Sex differences in prevalence of electrocardiographic and echocardiographic left ventricular hypertrophy among patients with coronary artery disease

Background

Both electrocardiographic left ventricular hypertrophy (ECG-LVH) and echocardiographic LVH (echo-LVH) are associated with higher risk of cardiovascular and sudden cardiac death. ECG-LVH seems to be partly distinct from echo-LVH as many subjects with echo-LVH do not have ECG-LVH and vice versa. The difference between sexes have not been studied earlier.

Purpose

The aim of this study was to determine sex differences in prevalence of ECG-LVH and echo-LVH among patients with coronary artery disease (CAD) and to study if ECG-LVH would have higher accuracy for echo-LVH in either of sexes.

Methods

Standard 12-lead electrocardiograms and echocardiographic measurements were studied from 1,894 subjects of ARTEMIS Study (31.8% women). Echo-LVH was determined as estimated left ventricular (LV) mass ≥201 g in men and ≥151 g in women and was categorized as mildly, moderately and severely abnormal. ECG-LVH was determined if either criteria of Sokolow-Lyon or Cornell were met.

Results

Echo-LVH was found from 1,162 of the study subjects (women 34.3%, p=0.004) and ECG-LVH only from 222 of the subjects (women 55.9%, p<0.001). Of those with ECG-LVH, 82.0% had increased LV mass (p<0.001), and ECG-LVH seemed to correlate slightly better to echo-LVH in women than in men (82.3% vs. 81.6%, p<0.001). Of those with ECG-LVH, 47.7% had severe echo-LVH (p<0.001). The prevalence of ECG-LVH was the higher the greater the LV mass was. Among men with ECG-LVH, 46.9% had severe echo-LVH (p<0.001). Among women with ECG-LVH, 16.1% had mild echo-LVH (p=0.029) and 48.4% severe echo-LVH (p<0.001). In addition, 18% of those with ECG-LVH did not have echo-LVH (p<0.001). This proportion was slightly smaller in women than in men (17.7% vs. 18.4%, p<0.001).

Only 15.7% of the subjects with echo-LVH had ECG-LVH (p<0.001). This proportion was significantly higher in women than in men (25.6% vs. 10.5%, p<0.001). ECG-LVH was more common finding in subjects with severe echo-LVH as 20.9% of those CAD patients had ECG-LVH (p<0.001). Among women with severe echo-LVH, ECG-LVH was found in 35.3% (p<0.001) whereas only in 13.7% of men with severe echo-LVH (p<0.001). The prevalence of ECG-LVH seemed to be considerably higher among female CAD patients with T2DM and without prior MI as ECG-LVH was seen in 33.0% of those subjects with at least midl echo-LVH (p<0.001) and 43.8% of those subjects with severe echo-LVH (p<0.001). In male patients from similar subgroup and some degree of echo-LVH, ECG-LVH was seen in 6.7% (p=0.042) and with severe echo-LVH in 12.2% (p<0.001) of the subjects.

Conclusions

In patients with CAD echo-LVH was often seen without signs of ECG-LVH, especially in men. Majority of the CAD patients with ECG-LVH had also echo-LVH and the prevalence on ECG-LVH was the higher the greater the LV mass was. ECG-LVH seemed to correlate better to anatomic LVH in women with CAD than in men, and the sex difference was highlighted in CAD patients with T2DM and no prior MI.

Funding Acknowledgement

Type of funding sources: None.

P481The genetic background of sudden cardiac deaths caused by single vessel coronary artery disease and myocardial hypertrophy with fibrosis

Funding Acknowledgements

Sigrid Juselius Foundation, Finnish Foundation for Cardiovascular Research, Aarne Koskelo Foundation, The Finnish Medical Foundation

Background

Coronary artery disease (CAD) is the most common underlying cause of sudden cardiac death (SCD). Cardiac hypertrophy with varying amount of myocardial fibrosis is a common risk factor for CAD related SCD especially in young SCD victims where severity of CAD seems not to entirely explain the cause of SCD.

Purpose

The aim was to study the genetic background of hypertrophy and fibrosis among young, ischemic SCD victims with single vessel CAD.

Methods

The study population was derived from the Fingesture study consisting of all autopsy-verified sudden cardiac deaths in Northern Finland between years 1998-2017 (n = 5,869). CAD was determined to be the cause of SCD in 4,392 victims (74.8%). We carried out targeted next-generation sequencing using a panel of 174 genes associated with myocardial structure and ion channel function in 95 ischemic-SCD victims (mean [standard error] age, 63.6 [1.06] years; 88.4% males) with single-vessel CAD and cardiac hypertrophy in the absence of previously diagnosed CAD, and whose DNA passed the quality control for further analysis. Assessment for pathogenicity of detected variants was based on American College of Medical Genetics consensus guidelines.

