Electrocardiographic Tracings Research Articles

Studies of Anti-arrhythmic and Hypercholesterolemic Activities of Ayurvedic Preparation ‘Lauhasab’ in Rat Model

Lauhasab, an Ayurvedic preparation, is widely used in anemia and cardiovascular diseases. Despite its claim as a cardio-tonic there is paucity of studies on pharmacological activities and toxicities. In this study, the anti-arrhythmic effect and impact on lipid profile were evaluated. Rats were pretreated with 0.28 and 2.8 ml/kg body weight of Lauhasab for 35 days and electrocardiographic tracings were recorded and analyzed to determine heart rate and occurrence of arrhythmia. Electrocardiogram recorded before digoxin administration showed significant decrease in mean heart rate along with longer duration of bradycardia than in digoxin control group after 35 days of chronic pretreatment with both doses of Lauhasab. In animal experiments, various arrhythmias were observed after intraperitoneal injection of digoxin. Lauhasab decreased the duration and delayed onset of time of various arrhythmias. It showed significant increase in cholesterol and triglyceride levels in a dose dependent manner. It can be concluded that Lauhasab possesses significant anti-arrhythmic activity against digoxin-induced arrhythmia. It also revealed hyperlipidemic effects.Dhaka Univ. J. Pharm. Sci. 16(1): 95-105, 2017 (June)

Coffee Consumption and Heart Rate Variability: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) Cohort Study.

Studies have shown that acute coffee ingestion can affect cardiovascular autonomic activity, although the chronic effects on heart rate variability (HRV) remain controversial. Method: A cross-sectional study with baseline data (2008–2010) from ELSA-Brasil cohort of 15,105 (aged 35–74), based in six Brazilian states. Coffee consumption in the previous 12 months was measured using the semi-quantitative food frequency questionnaire, and HRV was obtained through electrocardiographic tracings during 10 min at rest. Independent association between the frequency of coffee consumption “never or almost never”, “≤1 cup/day”, “2–3 cups/day”, “≥3 cups/day”, and HRV was estimated using generalized linear regression, adjusting for socio-demographic characteristics, health-related behavior, markers of abnormal metabolism, and the presence of coronary artery disease. Further, we applied Bonferroni correction in the full models. Results: The mean age was 52 years (standard deviation (SD) = 9.1), and 52% was female; 9.5% never/almost never consumed coffee. In univariate analysis, coffee consumers had reduced values of HRV indexes, but after full adjustments and correction for multiple comparisons, these associations disappeared. A trend of reduction in HRV vagal indexes was observed in those that consumed ≥3 cups of coffee/day. Conclusion: Most of the effects attributed to the chronic use of coffee on the HRV indexes is related to the higher prevalence of unhealthy habits in coffee users, such as smoking and alcohol use. Adjustment for confounding factors weaken this association, making it non-significant. The effect of higher daily doses of coffee on the autonomic system should be evaluated in further studies.

Analysis of the QT interval prolongation and pharmaceuticals in elderly patients in ambulatory care

OBJECTIVES: The objective of this study was to evaluate the frequency of long QT syndrome (LQTS) in the electrocardiographic tracing of elderly people and the concomitant use of drugs that can aggravate this condition. METHODS: This is a crosssectional, observational study of elderly patients in outpatient services at Hospital Santa Casa de Misericórdia de Vitória, over a six-month period. RESULTS: A total of 163 patients with 75 ± 8 (60–94) years of age, 60.7% (n = 99) of whom were female, participated in the study. Of the total number of patients, 33.1% (n = 54) were regularly taking at least one pharmaceutical that increased the risk of QTc prolongation; 34 patients (20.9%) had prolonged QTc and 15 (9,2%) had at-risk QTc. Of these patients with at-risk QTc, 4 (23.4%) were using at least 1 1 pharmaceutical that increases the risk of QT prolongation (p = 0.07). CONCLUSION: In this sample, a high frequency of LQTS was observed, as well as the use of pharmaceuticals that potentially cause LQTS and arrhythmias.

