-
1.
Parathyroid hormone is related to QT interval independent of serum calcium in patients with coronary artery disease.
Palmeri, NO, Davidson, KW, Whang, W, Kronish, IM, Edmondson, D, Walker, MD
Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc. 2018;(2):e12496
-
-
Free full text
-
Abstract
BACKGROUND Elevated serum parathyroid hormone (PTH) is associated with increased risk of cardiovascular death, including sudden cardiac death, in patients with and without parathyroid disease. In small studies, PTH levels have been associated with changes in cardiac conduction and repolarization. Changes in the corrected QT interval (QTc) in particular are thought to be mediated by the effect of PTH on serum calcium. There is limited evidence to suggest PTH may affect cardiac physiology independent of its effects on serum calcium, but there is even less data linking PTH to changes in electrical conduction and repolarization independent of serum calcium. METHODS ECG data were examined from the PULSE database-an observational cohort study designed to examine depression after acute coronary syndromes (ACS) at a single, urban American medical center. In all, 407 patients had PTH and ECG data for analysis. RESULTS The QTc was longer in patients with elevated PTH levels compared with those without elevated PTH levels (451 ± 38.6 ms vs. 435 ± 29.8 ms; p < .001). The difference remained statistically significant after controlling for calcium, vitamin D, and estimated glomerular filtration rate (p = .007). Inclusion of left ventricular ejection fraction in the model attenuated the association (p = .054), suggesting that this finding may be partly driven by changes in cardiac structure. CONCLUSIONS In one of the largest series to examine PTH, calcium, and QT changes, we found that elevated PTH is associated with longer corrected QT interval independent of serum calcium concentration in ACS survivors.
-
2.
Reduction over time of QTc prolongation in patients with sotalol after cardioversion of atrial fibrillation.
Lenhoff, H, Darpö, B, Ferber, G, Rosenqvist, M, Frick, M
Heart rhythm. 2016;(3):661-8
Abstract
BACKGROUND Sotalol is recommended to prevent relapse of atrial fibrillation after cardioversion (CV). Sotalol prolongs the action potential by blocking the rapid component of the delayed rectifier potassium current, which results in corrected QT (QTc) prolongation on the electrocardiogram. Pronounced QTc prolongation may lead to proarrhythmias and sudden death. OBJECTIVE We investigated the dynamics of the QTc interval during the week after CV in patients treated with sotalol compared with patients treated with a β-blocker. METHODS Patients who underwent elective CV for persistent atrial fibrillation and maintained sinus rhythm for 1 week were included prospectively. All patients were on the highest tolerable stable dose of metoprolol or sotalol. Twelve-lead electrocardiograms were recorded 1 hour and 1 week after CV. RESULTS A total of 104 patients on sotalol and 104 on metoprolol were included; clinical characteristics between groups were comparable. One hour after CV, the QTc interval was significantly longer in sotalol-treated patients than in metoprolol-treated patients (465 ± 25 ms vs 423 ± 30 ms; P ≤ .0001). After 1 week, the QTc interval was reduced by -20.3 ± 24 ms in sotalol-treated patients (P ≤ .001); no such effect was seen in metoprolol-treated patients (-2.5 ± 18 ms; P = 0.28). The heart rate was stable during the week in both groups. In multivariate analysis of sotalol-treated patients, factors contributing to pronounced reduction in the QTc interval were longer QTc interval after CV and renal function. CONCLUSION The QTc interval is significantly reduced during the week after CV to sinus rhythm in sotalol-treated patients. This provides insight into the increased risk of proarrhythmias in the immediate time period after CV.
-
3.
A comparison of the effects of lidocaine or magnesium sulfate on hemodynamic response and QT dispersion related with intubation in patients with hypertension.
Kiraci, G, Demirhan, A, Tekelioglu, UY, Akkaya, A, Bilgi, M, Erdem, A, Bayir, H, Yildiz, I, Kocoglu, H
Acta anaesthesiologica Belgica. 2014;(3):81-6
Abstract
BACKGROUND The aim of this study was to investigate the effect of magnesium administered before induction on the hemodynamic response and QT dispersion (QTd) related with intubation in hypertensive patients and to compare it with lidocaine. METHODS Patients with essential hypertension who were under ≤ 65 years old, scheduled for elective surgery with a Mallampati score of I-II were included in the study. Patients were randomly divided into three groups; group M (n = 20) received magnesium sulfate, group L was prescribed lidocaine, and group C (control group) received saline. Standard 12-lead ECG readings were taken before the induction of anesthesia and at the first and fifth minutes following intubation. RESULTS There were no statistically significant differences between the groups in terms of age, sex and demographic characteristics. There was no significant difference in the QT interval values before induction and 5 minutes after intubation in all groups. In group M, QTd values were significantly lower at the first and fifth minutes than before induction. There were no statistically significant differences in QTd values at different times in group L and group C. CONCLUSION QTd is not increased during tracheal intubation in hypertensive patients so there is no need for magnesium sulfate for these patients. But as QTd has been shown to increase during tracheal intubation for coronary artery disease patients, magnesium sulfate might be useful for those patients although future studies are required to confirm this statement.
