Detection of myocardial injury due to defibrillation threshold checking after insertion of implantable cardioverter/defibrillators.

AIMS: Possible myocardial damage caused by defibrillation threshold (DFT) control and its extent after insertion of implantable cardioverter/defibrillators (ICD) is still a matter for debate. This study aimed to identify the effect of DFT checking during ICD implantation, compared with permanent pacemaker (PPM) implantation, on the magnitude of myocardial damage as assessed by cardiac troponin-T (cTNT) and CK-MB. METHODS AND RESULTS: A total of 133 candidates for ICD implantation were enrolled in the ICD group (mean age 60.66 +/- 12.25 years; males 111 [83.5%]) as well as 130 candidates in the PPM group (mean age 69.56 +/- 12.86 years; males 64 [49.2%]). DFT was controlled in all of the ICD patients. Serum levels of cTNT and CK-MB were measured at baseline plus 8 and 24 hours following the procedure. The results were adjusted for age, gender, and other confounding factors. The amount of cTNT rise after 8 and 24 hours in the ICD group was significantly higher than in the PPM group (p < 0.001 for both). These differences remained significant after adjustment for confounding factors. The level of CK-MB rise after 8 and 24 hours was also significantly higher in the ICD group, although it lost its significance after adjustment for age, gender and other confounding variables. There was no significant relationship between the amount of energy delivered and enzyme elevation. CONCLUSION: Elevation of cTNT and CK-MB after the ICD implantation was significantly higher than that after the PPM implantation and may be attributed to the DFT testing shock and resulting myocardial injury.

Comparison between tissue doppler imaging (TDI) and tissue synchronization imaging (TSI) in evaluation of left ventricular dyssynchrony in patients with advanced heart failure.

BACKGROUND: Assessment of left ventricular (LV) dyssynchrony has an important role in optimizing the selection of cardiac resynchronization therapy (CRT) candidates. We compared a new semiautomatic echocardiographic modality, tissue synchronization imaging (TSI) with a manual method, color-coded tissue Doppler imaging (TDI), in the assessment of LV dyssynchrony in patients with heart failure (HF). METHODS: Ninety-five patients (age = 54.5 ± 17.1 years, 66.3% male) with advanced HF (NYHA functional class ≥III and ejection-fraction ≤35%) were included in the study and evaluated echocardiographically. The time to regional peak systolic velocity (Ts) in six basal and six middle segments of the LV was measured manually using velocity curves from TDI and semiautomatically using TSI and seven parameters of systolic dyssynchrony were computed. RESULTS: Overall, a moderate-to-good association was found between Ts derived by these two modalities, whereas the mean of Ts via TSI was significantly lower than that measured by TDI in many LV segments. The agreement between these two modalities in identifying LV dyssynchrony varied from weak to moderate according to various dyssynchrony indices. In comparison to the TDI-derived dyssynchrony indices, TSI showed a high sensitivity of more than 90% using Ts delay at the basal/all LV segments and the indices for their standard deviations (SD) for identifying LV dyssynchrony, whereas the highest specificity of 80% was achieved using the septal-lateral dyssynchrony index in the prediction of LV dyssynchrony. CONCLUSION: With the aid of selected LV dyssynchrony indices, the TSI method may confer enough sensitivity for a speedy evaluation and initial screening of LV dyssynchrony in HF patients; however, the current technology of TSI does not seem specific enough to replace TDI in the evaluation of dyssynchrony.

A new method for induction of atrioventricular nodal reentrant tachycardia in non-inducible cases.