Results

A total of 43 variants were detected in 43 of the study subjects (45.3 %). Five variants in eight subjects (8.4%) were classified as pathogenic or likely pathogenic. We observed 38 variants of uncertain significance in 39 victims (40.6 %). Variants were detected in myocardial structure protein coding genes, associated with arrhythmogenic right ventricular cardiomyopathy (13 variants), dilated cardiomyopathy (16 variants), hypertrophic cardiomyopathy (6 variants) and left ventricular non-compaction cardiomyopathy (3 variants). Five variants were detected in RYR2 associated with both cardiomyopathies and catecholaminergic polymorphic ventricular tachycardias. Seven variants were detected in multiple unrelated subjects. None of the subjects presented characteristic autopsy findings related to cardiomyopathies.

Conclusions

Variants associated with cardiomyopathies were common findings among CAD related SCD victims with single vessel disease and myocardial hypertrophy found at autopsies, suggesting that these variants may modulate the risk for fatal arrhythmias and sudden death in ischemic disease.

P4168Ischemic sudden cardiac deaths among victims under 50 years - Characteristics and autopsy findings

Background

Sudden cardiac death (SCD) is one of the most prevalent cause of death in Western countries representing nearly 20% of total mortality. About 70–80% of SCDs are due to coronary artery disease (CAD). Especially among young victims, whose first cardiac event is often SCD, decent risk prediction and prevention strategies are sadly lacking.

Purpose

The aim of this study was to determine the characteristics and autopsy findings of ischemic sudden cardiac deaths among young victims under the age of 50 years.

Methods

The study population is derived from Fingesture study, consisting of prospectively collected consecutive victims of SCD in Northern Finland among whom post-mortem examinations were performed between years 1998–2017 (n=5,869). According to Finnish law, all unexpected deaths undergo medico-legal autopsy. All post-mortem examinations included histological examinations, as well as a toxicology investigation was carried out if needed. Information about the victims was collected from autopsy data, death certificates, medical records, standardized questionnaire to the closest family members of the victims and police reports about the conditions of the death. 10% off all SCDs occurred among victims aged under 50 years (607 victims).

Results

CAD was the most common underlying cause of SCD among young victims (265 victims, 44%), followed by obesity related (102 victims, 17%) and alcoholic cardiomyopathy (67 victims, 11%). The mean age of ischemic SCD victims was 44±4 years and they were mostly men (89%). 90% of victims had no history of CAD prior to death and 34% of these had a myocardial scar at autopsy indicating previously unrecognized MI. 26% of SCDs occurred during physical activity. Hypertrophied hearts (59%) and myocardial fibrosis (83%) were common findings among young ischemic SCD victims. 27% of victims had a history of heavy drinking and alcohol was found in toxicology investigations in 35% of victims. At least one cardiovascular risk factor (diabetes mellitus, hypertension, dyslipidemia, obesity) was present in 51% of cases.

Conclusions

CAD was the most common cause of SCD among victims under 50 years. Most ischemic SCDs among young occurred without previously diagnosed CAD, and yet severe findings were seen at autopsy.

Acknowledgement/Funding

Sigrid Juselius Foundation, Finnish Foundation for Cardiovascular Research, Aarne Koskelo Foundation

P5647Temporal variability of T-wave morphology and risk of sudden cardiac death in patients with coronary artery disease

Background

The possible relationship between temporal variability of electrocardiographic spatial heterogeneity of repolarisation and the risk of sudden cardiac death (SCD) in patients with coronary artery disease (CAD) is not completely understood.

Purpose

To investigate the prognostic value of temporal variability of T-wave spatial heterogeneity in SCD in patients with CAD.

Methods

The Innovation to reduce Cardiovascular Complications of Diabetes at the Intersection (ARTEMIS) study population consisted of 1,946 patients with angiographically verified CAD. T-wave morphology dispersion (TMD), which estimates the average angle between all reconstruction vector pairs in T-wave loop based on leads I-II and V2-V6, was analysed on beat-to-beat basis from 10 minutes period of the baseline electrocardiographic recording in 1,678 study subjects. The temporal variability of TMD was evaluated by standard deviation of TMD (TMD-SD).

