Diagnosing Paroxysmal Atrial Fibrillation in Patients With Ischemic Strokes and Transient Ischemic Attacks Using Echocardiographic Measurements of Left Atrium Function

Twenty-five to 35 percentage of stroke cases are cryptogenic, and it has been demonstrated that paroxysmal atrial fibrillation (AF) is the causal agent in up to 25% of these incidents. The purpose of this study was to investigate if left atrial (LA) parameters have value for diagnosing paroxysmal AF in patients with ischemic stroke (IS) and transient ischemic attack (TIA). We retrospectively analyzed 219 patients who after acute IS or TIA underwent a transthoracic echocardiographic examination. Patients were designated as patients with paroxysmal AF if they had one or more reported incidents of AF before or after their echocardiographic examination. Patients in the paroxysmal AF group were significantly older and had higher CHA2DS2-VASc score than patients without paroxysmal AF (p <0.05 for both). None of the conventional echocardiographic parameters were significantly associated with paroxysmal AF. However, the atrial measurements evaluating LA function (min LA volume and LA emptying fraction) were significantly different (LA emptying fraction: 45% ± 10% vs 50% ± 10%, p = 0.004; minimal LA volume: 30.2 ml ± 17.3 ml vs 24 ml ± 10 ml, p = 0.035 in patients with paroxysmal AF, even after adjustment for age, gender, CHA2DS2-VASc score, and stroke severity [p <0.05 for both]). By combining the cut-off values of age, LA emptying fraction, and minimal LA volume the diagnostic accuracy of paroxysmal AF was improved, resulting in a sensitivity of 95% and negative predictive value of 97%. In conclusion, in patients with IS and TIA, LA function measurements (minimal LA volume and LA emptying fraction) are independently associated with paroxysmal AF and may improve risk stratification for paroxysmal AF presence after IS or TIA.

Global Longitudinal Strain Is a Superior Predictor of All-Cause Mortality in Heart Failure With Reduced Ejection Fraction

OBJECTIVES

The purpose of this study was to investigate the prognostic value of global longitudinal strain (GLS) in heart failure with reduced ejection fraction (HFrEF) patients in relation to all-cause mortality.

BACKGROUND

Measurement of myocardial deformation by 2-dimensional speckle tracking echocardiography, specifically GLS, may be superior to conventional echocardiographic parameters, including left ventricular ejection fraction, in predicting all-cause mortality in HFrEF patients.

METHODS

Transthoracic echocardiographic examinations were retrieved for 1,065 HFrEF patients admitted to a heart failure clinic. The echocardiographic images were analyzed, and conventional and novel echocardiographic parameters were obtained.

RESULTS

Many of the conventional echocardiographic parameters proved to be predictors of mortality. However, GLS remained an independent predictor of mortality in the multivariable model after adjusting for age, sex, body mass index, total cholesterol, mean arterial pressure, heart rate, ischemic cardiomyopathy, percutaneous transluminal coronary angioplasty, coronary artery bypass graft surgery, noninsulin dependent diabetes mellitus, and conventional echocardiographic parameters (hazard ratio [HR]: 1.15; 95% confidence interval [CI]: 1.04 to 1.27; p = 0.008, per 1% decrease). No other echocardiographic parameter remained an independent predictor after adjusting for these variables. Furthermore, GLS had the highest C-statistics of all the echocardiographic parameters and added incremental prognostic value with a significant increase in the net reclassification improvement (p = 0.009). Atrial fibrillation (AF) modified the relationship between GLS and mortality (p value for interaction = 0.036); HR: 1.08 (95% CI: 0.97 to 1.19), p = 0.150 and HR: 1.22 (95% CI: 1.15 to 1.29), p < 0.001, per 1% decrease in GLS for patients with and without AF, respectively. Sex also modified the relationship between GLS and mortality (p value for interaction = 0.047); HR: 1.23 (95% CI: 1.16 to 1.30), p < 0.001 and HR: 1.09 (95% CI: 0.99 to 1.20), p = 0.083, per 1% decrease in GLS for men and women, respectively.

CONCLUSIONS

GLS is an independent predictor of all-cause mortality in HFrEF patients, especially in male patients without AF. Furthermore, GLS was a superior prognosticator compared with all other echocardiographic parameters.