Dabigatran vs. warfarin in relation to the presence of left ventricular hypertrophy in patients with atrial fibrillation— the Randomized Evaluation of Long-term anticoagulation therapY (RE-LY) study

AimWe tested the hypothesis that left ventricular hypertrophy (LVH) interferes with the antithrombotic effects of dabigatran and warfarin in patients with atrial fibrillation (AF).Methods and resultsThis is a post-hoc analysis of the Randomized Evaluation of Long-term anticoagulation therapY (RE-LY) Study. We defined LVH by electrocardiography (ECG) and included patients with AF on the ECG tracing at entry. Hazard ratios (HR) for each dabigatran dose vs. warfarin were calculated in relation to LVH. LVH was present in 2353 (22.7%) out of 10 372 patients. In patients without LVH, the rates of primary outcome were 1.59%/year with warfarin, 1.60% with dabigatran 110 mg (HR vs. warfarin 1.01, 95% confidence interval (CI) 0.75–1.36) and 1.08% with dabigatran 150 mg (HR vs. warfarin 0.68, 95% CI 0.49–0.95). In patients with LVH, the rates of primary outcome were 3.21%/year with warfarin, 1.69% with dabigatran 110 mg (HR vs. warfarin 0.52, 95% CI 0.32–0.84) and 1.55% with 150 mg (HR vs. warfarin 0.48, 95% CI 0.29–0.78). The interaction between LVH status and dabigatran 110 mg vs. warfarin was significant for the primary outcome (P = 0.021) and stroke (P = 0.016). LVH was associated with a higher event rate with warfarin, not with dabigatran. In the warfarin group, the time in therapeutic range was significantly lower in the presence than in the absence of LVH.ConclusionsLVH was associated with a lower antithrombotic efficacy of warfarin, but not of dabigatran, in patients with AF. Consequently, the relative benefit of the lower dose of dabigatran compared to warfarin was enhanced in patients with LVH. The higher dose of dabigatran was superior to warfarin regardless of LVH status.Clinical trial registration http:www.clinicaltrials.gov. Unique identifier: NCT00262600.

The Girona Territori Cardioprotegit Project: Performance Evaluation of Public Defibrillators

Introduction and objectivesIn recent years, public access defibrillation programs have exponentially increased the availability of automatic external defibrillators (AED) in public spaces but there are no data on their performance in our setting. We conducted a descriptive analysis of the performance of AED since the launch of a public defibrillation program in our region. MethodsA retrospective analysis was conducted of electrocardiographic tracings and the performance of AED in a public defibrillation program from June 2011 to June 2015 in the province of Girona, Spain. ResultsThere were 231 AED activations. Full information was available on 188 activations, of which 82% corresponded to mobile devices and 18% to permanent devices. Asystole was the most prevalent rhythm (42%), while ventricular fibrillation accounted for 23%. The specificity of the device in identifying a shockable rhythm was 100%, but there were 8 false negatives (sensitivity 83%). There were 47 shockable rhythms, with a spontaneous circulation recovery rate of 49% (23 cases). There were no accidents related to the use of the device. ConclusionsNearly half of the recorded rhythms were asystole. The AED analyzed showed excellent safety and specificity, with moderate sensitivity. Half the patients with a shockable rhythm were successfully treated by the AED.

Proyecto Girona Territori Cardioprotegit: evaluación del funcionamiento de los desfibriladores públicos

Introduction and objectivesIn recent years, public access defibrillation programs have exponentially increased the availability of automatic external defibrillators (AED) in public spaces but there are no data on their performance in our setting. We conducted a descriptive analysis of the performance of AED since the launch of a public defibrillation program in our region. MethodsA retrospective analysis was conducted of electrocardiographic tracings and the performance of AED in a public defibrillation program from June 2011 to June 2015 in the province of Girona, Spain. ResultsThere were 231 AED activations. Full information was available on 188 activations, of which 82% corresponded to mobile devices and 18% to permanent devices. Asystole was the most prevalent rhythm (42%), while ventricular fibrillation accounted for 23%. The specificity of the device in identifying a shockable rhythm was 100%, but there were 8 false negatives (sensitivity 83%). There were 47 shockable rhythms, with a spontaneous circulation recovery rate of 49% (23 cases). There were no accidents related to the use of the device. ConclusionsNearly half of the recorded rhythms were asystole. The AED analyzed showed excellent safety and specificity, with moderate sensitivity. Half the patients with a shockable rhythm were successfully treated by the AED.Full English text available from:www.revespcardiol.org/en

Electrophysiological Adverse Effects of Direct Acting Antivirals in Patients With Chronic Hepatitis C.