AIM: In some patients with clinical paroxysmal supraventricular tachycardia (PSVT), who are candidates for radiofrequency (RF) catheter ablation, attempts for the induction of arrhythmia during the electrophysiological study (EPS) fail despite different stimulation protocols even during the isoproterenol infusion and atropine injection. The presence of an atrial-His interval (AH) jump during decremental pre-mature atrial stimulation is the only clue for slow pathway ablation in these patients; in occasional patients, however, the AH jump is an accidental finding and the real arrhythmia is not atrioventricularnodal reentrant tachycardia (AVNRT). We aimed to introduce a new method for the induction of AVNRT in these patients. METHODS AND RESULTS: Ten patients (50% male, mean age=44.40 ± 12.80 years) with clinical PSVT who were referred to our department for the EPS and RF catheter ablation were selected. These patients had documented clinical PSVT with non-inducible arrhythmia during the EPS with different stimulation protocols even during the isoproterenol infusion and atropine injection but they only showed an AH jump. To induce AVNRT, low-watt (15-20), low-temperature (40-45°C) RF currents were delivered into the slow pathway area for a maximum of 40 s. Atrioventricularnodal reentrant tachycardia was inducible in five cases (50%, three male, mean age=45.80 ± 9.65 years). Induction of AVNRT occurred either during the RF current application after the occurrence of junctional ectopic beats or after another stimulation protocol. CONCLUSION: A low-watt, low-temperature RF current application into the slow pathway area can be a provocative method for the induction of AVNRT probably by AV-junction warming and conduction-velocity augmentation.

Sodium bicarbonate in preventing contrast nephropathy in patients at risk for volume overload: a randomized controlled trial.

BACKGROUND: Sodium bicarbonate has been recently proposed as a prophylactic measure for the prevention of contrast-induced nephropathy (CIN). We aimed to compare the efficacy of the combination of sodium bicarbonate with half saline, and half saline alone in preventing CIN in patients having uncontrolled hypertension, compensated severe heart failure or a history of pulmonary edema. METHODS: Seventy-two patients undergoing elective coronary angiography with a serum creatinine level > or =1.5 mg/dL who had uncontrolled hypertension, compensated severe heart failure or a history of pulmonary edema were prospectively enrolled in a single-center, double-blind, randomized, controlled trial from August 2007 to July 2008 and were assigned to either an infusion of sodium bicarbonate plus half saline (n=36) or half saline alone (n=36). The primary end point was an absolute (> or =0.5 mg/dL) or relative (> or =25%) increase in serum creatinine 48 hours after the procedure (CIN). RESULTS: There were no significant differences between the groups regarding their baseline demographic and biochemical characteristics, as well as the underlying disease. A total of 6.1% of the patients receiving sodium bicarbonate plus half saline developed CIN as opposed to 6.3% of the patients in the half saline group, which was not statistically different (odds ratio = 0.97; 95% confidence interval, 0.13-7.3; p=1.0). CONCLUSION: The combination therapy of sodium bicarbonate plus half saline does not offer additional benefits over hydration with half saline alone in the prevention of CIN.

Ventricular asynchrony of time-to-peak systolic velocity in structurally normal heart by tissue Doppler imaging.

BACKGROUND: Echocardiographic measurements of time-to-peak systolic velocities (Ts) are helpful for assessing the degree of cardiac asynchrony. We assessed the degree of ventricular asynchrony in structurally normal heart according to Ts by tissue Doppler imaging. METHODS: We performed conventional echocardiography and tissue velocity imaging for 65 healthy adult volunteers to measure the Ts of 12 left ventricular segments in the mid and basal levels delay of Ts and standard deviation (SD) of Ts in all and basal segments. Six frequently used markers of dyssynchrony were measured and were also compared between men and women. Data are presented as median (25th and 75th percentile). RESULTS: Septal-lateral and anteroseptal-posterior delays were 50 (20, 90) and 20 (0, 55) ms. The delay between the longest and the shortest Ts in basal and all segments were 100 (80, 120) and 110 (83, 128) ms, respectively. SD of Ts was 39 (24, 52) ms for basal and 41 (28, 51) ms for all segments. Overall, 76.9% of cases had at least one marker of dyssynchrony. Frequencies of dyssynchrony markers were almost significantly higher in women compared to men. The most frequently observed dyssynchrony marker was SD of Ts of all segments (70.8%) and the lowest was anteroseptal-posterior delay (21.5%). CONCLUSIONS: Normal population almost had dyssynchrony by previously described markers and many of these markers were more frequent in women. Conducting more studies on normal population by other tissue Doppler modalities may give better description of cardiac synchronicity.

Comparison of heart rate variability and cardiac arrhythmias in polluted and clean air episodes in healthy individuals.