Predicting Paroxysmal Atrial Fibrillation in Cerebrovascular Ischemia Using Tissue Doppler Imaging and Speckle Tracking Echocardiography

BACKGROUND

Often the underlying cause of cerebral ischemia (CI) cannot be found during a routine diagnostic investigation, but paroxysmal atrial fibrillation (PAF) could be the culprit.

AIM

The objective of the study is to investigate whether advanced echocardiography improves the diagnostic approach for PAF in CI.

METHODS

The study included 286 CI patients with an echocardiogram in sinus rhythm. Patients were divided by PAF occurrence (PAF: n = 86, non-PAF: n = 200). PAF was defined as 1 or more reported episodes of atrial fibrillation. Echocardiograms consisted of conventional measures, tissue Doppler imaging (TDI), and speckle tracking. TDI was performed to acquire myocardial peak velocities during systole/ventricular contraction (global s'), early diastole/ventricular filling (global e'), and late diastole/atrial contraction (global a'). Speckle tracking was performed for myocardial strain analysis, thereby retrieving global longitudinal strain and global strain rate (s, e, a) values.

RESULTS

Patients with PAF exhibited significantly impaired atrial contractile measures: global a' (-7.0 cm/second versus -5.7 cm/second, P < .001) and global strain rate a (.97 second(-1) versus .81 second(-1), P < .001). Both were univariable markers of PAF, and along with age remained the only independent significant determinants of PAF after multivariable logistic regression. Area under the curve (AUC) for age, global a', and global strain rate a significantly exceeded AUC for age alone (.79 versus .76, P = .032). Cutoff values with the highest sensitivity and specificity for these 3 parameters improved the diagnostic accuracy (sensitivity = 97%, specificity = 32%, negative predictive value = 95%, and positive predictive value = 38%).

CONCLUSIONS

Atrial contractile measures by advanced echocardiography are significant determinants of PAF in CI. However, there is no discriminatory power to make them clinically useful at the current moment.

Tissue Doppler echocardiography predicts acute myocardial infarction, heart failure, and cardiovascular death in the general population

AIMS

To improve risk prediction of cardiovascular morbidity and mortality, we need sensitive markers of cardiac dysfunction; Echocardiographic Tissue Doppler Imaging (TDI) is feasible and harmless and may be ideal for this purpose.

METHODS AND RESULTS

Within the community-based Copenhagen City Heart Study, 2064 participants were examined by echocardiography including TDI and followed (median 10.9 years) with regard to cardiovascular death, heart failure, or acute myocardial infarction (n = 277). Impaired systolic (s') and diastolic (e' and a') function according to age and sex as assessed by TDI was associated with increased risk of the combined end point, even in the subgroup of persons with a normal conventional echocardiographic examination [per 1 cm/s decrease: s': HR 1.32 (1.12-1.57), P < 0.001; e': HR 1.17(1.04-1.31), P < 0.01; a': HR 1.17 (1.06-1.30), P < 0.005]. Interestingly, reduced early diastolic myocardial velocity (e') was associated with risk of acute myocardial infarction, whereas reduced systolic (s') or late diastolic function (a') was associated with heart failure and cardiovascular death independently of traditional risk factors, plasma proBNP, and conventional echocardiographic measures. Combining information on early and late diastolic function by TDI provided incremental prognostic information and improved risk classification (net reclassification improvement: 27%; P < 0.001) and remained a significant predictor of the combined end point even in the subgroup with a normal conventional echocardiographic examination [per cm/s decrease: HR 1.18 (1.08-1.28), P < 0.001].

CONCLUSION

In the general population, TDI identifies individuals with cardiac dysfunction and high risk of cardiovascular morbidity and mortality independently of traditional risk factors, even in persons with a normal conventional echocardiographic examination.

Diagnostic accuracy of pace spikes in the electrocardiogram to diagnose paced rhythm

OBJECTIVE

To determine how often cardiac resynchronization therapy (CRT) pacing systems generate visible pace spikes in the electrocardiogram (ECG).

METHODS

In 46 patients treated with CRT pacing systems, we recorded ECGs during intrinsic rhythm, atrial pacing and ventricular pacing. ECGs were analysed for atrial and ventricular pace spikes by two experienced ECG readers blinded to the pacing therapy and to the study purpose.

