Search results for "QRS complex"

Active-fixation coronary sinus pacing lead extraction: A hybrid approach

2012

Cardiac resynchronization therapy (CRT) can be considered as the standard treatment for patients suffering from heart failure (NYHA III–IV), severely reduced left ventricular (LV) function, and wide QRS complexes. Over the past years, the lead systems used to stimulate the left ventricle have evolved technically from epicardial approaches to a transvenous access accompanied by a significant reduction of procedure-related complication rates [1]. However, even today, LV dislodgement rates ranging 5–10% and the instability of thresholds over time remain the greatest challenges with transvenous LV leads in CRT. Therefore, a special LV lead utilizing active fixation (the Attain StarFix® active f…

Electrocardiogram Signal Analysing - Delineation and Localization of ECG Component

2016

In this paper, we develop a new approach based on nonlinear filtering scheme (NLFS) on cardiac signal to evaluate a robust single-lead electrocardiogram (ECG) delineation system and waves localization method based on nonlinear filtering approach. This system is built in two phases, in the first phase, we proposed a mathematical model for detecting ECG features like QRS complex peak, P and T-waves onsets and ends from noise free of synthetic ECG signal. Later, we develop a theoretical model to obtain real approach for detecting these features from real noisy ECG signals. Our method has been evaluated on electrocardiogram signals of QT-MIT standard database, the QRS peak achieve sensitivity (…

Electrocardiogram Signal Analysing

2016

In this paper, we develop a new approach based on nonlinear filtering scheme (NLFS) on cardiac signal to evaluate a robust single-lead electrocardiogram (ECG) delineation system and waves localization method based on nonlinear filtering approach. This system is built in two phases, in the first phase, we proposed a mathematical model for detecting ECG features like QRS complex peak, P and T-waves onsets and ends fromnoise free of synthetic ECG signal. Later, we develop a theoretical model to obtain real approach for detecting these features from real noisy ECG signals. Our method has been evaluated on electrocardiogram signals of QT-MIT standard database, the QRS peak achieve sensitivity (S…

Automatic detection of P, QRS and T patterns in 12 leads ECG signal based on CWT

2016

International audience; In this paper, a new method based on the continuous wavelet transform is described in order to detect the QRS, P and T waves. QRS, P and T waves may be distinguished from noise, baseline drift or irregular heartbeats. The algorithm, described in this paper, has been evaluated using the Computers in Cardiology (CinC) Challenge 2011 database and also applied on the MIT-BIH Arrhythmia database (MITDB). The data from the CinC Challenge 2011 are standard 12 ECG leads recordings with full diagnostic bandwidth compared to the MITDB which only includes two leads for each ECG signal. Firstly, our algorithm is validated using fifty 12 leads ECG samples from the CinC collection…

Genetic influences on resting electrocardiographic variables in older women: a twin study.

2009

Background: Previous studies in young and middle-aged men and women have shown that resting electrocardiographic (ECG) variables are influenced by genetic factors. However, the extent to which resting ECG variables are influenced by genetic factors in older women is unknown. Thus, the aim of this study was to estimate the relative contribution of genetic and environmental influences to individual differences in resting ECG variables among older female twins without overt cardiac diseases. Methods: Resting ECG recordings were obtained from 186 monozygotic and 203 dizygotic twin individuals, aged 63–76 years. Quantitative genetic modeling was used to decompose the phenotypic variance in each …

P319Is the measurement of QRS duration valid and reproducible in patients with left bundle branch block?

2018

The electrocardiographic ‘triangular QRS-ST-T waveform’ pattern : a marker of severe haemodynamic compromise in Takotsubo syndrome : a case report

2020

Abstract Background Takotsubo cardiomyopathy is characterized by transient regional systolic dysfunction of the left ventricle, mimicking myocardial infarction. Although systolic left ventricular (LV) function normalizes in most cases, the outcome is not always favourable. Recently, a rare electrocardiogram (ECG) finding, lambda wave ST elevation or ‘triangular QRS-ST-T waveform’, was suggested as a possible marker of poor outcome in Takotsubo patients Case summary After a brief episode of chest pain and shortness of breath, a 67-year-old woman developed cardiogenic shock. Her resting ECG showed widespread ST elevations, which soon evolved into a pattern of triangular QRS-ST-T waveforms in …

A particular bigeminy during atrial tachycardia.

2014

The ECG shows clearly visible P waves only in lead V1 (Fig. 1). Regular PP intervals and an isoelectric baseline are present between the P waves, so the diagnosis is atrial tachycardia [1]. During the ECG recording, lead V1 shows 12 P waves but some of these are not visible because they are concealed by the QRS complex (Fig. 2). In lead V1, the beats following the long RR intervals are conducted by the first and the seventh P wave and the premature QRS complexes are conducted by the third and the ninth P wave because the fourth and the tenth P wave are too close to the following QRS complex to conduct the impulse. Consequently, the atrial tachycardia presents an alternating 2:1 and 4:1 cond…

Genetic analyses of the QT interval and its components in over 250K individuals identifies new loci and pathways affecting ventricular depolarization…

2021

AbstractThe QT interval is an electrocardiographic measure representing the sum of ventricular depolarization (QRS duration) and repolarization (JT interval). Abnormalities of the QT interval are associated with potentially fatal ventricular arrhythmia. We conducted genome-wide multi-ancestry analyses in >250,000 individuals and identified 177, 156 and 121 independent loci for QT, JT and QRS, respectively, including a male-specific X-chromosome locus. Using gene-based rare-variant methods, we identified associations with Mendelian disease genes. Enrichments were observed in established pathways for QT and JT, with new genes indicated in insulin-receptor signalling and cardiac energy meta…

Survival with Cardiac-Resynchronization Therapy in Mild Heart Failure

2014

BACKGROUND The Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT) showed that early intervention with cardiac-resynchronization therapy with a defibrillator (CRT-D) in patients with an electrocardiographic pattern showing left bundle-branch block was associated with a significant reduction in heart-failure events over a median follow-up of 2.4 years, as compared with defibrillator therapy alone. METHODS We evaluated the effect of CRT-D on long-term survival in the MADIT-CRT population. Post-trial follow-up over a median period of 5.6 years was assessed among all 1691 surviving patients (phase 1) and subsequently among 854 patients who w…