Key result
Permanent RV pacing with a wide QRS (142 ± 12 ms) was associated with a significant reduction in SERCA mRNA levels and adverse LV remodelling compared to a narrow QRS (94 ± 2 ms).
Why the study?
Right ventricular apex pacing induces abnormal left ventricular activation leading to pacing-induced cardiomyopathy, but the impact of paced QRS duration on peripheral blood SERCA expression and its link to left ventricular remodelling remained unexamined.
Does wide paced QRS duration reduce SERCA expression and worsen LV remodeling compared to narrow paced QRS in patients with preserved EF undergoing RV apical pacing?
Cohort (n=52)
Does wide paced QRS duration reduce SERCA expression and worsen LV remodeling compared to narrow paced QRS in patients with preserved EF undergoing RV apical pacing?
Wide paced QRS duration during RV apical pacing is associated with reduced SERCA expression and subsequent adverse LV remodeling, suggesting a molecular mechanism for pacing-induced cardiomyopathy.
Wide paced QRS after RV pacing was associated with early SERCA decline preceding LV remodelling; leaves open whether molecular monitoring aids conduction-system pacing selection.
BACKGROUND: Right ventricular (RV) apex has proven to induce abnormal left ventricular (LV) activation pattern leading to pacing-induced cardiomyopathy (PICM) in a substantial percentage of paced patients. This study assessed the impact of paced QRS duration on the expression in the peripheral blood of sarcoplasmic reticulum calcium ATPase (SERCA) and investigated whether its width is related to the extend of LV remodelling. METHODS: We enrolled 52 consecutive patients with preserved ejection fraction (EF) who underwent pacemaker implantation for bradycardic indications. Group A consisted of 24 patients paced for atrioventricular conduction disturbances with QRS = 142 ± 12 ms post-implant and group B of 28 patients paced for sinus node disease with QRS = 94 ± 2%ms post-implant. mRNA levels of SERCA were assesed at implantation, 3, 6 and 12 months follow-up, while echocardiographic parameters at implantation, 1, 2 and 4 years. RESULTS: In group A, mRNA levels of SERCA decreased significantly at 3 months and remained low at 6 and 12 months' follow-up and were associated to the deterioration of LV function and geometry. Paced QRS duration was associated to both the alteration in the expression of SERCA and to the extend of LV remodelling. In group B no statistically significant change was demonstrated. CONCLUSIONS: Permanent RV pacing in patients with preserved EF and wide QRS post-implant is associated with a significant reduction of mRNA levels of SERCA. Paced QRS duration is associated to alterations in the expression of SERCA which precede adverse LV remodelling.
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Simantirakis et al. (2019) conducted a cohort in Bradycardic indications requiring pacemaker implantation (n=52). Wide paced QRS duration (142 ± 12 ms) vs. Narrow paced QRS duration (94 ± 2 ms) was evaluated on mRNA levels of SERCA and echocardiographic parameters of LV remodelling. Permanent RV pacing with a wide QRS (142 ± 12 ms) was associated with a significant reduction in SERCA mRNA levels and adverse LV remodelling compared to a narrow QRS (94 ± 2 ms).
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