average and the presence of obstructive CAD was independent of traditional risk factors, exercise test result or exercise-induced wall motion abnormalities (odds ratio=8.1, P<0.001).

CONCLUSION

Exercise-induced changes in E/E' ratio may offer significant assistance in the detection of CAD.