Risk Of Nonsudden Cardiac Death Research Articles

Prognostic significance of beat-to-beat variability of spatial heterogeneity of repolarisation analysed from 5-minute resting electrocardiogram in coronary artery disease

Abstract Background Data on the prognostic significance of temporal variability of spatial heterogeneity of electrocardiographic repolarisation in coronary artery disease (CAD) are limited. Purpose To evaluate the prognostic value of temporal variability of T-wave morphology analysed from 5-minute resting ECG in CAD. Methods The standard deviation (SD) of T-wave morphology dispersion (TMD-SD), the SD of T-wave heterogeneity (TWH-SD), and the SD of total cosine R-to-T (TCRT-SD) were analysed on beat-to-beat basis from a 5-minute period of resting 12-lead ECG obtained before a clinical stress test in 1702 patients with angiographically verified CAD and well-preserved left ventricular function. Results During an average of 8.7±2.2 years of follow-up, 60 (3.5 %) patients experienced sudden cardiac death (SCD) or were resuscitated from a sudden cardiac arrest (SCA), 69 (4.1 %) patients experienced non-sudden cardiac death (NSCD), and 161 (9.5 %) patients died due to non-cardiac death (NCD). TMD-SD was significantly higher in patients who experienced SCD/SCA compared with those without such an event (1.72 ± 2.00 vs. 1.12 ± 1.75, p= 0.01, respectively) and in patients who succumbed to NSCD compared with those without such an event (1.57 ± 1.74 vs. 1.12 ± 1.76, p=0.04, respectively), but did not differ significantly between patients who experienced NCD and those without such an event (1.16 ± 1.42 vs. 1.14 ± 1.79, p=0.86, respectively). After adjusting for relevant clinical risk factors in the Cox multivariate hazards model, TMD-SD retained its significant association with the risk of SCD/SCA (HR 1.119, 95 % CIs 1.015–1.233, p=0.024), but not with the risk of NSCD (HR 1.089, 95 % CIs 0.983–1.206, p=0.103). Conclusion TMD-SD, representing temporal variability of spatial heterogeneity of electrocardiographic repolarisation, is independently associated with the long-term risk of SCD/SCA in CAD patients with well-preserved left ventricular function.

Prognostic significance of beat-to-beat variability of spatial heterogeneity of repolarization analyzed from a 5-minute resting electrocardiogram in coronary artery disease

BackgroundData on the prognostic significance of temporal variability of spatial heterogeneity of electrocardiographic repolarization in coronary artery disease (CAD) are limited. ObjectiveThe purpose of this study was to evaluate the prognostic value of temporal variability of T-wave morphology analyzed from a 5-minute resting electrocardiogram in CAD. MethodsThe standard deviation (SD) of T-wave morphology dispersion (TMD-SD) and the SD of total cosine R-to-T were analyzed on a beat-to-beat basis from a 5-minute period of the standard resting 12-lead electrocardiogram obtained before the clinical stress test in 1702 patients with angiographically verified CAD and well-preserved left ventricular function. ResultsDuring an average of 8.7 ± 2.2 years of follow-up, 60 patients experienced sudden cardiac death/arrest (SCD/SCA) (3.5%), 69 patients nonsudden cardiac death (NSCD) (4.1%), and 161 patients noncardiac death (9.5%). TMD-SD was significantly higher in patients who experienced SCD/SCA than in other patients (1.72 ± 2.00 vs 1.12 ± 1.75; P = .01) and higher in patients who succumbed to NSCD than in other patients (1.57 ± 1.74 vs 1.12 ± 1.76; P = .04), but it did not differ significantly between patients who experienced noncardiac death and those without such an event (1.16 ± 1.42 vs 1.14 ± 1.79; P = .86). In the Cox multivariable hazards model, TMD-SD retained its significant association with the risk of SCD/SCA (hazard ratio 1.119; 95% confidence interval 1.015–1.233; P = .024) but not with the risk of NSCD (hazard ratio 1.089; 95% confidence interval 0.983–1.206; P = .103). ConclusionTMD-SD is independently associated with the long-term risk of SCD/SCA in patients with CAD.

Diabetes, glucose tolerance, and the risk of sudden cardiac death.

BackgroundDiabetes predisposes to sudden cardiac death (SCD). However, it is uncertain whether greater proportion of cardiac deaths are sudden among diabetes patients than other subjects. It is also unclear whether the risk of SCD is pronounced already early in the course of the disease. The relationship of impaired glucose tolerance (IGT) and SCD is scarcely documented.MethodsA general population cohort of 10594 middle-aged subjects (mean age 44 years, 52.6 % male, follow-up duration 35–41 years) was divided into diabetes patients (n = 82), subjects with IGT (n = 3806, plasma glucose ≥9.58 mmol/l in one-hour glucose tolerance test), and controls (n = 6706).ResultsDiabetes patients had an increased risk of SCD after adjustment confounders (hazard ratio 2.62, 95 % confidence interval 1.46–4.70, p = 0.001) but risk for non-sudden cardiac death was similarly increased and the proportion of SCD of cardiac deaths was not increased. The SCD risk persisted after exclusion of subjects with baseline cardiac disease or non-fatal cardiac events during the follow-up. Subjects with IGT were at increased risk for SCD (univariate hazard ratio 1.51; 95 % confidence interval 1.31–1.74; p < 0.001) and also for non-sudden cardiac deaths and non-fatal cardiac events but adjustments for other risk factors attenuated these effects.ConclusionsDiabetes was associated with increased risk of SCD but also the risk of non-sudden cardiac death was similarly increased. The proportion of cardiac deaths being sudden in subjects with diabetes was not increased. The higher SCD risk in diabetes patients was independent of known cardiac disease at baseline or occurrence of non-fatal cardiac event during the follow-up.

