Heart Rate Dependency of QT-Interval in Congenital and Acquired Prolonged Ventricular Repolarization: Long-Term Analysis by Holter Monitoring

2000 ◽  
pp. 155-160 ◽  
Author(s):  
Emanuela H. Locati ◽  
Giuseppe Bagliani
Keyword(s):  
Heart Rate ◽  
Qt Interval ◽  
Holter Monitoring ◽  
Ventricular Repolarization ◽  
Rate Dependency ◽  
Term Analysis

scholarly journals Heart Rate Dependency and Inter-Lead Variability of the T Peak – T End Intervals

2020 ◽  
Vol 11 ◽  
Author(s):  
Irena Andršová ◽  
Katerina Hnatkova ◽  
Martina Šišáková ◽  
Ondřej Toman ◽  
Peter Smetana ◽  
...  
Keyword(s):  
Heart Rate ◽  
Three Dimensional ◽  
Rate Dependency ◽  
Rate Dependent ◽  
Heart Rate Correction ◽  
Ecg Leads ◽  
Relationship Of ◽  
The Relationship ◽  
Vector Magnitude

The electrocardiographic (ECG) assessment of the T peak–T end (Tpe) intervals has been used in many clinical studies, but several related physiological aspects have not been reported. Specifically, the sources of the Tpe differences between different ECG leads have not been systematically researched, the relationship of Tpe duration to underlying heart rate has not been firmly established, and little is known about the mutual correspondence of Tpe intervals measured in different ECG leads. This study evaluated 796,620 10-s 12-lead ECGs obtained from long-term Holters recorded in 639 healthy subjects (311 female) aged 33.8 ± 9.4 years. For each ECG, transformation to orthogonal XYZ lead was used to measure Tpe in the orthogonal vector magnitude (used as a reference for lead-to-lead comparisons) and to construct a three-dimensional T wave loop. The loop roundness was expressed by a ratio between its circumference and length. These ratios were significantly related to the standard deviation of Tpe durations in different ECG leads. At the underlying heart rate of 60 beats per minute, Tpe intervals were shorter in female than in male individuals (82.5 ± 5.6 vs 90.0 ± 6.5 ms, p < 0.0001). When studying linear slopes between Tpe intervals measured in different leads and the underlying heart rate, we found only minimal heart rate dependency, which was not systematic across the ECG leads and/or across the population. For any ECG lead, positive Tpe/RR slope was found in some subjects (e.g., 79 and 25% of subjects for V2 and V4 measurements, respectively) and a negative Tpe/RR slope in other subjects (e.g., 40 and 65% for V6 and V5, respectively). The steepest positive and negative Tpe/RR slopes were found for measurements in lead V2 and V4, respectively. In all leads, the Tpe/RR slope values were close to zero, indicating, on average, Tpe changes well below 2 ms for RR interval changes of 100 ms. On average, longest Tpe intervals were measured in lead V2, the shortest in lead III. The study concludes that the Tpe intervals measured in different leads cannot be combined. Irrespective of the measured ECG lead, the Tpe interval is not systematically heart rate dependent, and no heart rate correction should be used in clinical Tpe investigations.

scholarly journals Gender-Specific Long-Term Prognostic Values of QRS Duration, QT Interval, and QTc from Automated ECG Analysis for Mortality and Adverse Outcomes in Patients Hospitalized for Heart Failure

2021 ◽  
Author(s):  
Jiandong Zhou ◽  
Sandeep Hothi ◽  
Jeffrey Shi Kai Chan ◽  
Sharen Lee ◽  
Wing Tak Wong ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Qt Interval ◽  
Adverse Outcomes ◽  
Tertiary Center ◽  
Qrs Duration ◽  
Secondary Outcomes ◽  
Gender Specific