Results

After on average of 7.4±2.0 years of follow-up, a total of 47 of the 1,678 study subjects (2.8%) had experienced SCD or were resuscitated from sudden cardiac arrest (SCA). TMD-SD was significantly higher in patients who had experienced SCD/SCA compared with those who remained alive (3.64±2.57 vs. 2.65±2.54, p<0.01, respectively), but did not differ significantly between the patients who had experienced non-sudden cardiac death (n=40, 2.4%) and those who remained alive (2.98±2.43 vs. 2.67±2.55, p=0.45, respectively) or between the patients who succumbed to non-cardiac death (n=88, 5,2%) and those who stayed alive (2.74±2.44 vs. 2.67±2.55, p=0.81). After adjustments with relevant clinical risk indicators of SCD/SCA, such as left ventricular ejection fraction, diabetes, left bundle branch block and Canadian Cardiac Society class, TMD-SD still predicted SCD/SCA (HR 1.113, 95% CIs 1.028–1.206, p<0.01). The discrimination and reclassification accuracy increased significantly (p=0.02, p=0.033) and the C-index increased from 0.733 to 0.741 when TMD-SD was added to the clinical risk model of SCD/SCA. The Kaplan-Meier survival curves show proportional probabilities of event-free survival for different modes of death for patients classified according to the optimised TMD-SD cut-off point (Figure).

Figure 1

Conclusions

Temporal variability of electrocardiographic spatial heterogeneity of repolarisation represented by TMD-SD independently predicts long-term risk of SCD/SCA in patients with CAD.

Acknowledgement/Funding

Sigrid Juselius Foundation and Finnish Foundation for Cardiovascular Research

Risk factors and the effect of cardiac resynchronization therapy on cardiac and non-cardiac mortality in MADIT-CRT

AIMS

To understand modes of death and factors associated with the risk for cardiac and non-cardiac deaths in patients with cardiac resynchronization therapy with implantable cardioverter-defibrillator (CRT-D) vs. implantable cardioverter-defibrillator (ICD) therapy, which may help clarify the action and limitations of cardiac resynchronization therapy (CRT) in relieving myocardial dysfunction.

METHODS AND RESULTS

In Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT), during 4 years of follow-up, 169 (9.3%) of 1820 patients died of known causes, 108 (63.9%) deemed cardiac, and 61 (36.1%) non-cardiac. In multivariate analysis, increased baseline creatinine was significantly associated with both cardiac and non-cardiac deaths [hazard ratio (HR) 2.97, P < 0.001; HR 1.80, P = 0.035, respectively], as was diabetes (HR 1.79, P = 0.006; HR 1.73, P = 0.038, respectively), and the worst New York Heart Association Class > II more than 3 months prior to enrolment (HR 1.90, P = 0.012; HR 2.46, P = 0.010, respectively). Baseline left atrial volume index was significantly associated only with cardiac mortality (HR 1.28 per 5 unit increase, P < 0.001). Ischaemic cardiomyopathy was associated only with non-cardiac death (HR 3.54, P = 0.001). CRT-D vs. an ICD-only was associated with a reduced risk for cardiac death in patients with left bundle branch block (LBBB) (HR 0.56, P = 0.029) but was associated with an increased risk for non-cardiac death in non-LBBB patients (HR 3.48, P = 0.048).

CONCLUSIONS

In MADIT-CRT, two-thirds of the deaths were cardiac and one-third non-cardiac. Many of the same risk factors were associated with both cardiac and non-cardiac mortalities. CRT-D was associated with a reduced risk for cardiac death in LBBB but an increased risk for non-cardiac death in non-LBBB.

CLINICAL TRIAL REGISTRATION

Information for the MADIT-CRT main study http://www.clinicaltrials.gov, NCT00180271.

Differences in 12-lead electrocardiogram between symptomatic and asymptomatic Brugada syndrome patients

INTRODUCTION

Brugada syndrome (BrS) is an inherited disorder that predisposes some subjects to sudden cardiac death (SCD). It is not well established which BrS patients are at risk of severe arrhythmias. Our aim was to study whether standard 12-lead electrocardiogram (ECG) would give useful information for this purpose.

METHODS

This study included 200 BrS probands (142 male, 62%; mean age 42 +/- 16 years). Symptoms related to BrS were defined as syncope, documented ventricular tachyarrhythmia, or SCD. We determined PR, QRS, QTc, T(peak), and T(end) interval from leads II and V(2) and QRS from lead V(5), R'/S ratio from lead aVR (aVR sign), QRS axis, and J-point elevation amplitude from right precordial leads from the baseline ECGs.

RESULTS

Sixty-six subjects (33%) had experienced symptoms related to BrS. The only significant difference between the symptomatic and asymptomatic BrS subjects was the QRS duration measured from lead II or lead V(2), for example, the mean QRS in V(2) was 115 +/- 26 ms in symptomatic versus 104 +/- 19 ms in asymptomatic patients (P < 0.001). The optimized cut-off point of V(2) QRS > or =120 ms gave an odds ratio (OR) of 2.5 (95% CI: 1.4-4.6, P = 0.003) for being symptomatic. In a multivariate analysis adjusted with gender, age, and SCN5A mutation, the OR was 2.6 (95% CI: 1.4-4.8, P = 0.004).

CONCLUSION

Prolonged QRS duration, measured from standard 12-lead ECG, is associated with symptoms and could serve as a simple noninvasive risk marker of vulnerability to life-threatening ventricular arrhythmias in BrS.