RESULTS

Atrial pacing generated visible pace spikes in less than 70% of the ECGs, whereas ventricular pacing generated visible pace spikes in about 90% of ECGs. The sensitivity of manual ECG interpretation for pace spikes was low for atrial pacing (Reader 1: 0.62 [95% confidence interval (CI) 0.50-0.74]; Reader 2: 0.65 [95% CI 0.53-0.77]) and moderate for ventricular pacing (Reader 1: 0.88 [95% CI 0.81-0.93]; Reader 2: 0.93 [95% CI 0.87-0.97]).

CONCLUSIONS

In patients with CRT pacing systems, the absence of visible pace spikes in the ECG does not rule out paced rhythm.

Prognostic value of cardiac time intervals measured by tissue Doppler imaging M-mode in the general population

OBJECTIVE

Tissue Doppler imaging (TDI) M-mode through the mitral leaflet is an easy and precise method to estimate the cardiac time intervals. The aim was to evaluate the usability of the cardiac time intervals in predicting major cardiovascular events (MACE) in the general population.

METHODS

In a large prospective community-based study, cardiac function was evaluated in 1915 participants by both conventional echocardiography and TDI. The cardiac time intervals, including the isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT) and ejection time (ET), were obtained by TDI M-mode through the mitral leaflet. IVCT/ET, IVRT/ET and the myocardial performance index (MPI=(IVRT+IVCT)/ET) were calculated.

RESULTS

During follow-up (median 10.8 years), 383 (20%) participants reached the combined endpoint MACE (ischaemic heart disease, heart failure or cardiac death). After multivariable adjustment for clinical predictors and conventional echocardiography, only the combined indexes, including information on both systolic and diastolic performance (IVRT/ET and MPI), remained significant prognosticators (p<0.05 for both). Adding IVRT/ET or MPI to a model already including all other echocardiographic parameters resulted in a significant increase in the c-statistics (0.76 vs 0.75 p<0.01 for both). IVRT/ET or MPI improved reclassification significantly when added to the clinical predictors (p<0.05 for both).

CONCLUSIONS

In the general population, the combined cardiac time intervals that include information on both systolic and diastolic function in one index (IVRT/ET and MPI) are not only powerful and independent predictors of future MACE, but provide additional prognostic information to clinical and conventional echocardiographic measures of systolic and diastolic function.

Prevalence of systolic and diastolic dysfunction in patients with type 1 diabetes without known heart disease: the Thousand & 1 Study

AIMS/HYPOTHESIS

Heart failure is one of the leading causes of mortality in type 1 diabetes. Early identification is vitally important. We sought to determine the prevalence and clinical characteristics associated with subclinical impaired systolic and diastolic function in type 1 diabetes patients without known heart disease.

METHODS

In this cross-sectional examination of 1,093 type 1 diabetes patients without known heart disease, randomly selected from the Steno Diabetes Center, complete clinical and echocardiographic examinations were performed and analysed in uni- and multivariable regression models.

RESULTS

The mean (SD) age was 49.6 (15) years, 53% of participants were men, and the mean duration of diabetes was 25.5 (15) years. Overall, 15.5% (n = 169) of participants had grossly abnormal systolic or diastolic function, including 1.7% with left ventricular ejection fraction (LVEF) < 45% and 14.4% with evidence of long-standing diastolic dysfunction. In univariable models, clinical characteristics associated with abnormal myocardial function were: age (per 10 years), OR (95% CI) 2.1 (1.8, 2.4); diabetes duration (per 10 years), 1.7 (1.4, 1.9); systolic BP ≥ 140 mmHg, 2.7 (1.9, 3.8); diastolic BP ≥ 90 mmHg, 1.8 (1.0, 3.1); estimated (e)GFR < 60 ml min(-1) 1.73 m(-2), 3.8 (2.5, 5.9); microalbuminuria, 2.0 (1.3, 3.0); macroalbuminuria, 5.9 (3.8, 9.3); proliferative retinopathy, 3.6 (2.3, 5.8); blindness, 10.1 (3.2, 31.6); and peripheral neuropathy, 3.8 (2.7, 5.3). In multivariable models only age (2.1 [1.7, 2.5]), female sex, (1.9 [1.2, 2.8]) and macroalbuminuria (5.2 [2.9, 10.3]) remained significantly associated with subclinical grossly abnormal myocardial function.

