Low QRS voltage and its causes

An experimental ovine Theileriosis: The effect of Theileria lestoquardi infection on cardiovascular system in sheep

The malignant ovine theileriosis is caused by Theileria lestoquardi, which is highly pathogenic in sheep. Theileriosis involves different organs in ruminants, but the effect of the disease on the cardiovascular system is unclear. To understand the pathogenesis of T. lestoquardi on the cardiovascular system, Baluchi breed sheep were infected with the mentioned parasite by releasing unfed adults of Hyalomma anatolicum anatolicum, which were infected with T. lestoquardi. The infected sheep were clinically examined on days 0, 2, 5, 7, 10, 12, 14, 17, and 21, and the blood samples were collected for biochemical parameters measurement. At termination of the experiment, the infected sheep were euthanized and pathological examinations of heart tissue were conducted. During experimental infection of sheep with T. lestoquardi, activities of cardiac troponin I (cTnI), lactate dehydrogenase, and aspartate aminotransferase, were significantly increased (P˂0.05), while a conspicuous decrease (P˂0.05) was observed in creatine phosphokinase activities. Alterations made in biochemical factors almost coincided with the presence of piroplasm in the blood and schizont in lymph nodes. Maximum and minimum of parasitemia in the sheep stood between 3.3% and 0.28%, respectively. In addition, electrocardiography revealed sinus tachycardia, sinus arrhythmia, sino-atrial block and ST-elevation, atrial premature beat, and alteration in QRS and in T waves' amplitude. Heart histopathological examination showed hyperemia, infiltration of mononuclear inflammatory cells into interstitial tissue, endocarditis, and focal necrosis of cardiac muscle cells. In addition, in one of the sheep, definite occurrence of infarction was observed. The results indicate that T. lestoquardi infection has devastating pathological impacts on the cardiovascular system of sheep. Furthermore, measurement of the cTnI amount is a useful biochemical factor for diagnosis and for better understanding of the severity and progression of the disease and its effects on cardiac tissue.

Nonischemic left ventricular scar and cardiac sudden death in the young

Nonischemic left ventricular scar (NLVS) is a pattern of myocardial injury characterized by midventricular and/or subepicardial gadolinium hyperenhancement at cardiac magnetic resonance, in absence of significant coronary artery disease. We aimed to evaluate the prevalence of NLVS in juvenile sudden cardiac death and to ascertain its etiology at autopsy. We examined 281 consecutive cases of sudden death of subjects aged 1 to 35 years. NLVS was defined as a thin, gray rim of subepicardial and/or midmyocardial scar in the left ventricular free wall and/or the septum, in absence of significant stenosis of coronary arteries. NLVS was the most frequent finding (25%) in sudden deaths occurring during sports. Myocardial scar was localized most frequently within the left ventricular posterior wall and affected the subepicardial myocardium, often extending to the midventricular layer. On histology, it consisted of fibrous or fibroadipose tissue. Right ventricular involvement was always present. Patchy lymphocytic infiltrates were frequent. Genetic and molecular analyses clarified the etiology of NLVS in a subset of cases. Electrocardiographic (ECG) recordings were available in more than half of subjects. The most frequent abnormality was the presence of low QRS voltages (<0.5 mV) in limb leads. In serial ECG tracings, the decrease in QRS voltages appeared, in some way, progressive. NLVS is the most frequent morphologic substrate of juvenile cardiac sudden death in sports. It can be suspected based on ECG findings. Autopsy study and clinical screening of family members are required to differentiate between arrhythmogenic right ventricular cardiomyopathy/dysplasia and chronic acquired myocarditis.