OBJECTIVE: Pathophysiological mechanisms and pathways linking cardiovascular mortality and morbidity with air pollution were recently hypothesized. The present study evaluated association between air pollution and changes in heart rate variability as a marker of cardiac autonomic function in healthy individuals, and also determined the frequency of cardiac arrhythmias and QT interval changes on polluted compared to unpolluted days. METHODS: Continuous Holter electrocardiography (ECG) monitoring was conducted on 21 young healthy individuals in the two episodes of clean air and elevated air pollution in Tehran. All subjects underwent a medical history review, a physical examination and echocardiography in order to rule out structural heart diseases. Measured pollutants and parameters included NO(2), CO(2), O(3), SO(2), and PM10, which all showed significantly higher concentrations on polluted days. Holter parameters were measured for 24-h time segments and compared. RESULTS: Maximum heart rate was significantly lower in polluted air conditions in comparison with clean air conditions (115.1 ± 32.2 vs. 128.9 ± 17.7), and the square root of the mean of squared differences between adjacent NN intervals (r-MSSD) was higher in polluted air compared to clean air (99.0 ± 58.2 vs. 58.5 ± 26.4). Also, the occurrence of nonsustained supraventricular tachycardia was reported in 42.9% of participants in air pollution episodes, whereas this arrhythmia was not seen in clear air conditions (p = 0.001). CONCLUSION: Changes in air pollution indices may lead to the occurrence of nonsustained supraventricular tachycardia, a slight reduction in maximum heart rate, and an increase in r-MSSD in healthy individuals. Air quality monitoring in cities associated with a high exposure to air pollutants is recommended in order to prevent such events.

Premedication for coronary angiography: effects on anxiety and hemodynamic status.

AIM: This study was designed to compare the outcomes of two current methods of premedication, for coronary angiography with placebo, on the level of anxiety and hemodynamic status. METHODS AND RESULTS: In all, 151 patients referring for coronary angiography were randomized into three groups with equal populations. The first group (group M) received 0.02 mg/kg intravenous midazolam; the second (group DP7rpar; received intramuscular injection of 5mg diazepam + 25 mg promethazine; and the third (group P) received 2cc of intravenous normal saline solution. Vital signs, blood pressure, and peripheral O2 saturation were recorded in specifically-designed questionnaires. The level of anxiety before and after angiography was documented according to the Visual Analog Scale. Patients in the group M accidentally had higher pre-procedural anxiety level (p < 0.05). There was no significant difference in pulse rate, respiratory rate, and mean blood pressure (BP) between these groups prior to angiography. In the group M, diastolic BP decreased more significantly than the other 2 groups during angiography (p < 0.05). Although number of punctures, pain at catheterization site, dose of lidocaine, level of consciousness, and patient satisfaction did not show a significant difference between the three groups; midazolam induced higher level of amnesia than the other 2 groups and the physicians were more satisfied with it only compared with diazepam + promethazine (p < 0.05). CONCLUSION: Because of the importance of hemodynamic stability and comfort during angiography, non-pharmacologic approaches are preferred. In case of severity and persistence of autonomic system stimulation, the least effective dose of midazolam for a short period of time may be used.

Association between Latest Activated Sites in the Left Ventricle and Akinetic Segments in Patients with Ischemic Cardiomyopathy.

Background: It is not clear whether the latest activation sites in the left ventricle (LV) are matched with infracted regions in patients with ischemic cardiomyopathy (ICM). We aimed to investigate whether the latest activation sites in the LV are in agreement with the region of akinesia in patients with ICM. Methods: Data were analyzed in 106 patients (age = 60.5 ± 12.1 y, male = 88.7%) with ICM (ejection fraction ≤ 35%) who were refractory to pharmacological therapy and were referred to the echocardiography department for an evaluation of the feasibility of cardiac resynchronization therapy. Wall motion abnormalities, time to peak systolic myocardial velocity (Ts) of 6 basal and 6 mid-portion segments of the LV, and 4 frequently used dyssynchrony indices were measured using 2-dimensional echocardiography and tissue Doppler imaging (TDI). To evaluate the influence of the electrocardiographic pattern, we categorized the patients into 2 groups: patients with QRS ≤ 120 ms and those with QRS >120 ms. Results: A total of 1 272 segments were studied. The latest activation sites (with longest Ts) were most frequently located in the mid-anterior (n = 32, 30.2%) and basal-anterior segments (n = 29, 27.4%), while the most common sites of akinesia were the mid-anteroseptal (n = 65, 61.3%) and mid-septal (n = 51, 48.1%) segments. Generally, no significant concordance was found between the latest activated segments and akinesia either in all the patients or in the QRS groups. Detailed analysis within the segments indicated a good agreement between akinesia and delayed activation in the basal-lateral segment solely in the patients with QRS duration ≤ 120 ms (Φ = 0.707; p value ≤ 0.001). Conclusion: The akinetic segment on 2-dimensional echocardiogram was not matched with the latest activation sites in the LV determined by TDI in patients with ICM.