-
4.
Left ventricular hypertrophy by electrocardiography and echocardiography in the African American Study of Kidney Disease Cohort Study.
Esquitin, R, Razzouk, L, Peterson, GE, Wright, JT, Phillips, RA, De Backer, TL, Baran, DA, Kendrick, C, Greene, T, Reiffel, J, et al
Journal of the American Society of Hypertension : JASH. 2012;(3):193-200
Abstract
Although electrocardiographic criteria for diagnosing left ventricular hypertrophy have a low sensitivity in the general population, their test characteristics have not been evaluated in the high-prevalence group of American Americans with chronic kidney disease. The purpose of the current study was to evaluate these test characteristics among African Americans (n = 645) with hypertensive kidney disease as part of the African-American Study of Kidney Disease and Hypertension cohort. Electrocardiograms were read by 2 cardiologists at an independent core laboratory using the 2 Sokolow-Lyon criteria and the Cornell criteria. Left ventricular hypertrophy on echocardiography was defined as left ventricular mass index greater than 49.2 and greater than 46.7 g/m(2.7) in men and women, respectively. Sixty-nine percent of the population had left ventricular hypertrophy on echo, whereas 34% had left ventricular hypertrophy by any of the electrocardiographic criteria. Sensitivity by individual electrocardiographic criteria was 16.5% by Sokolow-Lyon-1, 19.3% by Sokolow-Lyon-2, and 24.7% by Cornell criteria, with specificity ranging from 89% to 92%. When using any of the 3 criteria, sensitivity increased to 40.4% with a decrease in specificity to 78.0%. Consistent with findings in a general population, left ventricular hypertrophy by electrocardiography had low sensitivity and high specificity in this cohort of African Americans with hypertensive kidney disease.
-
5.
The effect of different dialysate magnesium concentrations on QTc dispersion in hemodialysis patients.
Afshinnia, F, Doshi, H, Rao, PS
Renal failure. 2012;(4):408-12
-
-
Free full text
-
Abstract
BACKGROUND Electrolyte changes during dialysis affect corrected QT (QTc) and QTc dispersion (QTcd), a surrogate marker of arrhythmogenicity. The impact of magnesium on QTcd is not clear. METHODS Twenty-two stable patients on maintenance hemodialysis were enrolled in this study. Each underwent two consecutive hemodialysis sessions at least 2 days apart, the first against normal magnesium dialysate (with magnesium at 1.8 mg/dL) followed by a low magnesium dialysate (with magnesium at 0.6 mg/dL). Pre- and post-dialysis weights, blood pressure, electrolytes, and 12-lead surface EKG were recorded. The QT interval and the QTcd were calculated before and after dialysis in both sessions. RESULTS Of 22 patients, 16 were female. The mean age ± SD was 53.7 ± 18.0 years. The mean change of QTcd (pre- vs. post-dialysis) was 9.5 ms (p = 0.120) and 9.3 ms (p = 0.145) in low and normal magnesium groups, respectively. Using univariate analysis, there was a statistically significant decrease in the mean blood pressure, weight, potassium, magnesium, and QTc interval post-dialysis (compared to pre-dialysis) in both groups (p ≤ 0.049). Post-dialysis concentrations of sodium and calcium were unchanged (compared to pre-dialysis) but bicarbonate increased with both dialysate groups (p < 0.001). The mean change of QTcd was not significant pre- versus post-dialysis by univariate analysis in either group. Multiple linear regression analysis adjusting for pertinent factors did not change the results in either of the two groups. CONCLUSION Using a low magnesium dialysate bath in hemodynamically stable hemodialysis patients without preexisting advanced cardiac disease does not significantly impact QTcd.
-
6.
Dietary sodium alters the prevalence of electrocardiogram determined left ventricular hypertrophy in hypertension.
