Displaying publications 41 - 60 of 209 in total

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  1. Koh HM, Chong PF, Tan JN, Chidambaram SK, Chua HJ
    J Clin Pharm Ther, 2021 Jun;46(3):800-806.
    PMID: 33768612 DOI: 10.1111/jcpt.13356
    WHAT IS KNOWN AND OBJECTIVE: Hydroxychloroquine and protease inhibitors were widely used as off-label treatment options for COVID-19 but the safety data of these drugs among the COVID-19 population are largely lacking. Drug-induced QTc prolongation is a known adverse reaction of hydroxychloroquine, especially during chronic treatment. However, when administered concurrently with potential pro-arrhythmic drugs such as protease inhibitors, the risk of QTc prolongation imposed on these patients is not known. We aim to investigate the incidence of QTc prolongation events and potential factors associated with its occurrence in COVID-19 population.

    METHODS: We included 446 SARS-CoV-2 RT-PCR-positive patients taking at least one treatment drug for COVID-19 within a period of one month (March-April 2020). In addition to COVID-19-related treatment (HCQ/PI), concomitant drugs with risks of QTc prolongation were considered. We defined QTc prolongation as QTc interval of ≥470 ms in postpubertal males, and ≥480 ms in postpubertal females.

    RESULTS AND DISCUSSION: QTc prolongation events occurred in 28/446 (6.3%) patients with an incidence rate of 1 case per 100 person-days. A total of 26/28 (93%) patients who had prolonged QTc intervals received at least two pro-QT drugs. Multivariate analysis showed that HCQ and PI combination therapy had five times higher odds of QTc prolongation as compared to HCQ-only therapy after controlling for age, cardiovascular disease, SIRS and the use of concurrent QTc-prolonging agents besides HCQ and/or PI (OR 5.2; 95% CI, 1.11-24.49; p = 0.036). Independent of drug therapy, presence of SIRS resulted in four times higher odds of QTc prolongation (OR 4.3; 95% CI, 1.66-11.06; p = 0.003). In HCQ-PI combination group, having concomitant pro-QT drugs led to four times higher odds of QTc prolongation (OR 3.8; 95% CI, 1.53-9.73; p = 0.004). Four patients who had prolonged QTc intervals died but none were cardiac-related deaths.

    WHAT IS NEW AND CONCLUSION: In our cohort, hydroxychloroquine monotherapy had low potential to increase QTc intervals. However, when given concurrently with protease inhibitors which have possible or conditional risk, the odds of QTc prolongation increased fivefold. Interestingly, independent of drug therapy, the presence of systemic inflammatory response syndrome (SIRS) resulted in four times higher odds of QTc prolongation, leading to the postulation that some QTc events seen in COVID-19 patients may be due to the disease itself. ECG monitoring should be continued for at least a week from the initiation of treatment.

    Matched MeSH terms: Electrocardiography
  2. Akhtar Z, Gallagher MM, Yap YG, Leung LWM, Elbatran AI, Madden B, et al.
    Pacing Clin Electrophysiol, 2021 05;44(5):875-882.
    PMID: 33792080 DOI: 10.1111/pace.14232
    BACKGROUND: Coronavirus disease-2019 (COVID-19) causes severe illness and multi-organ dysfunction. An abnormal electrocardiogram is associated with poor outcome, and QT prolongation during the illness has been linked to pharmacological effects. This study sought to investigate the effects of the COVID-19 illness on the corrected QT interval (QTc).

    METHOD: For 293 consecutive patients admitted to our hospital via the emergency department for COVID-19 between 01/03/20 -18/05/20, demographic data, laboratory findings, admission electrocardiograph and clinical observations were compared in those who survived and those who died within 6 weeks. Hospital records were reviewed for prior electrocardiograms for comparison with those recorded on presentation with COVID-19.

    RESULTS: Patients who died were older than survivors (82 vs 69.8 years, p 455 ms (males) and >465 ms (females) (p = 0.028, HR 1.49 [1.04-2.13]), as predictors of mortality. QTc prolongation beyond these dichotomy limits was associated with increased mortality risk (p = 0.0027, HR 1.78 [1.2-2.6]).