Generator and lead-related complications of implantable cardioverter defibrillators.

BACKGROUND: Increase in the number of patients treated with Implantable Cardioverter Defibrillator (ICD) requests more attention regarding its complications. OBJECTIVES: This study aimed to assess the generator- and lead-related complications at implantation and during follow-up in the patients who were treated with ICD for primary and secondary prevention reasons. METHODS: We retrospectively reviewed 255 consecutive patients who underwent transvenous ICD implantation for the first time in a 7-year period and were followed-up for 3 years at Tehran Heart Center. The personal and clinical data of the patients as well as specific data on the ICD implantation were retrieved. The frequency of each of the complications was reported and the study variables were compared between the patients with and without complications using Student's t-test and chi-square test where appropriate. P values less than 0.05 were considered as statistically significant. RESULTS: Out of a total of 525 implanted leads and 255 implanted devices in 255 patients (mean age = 62.57 ± 13.50 years; male = 196 [76.9%]), complications leading to generator or lead replacement occurred in 32 patients (12.5%). The results revealed no significant difference between the patients with and without complications regarding gender and age (P = 0.206 and P = 0.824, respectively). Also, no significant difference was found between the two groups concerning the ejection fraction (P = 0.271). Lead fracture was the most frequent lead-related complication and was observed in 17 patients (6.6%). Besides, it was mainly observed in the RV leads. Generator-related complications leading to generator replacement were observed in 2 patients (0.7%). CONCLUSIONS: Despite considerable improvements in the ICD technology, the rate of the ICD complications leading to device replacement and surgical revision, especially those related to the leads, is still clinically important.

Coronary anatomy characteristics in patients with isolated right bundle branch block versus subjects with normal surface electrocardiogram.

INTRODUCTION AND OBJECTIVE: Isolated right bundle branch block is a common finding in the general population. It may be associated with variations in detailed coronary anatomy characteristics. The aim of this study was to investigate the coronary anatomy in patients with isolated right bundle branch block and to compare that with normal individuals. METHOD: In this case-control study we investigated the coronary anatomy by reviewing angiographic films in two groups of normal coronary artery patients: patients with right bundle branch block (RBBB) (n = 92) and those with normal electrocardiograms (n = 184). RESULTS: There was no significant difference between the two groups in terms of diminutive left anterior descending artery, dominancy, number of obtuse marginal artery, diagonal, acute marginal artery, the position of the first septal versus diagonal branch, presence of ramus artery, and size of left main artery. The number of septal branches was higher in the case group (p-value <0.001). Origination of the atrioventricular node artery from the right circulatory system was more common in both groups but cases showed more tendency to follow this pattern (p-value = 0.021). The frequency of the normal conus branch was higher in the cases versus controls (p-value = 0.009). CONCLUSIONS: Coronary anatomy characteristics are somewhat different in subjects with RBBB compared to normal individuals.

Anatomy of Atrioventricular Node Artery and Pattern of Dominancy in Normal Coronary Subject: A Comparison between Individuals with and without Isolated Right Bundle Branch Block.

BACKGROUND: Isolated right bundle branch block (RBBB) is a common finding in the general population. The atrioventricular node (AVN) artery contributes to the blood supply of the right bundle branch. Our hypothesis was that the anatomy of the AVN artery and the pattern of dominancy differ between subjects with and without RBBB. METHODS: We retrospectively studied the coronary angiography of 92 patients with RBBB and 184 age- and gender-matched controls without RBBB. All the subjects had angiographically proven normal coronary arteries. The dominant circulation and precise origin of the AVN artery were determined in each subject. Obtained data were compared between the two study groups. RESULTS: There was no significant difference between the two groups in terms of dominancy (p value = 0.200). Origination of the AVN artery from the right circulatory system was more common in both groups, but this pattern was more prevalent in the cases than in the controls (p value = 0.021). There was a great variation of the AVN artery origin. In the total study population, the AVN artery was more commonly separated from a non crux origin than from the crux area. The prevalence of the non-crux origination of the AVN artery was significantly higher in the cases than in the controls (p value < 0.001). While the origination of the AVN artery from the right circulatory system was more common in both groups, the prevalence of the right origin of the AVN artery was significantly higher in the cases than in the controls. We observed that the AVN artery most commonly originated from the dominant artery but not necessarily from the crux. CONCLUSION: The anatomy of the AVN artery but not the pattern of dominancy is somewhat different in subjects with RBBB compared with normal individuals.