Vaidya, A, Bentley-Lewis, R, Jeunemaitre, X, Adler, GK, Williams, JS
American journal of hypertension. 2009;(6):669-73
-
-
Free full text
-
Abstract
BACKGROUND Determination of left ventricular hypertrophy (LVH) via electrocardiogram (ECG) is a known independent risk factor for cardiovascular morbidity and mortality in hypertension (HTN). Dietary sodium and HTN are both associated with unfavorable alterations in left ventricular mass, however, to what extent their interplay affects ECG screening for LVH is unclear. METHODS The effects of controlled dietary sodium manipulation on ECG determinants of LVH in hypertensive subjects were evaluated using well-established voltage criteria for LVH. ECGs from 80 hypertensive subjects were evaluated following random sequence assignment to 7 days of high sodium (HS) intake (200 mEq/24 h), and then 7 days of low sodium (LS) intake (10 mEq/24 h). RESULTS Sodium restriction over 7 days resulted in significant decreases in overall, and LVH-specific, ECG voltages. Most subjects exhibited decrements in overall ECG voltage with sodium restriction (72%); however, a smaller subset displayed higher voltages when on LS intake (28%). The prevalence of ECG-determined LVH was significantly lowered with LS diet (HS diet 22/80 (28%) vs. LS diet 8/80 (10%), P < 0.05). Subjects exhibiting reversal of LVH status with sodium restriction were younger, demonstrated salt sensitivity of blood pressure, and lower LVH-specific ECG voltage. CONCLUSIONS Short-term dietary sodium fluctuations can significantly alter overall ECG voltage and the prevalence of ECG-determined LVH in hypertensive individuals. Inclusion of dietary sodium assessment when screening hypertensive subjects for LVH by ECG may improve the consistency of cardiac risk assessment.
-
7.
Rate control in atrial fibrillation: looking beyond the average heart rate.
Ahmad, K, Dorian, P
Current opinion in cardiology. 2006;(2):88-93
Abstract
PURPOSE OF REVIEW The aim of this article is to provide a perspective on rate control in atrial fibrillation which emphasizes patient wellbeing (exercise tolerance, symptoms, quality of life) over attempts to reduce resting or exercise heart rate to an arbitrary range. RECENT FINDINGS Recent trials of rhythm versus rate control strategies of treatment in patients with atrial fibrillation suggest that rate control is a viable first line strategy in many patients. The adverse consequences of atrial fibrillation with rapid ventricular response are partly due to factors other than rate itself, such as irregularity of ventricular response, and variable changes in autonomic nervous system output. Digoxin, calcium channel blockers, and beta-blockers cause a similar reduction in resting heart rate. Beta blockers are the most potent at reducing exercise heart rate, followed by calcium channel blockers and digoxin. Exercise tolerance is occasionally improved by digoxin, sometimes improved by calcium channel blockers and not improved by (and sometimes decreased by) beta-blockers. Information about quality of life with different rate control regimens is sparse. SUMMARY Rate control in atrial fibrillation provides important benefits to patients in terms of symptoms, quality of life and prevention of late consequences of uncontrolled rate (such as tachycardia induced cardiomyopathy). Restricting treatment objectives to achievement of a specific heart rate range on resting or exercise electrocardiogram may result in lack of patient benefit or worsened symptoms. Understanding the nuances of rate control when treating individual patients and interpreting existing evidence allows patients to experience the most benefit from this treatment strategy.
-
8.
Effect of weight loss on P wave dispersion in obese subjects.
Duru, M, Seyfeli, E, Kuvandik, G, Kaya, H, Yalcin, F
Obesity (Silver Spring, Md.). 2006;(8):1378-82
Abstract
OBJECTIVE The aim of this study was to investigate effect of loss weight on P wave dispersion in obese subjects. RESEARCH METHODS AND PROCEDURES After a 12-week weight loss program (diet and medical therapy), a total of 30 (24 women and six men) obese subjects who had lost at least 10% of their original weight were included in the present study. All subjects underwent a routine standard 12-lead surface electrocardiogram. Electrocardiograms were transferred to a personal computer by a scanner and then magnified 400 times by Adobe Photoshop software (Adobe Systems, Mountain View, CA). P wave dispersion, which is also defined as the difference between the maximum P wave duration and the minimum P wave duration, was also calculated. RESULTS After a 12-week weight loss program, BMI (p < 0.001), maximum P wave duration (p < 0.001), and P wave dispersion (p < 0.001) significantly decreased. The mean percentage of weight loss was 13% (10% to 20.3%). The decrease in the level of P wave dispersion (21 +/- 10 and 7 +/- 12 ms, p < 0.002) was more prominent in Group II (>or=12% loss of their original weight) than Group I (<12% loss of their original weight) after the weight loss program. A statistically significant correlation between decrease in the level of P wave dispersion and percentage of weight loss was found (r = 0.624, p < 0.001). DISCUSSION Substantial weight loss in obese subjects is associated with a decrease of P wave duration and dispersion. Therefore, these observations suggest that substantial weight loss is associated with improvement in atrial repolarization abnormalities in obese subjects.