    CONCLUSION: QTc prolongation occurs in COVID-19 illness and is associated with poor outcome.

    Matched MeSH terms: Electrocardiography
  3. Jeyamalar R, Pathmanathan R, Yap SF, Kannan P
    Ann Acad Med Singap, 1991 Nov;20(6):795-7.
    PMID: 1803972
    Cardiac amyloidosis is an uncommon and often unrecognised cause of cardiac failure. It is an infiltrative disease that may mimic either a restrictive or hypertrophic cardiomyopathy, constrictive pericarditis, coronary artery disease or valvular heart disease. The diagnosis should be suspected in a patient with cardiac failure who has low voltage complexes on the electrocardiogram, in association with increased myocardial mass and echogenicity on the echocardiogram. The definitive diagnosis, however, can only be made by endomyocardial biopsy or biopsy of any involved organ in systemic amyloidosis. Prognosis is poor and treatment ineffective.
    Matched MeSH terms: Electrocardiography
  4. Garweg C, Khelae SK, Steinwender C, Chan JYS, Ritter P, Johansen JB, et al.
    Heart Rhythm, 2020 12;17(12):2037-2045.
    PMID: 32717315 DOI: 10.1016/j.hrthm.2020.07.024
    BACKGROUND: The MARVEL (Micra Atrial TRacking Using a Ventricular AccELerometer) 2 study assessed the efficacy of atrioventricular (AV) synchronous pacing with a Micra leadless pacemaker. Average atrioventricular synchrony (AVS) was 89.2%. Previously, low amplitude of the Micra-sensed atrial signal (A4) was observed to be a factor of low AVS.

    OBJECTIVE: The purpose of this study was to identify predictors of A4 amplitude and high AVS.

    METHODS: We analyzed 64 patients enrolled in MARVEL 2 who had visible P waves on electrocardiogram for assessing A4 amplitude and 40 patients with third-degree AV block for assessing AVS at rest. High AVS was defined as >90% correct atrial-triggered ventricular pacing. The association between clinical factors and echocardiographic parameters with A4 amplitude was investigated using a multivariable model with lasso variable selection. Variables associated with A4 amplitude together with premature ventricular contraction burden, sinus rate, and sinus rate variability (standard deviation of successive differences of P-P intervals [SDSD]) were assessed for association with AVS.

    RESULTS: In univariate analysis, low A4 amplitude was inversely related to atrial function assessed by E/A ratio and e'/a' ratio, and was directly related to atrial contraction excursion (ACE) and atrial strain (Ɛa) on echocardiography (all P ≤.05). The multivariable lasso regression model found coronary artery bypass graft history, E/A ratio, ACE, and Ɛa were associated with low A4 amplitude. E/A ratio and SDSD were multivariable predictors of high AVS, with >90% probability if E/A <0.94 and SDSD <5 bpm.

    CONCLUSION: Clinical parameters and echocardiographic markers of atrial function are associated with A4 signal amplitude. High AVS can be predicted by E/A ratio <0.94 and low sinus rate variability at rest.

