Analysis of six cancer patients with persistent left superior vena cava identified during central venous access device placement via an intracavitary electrocardiogram

Persistent left superior vena cava (PLSVC) is a rare congenital anomaly. PLSVC can be associated with clinically significant atrial septal defect (ASD) or ventricular septal defect (VSD). It is usually asymptomatic and accidentally detected during invasive procedures or imaging examinations. However, whether central venous access device (CVAD) can be placed and used in patients with PLSVC is controversial. A total of six patients were diagnosed with PLSVC and confirmed by chest CT among 3391 cancer patients who underwent CVAD placement via intracavitary electrocardiogram (IC-EKG) at the Venous Access Center (VAC) from May 2019 to December 2020. The CVADs (peripherally inserted central catheter in four patients and Ports in two patients) of these six patients were left in PLSVC. We analyzed changes in the P-wave in the IC-EKG during CVAD placement and the characteristics of the body surface electrocardiogram in these patients and discussed the catheter tip position in PLSVC. All six patients showed negative P-waves in lead II via IC-EKG from the beginning of catheterization: four patients showed negative P-waves and two showed biphasic P-waves in the body surface electrocardiogram (lead III) before catheterization. CVAD function was normal and no obvious complications were observed during the treatment of these patients. The total retention time of CVADs was 1537 days. For patients with a negative P-wave in lead II via IC-EKG during catheterization, especially in those with a negative or biphasic P-wave in lead III of the body surface electrocardiogram, PLSVC should be considered. CVAD insertion in patients with type I PLSVC is safe under certain conditions, with the proper tip position in the middle to lower part of PLSVC.

Evaluation of Tp-e interval, Tp-e/QT ratio and index of cardiac-electrophysiological balance in patients with tinnitus

Background Tinnitus is a common auditory symptom. Dysfunction in the autonomic nervous system (ANS) is an essential part of the etiopathogenesis of tinnitus. ANS regulates heart rate and heart rhythm and can lead to ventricular repolarization changes, which can cause malignant ventricular arrhythmias. T wave peak-to-end T(p-e) interval and T(p-e)/QT ratio are known ventricular arrhythmia indexes, and the index of cardiac-electrophysiological balance (iCEB) is a novel index that can be used to predict the risk of malignant ventricular arrhythmia. The goal of the study was to investigate these ventricular arrhythmia indexes in patients with tinnitus. Methods The study population consisted of 240 patients with tinnitus and 240 healthy subjects. A standard 12-channel surface electrocardiogram was applied to both groups. T(p-e) interval, QT interval and QRS duration were determined. Corrected QT (QTc) was determined via Bazett’s formula. To predict ventricular arrhythmia, iCEB (QT/QRS), T(p-e)/QT, corrected iCEB (QTc/QRS) and T(p-e)/QTc values were determined and compared between groups. Results Compared to the control group, QT (376.46 ± 36.54 vs 346.52 ± 24.51 ms), QTc (426.68 ± 24.68 vs 390.42 ± 24.04 ms), T(p-e) (75.86 ± 14.68 vs 62.42 ± 8.64 ms), T(p-e)/QT (0.201 ± 0.06 vs 0.180 ± 0.01) and T(p-e)/QTc (0.177 ± 0.06 vs 0.159 ± 0.02) were significantly higher in patients with tinnitus (p < 0.001 for all). QT/QRS (3.92 ± 0.68 vs 3.56 ± 0.32) and QTc/QRS (4.44 ± 1.03 vs 4.01 ± 0.64) were also significantly higher in patients with tinnitus (p = 0.018 and p = 0.008, respectively). In addition, significant positive correlations were found between T(p-e), T(p-e)/QTc ratio and disease duration (r = 0.792, p < 0.001; r = 0.500, p < 0.001, respectively). Conclusion As a result, patients with tinnitus may have an increased risk of malignant ventricular arrhythmia.

Severe Bradycardia Increases the Incidence and Severity of Torsade de Pointes Arrhythmias by Augmenting Preexistent Spatial Dispersion of Repolarization in the CAVB Dog Model

IntroductionTorsade de pointes arrhythmias (TdP) in the chronic atrioventricular block (CAVB) dog model result from proarrhythmic factors, which trigger TdP and/or reinforce the arrhythmic substrate. This study investigated electrophysiological and arrhythmogenic consequences of severe bradycardia for TdP.MethodsDofetilide (25 μg/kg per 5 min) was administered to eight anesthetized, idioventricular rhythm (IVR) remodeled CAVB dogs in two serial experiments: once under 60 beats per minute (bpm), right ventricular apex paced (RVA60) conditions, once under more bradycardic IVR conditions. Recordings included surface electrocardiogram and short-term variability (STV) of repolarization from endocardial unipolar electrograms. TdP inducibility (three or more episodes within 10 min after start of dofetilide) and arrhythmic activity scores (AS) were established. Mapping experiments in 10 additional dogs determined the effect of lowering rate on STV and spatial dispersion of repolarization (SDR) in baseline.ResultsIVR-tested animals had longer baseline RR-interval (1,403 ± 271 ms) and repolarization intervals than RVA60 animals. Dofetilide increased STV similarly under both rhythm strategies. Nevertheless, TdP inducibility and AS were higher under IVR conditions (6/8 and 37 ± 27 vs. 1/8 and 8 ± 12 in RVA60, respectively, both p &lt; 0.05). Mapping: Pacing from high (128 ± 10 bpm) to middle (88 ± 10 bpm) to experimental rate (61 ± 3 bpm) increased all electrophysiological parameters, including interventricular dispersion, due to steeper left ventricular restitution curves, and intraventricular SDR: maximal cubic dispersion from 60 ± 14 (high) to 69 ± 17 (middle) to 84 ± 22 ms (p &lt; 0.05 vs. high and middle rate).ConclusionIn CAVB dogs, severe bradycardia increases the probability and severity of arrhythmic events by heterogeneously causing electrophysiological instability, which is mainly reflected in an increased spatial, and to a lesser extent temporal, dispersion of repolarization.

Accelerated Idioventricular Rhythm and Hypokalemia, Atypical Presentation in the Midst of a Pandemic

A 34-year-old female patient was referred to a private center from a rural population due to exertional dyspnea and palpitations for 15 days being previously asymptomatic, a surface electrocardiogram diagnoses sinus rhythm alternating with accelerated idioventricular rhythm with episodes of short-coupling intervals. When conducting a diagnostic investigation, hypokalemia and decreased serum magnesium were evidenced and, after correction of the water-electrolyte imbalance, the electrocardiographic disorders disappeared.

Basic surface electrocardiogram interpretation for the pharmacist

Purpose The electrocardiogram (ECG) is an invaluable tool for clinicians that provides important information about a patient’s heart. As clinical pharmacists play an ever-increasing role in cardiovascular care, ECG interpretation is an important skill with which to become familiar. Summary The ECG provides information on both electrical and biomechanical aspects of the heart. Electrical information such as the rhythm, rate, and axis of the electrical activity can all be provided by the ECG. Biomechanical information about the heart, such as the presence of ventricular hypertrophy and repolarization changes that may be associated with ischemia or myocardial injury, can also easily be gleaned from the ECG. Furthermore, the ECG plays a central role in both the diagnosis and treatment of common clinical conditions such as atrial fibrillation, ischemic heart disease, and QT interval prolongation Conclusion The ECG is one of the most commonly performed diagnostic tests, and clinicians should become familiar with its basic interpretation.