Background: Gender-specific prognostic values of electrocardiographic (ECG) measurements in patients hospitalized for heart failure (HF) are lacking, which we hence investigated in this study. Methods: Patients admitted to a single tertiary center for HF between 1 January 2010 and 31 December 2016 without atrial fibrillation and with at least one baseline ECG were included. Automated ECG measurements were performed. The primary outcomes were all-cause and cardiovascular (CAD) mortality, and the secondary outcomes were stroke, and ventricular arrhythmia and sudden cardiac death (VA/SCD). The prognostic values of the heart rate, PR segment, QRS duration, PT interval, QT interval, and QTc were assessed. Gender-specific optimal cutoffs of the above measurements were identified with the maximally selected rank statistics approach. Results: In total, 2718 patients (median age 77 years; 1302 males) were included with a median follow-up of 4.8 years; the females were significantly older (p<0.0001). Females had higher rates of all-cause (p=0.04) and CAD mortality (p=0.02), while males had higher rates of VA/SCD (p=0.02). Higher heart rate, longer PT interval, wider QRS, and longer QT interval and QTc predicted all-cause mortality in males, while only shorter PR segment, longer QRS duration and QTc predicted the same in females. Longer QRS duration, QT interval, and QTc predicted CAD mortality in males, while longer PT interval, wider QRS and longer QTc predicted the same in females. ECG measurements also predicted the secondary outcomes to different extents depending on genders. Conclusions: Selected ECG measurements have significant gender-specific prognostic value in patients admitted for heart failure.

scholarly journals Leptin decreases heart rate associated with increased ventricular repolarization via its receptor

2015 ◽  
Vol 309 (10) ◽  
pp. H1731-H1739 ◽  
Author(s):  
Yen-Chang Lin ◽  
Jianying Huang ◽  
Stan Hileman ◽  
Karen H. Martin ◽  
Robert Hull ◽  
...  
Keyword(s):  
Heart Rate ◽  
Electrical Properties ◽  
Adrenergic Receptor ◽  
Qt Interval ◽  
Ventricular Myocytes ◽  
Receptor Activation ◽  
Ventricular Repolarization ◽  
High Dose ◽  
Resting Heart Rate ◽  
Leptin Receptors

Leptin has been proposed to modulate cardiac electrical properties via β-adrenergic receptor activation. The presence of leptin receptors and adipocytes in myocardium raised a question as to whether leptin can directly modulate cardiac electrical properties such as heart rate and QT interval via its receptor. In this work, the role of local direct actions of leptin on heart rate and ventricular repolarization was investigated. We identified the protein expression of leptin receptors at cell surface of sinus node, atrial, and ventricular myocytes isolated from rat heart. Leptin at low doses (0.1–30 μg/kg) decreased resting heart rate; at high doses (150–300 μg/kg), leptin induced a biphasic effect (decrease and then increase) on heart rate. In the presence of high-dose propranolol (30 mg/kg), high-dose leptin only reduced heart rate and sometimes caused sinus pauses and ventricular tachycardia. The leptin-induced inhibition of resting heart rate was fully reversed by leptin antagonist. Leptin also increased heart rate-corrected QT interval (QTc), and leptin antagonist did not. In isolated ventricular myocytes, leptin (0.03–0.3 μg/ml) reversibly increased the action potential duration. These results supported our hypothesis that in addition to indirect pathway via sympathetic tone, leptin can directly decrease heart rate and increase QT interval via its receptor independent of β-adrenergic receptor stimulation. During inhibition of β-adrenergic receptor activity, high concentration of leptin in myocardium can cause deep bradycardia, prolonged QT interval, and ventricular arrhythmias.

scholarly journals Electrocardiographic Abnormalities and Mortality in Epilepsy Patients

Medicina ◽  
2021 ◽  
Vol 57 (5) ◽  
pp. 504
Author(s):  
Normunds Suna ◽  
Inga Suna ◽  
Evija Gutmane ◽  
Linda Kande ◽  
Guntis Karelis ◽  
...  
Keyword(s):  
Heart Rate ◽  
General Population ◽  
Left Ventricular Hypertrophy ◽  
Qt Interval ◽  
Ventricular Hypertrophy ◽  
Left Ventricular ◽  
Mortality Data ◽  
Qtc Interval ◽  
Study Objective