Recently, several cases of symptomatic, sometimes fatal bradycardia during the first days of direct-acting antiviral (DAA) (eg, sofosbuvir [SOF]) administration have been reported. We analyzed in detail electrocardiographic (ECG) changes during SOF- or non-SOF-based chronic hepatitis C (CHC) treatment, specifically focusing on bradyarrhythmias. All 39 consecutive patients treated at our center with any interferon-free regimen between June and December 2015 were included in this study (26 SOF-based therapy vs 13 no-SOF interferon-free regimens). ECG tracings were obtained from all patients the first day of treatment and after 7, 14, and 28 days. ECG parameters (P-wave, QRS, QT interval, JT interval, Tapex -Tend interval duration) were compared between the 2 groups at baseline and at the 3 different time points during antiviral therapy. There were no cases of symptomatic bradycardia/syncope. In the SOF group, QTc duration rose after 1 week (from 424.3 to 431.2 milliseconds; P = .013) and returned to baseline during therapy. QT dispersion dropped since week 1 (from 85.6 to 67.2 milliseconds) and remained significantly reduced until the end of the observation period (72.9 msec) (P = .003). JT dispersion reduced up to week 2 (P = .010) and returned to baseline at week 4; in the no-SOF group, QRS dispersion transiently reduced (from 41 to 34.5 milliseconds, day 7). No other significant changes were observed in the remaining parameters. In CHC patients treated with SOF and other DAAs, ECG parameter changes were mild and/or transient and did not translate into clinically significant electrophysiological effects in the absence of amiodarone coadministration.

An analysis of the factors producing multiple ventricular arrhythmias during pulmonary artery catheterization.

Background:The development of arrhythmias during placement of a pulmonary artery catheter (PAC) is common.Aims:This study was designed to examine factors influencing development of ventricular arrhythmias in adult patients undergoing cardiovascular operations during the catheter placement.Settings and Designs:Prospective, observational, cohort study.Methods:We prospectively studied 174 patients undergoing cardiovascular operations. A PAC was inserted through the right internal jugular vein by staff anesthesiologists. Electrocardiography tracings were recorded as the catheter was advanced from the right atrium to the pulmonary artery. Arrhythmias were classified as absent, single, or multiple (two or more consecutive) ventricular arrhythmias. We examined risk factors to produce ventricular arrhythmias during the placement.Statistical Analysis:The data were analyzed using logistic regression analysis to assess factors for the occurrence of ventricular arrhythmias after univariate analyses.Results:Ventricular arrhythmias (single and multiple) occurred in 149 patients (85.6%) and multiple arrhythmias were observed in 78 patients (44.8%). There were no factors to facilitate the ventricular arrhythmias (single and multiple), whereas it showed that valvular diseases (P = 0.049) and the placement time (P < 0.001) are significant factors to produce multiple arrhythmias.Conclusion:Both valvular diseases and long placement time were significant risk factors to produce multiple ventricular arrhythmias during placement of a PAC.

Association between sleep disordered breathing and electrocardiographic markers of atrial abnormalities: the MESA study.

Electrocardiographic (ECG) markers of left atrial (LA) abnormalities have been linked to increased risk of atrial fibrillation (AF). Sleep disordered breathing (SDB) has been associated with increased risk of AF. We aimed to examine the association of ECG markers of LA abnormalities with SDB. 1546 participants (mean age 67.2 years, 53.4% women, and 63.3% non-whites) from the Multi-Ethnic Study of Atherosclerosis Exam 5 Sleep ancillary study were included in this analysis. ECG markers of LA abnormalities (P wave terminal force in V1 (PTFV1), maximum P wave duration, PR interval and heart rate corrected PR interval) were measured from resting standard digital ECG tracings using standardized processing. Linear and logistic regression analyses were utilized to examine the cross-sectional associations of measures of SDB (apnea hypopnea index [AHI] and % time spent with oxygen saturation <90% [%SpO290]) with each ECG marker. In a multivariable analysis adjusting for demographics, cardiovascular risk factors, and comorbidities, AHI was associated with greater PTFV1 but not with other ECG markers of LA abnormalities. A 1-SD increase of AHI (16.6/hr) was associated with higher levels of PTFV1 (175.1 µV.ms, 95% confidence interval [95%CI] 75.4, 274.7) and higher odds of abnormally elevated PTFV1 (≥4000 µV.ms) (Odds Ratio: 1.21 [95%CI 1.05, 1.39]). No association was found between %SpO290 and ECG markers of LA abnormalities. Severity of SDB, as measured by AHI, is associated with subclinical LA disease, as indicated by PTFV1. PTFV1 may be an important ECG marker linking SDB and AF.