    Matched MeSH terms: Electrocardiography
  5. Saedon NI, Zainal-Abidin I, Chee KH, Khor HM, Tan KM, Kamaruzzaman SK, et al.
    Clin Auton Res, 2016 Feb;26(1):41-8.
    PMID: 26695401 DOI: 10.1007/s10286-015-0327-5
    To determine the magnitude of postural blood pressure change, differences in ECG between fallers and non-fallers were measured. Postural blood pressure change is associated with symptoms of dizziness, presyncope, and syncope.
    Matched MeSH terms: Electrocardiography
  6. Toh KW, Nadesan K, Sie MY, Vijeyasingam R, Tan PS
    Anesth Analg, 2004 Aug;99(2):350-2, table of contents.
    PMID: 15271703
    Arrhythmogenic right ventricular dysplasia is an inherited disease causing fatty replacement of heart tissue. This disease often presents as T-wave inversion in the anterior leads of the electrocardiogram (ECG) with life-threatening ventricular arrhythmias. In older patients, progressive right and left ventricular failure can develop. This is a case report of postoperative death occurring in a 59-yr-old woman with undiagnosed arrhythmogenic right ventricular dysplasia after hepatic cystectomy. The patient had T-wave inversion in the inferior ECG leads and no history of arrhythmias. During general anesthesia, cardiovascular collapse occurred in the absence of arrhythmias that was unresponsive to resuscitation.
    Matched MeSH terms: Electrocardiography
  7. Chuah JS, Wong WL, Bakin S, Lim RZM, Lee EP, Tan JH
    Ann Med Surg (Lond), 2021 May;65:102294.
    PMID: 33948169 DOI: 10.1016/j.amsu.2021.102294
    Introduction and importance: A totally implantable venous access device (TIVAD), also referred to as 'chemoport', is frequently used for oncology patients. Chemoport insertion via the subclavian vein access may compress the catheter between the first rib and the clavicle, resulting in pinch-off syndrome (POS). The sequela includes catheter transection and subsequent embolization. It is a rare complication with incidence reported to be 1.1-5.0% and can lead to a devastating outcomes.

    Case presentation: 50-year-old male had his chemoport inserted for adjuvant chemotherapy 3 years ago. During the removal, remaining half of the distal catheter was not found. There was no difficulties during the removal. Chest xray revealed that the fractured catheter had embolized to the right ventricle. Further history taking, he did experienced occasional palpitation and chest discomfort for the past six months. Electrocardiogram and cardiac enzymes were normal. Urgent removal of the fractured catheter via the percutaneous endovascular approach, under fluoroscopic guidance by an experience interventional radiologist was done. The procedure was successful without any complication. Patient made an uneventful recovery. He was discharged the following day, and was well during his 3rd month follow up.

    Conclusion: Early detection and preventive measures can be done to prevent pinch-off syndrome. Unrecognized POS can result in fatal complications such as cardiac arrhythmia and septic embolization. Retrieval via the percutaneous endovascular approach provide excellent outcome in the case of embolized fractured catheter.

    Matched MeSH terms: Electrocardiography
  8. Oon YY, Koh KT, Khaw CS, Mohd Amin NH, Ong TK
    Med J Malaysia, 2019 08;74(4):328-330.
    PMID: 31424042
    Arrhythmogenic right ventricular cardiomyopathy (ARVC) is primarily a familial disease with autosomal dominant inheritance. Incomplete penetrance and variable expression are common, resulting in broad disease spectrum. Three patterns of phenotypic expression have been described: (1) "classic" subtype, with predominant right ventricle involvement, (2) "left dominant" subtype, with early and dominant left ventricle involvement, and (3) "biventricular" subtype, with both ventricles equally affected. Genotypephenotype associations have been described, but there are other genetic and non-genetic factors that can affect disease expression. We describe two different phenotypic expressions of ARVC in a family.
    Matched MeSH terms: Electrocardiography
  9. Tan SK, Ng KH, Yeong CH, Raja Aman RRA, Mohamed Sani F, Abdul Aziz YF, et al.
    Quant Imaging Med Surg, 2019 Apr;9(4):552-564.
    PMID: 31143647 DOI: 10.21037/qims.2019.03.13
    Background: High delivery rate is an important factor in optimizing contrast medium administration in coronary computed tomography angiography (CCTA). A personalized contrast volume calculation algorithm incorporating high iodine delivery rate (IDR) can reduce total iodine dose (TID) and produce optimal vessel contrast enhancement (VCE) in low tube voltage CCTA. In this study, we developed and validated an algorithm for calculating the volume of contrast medium delivered at a high rate for patients undergoing retrospectively ECG-gated CCTA with low tube voltage protocol.

    Methods: The algorithm for an IDR of 2.22 gI·s-1 was developed based on the relationship between VCE and contrast volume in 141 patients; test bolus parameters and characteristics in 75 patients; and, tube voltage in a phantom study. The algorithm was retrospectively tested in 45 patients who underwent retrospectively ECG-gated CCTA with a 100 kVp protocol. Image quality, TID and radiation dose exposure were compared with those produced using the 120 kVp and routine contrast protocols.