CD11c.DTR mice develop a fatal fulminant myocarditis after local or systemic treatment with diphtheria toxin

To assess the role of alveolar macrophages (AMs) during a pulmonary Aspergillus fumigatus infection AMs were depleted by intratracheal application of diphtheria toxin (DTX) to transgenic CD11c.DTR mice prior to fungal infection. Unexpectedly, all CD11c.DTR mice treated with DTX died within 4-5 days, whether being infected with A. fumigatus or not. Despite measurable impact of DTX on lung functional parameters, these constrictions could not explain the high mortality rate. Instead, DTX-treated CD11c.DTR animals developed fulminant myocarditis (FM) characterized by massive leukocyte infiltration and myocardial cell destruction, including central parts of the heart's stimulus transmission system. In fact, standard limb lead ECG recordings of diseased but not healthy mice showed a "Brugada"-like pattern with an abnormally high ST segment pointing to enhanced susceptibility for potential lethal arrhythmias. While CD11c.DTR mice are extensively used for the characterization of CD11c(+) cells, including dendritic cells, several studies have already mentioned adverse side effects following DTX treatment. Our results demonstrate that this limitation is based on severe myocarditis but not on the expected lung constrictions, and has to be taken into consideration if this animal model is used. Based on these properties, however, the CD11c.DTR mouse might serve as useful animal model for FM.

Identification of electrocardiographic values that indicate chronic obstructive pulmonary disease

BACKGROUND

The purpose of this study was to investigate the association between respiratory function and electrocardiogram (ECG) characteristics in patients with chronic obstructive pulmonary disease (COPD), and to identify the ECG results that indicate possible COPD.

METHODS

The association between respiratory function and ECG results was retrospectively analyzed in 45 patients with COPD and 100 patients without COPD (controls).

RESULTS

Multiple logistic regression analysis revealed that QRS amplitude in lead І was a significant predictor of COPD (partial regression coefficient = -4.208, p = 0.002). Receiver operating characteristic curve analysis showed that a QRS amplitude less than 0.54 mV in lead І indicated possible COPD (sensitivity: 71%, specificity: 76%, area under the curve: 0.78 [95% confidence interval: 0.69-0.86], p < 0.001).

CONCLUSION

Low voltage in lead І (QRS less than 0.54 mV) is an important criterion in detecting COPD.

ECG low QRS voltage and wide QRS complex predictive of centenarian 360-day mortality

We examined the electrocardiographic (ECG) findings of centenarians and associated them with >360-day survival. Physical and functional assessment, resting electrocardiogram and laboratory tests were performed on 86 study participants 101.9 ± 1.2 years old (mean ± SD) (70 women, 16 men) and followed for at least 360 days. Centenarian ECGs were assessed for left ventricular hypertrophy (LVH) according to the Romhilt-Estes score, Sokolow-Lyon criteria and Cornell voltage criteria which were positive for 12.8, 6.98, and 10.5 % of participants, respectively. Fifty-two study participants (60 %) survived ≥360 days. Multivariate logistic regression analysis revealed a negative relationship between 360-day survival and the following: R II <0.45 mV adjusted for CRP (odds ratio (OR) = 0.108, 95 % confidence interval (CI) = 0.034-0.341, P < .001), R aVF < 0.35 mV adjusted for CRP (OR = 0.151, 95 % CI = 0.039-0.584, P < .006), Sokolow-Lyon voltage <1.45 mV adjusted for CRP (OR = 0.178, 95 % CI = 0.064-0.492, P = .001), QRS ≥90 ms adjusted for CRP (OR = 0.375, 95 % CI = 0.144-0.975, P = .044), and Romhilt-Estes score ≥5 points adjusted for sex and Barthel Index (OR = 0.459, 95 % CI = 0.212-0.993, P = .048) in single variable ECG models. QRS voltage correlated positively with systolic and pulse pressure, serum vitamin B12 level, sodium, calcium, phosphorous, TIMP-1, and eGFR. QRS voltage correlated negatively with BMI, WHR, serum leptin, IL-6, TNF-α, and PAI-1 levels. QRS complex duration correlated positively with CRP; QTc correlated positively with TNF-α. Results suggest that Romhilt-Estes LVH criteria scores ≥5 points, low ECG QRS voltages (Sokolow-Lyon voltage <1.45 mV), and QRS complexes ≥90 ms are predictive of centenarian 360-day mortality.