Pathological Q waves as an indicator of prior myocardial infarction in patients with coronary artery disease and diabetes mellitus: a comparison of the prevalence and diagnostic accuracy according to present and former criteria

Introduction. Electrocardiography (ECG) is a widely used diagnostic method for identification of patients with previous myocardial infarction (MI). The ECG manifestation of prior MI is the presence of the pathological Q waves. Patients with coronary artery disease (CAD) and diabetes are at high risk of MI. The aim of this study was to compare the prevalence and diagnostic accuracy of the pathological Q waves as an indicator of prior MI in patients with CAD and diabetes according to the present and former criteria. Methods. A cross-sectional, multi-centre study was conducted in outpatient clinics across Poland. Family physicians performed physical examinations, registered ECGs, and collected relevant information about onset of CAD and diabetes, presence and onset of hypertension, dyslipidaemia, heart failure, diabetic complications, history of MI, and pharmacotherapy. Centralised manual assessment of the obtained ECG tracings was performed. Two definitions of the pathological Q-waves were used — a present one according to the Universal Definition of MI and a former one based on the definition of MI developed by the World Health Organization. Results. We enrolled 796 patients (48.1% women, mean age 67.5 ± 10.2 years, and 51.9% men, mean age 64.3 ± 10.3 years) into the study. There were 158 patients (19.8%) — 102 men (24.7%) and 56 women (14.6%), who met the present definition of the pathological Q waves and 106 patients (13.3%) — 74 men (17.9%) and 32 women (8.4%), who met the former definition of the pathological Q waves. The prevalence of the pathological Q waves varied due to the certain group of leads. It was highest in the inferior leads — 104 and 75 according to the present and former definitions, respectively. Of note, the rate of the pathological Q waves increased up to 2.6 times in the lateral leads after the introduction of the less restrictive present definition. Sensitivity of prior MI detection by means of the present and former criteria was 26.8% and 19.8%, and specificity was 87.0% and 92.8%, respectively. The application of the present and former definitions detected prior MI with 65.6% and 71.6% positive predictive value, and with 56.3% and 55.6% negative predictive value, respectively. Conclusions. In the era of reperfusion therapy, ECG appears to be a poor diagnostic tool for detection of previous MI due to its low sensitivity. However, it may identify individuals without previous MI with rather high specificity. In diabetics with CAD, the present definition of the pathological Q waves increases sensitivity of prior MI detection by 7%, with a decrease in specificity by 6% as compared with the former definition.

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.

Prevalence of electrocardiographic left ventricular hypertrophy among patients with coronary artery disease and diabetes mellitus