    Results: Age, sex, body surface area (BSA) and peak contrast enhancement (PCE) were significant predictors for VCE (P<0.05). A strong linear correlation was observed between VCE and contrast volume (r=0.97, P<0.05). The 100-to-120 kVp contrast enhancement conversion factor (Ec) was calculated at 0.81. Optimal VCE (250 to 450 HU) and diagnostic image quality were obtained with significant reductions in TID (32.1%) and radiation dose (38.5%) when using 100 kVp and personalized contrast volume calculation algorithm compared with 120 kVp and routine contrast protocols (P<0.05).

    Conclusions: The proposed algorithm could significantly reduce TID and radiation exposure while maintaining optimal VCE and image quality in CCTA with 100 kVp protocol.

    Matched MeSH terms: Electrocardiography
  10. Sidek KA, Khalil I
    PMID: 22255160 DOI: 10.1109/IEMBS.2011.6090644
    This paper presents a person identification mechanism in irregular cardiac conditions using ECG signals. A total of 30 subjects were used in the study from three different public ECG databases containing various abnormal heart conditions from the Paroxysmal Atrial Fibrillation Predicition Challenge database (AFPDB), MIT-BIH Supraventricular Arrthymia database (SVDB) and T-Wave Alternans Challenge database (TWADB). Cross correlation (CC) was used as the biometric matching algorithm with defined threshold values to evaluate the performance. In order to measure the efficiency of this simple yet effective matching algorithm, two biometric performance metrics were used which are false acceptance rate (FAR) and false reject rate (FRR). Our experimentation results suggest that ECG based biometric identification with irregular cardiac condition gives a higher recognition rate of different ECG signals when tested for three different abnormal cardiac databases yielding false acceptance rate (FAR) of 2%, 3% and 2% and false reject rate (FRR) of 1%, 2% and 0% for AFPDB, SVDB and TWADB respectively. These results also indicate the existence of salient biometric characteristics in the ECG morphology within the QRS complex that tends to differentiate individuals.
    Matched MeSH terms: Electrocardiography/methods*
  11. Sivalingam N, Anwar K, Chandran K
    Singapore Med J, 2001 Mar;42(3):122-3.
    PMID: 11405564
    Peripartal cardiomyopathy is a rare form of heart disease in pregnancy with an unpredictable outcome. We describe one patient who presented in a decompensated state who was successfully managed with medical antifailure treatment. The etiology, management and future obstetric outcome are discussed.
    Matched MeSH terms: Electrocardiography
  12. Hussein AF, Hashim SJ, Aziz AFA, Rokhani FZ, Adnan WAW
    J Med Syst, 2017 Nov 29;42(1):15.
    PMID: 29188389 DOI: 10.1007/s10916-017-0871-8
    The non-stationary and multi-frequency nature of biomedical signal activities makes the use of time-frequency distributions (TFDs) for analysis inevitable. Time-frequency analysis provides simultaneous interpretations in both time and frequency domain enabling comprehensive explanation, presentation and interpretation of electrocardiogram (ECG) signals. The diversity of TFDs and specific properties for each type show the need to determine the best TFD for ECG analysis. In this study, a performance evaluation of five TFDs in term of ECG abnormality detection is presented. The detection criteria based on extracted features from most important ECG signal components (QRS) to detect normal and abnormal cases. This is achieved by estimating its energy concentration magnitude using the TFDs. The TFDs analyse ECG signals in one-minute interval instead of conventional time domain approach that analyses based on beat or frame containing several beats. The MIT-BIH normal sinus rhythm ECG database total records of 18 long-term ECG sampled at 128 Hz have been analysed. The tested TFDs include Dual-Tree Wavelet Transform, Spectrogram, Pseudo Wigner-Ville, Choi-Williams, and Born-Jordan. Each record is divided into one-minute slots, which is not considered previously, and analysed. The sample periods (slots) are randomly selected ten minutes interval for each record. This result with 99.44% detection accuracy for 15,735 ECG beats shows that Choi-Williams distribution is most reliable to be used for heart problem detection especially in automated systems that provide continuous monitoring for long time duration.
    Matched MeSH terms: Electrocardiography/methods*
  13. Aung T
    Med J Malaysia, 1997 Dec;52(4):441-3.
    PMID: 10968125
    A case of unsuspected penetrating cardiac injury is presented. It was recognised by the presence of bleeding into peritoneal cavity even after the source of bleeding from intra-abdominal organs had been stopped. It highlights the importance of high index of suspicion of associated cardiac injury in high epigastric penetrating injury.
    Matched MeSH terms: Electrocardiography
  14. Boon KH, Khalil-Hani M, Malarvili MB
    Comput Methods Programs Biomed, 2018 Jan;153:171-184.
    PMID: 29157449 DOI: 10.1016/j.cmpb.2017.10.012
