Fragmented QRS complex could predict all-cause mortality in patients with connective tissue disease-associated pulmonary arterial hypertension

OBJECTIVES

To investigate the prognostic impact and pathophysiological characteristics of fragmented QRS complex (fQRS) on patients with CTD-associated pulmonary arterial hypertension (CTD-PAH).

METHODS

This was a multicentre retrospective study recruiting 141 patients with CTD-PAH diagnosed by right heart catheterization (114 cases in the discovery cohort and 27 cases in the validation cohort). fQRS and ST-T change were detected on conventional 12-lead ECG. Patients were followed up every 3 months to update their status and the primary endpoint was all-cause death. Clinical information and ECG characteristics were compared between survival and death groups and Kaplan-Meier curve was used for survival analysis.

RESULTS

There were significant differences in age, gender, 6-min walk distance, N-terminal pro-brain natriuretic peptide, World Health Organization class, presence of fQRS, and presence of ST-T change in inferior leads between survival group and death group. Inferior fQRS and ST-T change were significantly associated with right ventricular dilatation and reduced right ventricular ejection fraction. Kaplan-Meier curve showed that all-cause mortality was higher in CTD-PAH with fQRS (P = 0.003) and inferior ST-T change (P = 0.012). Low- and intermediate-risk CTD-PAH with inferior ST-T change had higher all-cause mortality (P = 0.005). The prognostic value of fQRS and inferior ST-T change was validated in external validation cohort.

CONCLUSION

The presence of inferior fQRS and ST-T change could predict poor prognosis in CTD-PAH.

CLINICAL TRIAL REGISTRATION

NCT05980728, https://clinicaltrials.gov.

Interactive effects of short-term ozone exposure and plasma biomarkers related to nitric oxide pathway and inflammation on myocardial ischemia

BACKGROUND

No study has explored the possible interactive effects of short-term ozone (O3) exposure and plasma endothelial and inflammatory biomarkers, including cyclic guanosine monophosphate (cGMP), nitric oxide metabolite (NOx), myeloperoxidase (MPO), and high-sensitive C-reactive protein (hs-CRP), on myocardial ischemia, indicated by ST-segment depression events (STDE) recorded in ambulatory electrocardiograms.

METHODS

A L-arginine (L-Arg) intervention study with 118 participants was carried out using a standardized 24-h exposure protocol, employing a multivariable linear regression model to assess the effects of O3 exposure on plasma biomarkers, and a generalized linear model to investigate the effects on 24-hour STDE. The possible interactive effects of short-term O3 exposure and plasma biomarkers on indicators of myocardial ischemia were also investigated by including product interaction terms between ambient O3 and plasma biomarkers in the models. We also explored whether L-Arg supplementation could alleviate the adverse effects of ambient O3 exposure.

RESULTS

Data from 107 participants were included in final analysis. Short-term O3 exposure was associated with significantly decreased plasma cGMP and MPO levels, and increased 24-h STDE risk, with plasma cGMP and MPO modifying the O3-STDE associations. Participants with lower plasma levels of cGMP or higher MPO demonstrated increased vulnerability to the harmful effects of ambient O3 on 24-h STDE in inferior leads. L-Arg supplementation attenuated the effects of short-term O3 exposure on plasma MPO and hs-CRP.

CONCLUSIONS

Plasma biomarkers (cGMP and MPO) are likely involved in the potential pathways connecting ambient O3 exposure and harmful cardiac effects. Supplementation with L-Arg showed the potential to mitigate the inverse effects of ambient O3 exposure on inflammation.

Short-term effects of ambient gaseous air pollution on blood platelet mitochondrial DNA methylation and myocardial ischemia

BACKGROUND

The potential effects of short-term exposure to major ambient gaseous pollutants (ozone: O3, carbon monoxide: CO, and sulfur dioxide: SO2) on platelet mitochondrial DNA (mtDNA) methylation have been uncertain and no studies have examined whether platelet mtDNA methylation levels could modify the associations between ambient gaseous pollutants and the risks of ST-segment depression (STDE) and T-wave inversion events (TIE), two indicators of myocardial ischemia.

METHODS

This study used data from a randomized, double-blind, placebo-controlled intervention study with a standardized 24-hour exposure protocol among 110 participants in Beijing. Absolute changes in platelet mtDNA methylation (ACmtDNAm) levels were determined by two repeated measurements on platelet mtDNA methylation levels in blood samples collected before and after the 24-hour exposure period. A multivariable linear regression model and a generalized linear model with a Poisson link function were used to investigate the associations of ambient gaseous pollutants with platelet mtDNA methylation levels, STDE, and TIE, respectively.

RESULTS

Short-term O3 exposure was significantly associated with decreased ACmtDNAm at ATP6_P1 but increased ACmtDNAm at mt12sRNA, MT-COX1, and MT-COX1_P2; short-term CO and SO2 exposures were significantly associated with decreased ACmtDNAm at D-loop, MT-COX3- and ATP-related genes. Moreover, short-term O3 exposure was significantly associated with increased risks of STDE and TIE, and ACmtDNAm at MT-COX1 and MT-COX1_P2 modified the association between short-term O3 exposure and STDE events. L-Arg supplementation attenuated the effects of ambient gaseous pollutants, particularly O3, on ACmtDNAm and STDE.

CONCLUSIONS

Platelet mtDNA methylation levels are promising biomarkers of short-term exposure to ambient gaseous air pollution, and are likely implicated in the mechanism behind the association of ambient O3 pollution with adverse cardiovascular effects. L-Arg supplementation showed the potential to mitigate the adverse effects of ambient O3 pollution.