Background and Objectives: People with epilepsy (PWE) have a 2–3 times higher mortality rate than the general population. Sudden unexpected death in epilepsy (SUDEP) comprises a significant proportion of premature deaths, whereas sudden cardiac death (SCD) is among the leading causes of sudden death in the general population. Cardiac pathologies are significantly more prevalent in PWE. Whether electrocardiographic (ECG) parameters are associated with remote death in PWE has yet to be elucidated. The study objective was to assess whether interictal ECG parameters are associated with mortality in the long-term. Materials and Methods: The study involved 471 epilepsy patients who were hospitalized after a bilateral tonic-clonic seizure(s). ECG parameters were obtained on the day of hospitalization (heart rate, PQ interval, QRS complex, QT interval, heart rate corrected QT interval (QTc), ST segment and T wave changes), as well as reported ECG abnormalities. Mortality data were obtained from the Latvian National Cause-of-Death database 3–11, mean 7.0 years after hospitalization. The association between the ECG parameters and the long-term clinical outcome were examined. Results: At the time of assessment, 75.4% of patients were alive and 24.6% were deceased. Short QTc interval (odds ratio (OR) 4.780; 95% confidence interval (CI) 1.668–13.698; p = 0.004) was associated with a remote death. After the exclusion of known comorbidities with high mortality rates, short QTc (OR 4.631) and ECG signs of left ventricular hypertrophy (OR 5.009) were associated with a remote death. Conclusions: The association between routine 12-lead rest ECG parameters—short QTc interval and a pattern of left ventricular hypertrophy—and remote death in epilepsy patients was found. To the best of our knowledge, this is the first study to associate rest ECG parameters with remote death in an epileptic population.

A Rapid Method to Evaluate Cardiac Repolarization Changes: The Effect of Two Coffee Strengths on the QT Interval

Cardiology ◽  
2015 ◽  
Vol 131 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Janos Molnar ◽  
John C. Somberg
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Healthy Volunteers ◽  
Qt Interval ◽  
Ventricular Repolarization ◽  
Cardiac Repolarization ◽  
Qtc Prolongation ◽  
Time Points ◽  
Time Point

Objectives: To assess the effect of coffee on ventricular repolarization as measured by an electrocardiogram. Methods: Fifty-four healthy volunteers (34 males and 20 females, age 23 ± 5 years) received 1 cup of coffee (caffeine content 120 mg) and 11 participants received 2 cups. Blood pressure and heart rate were measured prior to coffee and every hour thereafter for 5 h. A 12-lead digital Holter recorded continuously, and RR, QT, and QTc intervals were obtained every 30 min. Results: Following coffee, RR increased from 802 ± 102 to 873 ± 126 ms (p = 0.001), QT increased from 359 ± 26 to 367 ± 27 ms at 1.5 h (p = 0.047), and QTc decreased from 387 ± 21 to 381 ± 23 ms at 30 min (p = 0.001), with no changes noted at other time points. Caffeine users and caffeine-naive subjects did not differ in QTc effects (p = 0.971). Females had longer QTc at each time point than males (p = 0.037), but neither had QTc prolongation following coffee. The heart rate decreased from 73 ± 9 to 69 ± 11 bpm at 1 h (p = 0.018), and no significant changes in blood pressure were noted. The effects of 1 or 2 cups of coffee did not differ in terms of QTc (p = 0.663), heart rate (p = 0.161), diastolic (p = 0.250), or systolic blood pressure (p = 0.168). Conclusion: Neither 1 nor 2 cups of coffee increased ventricular repolarization.

scholarly journals The association of long-term glycaemic variability versus sustained chronic hyperglycaemia with heart rate-corrected QT interval in patients with type 2 diabetes

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183055 ◽  
Author(s):  
Jian-bin Su ◽  
Xiao-hua Yang ◽  
Xiu-lin Zhang ◽  
Hong-li Cai ◽  
Hai-yan Huang ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Heart Rate ◽  
Qt Interval ◽  
Glycaemic Variability ◽  
Corrected Qt Interval ◽  
Chronic Hyperglycaemia
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