CONCLUSIONS/INTERPRETATION

Subclinical myocardial dysfunction is a common finding in type 1 diabetes patients without known heart disease. Type 1 diabetes patients with albuminuria are at greatly increased risk of having subclinical abnormal myocardial function compared with patients without albuminuria. Echocardiography may be particularly warranted in patients with albuminuria.

Cardiac arrhythmias the first month after acute traumatic spinal cord injury

OBJECTIVE

Cardiovascular complications including cardiac arrest and arrhythmias remain a clinical challenge in the management of acute traumatic spinal cord injury (SCI). Still, there is a lack of knowledge regarding the characteristics of arrhythmias in patients with acute traumatic SCI. The aim of this prospective observational study was to investigate the occurrence of cardiac arrhythmias and cardiac arrests in patients with acute traumatic SCI.

METHODS

As early as possible after SCI 24-hour Holter monitoring was performed. Additional Holter recordings were performed 1, 2, 3, and 4 weeks after SCI. Furthermore, 12-lead electrocardiograms (ECGs) were obtained shortly after SCI and at 4 weeks.

RESULTS

Thirty patients were included. Bradycardia (heart rate (HR) <50 b.p.m.) was present in 17-35% of the patients with cervical (C1-C8) SCI (n = 24) within the first 14 days. In the following 14 days, the occurrence was 22-32%. Bradycardia in the thoracic (Th1-Th12) SCI group (n = 6) was present in 17-33% during the observation period. The differences between the two groups were not statistically significant. The mean minimum HR was significantly lower in the cervical group compared with the thoracic group both on 12-lead ECGs obtained shortly after SCI (P = 0.030) and at 4 weeks (P = 0.041).

CONCLUSION

Many patients with cervical SCI experience arrhythmias such as bradycardia, sinus node arrest, supraventricular tachycardia, and more rarely cardiac arrest the first month after SCI. Apart from sinus node arrests and limited bradycardia, no arrhythmias were seen in patients with thoracic SCI. Standard 12-lead ECGs will often miss the high prevalence these arrhythmias have.

Myocardial Strain Analysis by 2-Dimensional Speckle Tracking Echocardiography Improves Diagnostics of Coronary Artery Stenosis in Stable Angina Pectoris

Background—

Two-dimensional strain echocardiography detects early signs of left ventricular dysfunction; however, it is unknown whether myocardial strain analysis at rest in patients with suspected stable angina pectoris predicts the presence of coronary artery disease (CAD).

Methods and Results—

In total, 296 consecutive patients with clinically suspected stable angina pectoris, no previous cardiac history, and normal left ventricular ejection fraction were included. All patients were examined by 2-dimensional strain echocardiography, exercise ECG, and coronary angiography. Two-dimensional strain echocardiography was performed in the 3 apical projections. Peak regional longitudinal systolic strain was measured in 18 myocardial sites and averaged to provide global longitudinal peak systolic strain. Duke score, including ST-segment depression, chest pain, and exercise capacity, was used as the outcome of the exercise test. Patients with an area stenosis ≥70% in ≥1 epicardial coronary artery were categorized as having significant CAD (n=107). Global longitudinal peak systolic strain was significantly lower in patients with CAD compared with patients without (17.1±2.5% versus 18.8±2.6%; P <0.001) and remained an independent predictor of CAD after multivariable adjustment for baseline data, exercise test, and conventional echocardiography (odds ratio, 1.25 [ P =0.016] per 1% decrease). Area under receiver operating characteristic curve for exercise test and global longitudinal peak systolic strain in combination was significantly higher than that for exercise test alone (0.84 versus 0.78; P =0.007). Furthermore, impaired regional longitudinal systolic strain identifies which coronary artery is stenotic.

Conclusions—

In patients with suspected stable angina pectoris, global longitudinal peak systolic strain assessed at rest is an independent predictor of significant CAD and significantly improves the diagnostic performance of exercise test. Furthermore, 2-dimensional strain echocardiography seems capable of identifying high-risk patients.

Cardiac arrhythmias associated with spinal cord injury

CONTEXT/OBJECTIVES

To review the current literature to reveal the incidence of cardiac arrhythmias and its relation to spinal cord injury (SCI).