    This paper presents a method that able to predict the paroxysmal atrial fibrillation (PAF). The method uses shorter heart rate variability (HRV) signals when compared to existing methods, and achieves good prediction accuracy. PAF is a common cardiac arrhythmia that increases the health risk of a patient, and the development of an accurate predictor of the onset of PAF is clinical important because it increases the possibility to electrically stabilize and prevent the onset of atrial arrhythmias with different pacing techniques. We propose a multi-objective optimization algorithm based on the non-dominated sorting genetic algorithm III for optimizing the baseline PAF prediction system, that consists of the stages of pre-processing, HRV feature extraction, and support vector machine (SVM) model. The pre-processing stage comprises of heart rate correction, interpolation, and signal detrending. After that, time-domain, frequency-domain, non-linear HRV features are extracted from the pre-processed data in feature extraction stage. Then, these features are used as input to the SVM for predicting the PAF event. The proposed optimization algorithm is used to optimize the parameters and settings of various HRV feature extraction algorithms, select the best feature subsets, and tune the SVM parameters simultaneously for maximum prediction performance. The proposed method achieves an accuracy rate of 87.7%, which significantly outperforms most of the previous works. This accuracy rate is achieved even with the HRV signal length being reduced from the typical 30 min to just 5 min (a reduction of 83%). Furthermore, another significant result is the sensitivity rate, which is considered more important that other performance metrics in this paper, can be improved with the trade-off of lower specificity.
    Matched MeSH terms: Electrocardiography
  15. Mulyadi IH, Fiedler P, Eichardt R, Haueisen J, Supriyanto E
    Med Biol Eng Comput, 2021 Feb;59(2):431-447.
    PMID: 33495984 DOI: 10.1007/s11517-021-02319-9
    Wearable electronics and sensors are increasingly popular for personal health monitoring, including smart shirts containing electrocardiography (ECG) electrodes. Optimal electrode performance requires careful selection of the electrode position. On top of the electrophysiological aspects, practical aspects must be considered due to the dynamic recording environment. We propose a new method to obtain optimal electrode placement by considering multiple dimensions. The electrophysiological aspects were represented by P-, R-, and T-peak of ECG waveform, while the shirt-skin gap, shirt movement, and regional sweat rate represented the practical aspects. This study employed a secondary data set and simulations for the electrophysiological and practical aspects, respectively. Typically, there is no ideal solution that maximizes satisfaction degrees of multiple electrophysiological and practical aspects simultaneously; a compromise is the most appropriate approach. Instead of combining both aspects-which are independent of each other-into a single-objective optimization, we used multi-objective optimization to obtain a Pareto set, which contains predominant solutions. These solutions may facilitate the decision-makers to decide the preferred electrode locations based on application-specific criteria. Our proposed approach may aid manufacturers in making decisions regarding the placement of electrodes within smart shirts.
    Matched MeSH terms: Electrocardiography*
  16. McDOUGALL C
    Med J Malaya, 1955 Mar;9(3):195-204.
    PMID: 14393209
    Matched MeSH terms: Electrocardiography/instrumentation*
  17. Bakar AA, Lim YL, Wilson SJ, Fuentes M, Bertling K, Taimre T, et al.
    Physiol Meas, 2013 Feb;34(2):281-9.
    PMID: 23363933 DOI: 10.1088/0967-3334/34/2/281
    Optical sensing offers an attractive option for detection of surface biopotentials in human subjects where electromagnetically noisy environments exist or safety requirements dictate a high degree of galvanic isolation. Such circumstances may be found in modern magnetic resonance imaging systems for example. The low signal amplitude and high source impedance of typical biopotentials have made optical transduction an uncommon sensing approach. We propose a solution consisting of an electro-optic phase modulator as a transducer, coupled to a vertical-cavity surface-emitting laser and the self-mixing signal detected via a photodiode. This configuration is physically evaluated with respect to synthesized surface electrocardiographic (EKG) signals of varying amplitudes and using differing optical feedback regimes. Optically detected EKG signals using strong optical feedback show the feasibility of this approach and indicate directions for optimization of the electro-optic transducer for improved signal-to-noise ratios. This may provide a new means of biopotential detection suited for environments characterized by harsh electromagnetic interference.
    Matched MeSH terms: Electrocardiography/instrumentation*
  18. Khor KH, Chin MX
    J Adv Vet Anim Res, 2020 Sep;7(3):501-508.
    PMID: 33005676 DOI: 10.5455/javar.2020.g446
    Objective: Annual health screening inclusive of heart workup is recommended for the detection of heart diseases, especially in asymptomatic patients (no clinical signs). This study determined the occurrences of the common heart disease and the risk factors in apparently healthy cats.