Glomerular filtration rate is related to severity of obstructive coronary artery disease in patients undergoing coronary angiography.

PURPOSE: Chronic kidney disease is independently associated with an increased risk of cardiovascular events; however, the relationship between the glomerular filtration rate (GFR) and coronary artery disease (CAD) in patients undergoing coronary angiography has yet to be fully elucidated. METHODS: This retrospective study enrolled a total of 7968 patients who underwent diagnostic coronary artery catheterization [mean age = 54.8 ± 10.6 years, 74.4% males] and did not have any previous history of coronary revascularization, diabetes mellitus, hypertension, end-stage renal disease treated by dialysis or renal transplantation, and were not taking diuretics or drugs acting on renin angiotensin system. The severity of CAD was defined as the number of coronary arteries with a luminal stenosis ≥50% on the angiogram, and the GFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). RESULTS: There were 2133 (26.8%) patients with GFR ≥ 90 ml/min/1.73 m(2), 4574 (57.4%) patients with 60 ≤ GFR < 90 ml/min/1.73 m(2), 1073 (13.5%) with 45 ≤ GFR < 60 ml/min/1.73 m(2) and 181 (2.3%) with 15 < GFR < 45 ml/min/1.73 m(2). After adjustment for traditional cardiovascular risk factors (age, sex, dyslipidemia, low to high-density lipoprotein ratio, smoking status, and family history), the GFR showed a significant association with the severity of CAD and remained a significant predictor of CAD (Odds Ratio raised from 1.1 in patients with 60 ≤ GFR < 90 ml/min/1.73 m(2) to 1.8 in patients with 15 < GFR < 45 ml/min/1.73 m(2)). CONCLUSIONS: A reduced kidney function, even mildly, is significantly associated with CAD severity, independently of other traditional CAD risk factors.

Characterization of suitability of coronary venous anatomy for targeting left ventricular lead placement in patients undergoing cardiac resynchronization therapy.

BACKGROUND: Differences in the quantity and distribution of coronary veins between patients with ischemic and nonischemic cardiomyopathy might affect the potential for the left ventricular (LV) lead targeting in patients undergoing cardiac resynchronization therapy (CRT). In the current study, we assessed and compared the suitability of the coronary venous system for the LV lead placement in ischemic and dilated cardiomyopathy. METHODS: This single-centre study, performed at our hospital, retrospectively studied 173 patients with the New York Heart Association class III or IV who underwent CRT. The study population was comprised of 74 patients with an ischemic underlying etiology and 99 patients with a non-ischemic etiology. The distribution of the veins as well as the final lead positions was recorded. RESULTS: There was no significant difference between the two groups in terms of the position of the available suitable vein with the exception of the posterior position, where the ischemic group had slightly more suitable veins than did the dilated group (48.4% versus 32.1%, p value = 0.049). There was also no significant difference with respect to the final vein, through which the LV lead was inserted. Comparative analysis showed that the patients with previous coronary artery bypass grafting surgery (CABG) had significantly fewer suitable veins in the posterolateral position than did the non-CABG group (16.3% versus 38.7%, p value = 0.029). There was, however, no significant difference between the two subgroups regarding the final vein position in which the leads were inserted. CONCLUSION: The final coronary vein position suitable and selected for the LV lead insertion was not different between the cases with cardiomyopathy with different etiologies, and nor was it different between the ischemic cases with and without a history of CABG. Patients with a history of procedures around the coronary vessel may have an intact or recovered venous system and may, therefore, benefit from transvenous LV lead placement for CRT.

Assessment of Left Ventricular Dyssynchrony in Heart Failure Patients Regarding Underlying Etiology and QRS Duration.