Introduction. Electrocardiography (ECG) is a widely used non-invasive diagnostic method for assessment of patients with cardiovascular diseases. Numerous different electrocardiographic criteria exist for detection of left ventricular hypertrophy (LVH). LVH is an important risk factor in patients with coronary artery disease (CAD) or diabetes mellitus and its presence is associated with increased cardiovascular morbidity and mortality. The aim of this study was to evaluate the prevalence of the most frequently used electrocardiographic left ventricular hypertrophy (ECG-LVH) criteria among patients with CAD and diabetes. Methods. A cross-sectional, multicenter study was conducted in outpatient clinics across Poland. Family physicians performed physical examinations and collected relevant information about: onset of CAD and diabetes, presence and onset of hypertension, dyslipidemia, heart failure, diabetic complications, history of acute coronary syndrome and pharmacotherapy. In order to detect LVH, we used seven ECG criteria: 1) the Sokolow-Lyon voltage, 2) the Gubner voltage, 3) the criterion of the R wave amplitude on the leads V5–V6 and 4) aVL, 5) the gender specific Cornell voltage and 6) product, and 7) the Romhilt-Estes point score. Centralized manual assessment of the obtained ECG tracings were performed. Results. We enrolled 1001 patients (48.5% women, 51.5% men, mean age 65 ± 11 years) into the study. At least one ECG-LVH criterion was met in 20.0% (n = 200) of the study participants. The ECG-LVH diagnosis was the most common when using the Romhilt-Estes point score (n = 138; 13.8%). The corresponding prevalence rates for the Cornell voltage, the Cornell product, the R wave amplitude on the lead aVL, the Sokolow-Lyon voltage, the Gubner voltage and the R wave amplitude on the leads V5-V6 criteria were 5.5% (n = 55), 5.2% (n = 52), 3.2% (n = 32), 2.2% (n = 22), 1.9% (n = 19) and 1.3% (n = 13) respectively. Subsequently, the prevalence of the three most frequently used in clinical practice electrocardiographic criteria for LVH (the Sokolow-Lyon voltage, the Cornell voltage and the Romhilt-Estes point score) was analyzed. At least one of them was fulfilled in 185 ECGs. All three criteria at the same time were met only in 5 ECGs (2.7% of 185). Two and only one out of three criteria were fulfilled in 20 (10.8%) and 160 (86.5%) ECGs respectively. Conclusions. The co-occurrence of all assessed ECG-LVH criteria, including the three most frequently applied in clinical practice, is very low in diabetic CAD patients. The Romhilt-Estes point score identifies the highest number of ECG-LVH cases in this setting. However, it seems reasonable to use routinely several ECG criteria for detection of LVH. Further studies are needed to compare diagnostic values of ECG-LVH criteria with imaging methods and to assess prognostic values of various ECG-LVH criteria.

Risk prediction for myocardial infarction via generalized functional regression models

In this paper, we propose a generalized functional linear regression model for a binary outcome indicating the presence/absence of a cardiac disease with multivariate functional data among the relevant predictors. In particular, the motivating aim is the analysis of electrocardiographic traces of patients whose pre-hospital electrocardiogram (ECG) has been sent to 118 Dispatch Center of Milan (the Italian free-toll number for emergencies) by life support personnel of the basic rescue units. The statistical analysis starts with a preprocessing of ECGs treated as multivariate functional data. The signals are reconstructed from noisy observations. The biological variability is then removed by a nonlinear registration procedure based on landmarks. Thus, in order to perform a data-driven dimensional reduction, a multivariate functional principal component analysis is carried out on the variance-covariance matrix of the reconstructed and registered ECGs and their first derivatives. We use the scores of the Principal Components decomposition as covariates in a generalized linear model to predict the presence of the disease in a new patient. Hence, a new semi-automatic diagnostic procedure is proposed to estimate the risk of infarction (in the case of interest, the probability of being affected by Left Bundle Brunch Block). The performance of this classification method is evaluated and compared with other methods proposed in literature. Finally, the robustness of the procedure is checked via leave-j-out techniques.

Differences in cardiovascular function comparing prior preeclamptics with nulliparous controls.

The objective of the current study was to evaluate cardiovascular function; including blood pressure, cardiac output, pulse wave velocity and vascular compliance in nonpregnant nulliparous women compared to women with a history of preterm preeclampsia. This was a case control study. Blood pressure was measured using the Finapres Pro. Baseline cardiac output was determined by echocardiography. Pulse wave velocity was estimated using simultaneous electrocardiographic tracings and ultrasound determined arterial flow waveforms and calculated as estimated distance divided by the time interval between EKG r-wave peak and ultrasound derived peak popliteal artery flow. During volume challenge, 500mL of lactated Ringers solution was infused through an indwelling antecubital catheter over 10min. Cardiac output and blood pressure during and 15min after the infusion were estimated using the Finapres Pro. Indices of arterial stiffness and vascular compliance. Previous preeclamptics exhibited a significant increase in pulse pressure and cardiac output in response to volume challenge when compared with nulliparous controls. Prior preeclamptics had a strong positive correlation between blood pressure indices (r=0.50-0.68, p⩽0.01) and pulse pressure (r=0.58, P=0.008) with pulse wave velocity that was not evident in control women. In women with prior preterm preeclampsia a relationship between blood pressure, intravascular volume and arterial stiffness, is evident in the nonpregnant state and in the absence of hypertension or overt cardiovascular disease. This supports an overarching hypothesis that nonpregnant physiology is an important contributor to pregnancy adaptations.