    Materials and methods: This prospective study that screened 59 healthy cats and the status of the heart were evaluated based on a combination of findings from physical examination, electrocardiography, blood pressure measurement, routine blood test, urinalysis, and total thyroid level.

    Results: Approximately 40.7% (n = 24/59) of the apparently healthy cats were diagnosed with heart disease hypertrophic cardiomyopathy (62.5%) remains to be the most commonly diagnosed. The mean age was 4.9-year old (age range, 7-month-old to 19-year-old). The prevalence was higher in males (45.0%; n = 17/38) cats, especially the domestic shorthairs (46.0%; n = 11/24). Among the healthy cats with vertebral heart scale (VHS) > 8.0, only 52% (n = 12/23) of them were diagnosed with cardiomyopathy. However, 33% (n = 12/36) of the cats with normal VHS ≤ 7.9 were diagnosed with heart disease. Consistently, all healthy cats with abnormal heart sounds were diagnosed with heart disease. About 31.4% (n = 16/51) of these cats with typical heart sound had cardiomyopathy too.

    Conclusion: The occurrence of cardiomyopathy in apparently healthy cats has no association with the patient's age, sex, and VHS, except for the heart sound. Echocardiography remains the best diagnostic tool, as normal heart size and normal heart sound do not exclude cardiomyopathy in this group of apparently healthy cats.

    Matched MeSH terms: Electrocardiography
  19. Ibrahim, N.U.A., Abd Aziz, S., Nawi, N.M.
    MyJurnal
    Soluble solid content (SSC) is one of the important traits that indicate the ripeness of banana fruits.
    Determination of SSC for banana often requires destructive laboratory analysis on the fruit. An impedance measurement technique was investigated as a non-destructive approach for SSC determination of bananas. A pair of electrocardiogram (ECG) electrode connected to an impedance analyser board was used to measure the impedance value of bananas over the frequency of 19.5 to 20.5 KHz. The SSC measurement was conducted using a pocket refractometer and data was analysed to correlate SSC with impedance values. It was found that the mean of impedance, Z decreased from 10.01 to 99.93 KΩ at the frequency of 20 KHz, while the mean value of SSC increased from 0.58 to 4.93 % Brix from day 1 to day 8. The best correlation between impedance and SSC was found at 20 KHz, with the coefficient of determination, R2 of 0.87. This result indicates the potential of impedance measurement in predicting SSC of banana fruits.
    Matched MeSH terms: Electrocardiography
  20. Ng WH, Ahmad Z
    Med J Malaysia, 1978 Dec;33(2):128-32.
    PMID: 755162
    Matched MeSH terms: Electrocardiography*
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