DATA SOURCE

MEDLINE database, 304 hits, and 32 articles were found to be relevant. The relevant articles all met the inclusion criteria: (1) contained original data (2) on cardiac arrhythmias (3) in humans with (4) traumatic SCI.

RESULTS

In the acute phase of SCI (1-14 days after injury) more cranial as well as more severe injuries seemed to increase the incidence of bradycardia. Articles not covering the first 14 days after injury, thus describing the chronic phase of SCI, showed that individuals with SCI did not have a higher incidence of cardiac arrhythmias compared with able-bodied controls. Furthermore, their heart rate did not differ significantly. Penile vibro-stimulation was the procedure investigated most likely to cause bradycardia, which in turn was associated with episodes of autonomic dysreflexia. The incidence of bradycardia was found to be 17-77% for individuals with cervical SCI. For individuals with thoracolumbar SCI, the incidence was 0-13%.

CONCLUSION

Bradycardia was commonly seen in the acute stage after SCI as well as during procedures such as penile vibro-stimulation and tracheal suction. These episodes of bradycardia were seen more often in individuals with cervical injuries. Longitudinal studies with continuous electrocardiogram recordings are needed to uncover the true relation between cardiac arrhythmias and SCI.

Abstract 209: Final Results of the Surprise Study:Long-term Monitoring For Atrial Fibrillation (AF) in Cryptogenic Stroke

Background The true frequency of AF in patients with cryptogenic stroke or TIA is not well defined. The aim was to estimate the frequency and burden of AF in patients with apparent cryptogenic minor stroke or TIA by long term monitoring providing complete data on arrhythmia occurrence.

Methods Patients with minor stroke or DWI-positive TIA were included if stroke causation remained unknown during standardized work up including 24 hours telemetry. A Reveal XT®, an atrial fibrillation sensitive loop-recorder, was implanted subcutaneously allowing continuous monitoring for up to 3 years. Arrhythmia episodes were adjudicated by senior consultant cardiologist. Endpoints include episodes of AF, time and burden of AF. A total of 84 patients were included and had a minimum of three months of monitoring before final analysis. Five patients were explanted due to local infections or discomfort. (fig.2)

Results In 13 patients (15.5 %) AF was documented by long term monitoring. The mean burden of AF was 2 hours pr day monitored, varying from less than a minute to 17 hours pr day monitored. (median 20 minutes pr day monitored) Kaplan Meier (fig.1) presents time from stroke onset to first AF event, mean time was 106,0 days (SD 47,9 days) Time from stroke onset to implantation was at a median of 56 days. (Mean 80 days, SD 74,9). Logistic regression analysis including all elements of CHADS2VAS found increasing risk of AF with an OR = 1.096 (p=0.015) with increasing age in years. CHADS 2 VAS score was 4.14 in the AF group vs. 3.24 (p=0.03).

Conclusion Paroxysmal AF is frequent and brief in patients with cryptogenic stroke. Long term monitoring resulted in change of treatment in one out of 6 patients in this cohort.

Tissue Doppler echocardiography reveals impaired cardiac function in patients with reversible ischaemia

AIMS

To determine if echocardiographic tissue Doppler imaging (TDI) performed at rest detects reduced myocardial function in patients with reversible ischaemia.

METHODS AND RESULTS

Eighty-four patients with angina pectoris, no previous history of ischaemic heart disease and normal left ventricular ejection fraction were examined with colour TDI, single-photon emission computed tomography (SPECT), and coronary angiography (CAG). Patients with a normal SPECT (n= 42) constituted the control group and patients with a positive SPECT (n= 42) were divided into patients with (true-positive SPECT, n= 30) or without (false-positive SPECT, n= 12) significant coronary stenoses assessed by CAG. Regional longitudinal systolic (s'), early diastolic (e'), and late diastolic (a') myocardial velocities were measured by colour TDI at six mitral annular sites and averaged to provide global estimates. In patients with reversible ischaemia both global systolic and diastolic function were impaired in terms of reduced average s' (5.6 ± 0.9 vs. 6.1 ± 1.1 cm/s; P< 0.05), reduced average e' (5.9 ± 1.8 vs. 7.0 ± 1.7 cm/s; P< 0.01) and increased average E/e' (14.2 ± 5.0 vs. 11.5 ± 3.9; P< 0.01). This impairment of the cardiac function was even more evident in patients with a true-positive SPECT with reduced average s' (5.5 ± 0.8 vs. 6.1 ± 1.1 cm/s; P< 0.01), reduced average e' (5.2 ± 1.5 vs. 7.0 ± 1.7 cm/s; P< 0.001), and increased average E/e' (15.5 ± 5.2 vs. 11.5 ± 3.9; P< 0.001), whereas no difference in myocardial velocities could be demonstrated in patients with a false-positive SPECT compared with controls.