HRV Influence During Renal Transplantation Procedure on Long-Term Mortality

BackgroundThe autonomic nervous system plays an important role in heart function regulation. One of the most acknowledged methods for noninvasive measurement of autonomic system activity is to determine heart rate variability (HRV). Reduced HRV parameters—heart rate rigidity/stiffness—are an independent prognostic factor of sudden cardiac death risk because of arrhythmia. Renal transplantation is an important factor in HRV changes because of hemodynamic and ion disturbances. The main purpose of this study was to determine the influence of HRV disturbances during renal transplantation procedures on long-term mortality in patients with chronic kidney disease. MethodsA prospective observation study was performed in the Department of Anesthesiology, Intensive Care, and Acute Poisoning, Pomeranian Medical University, Szczecin, Poland. There were 75 patients (mean age, 47 ± 12 years; 42 men) treated with renal transplantation between 2008 and 2010. Patients were monitored with electrocardiographic tracing with the use of 7 electrodes in position type B. The final stage of analysis was to determine the possible relationship between HRV parameters during the perioperative period and the number of deaths within a 5-year follow-up. ResultsHRV parameters during the perioperative period of renal transplantation and the number of deaths within a 5-year follow-up, measured by use of the Holter method, did not differ among patients in the studied population. ConclusionsHRV is a noninvasive and confirmed tool used for the evaluation of autonomic function and mortality risk in patients with end-stage renal disease. HRV parameters recorded in the perioperative period are not optimal stratification tools for estimating the risk of cardiac deaths in patients with end-stage renal disease.

Electrocardiographic parameters of the American Miniature Horse: influence of age and sex

Abstract: The veterinary cardiology has growing importance in equine medicine. There are studies of standardization of electrocardiographic parameters of many races, according to their stature and ability. However, no studies are in the literature with the American Miniature Horse. To evaluate the electrocardiogram (ECG) tracing configuration of this breed at rest and to verify the influence of age and sex on ECG parameters, 203 horses including 143 females and 60 males were divided into four age groups (foals, yearlings, adults and elderly). Electrocardiographic parameters were performed by computerized electrocardiogram (TEB), and the parameters were evaluated in six leads of frontal plane (Lead I, II, III, aVR, aVL and aVF) and base-apex (BA). Heart rates (HR) decreased with increasing age were higher in males than in females. Sinus tachycardia followed by sinus arrhythmia was dominant in both sexes. The cardiac axis was higher in males and ranged between 120° and 150° for foals, 30° and 60° for yearlings and adults, and 60° and 90° for the elderly. The P wave was bifid in several animals. The P-wave amplitude and T-wave duration from lead II and BA were larger in males than in females. The majority of the animals exhibited ST segment depression and a negative T-wave. The most common QRS complex morphology was Qr. Differences were observed between the electrocardiographic tracings of males and females, and age influenced the ECG parameters. Therefore, this study established the ECG patterns for the American Miniature Horse breed and could be used to determine the influence of age and sex on several of the studied variables.

