Key result
Chagas cardiomyopathy linked to ~3.3-fold higher mortality compared to matched controls.
Why the study?
Are surface ECG repolarization parameters (QTd, Tp-Te, and (Tp-Te)d) prolonged and associated with mortality or need for cardiac transplant in Chagas disease patients with cardiomyopathy or bundle branch block living in the United States compared to matched controls?
Case-Control (n=62)
Standard 12-lead ECGs were reviewed by two physicians blinded to patient groups
No
Are surface ECG repolarization parameters (QTd, Tp-Te, and (Tp-Te)d) prolonged and associated with mortality or need for cardiac transplant in Chagas disease patients with cardiomyopathy or bundle branch block living in the United States compared to matched controls?
In US immigrants with Chagas heart disease, ECG markers of repolarization dispersion (QTd and (Tp-Te)d) are significantly prolonged even in patients with bundle branch block and preserved ejection fraction, and are associated with increased risk of death or cardiac transplant.
May inform risk stratification in Chagas cardiomyopathy; extends associations to US immigrants but remains hypothesis-generating.
OBJECTIVE: The goal of this study was to examine the association between ECG repolarization parameters and mortality in Chagas disease (CD) patients living in the United States. METHODS: CD patients with cardiomyopathy (CM) and bundle branch block (BBB) or BBB alone were compared to age- and sex-matched controls. QT interval, QT dispersion (QTd), T wave peak to T wave end duration (Tp-Te) and T wave peak to T wave end dispersion ((Tp-Te)d) were measured. Presence of fractionated QRS (fQRS) was also assessed. The main outcome measure was the association between ECG parameters and mortality or need for cardiac transplant. RESULTS: A total of 18 CM and 13 BBB CD patients were studied with 97% originating from Mexico or Central America. QTd (60.0±15.0 ms vs 43.5±9.8 ms, P=0.0002), Tp-Te (102.6±29.3 ms vs 77.1±11.0 ms, P=0.0002) and (Tp-Te)d (39.5±9.4 ms vs 22.7±7.6 ms, P<0.0001) were prolonged in CD CM patients compared to CM controls. Chagas CM patients had more fQRS then controls (84.2±0.10% vs 33.3±0.11%, p=0.0005). QTd (59.9±15.0 ms vs 29.5±6.9 ms, P=0.0001) and (Tp-Te)d (40.0±15.9 ms vs 18.5±5.4 ms, p<0.0001) were longer in the CD BBB group compared to BBB controls. Univariate analysis showed QTd (56.9±15.0 ms vs 46.5±17.3 ms, p=0.0412) and (Tp-Te)d (36.8±13.5 ms vs 28.5±13.3 ms, p=0.0395) were associated with death and/or need for cardiac transplant. CONCLUSION: Our results indicate that P-max and PD are useful electrocardiographic markers for identifying the β-TM-high-risk patients for AF onset, even when the cardiac function is conserved.
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Bradfield et al. (2014) conducted a case-control in Chagas disease with cardiomyopathy and bundle branch block or bundle branch block alone (n=62). Chagas disease (with cardiomyopathy and/or bundle branch block) and ECG repolarization parameters (QTd, Tp-Te, (Tp-Te)d) vs. Age- and sex-matched controls from endemic regions with negative Chagas disease titers and similar cardiomyopathy and/or bundle branch block was evaluated on Mortality in the cardiomyopathy group (CD-CM vs control-CM); univariate association of QTd and (Tp-Te)d with death or need for cardiac transplant (p=0.022). Chagas cardiomyopathy patients had higher mortality than controls (56% vs 17%, p=0.022), with prolonged QTd (p=0.0412) and (Tp-Te)d (p=0.0395) associated with death or transplant.
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