Influence of atropine on fractal and complexity measures of heart rate variability

BACKGROUND

Measurement of short-term fractal-like correlation properties of heart rate dynamics has been shown to be a useful prognostic indicator of adverse events in cardiac patients. Complexity measurements of heart rate variability (HRV) have already provided important information in many cardiac conditions. However, data on the physiological background of these newer nonlinear measures of HRV are limited.

METHODS

Nine healthy subjects (aged from 22 to 35 years, 6 males, 3 females) had an electrocardiographic (ECG) recording during controlled breathing in supine position. HRV was analyzed for 5 min periods before and after intravenous injection of 0.6 mg of atropine using conventional HRV measures and newer nonlinear HRV measures including the short-term scaling exponent (alpha(1)) and approximate entropy (ApEn).

RESULTS

The short-term scaling exponent alpha(1) increased significantly after atropine injection (1.01 +/- 0.23 vs 1.43 +/- 0.19, P = 0.001). There was no significant difference between ApEn values before and after atropine injection (0.87 +/- 0.17 vs 0.70 +/- 0.31, respectively, P = 0.27). At baseline before atropine administration, alpha(1) had a significant negative correlation with SDNN, RMSSD, and HF (r = -0.70, -0.76, -0.67, respectively, P < 0.05 for all), and a significant positive correlation with heart rate (r = 0.76, P < 0.05). After atropine injection, alpha(1) did not have significant correlation with any of the HRV parameters or heart rate. There were no significant correlations between ApEn and any of the HRV measures or heart rate either before or after atropine administration.

CONCLUSIONS

Vagal tone has an important influence on the values of the short-term scaling exponent alpha(1). However, vagal modulation is not a major determinant of the values of ApEn.

Temporal complexity of repolarization and mortality in patients with implantable cardioverter defibrillators

Increased repolarization variability has been observed in various cardiac conditions. However, data on its relation to heart rate variability and on its value in predicting adverse outcomes in high risk patients are limited. Forty-seven patients with decreased left ventricular function and ICDs had high resolution 10-minute ECG recordings and were followed for 781 +/- 258 days (mean +/- SD) on average. The interval from the R peak to the T wave peak with maximum amplitude (RTmax) and from the R peak to the T wave offset (RToff) were determined automatically on a beat-to-beat basis. Temporal beat-to-beat RTmax and RToff variability were analyzed using traditional summary statistics, a complexity measure (approximate entropy [ApEn]), and the short-term scaling exponent (alpha1). Eight (17%) patients died and 16 (34%) patients experienced death/appropriate ICD shock during follow-up. RTmax-ApEn was significantly higher in patients who died compared with patients who survived (1.24 +/- 0.13 vs 1.01 +/- 0.21, respectively, P=0.008). When RTmax-ApEn was tested together with the alpha1 of the RR intervals, occurrence of ventricular arrhythmias before ICD implantation, and beta-blockers usage in the Cox regression analysis, it still independently predicted mortality; hazard ratio=3.36 (1.28-8.83, 95% CI, P=0.014) for every 0.10-increase in RTmax-ApEn. None of the repolarization variability parameters independently predicted death/appropriate ICD shocks. Increased temporal complexity of repolarization (RTmax-ApEn) independently predicts mortality in ICD patients.

Usefulness of standard electrocardiographic parameters for predicting cardiac events after acute myocardial infarction during modern treatment era

Comprehensive information about the independent value of different electrocardiographic (ECG) variables in predicting cardiac events after acute myocardial infarction (AMI) in the era of modern therapy is limited. Patients (n = 1,034) underwent standard electrocardiography from 5 to 7 days after an AMI. Several time intervals and PQRST abnormalities were analyzed from the electrocardiogram. During a mean +/- SD follow-up of 752 +/- 301 days on average, 42 patients (4%) experienced cardiac death, and 259 patients (25%) a cardiac death, nonfatal AMI, or unstable angina. Several ECG variables had a significant association with cardiac events in univariate comparisons. After adjustment for all risk variables in the Cox hazards model, lateral ST-segment depression (hazard ratio [HR] 4.76, 95% confidence interval [CI] 2.40 to 9.44, p <0.0001) and atrial abnormality with a terminal deflection of the P wave > or =0.1 mV deep and > or =40 ms in duration in lead V(1) (HR 2.46, 95% CI 1.25 to 4.82, p = 0.009) were the only ECG variables that independently predicted cardiac death. Lateral ST-segment depression also predicted the combined end point of cardiac death/nonfatal AMI/unstable angina in this model (HR 1.49, 95% CI 1.14 to 1.94, p = 0.003). In conclusion, lateral ST depression and atrial abnormality on the electrocardiogram are independent predictors of cardiac death after AMI. Lateral ST depression is also associated with ischemic cardiac events.