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. 2014 Jun;102(6):579-87.
doi: 10.5935/abc.20140066. Epub 2014 May 27.

Baroreflex sensitivity and its association with arrhythmic events in Chagas disease

[Article in English, Portuguese]
Astrid Meireles Santos, Mauricio Ibrahim Scanavacca, Francisco Darrieux, Bárbara Ianni, Sissy Lara de Melo, Cristiano Pisani, Francisco Santos Neto, Eduardo Sosa, Denise Tessariol Hachul

Baroreflex sensitivity and its association with arrhythmic events in Chagas disease

[Article in English, Portuguese]
Astrid Meireles Santos et al. Arq Bras Cardiol. 2014 Jun.

Abstract

Background: Sudden death is the leading cause of death in Chagas disease (CD), even in patients with preserved ejection fraction (EF), suggesting that destabilizing factors of the arrhythmogenic substrate (autonomic modulation) contribute to its occurrence.

Objective: To determine baroreflex sensitivity (BRS) in patients with undetermined CD (GI), arrhythmogenic CD with nonsustained ventricular tachycardia (NSVT) (GII) and CD with spontaneous sustained ventricular tachycardia (STV) (GIII), to evaluate its association with the occurrence and complexity of arrhythmias.

Method: Forty-two patients with CD underwent ECG and continuous and noninvasive BP monitoring (TASK force monitor). The following were determined: BRS (phenylephrine method); heart rate variability (HRV) on 24-h Holter; and EF (echocardiogram).

Results: GIII had lower BRS (6.09 ms/mm Hg) as compared to GII (11.84) and GI (15.23). The difference was significant between GI and GIII (p = 0.01). Correlating BRS with the density of ventricular extrasystoles (VE), low VE density (<10/h) was associated with preserved BRS. Only 59% of the patients with high VE density (> 10/h) had preserved BRS (p = 0.003). Patients with depressed BRS had higher VE density (p = 0.01), regardless of the EF. The BRS was the only variable related to the occurrence of SVT (p = 0.028).

Conclusion: The BRS is preserved in undetermined CD. The BRS impairment increases as disease progresses, being more severe in patients with more complex ventricular arrhythmias. The degree of autonomic dysfunction did not correlate with EF, but with the density and complexity of ventricular arrhythmias.

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Conflict of interest statement

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Figures

Graph 1
Graph 1
Distribution of ventricular extrasystoles (VE) in the groups studied.
Graph 2
Graph 2
Correlation between the measure of baroreflex sensitivity (BRS) and density of ventricular arrhythmias. Note: BRS: baroreflex sensitivity; LV ectopia > 10/h: left ventricular ectopia greater than 10 per hour; LV ectopia > 10/h: left ventricular ectopia smaller than 10 per hour.
See this image and copyright information in PMC

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