Electrocardiographic evolution in patients with hypertrophic cardiomyopathy who develop a left ventricular apical aneurysm

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) patients with apical aneurysm have a largely unfavourable clinical course, and are often unrecognised because echocardiography is limited in the assessment of the left ventricular (LV) apex. The aim of this study is the identification of electrocardiographic (ECG) abnormalities associated with the development of apical aneurysm in HCM patients.

MATERIALS AND METHODS

Electrocardiographic features were assessed in 14 HCM patients who had a good-quality baseline ECG recorded before and after the diagnosis of apical aneurysm.

RESULTS

During follow-up (8.8±7.5years), the following ECG changes were observed: increase in QRS-complex duration (87±12ms to 118±34ms, p=0.006), QRS-complex fragmentation, decrease in QRS-complex amplitude (SV1+RV5-6, from 41±18mm to 26±11mm, p=0.015), ST-segment elevation in V4-V6 (J-point in V5, from -0.9±1.3mm to +0.7±1.3, p=0.003), positivisation of negative T waves in V3-V6 (T-wave depth in V5, from -3.4±6.6 to +3.1±4.1, p=0.005).

CONCLUSIONS

HCM patients who develop LV apical aneurysm exhibit distinctive ECG changes along with apical remodelling. Suggestive ECGs should lead the physician to study LV apex by nonstandard echocardiographic views, and perform MRI.

Risk of mortality in individuals with low QRS voltage and free of cardiovascular disease

The prognostic significance of low QRS voltage (LQRSV) in the electrocardiogram (ECG) of individuals free of cardiovascular disease (CVD) is unclear. We evaluated the association between LQRSV and all-cause mortality in 6,440 participants (53% women, mean age 60 years) from the Third National Health and Nutrition Examination Survey, a representative sample of the US population. Participants with history of CVD or major ECG abnormalities were excluded. LQRSV was automatically defined from standard 12-lead ECG as QRS complex amplitudes of <0.5 mV in all frontal leads and/or <1.0 mV in all precordial leads. Mortality data through 2006 were obtained from National Death Index records. LQRSV was detected in 1.4% (n = 89) of the participants. During a median follow-up of 13.8 years, 2,000 deaths occurred. The mortality rate in individuals with LQRSV was almost twice that in those without LQRSV (51.1 vs 23.5 events per 1,000 person-years, p <0.01). In a demographic-adjusted model, LQRSV was associated with 63% increased risk of mortality (hazard ratio 1.63, 95% confidence interval [1.21, 2.18]). The magnitude of this risk did not appreciably change after additional adjustment for body mass index, smoking status, systolic blood pressure, blood pressure medication use, dyslipidemia, diabetes, cancer, pulmonary disease, and ECG abnormalities (hazard ratio 1.61, 95% confidence interval [1.20, 2.16]) and was consistent across age, race, and sex subcategories. In conclusion, LQRSV is associated with an increased risk of mortality in individuals free of apparent CVD. More research is warranted to determine the mechanisms by which LQRSV is associated with increased risk of mortality in apparently healthy individuals.

Progressive loss in circulating volume during haemodialysis can be monitored by time voltage integral area of QRS complex: pilot study

INTRODUCTION

Time voltage area of QRS is a parameter that showed a close association with modifications in endoventricular volume. The aim of the study was to investigate the efficacy of this parameter in identifying progressive reduction in circulating blood volume (BV) during haemodialytic treatment (HT).

MATERIAL AND METHODS

Thirteen uraemic patients were studied. XYX like leads were monitored before, during and after HT. Summation of areas of each QRS complex was named QRS total area (TA).

RESULTS

Increase in QRS TA and decrease in BV were found after vs. before HT. Progressive increase in QRS TA is strongly linked to a progressive reduction of BV during HT.

CONCLUSIONS

THESE FINDINGS ENCOURAGE USE OF ECG MONITORING DURING HT WITH A DUAL PURPOSE: rhythm and haemodynamic control. In fact, excessive or insufficient subtractions of water, with consequent hypotensive or cardiorespiratory crisis, are the most frequent complications in these patients.