Avaliação dos indicadores de lesão miocárdica em cães com leishmaniose visceral

O objetivo deste estudo foi avaliar os indicadores laboratoriais, eletrocardiográficos e histológicos de lesão cardíaca em diferentes grupos clínicos de cães com leishmaniose visceral. Foram analisados marcadores séricos, traçado eletrocardiográfico e fragmentos de tecido cardíaco de 41 cães naturalmente infectados, distribuídos em três grupos: assintomático, oligossintomático e sintomático. Todos os animais apresentaram aumento na atividade sérica da enzima creatina quinase fração MB. No traçado eletrocardiográfico, o complexo de baixa voltagem foi o distúrbio de condução mais frequente (8/10). Na análise histológica, 75,6% dos cães apresentaram reação inflamatória com predomínio de infiltrados linfo-histiocítico (13/31) de intensidade discreta a moderada e distribuição multifocal. As alterações microscópicas identificadas no miocárdio foram independentes dos achados laboratoriais, eletrocardiográficos e do quadro clínico apresentado pelos animais estudados. A ausência de associação entre alterações histopatológicas e os parâmetros investigados alerta para a dificuldade de identificação de cardiopatia em cães com leishmaniose visceral e ressalta a importância de incluir a leishmaniose visceral no diagnóstico de patologias cardíacas principalmente em regiões endêmicas para o agente.

Bradyarrhythmias

Bradyarrhythmias can present as an incidental electrocardiographic (ECG) finding or a life-threatening condition requiring immediate intervention. They are caused by sinus node disease or atrioventricular block. This review covers pathophysiology, stabilization and assessment, diagnosis and treatment options, and disposition and outcomes for patients with bradycardia. Figures in the review demonstrate characteristic ECG tracings. Tables list classifications of sinus node dysfunction as well as of sinoatrial and atrioventricular blocks, presenting symptoms, important information to elicit on history taking, various causes of bradycardia, and specific interventions for toxicologic etiologies. Key words: atrioventricular block, atropine, bradyarrhythmia, bradycardia, first-degree atrioventricular block, second-degree atrioventricular block, sinoatrial block, sinus bradycardia, sinus node disease, tachycardia-bradycardia syndrome, third-degree atrioventricular block This review contains 9 highly rendered figures, 7 tables, and 92 references.

Analysis of Base-Apex Lead Electrocardiogram in Clinically Healthy Kermani Sheep

The normal electrocardiographic (ECG) parameters in the base-apex lead were evaluated in 40 clinically healthy Kermani sheep, and compared between sexes and three age groups. The heart rate varied from 83-192 beats/min with a mean of 128.9±4.7 beats/min (Mean±SEM). Sinus arrhythmia was the only observed cardiac dysrhythmia on the ECG traces diagnosed in 45% of animals. No significant difference was found in heart rate, amplitude, and duration of ECG waves and intervals between two sexes. Nevertheless, the heart rate, amplitude of ECG waves, duration of T waves and duration of P-R, Q-T and R-R intervals showed significant difference between the age groups. This study provides information on the cardiac rhythm, heart rate, duration, and amplitude of ECG deflections in Kermani sheep. We proposed the base-apex lead as a suitable lead for ECG evaluation in this species.

Effect of Different Pranayamas on Respiratory Sinus Arrhythmia.

Respiratory Sinus Arrhythmia (RSA) is the differential change of Heart Rate (HR) in response to inspiration and expiration. This is a noninvasive sensitive index of parasympathetic cardiac control. To evaluate changes in RSA by utilizing a simple and cost-effective analysis of electrocardiographic (ECG) tracings obtained during performance of four pranayama techniques. Fifty two trained volunteers performed the following pranayamas with different ratios for inspiration and expiration: sukha (1:1), traditional (1:2), pranava (1:3) and savitri (2:1:2:1) and ECG was recorded while performing the techniques with rest period of 5 minutes in-between. HR was calculated and maximum HR during inspiration (Imax), minimum HR during expiration (Emin), differences between Imax and Emin (Δ), percentage differences between I(max) and Emin (Δ%) and expiration: inspiration ratio (E:I) calculated by respective formulae. Statistical analysis was carried out using repeated measures of ANOVA with Tukey-Kramer multiple comparisons test. There were significant differences between groups in all five aspects namely: p= 0.0093 for mean Imax, p = 0.0009 for mean Emin, and p < 0.0001 for Δ HR (I-E), Δ% HR (I-E) and E:I ratio. Pranava pranayama produced the greatest changes in all five comparisons. We suggest that further short and long term studies be undertaken with pranava pranayama in patients to further qualitatively and quantitatively evaluate inherent mechanisms of this simple technique. Addition of these cost-effective techniques to the medical armory will help patients of rhythm disorders and other cardiovascular conditions.