-
9.
Chromium supplementation shortens QTc interval duration in patients with type 2 diabetes mellitus.
Vrtovec, M, Vrtovec, B, Briski, A, Kocijancic, A, Anderson, RA, Radovancevic, B
American heart journal. 2005;(4):632-6
Abstract
BACKGROUND We investigated the potential effects of chromium supplementation on QTc interval duration in type 2 diabetic patients. METHODS Of 60 patients with type 2 diabetes mellitus, 30 were randomly assigned to group A, and 30 to group B. Group A received 1000 microg of chromium picolinate (CrPic) daily for 3 months, followed by placebo in the next 3 months; group B was treated with placebo for the first 3 months and CrPic in the next 3 months. At each visit, QT interval was measured on a standard electrocardiogram by averaging 3 consecutive beats in leads II and V4 and corrected for heart rate with Bazett formula. RESULTS Although baseline QTc interval was similar in both groups (422 +/- 34 milliseconds in group A vs 425 +/- 24 milliseconds in group B, P = .77), QTc interval at 3 months was shorter in group A (406 +/- 35 milliseconds) than in group B (431 +/- 26 milliseconds, P = .01). In the following 3 months, QTc interval shortened in group B but not in group A, which resulted in a comparable QTc interval duration of both groups at the end of the study (414 +/- 28 milliseconds in group A vs 409 +/- 22 milliseconds in group B, P = .50). Apart from body mass index (31.4 +/- 4.2 kg/m2 in patients with QTc shortening vs 28.7 +/- 4.2 kg/m2 in patients without QTc shortening, P = .03), none of the clinical and laboratory variables predicted QTc interval shortening in our patient cohort. CONCLUSIONS Short-term chromium supplementation shortens QTc interval in patients with type 2 diabetes mellitus.
-
10.
Comparison of the 80-lead body surface map to physician and to 12-lead electrocardiogram in detection of acute myocardial infarction.
McClelland, AJ, Owens, CG, Menown, IB, Lown, M, Adgey, AA
The American journal of cardiology. 2003;(3):252-7
Abstract
Diagnosis of non-ST-elevation acute myocardial infarction (AMI) by a 12-lead electrocardiogram has poor sensitivity and specificity and, therefore, relies on biochemical markers of myocardial necrosis, which can only be reliably detected within 14 to 16 hours from symptom onset. The body surface map (BSM) improves AMI detection but is limited by its interpretation by inexperienced medical staff. To facilitate interpretation, an automated BSM algorithm was developed and is evaluated in this study. One hundred three patients with ischemic-type chest pain were recruited for this study from December 2001 to April 2002. A 12-lead electrocardiogram (Marquette Mac 5K) and BSM (PRIME-ECG) were recorded at initial presentation, and cardiac troponin I and/or creatine kinase-MB levels measured at 12 hours after symptom onset. The admitting physician's 12-lead electrocardiographic (ECG) interpretation, 12-lead ECG algorithm (Marquette 12 SL V233) diagnosis, and BSM algorithm diagnosis were documented for each patient. AMI, defined by elevation of troponin I to >1 microg/L and/or creatine kinase-MB to >25U/L, occurred in 53 patients. The admitting physician diagnosed 24 patients with AMI (sensitivity 45%, specificity 94%), the 12-lead ECG algorithm diagnosed 17 patients with AMI (sensitivity 32%, specificity 98%), and the BSM algorithm diagnosed 34 patients with AMI (sensitivity 64%, specificity 94%). The BSM algorithm improved the diagnostic sensitivity by 2.0 (p <0.001) and 1.4 (p = 0.002) compared with the 12-lead ECG algorithm or the admitting physician, respectively. There was no significant difference in specificity. Thus, the BSM algorithm improves detection of AMI compared with the 12-lead ECG algorithm or physician's 12-lead ECG interpretation.