BACKGROUND: Left ventricular (LV) dyssynchrony is a prevalent feature in heart failure (HF) patients. The current study aimed to evaluate the prevalence of inter and intraventricular dyssynchrony in HF patients with regard to the QRS duration and etiology. METHODS: The available data on the tissue Doppler imaging (TDI) of 230 patients with refractory HF were analyzed. The patients were divided into three groups according to the QRS duration: QRS duration < 120 ms; 120-150 ms; and ≥ 150 ms and the patients were re-categorized into two subgroups depending on the underlying etiology: ischemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM). The time-to-peak myocardial sustained systolic velocity (Ts) in six basal and six middle segments of the LV was measured manually using the velocity curves from TDI. LV dyssynchrony was defined as interventricular mechanical delay ≥ 40 ms and tissue Doppler velocity all segments delay ≥ 105 ms; standard deviation (SD) of all segments ≥ 34.4 ms; basal segments delay ≥ 78 ms; SD of basal segments ≥ 34.5 ms; and opposing wall delay ≥ 65 ms. RESULTS: After adjustment for the possible confounders, interventricular dyssynchrony was more prevalent in the patients with QRS duration ≥ 150 ms than in those with QRS duration 120-150 ms and < 120 ms. The patients with DCM also had a higher percentage of interventricular dyssynchrony than those with ICM in the wide QRS groups. Turning to the intraventricular dyssynchrony indices, the patients with QRS duration ≥ 150 ms and 120-150 ms revealed a significantly greater delay between Ts at the basal and all segments than did those with QRS duration < 120 ms, while etiology did not influence the frequency of these indices in each QRS group. CONCLUSION: The prevalence of both inter and intraventricular dyssynchrony indices was greater in the patients with wide QRS than in those with narrow QRS duration. The underlying etiology may affect the frequency of interventricular but not intraventricular dyssynchrony indices.

The relationship between level of androgenic hormones and coronary artery disease in men.

BACKGROUND: Previous studies have shown controversial results on the role of androgens in coronary artery disease (CAD). We performed this study to assess the relationship between androgen levels and selective coronary angiography (SCA) findings. METHODS: This study was conducted on 502 consecutive men who underwent SCA with different indications in our centre. Medical history and blood samples were taken from all subjects prior to angiography. Free testosterone (FREET) was measured with enzyme-linked immunosorbent assay, and total testosterone (TES) plus dehydroepiandrosterone sulfate (DHEA) were checked with radio-immunoassay. Total cholesterol, high- and low-density lipoprotein cholesterol (HDL and LDL), triglycerides, lipoprotein (a) [Lp(a)] and C-reactive protein (CRP) were also tested in all patients. Angiographic results were reported by two cardiologists and checked for intra- and inter-observer reliability, then interpreted as Gensini score, and on the basis of the number of segments involved. The relationships were assessed with the chi-square test, independent sample t-test, one-way analysis of variances, Pearson's correlation, and univariate and multivariate logistic regression tests. RESULTS: Eighty-three (16.5%) of the subjects had single-vessel disease, 108 (21.5%) had two-vesssel, 197 (39.2%) had three-vessel disease, and 114 (22.7%) had normal angiograms or minimal lesions. FREET, TES and DHEA in patients with significant CAD vs normal individuals were 6.69 +/- 3.20 pg/ml, 16.60 +/- 6.66 nm/l and 113.38 +/- 72.9 microg/dl vs 7.12 +/- 3.58 pg/ml, 15.82 +/- 7.26 nm/l and 109.03 +/- 68.19 microg/ dl, respectively (p > 0.1). There was no correlation between the Gensini score or the number of involved segments and androgen levels. Triglyceride, total cholesterol, LDL and HDL cholesterol levels also had no correlation with androgenic hormones. However, FREET showed a negative correlation with Lp(a) and CRP (p = 0.01, r = -0.12; p = 0.03, r = -0.096, respectively). Moreover, the level of DHEA was lower in diabetics (94.5 +/- 59.19 microg/dl vs 117.97 +/- 74.54 microg/dl, p = 0.004). CONCLUSIONS: There was no significant correlation between FREET, TES, DHEA and the presence or severity of CAD. Also, no correlation was found between androgen levels and triglyceride, total cholesterol, LDL and HDL cholesterol levels.