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Microvasculature and incident atrioventricular conduction abnormalities in the Multi-Ethnic Study of Atherosclerosis
Billy G Chacko1, Matthew S Edwards2, A Richey Sharrett3
1Department of Vascular and Endovascular Surgery, Section on Vascular Medicine, Harbin Clinic, Rome, GA, USA bchacko@harbinclinic.com.
Insights
Narrower retinal arteriolar caliber, a microvasculature measure, is linked to new atrioventricular conduction abnormalities (AVCA). This finding suggests microvascular health impacts heart rhythm development.
Area of Science:
- Ophthalmology
- Cardiology
- Vascular Biology
Background:
- Microvascular abnormalities are associated with major cardiac events.
- The role of microvasculature in atrioventricular conduction abnormalities (AVCA) is not well understood.
Purpose of the Study:
- To investigate the association between central retinal arteriolar equivalent (CRAE), a microvasculature measure, and the incidence of AVCA.
Main Methods:
- Analysis of 3975 Multi-Ethnic Study of Atherosclerosis (MESA) participants without baseline AVCA.
- Incident AVCA defined as new PR interval >= 200 ms or advanced block on MESA exam 5 ECG.
- CRAE measured from retinal photographs at MESA exam 2.
Main Results:
- Incident AVCA occurred in 7.4% of participants, predominantly first-degree AV block (94%).
- AVCA incidence increased with narrower CRAE (10.8% in Q1 vs. 4.6% in Q4).
- Narrowest CRAE (Q1) was associated with nearly double the odds of incident AVCA (OR: 1.68), even after risk adjustment.
Conclusions:
- Narrower retinal arteriolar caliber is significantly associated with the development of new atrioventricular conduction abnormalities.
- This suggests a link between microvascular function and cardiac electrical conduction.
- Further research into microvascular contributions to heart rhythm disorders is warranted.
Abstract:
Abnormalities of the microvasculature are linked to major cardiac events, but their role in the development of atrioventricular conduction abnormalities (AVCA) is unknown. We examined the association between central retinal arteriolar equivalent (CRAE), a measure of the microvasculature, and incident AVCA. This analysis included 3975 participants free of AVCA at baseline from the Multi-Ethnic Study of Atherosclerosis (MESA). Incident AVCA was defined as a composite of new heart rate-adjusted PR interval ⩾ 200 ms (first-degree AV block) and advanced block (second-degree or complete AV block) detected from the MESA exam 5 electrocardiogram (ECG). CRAE was measured from retinal photographs at exam 2. Both ECGs and retinal photographs were collected using standardized methods and read and graded at central core labs. Incident AVCA were present in 7.4% (n=290) of the participants, of which 94% were first-degree AV block. Incident AVCA were increasingly more common in participants with narrower CRAE (4.6% in Q4, 6.4% in Q3, 7.0% in Q2 and 10.8% in Q1, p-value for trend < 0.0001). The socio-demographic and cardiovascular disease risk-adjusted odds of incident AVCA in the Q1 group (the group with the narrowest retinal arteriolar diameter) was nearly twice the odds in the Q4 group (OR: 1.68, 95% CI: 1.15-2.51). This association remained significant after adjustment for major ECG abnormalities and incident cardiovascular disease (Q1 vs Q4, OR: 1.65, 95% CI: 1.01-2.71). In conclusion, narrower retinal arteriolar caliber is associated with development of new AV conduction abnormalities.