CONCLUSION

In patients with stable angina pectoris, preserved ejection fraction, and reversible ischaemia assessed by SPECT, echocardiographic colour TDI performed at rest reveals impaired cardiac function. The impairment of the cardiac function seems to be evident only in patients with a true-positive SPECT and colour TDI may therefore increase its diagnostic value.

Usefulness of the myocardial performance index determined by tissue Doppler imaging m-mode for predicting mortality in the general population

The objective of this study was to evaluate the prognostic value of the myocardial performance index (MPI), assessed by color-coded tissue Doppler imaging (TDI) M-mode through the anterior mitral leaflet. Color TDI M-mode through the mitral leaflet is an easy, very fast, and precise method to estimate cardiac intervals and thus obtain the MPI, but the diagnostic and prognostic values of this parameter are unknown. In a large population study, cardiac function was evaluated in 1,100 participants by conventional echocardiography and TDI. MPI was calculated from pulse-wave Doppler analyses of left ventricular in- and outflow using standard procedures (MPI(conv)) and by color-coded TDI M-mode through the mitral leaflet in the apical 4-chamber view (MPI(TDI)). MPI(TDI) was increased in subjects with coronary heart disease (CHD) compared to controls, even after multivariable adjustment (p <0.002). During follow-up (median 5.3 years), 90 participants died. MPI(TDI) was significantly associated with overall mortality, and risk of dying increased by 31% per 0.1 increase in MPI(TDI). In contrast to MPI(conv), MPI(TDI) provided independent prognostic information in a multivariable Cox proportional hazard model (adjusting for age, gender, body mass index, heart rate, mean arterial blood pressure, and CHD), with a hazard ratio of 1.18 (p = 0.01) per 0.1 increase in MPI(TDI). In conclusion, MPI(TDI) is a quick, simple, and reproducible measurement, which is increased in subjects with CHD and provides independent prognostic information in a low-risk population.

Home aids and personal assistance 10-45 years after spinal cord injury

OBJECTIVE

Assessment of home aids, adaptations and personal assistance received after traumatic spinal cord injury (SCI).

SETTING

Clinic for Spinal Cord Injuries, Denmark. Uptake area, 2.5 million inhabitants.

STUDY DESIGN AND METHODS

Cross-sectional follow-up with retrospective data from medical files.

MATERIALS

Individuals with traumatic SCI before 1 January 1991, still in regular follow-up and with sufficient medical record. In all, 279 were included, and 236 answered the questionnaire (193 men and 43 women), with a response rate of 84.6%. Mean age at follow-up was 50.5 years, and mean follow-up time, 24.1 years. One hundred and twenty-six were paraplegic and 110, tetraplegic. Responders and non-responders were comparable.

RESULTS

Most common aids or adaptations reported were commode/shower chair on wheels or a seat (69%), grab bar by the toilet (41%), electrical bed (44%), special mattress (28%), lift/hoist (20%), computers (39%) and kitchen tools or cutlery with special handles (14%). In all, 7.6% of the participants reported no aids. Eighty-two percent answered 'Yes' to the question 'Have the aids, you currently or previously needed, been available to you?' The majority reported that their source of information about aid had been various journals and magazines. Twenty-one percent had personal helpers, with 60 h per week in median (range 2-168). Thirty-three percent received domestic help with 2.5 h per week in median (range 0.5-37). Eight percent had a home nurse. A total of 98.7% were living in their own homes.

CONCLUSIONS

This is the first study of a representative SCI population giving information on home aids. Individuals with SCI in Denmark seem to be sufficiently supplied with aids and personal assistance.