This investigation discovered that an elevated MHR, considered a reliable inflammatory marker, had an independent statistical relationship with frequent PVCs. In ROC analyses, an MHR>254.6 determined on admission featured 67.50% sensitivity and 67.14% specificity for predicting frequent PVCs in patients who developed frequent PVCs. The investigation confirmed that an elevated MHR is an RF for persons at medium-/high risk of frequent PVCs and that these patients may be at risk of an adverse prognosis as predicted by the ARS.
PVCs are clinically common arrhythmias. In the 6th century BC, Pien Ts’Io, a Chinese physician, noted that the irregularity frequency could predict mortality [24]. In the late 1800s, Étienne-Jules Marey, a French physiologist and scientist [25], first found that PVCs can result in symptoms such as dizziness or palpitations, but fortuitous PVCs are typically regarded as harmless. Highly frequent PVCs, nonetheless, may damage left ventricular function and can aggravate heart failure [1,2]. Additionally, PVCs can act as triggers for idiopathic ventricular fibrillation [26].
Recently, the MHR has become a convenient novel marker integrating anti-inflammatory and proinflammatory considerations [16,27-30]. For example, a study found that the occurrence of cardiac syndrome X had a positive correlation with a higher MHR [31]. Moreover, in persons who underwent coronary angiography, a higher MHR was related to reduced event-free survival and an increased incidence of mainly negative cardiac events [16]. Increased MHR was discovered to have a positive relationship with no reflow [32], stent thrombosis [19], and long-term as well as in-hospital mortality in persons who suffer from myocardial infarction (ST segment elevation in the electrocardiograph) and who underwent percutaneous coronary intervention [33]. Cryoballoon-based catheter ablation is considered a key index for predicting AF recurrence [20]. Nonetheless, little is known about the links between the MHR and frequent PVCs. The current study is the first to reveal that an increased MHR is positively correlated with frequent PVCs and may be associated with an adverse outcome, through ARS prediction.
The precise etiologies of PVCs are still unclear, but the potential mechanisms for any given PVC includes triggered activity, reentry, and automaticity [34]. Studies have found that inflammation is key to arrhythmia progression and development, leading to arrhythmia triggers and reentry [35]. PVC automaticity also has a close connection with inflammation [36]. The MHR, as a novel biomarker of systemic inflammation, may affect the above mechanism. PVCs have been closely linked with myocardial inflammatory conditions [37,38]. In fact, the production and upregulation of proinflammatory cytokines denote an innate or intrinsic stress response to protect the injured myocardium [39]. In addition, in comparison to healthy participants, circulating proinflammatory cytokines were discovered to be elevated in the sera of young patients with no structural heart disorder who developed ventricular arrhythmias [40]. Based on these studies, Yildiz et al. suggested that the inflammatory course may involve structural ventricular remodeling and electrophysiological changes in relation to PVC development [41]. The MHR may have a similar effect.
Frequent PVCs may cause cardiomyopathy that can be reversed by appropriate PVC inhibition, while some PVCs could lead to sudden death [42]. Hence, it is essential to confirm PVC damage early to guide further treatment options. More recently, it was found that the ARS could predict adverse prognoses of patients who had frequent PVCs [21]. In the British Columbia PVC Registry population, Thibet et al. conducted an external verification of the ARS [22]. The investigation confirmed that an increased MHR was correlated with the ARS to a certain extent and was a risk factor for the medium-/high-risk ARS subgroup, thus, the ARS has certain clinical importance in guiding the treatment strategy for patients with PVCs.
Comparisons with other studies and what the current work adds to existing knowledge
Earlier investigations demonstrated that the MHR was correlated with multiple disorders, especially arrhythmia diseases such as AF. However, the relationship between the MHR and frequent PVCs as well as patient prognosis is still unclear. The current investigation demonstrated that an elevated MHR can be key to frequent PVC occurrence. Moreover, participants with frequent PVCs who had medium-/high MHRs seemed to experience more adverse events.
Study strengths and limitations
This investigation possesses some strengths. The current investigation demonstrated that the MHR can be used as a practical, cost-saving and simple biomarker of inflammation owing to its value in the prediction of frequent PVCs. Moreover, the current investigation used a new score to evaluate the prognosis of patients with frequent PVCs. The current investigation also has certain limitations. Firstly, this investigation was a simple retrospective study. Secondly, the evaluation of a single sample may not identify variations in the MHR over time.