71 Identifying Patients with Less Potential to Benefit from Implantable Cardiac Defibrillator Therapy

Background Implantable cardiac defibrillator (ICD) therapy reduces mortality in selected patients at high risk of sudden cardiac death. However, patients at high risk of non-sudden cardiac death, whose risk of short-term mortality following device implantation is high, may gain no significant benefit from an ICD. A number of approaches have been proposed to identify these high-risk patients, including single clinical markers and more complex scoring systems. The aims of this study were to use the proposed scoring systems to: (1) establish how many current ICD recipients may be too high risk to derive significant benefit from ICD therapy and (2) evaluate how well the proposed scoring systems predict short-term mortality in an unselected cohort of ICD recipients. Methods We performed asingle-centre retrospective observational study of all new ICD implants over 5years (2009–2013). We used 3 published scoring systems (Kramer et al 1 ; Barsheshet et al 2 ; Parkash et al 3 ) to identify new ICDrecipients whose short-term risk of death following ICD implantation waspredicted to be high. We then evaluated how well the scoring systems predicteddeath during follow-up. Results Over 5 years there were 406 new implants (79% male, age 67 ± 13 years). The majority (58%) were primary prevention implants and 45% were cardiac resynchronisation therapy-defibrillator devices. During a mean follow-up of 936 ± 560 days, 77 patients died. Using the published scoring systems, the proportion of ICD recipients predicted to be at high risk of short-term mortality were 4% (Kramer), 36% (Barsheshet) and 23% (Parkash). Three-year mortality rates in these high-risk groups were 76%, 32% and 36% respectively; in the overall study population 3-year mortality was 20%. In univariate Cox regression analyses, all 3 scoring systems predicted death (p Conclusions Using published scoring systems, a significant proportion of current ICD recipients are at high risk of short-term mortality following device implantation. Although all 3 scoring systems predicted mortality during follow-up, only the Kramer model added predictive accuracy compared to renal function alone. RENCES Kramer DB, Friedman PA, Kallinen LM, Morrison TB, Crusan DJ, Hodge DO, Reynolds MR, Hauser RG. Development and validation of a risk score to predict early mortality in recipients of implantable cardioverter-defibrillators. Heart Rhythm 2012; 9 :42–6 Barsheshet A, Moss AJ, Huang DT, McNitt S, Zareba W, Goldenberg I. Applicability of a risk score for prediction of the long-term (8-year) benefit of the implantable cardioverter-defibrillator. J Am Coll Cardiol 2012; 59 :2075–9 Parkash R, Stevenson WG, Epstein LM, Maisel WH. Predicting early mortality after implantable defibrillator implantation: a clinical risk score for optimal patient selection. Am Heart J 2006; 151 :397–403

Proarrhytmic effect of amiodarone can cause “electrical storm” in patient with ischaemic cardiomyopathy and implantable cardioverter defibrillator

The goal: Electrical storm (ES) is a life-threatening syndrome that involves recurrent episodes of ventricular arrhythmias. Data on its prognostic significance strongly suggest that these patients have a poor outcome and had an increased risk of non-sudden cardiac death. The goal of this case report is to show the importance of clinical judgment in the treatment of post myocardial arrhythmia in complex patients, such as those with an implantable cardioverter defibrillator (ICD). Case presentation: A 61-year-old male patient experienced sustained ventricular tachycardia after myocardial infarction. Due to severely impaired left ventricular function, he underwent maximal medical treatment for heart failure together with amiodarone and ICD implantation. Following ICD implantation, he presented with ES and we noticed a prolongation of the QT interval in ECG. We excluded amiodarone because of the evident proarrhythmic effect. During hospitalization and in outpatient follow-up, we detected no ventricular tachycardia, neither in ECG monitoring, nor in the ICD device record. In the one month follow-up we detected normalization of the QT interval. However, after 9 months, the patient experienced VT episodes and one of them was terminated by ICD shock. This event was complicated by head trauma and subsequent subdural hematoma and posttraumatic subarachnoid hemorrhage. The patient underwent urgent neurocranial surgery. Unfortunately, the patient died on the third day after the surgery. Conclusion: Cardiac mortality of patients with all types of ventricular tachyarrhythmias is high. The use of antiarrhytmic agents may predispose the patient to proarrhythmic complications that might pose a significant threat to life. Though amiodarone has become the first line drug to treat ventricular tachyarrhythmias in patients with cardiac dysfunction, it is important to be aware of its proarrhythmic effect, which may lead to an ES of monomorphic VT. Druginduced effects on the QT interval with the associated possibility of inducing fatal arrhythmias have become a new challenge for the practitioner, the drug development process and the regulatory agencies.

Sudden Cardiac Death Risk Prediction

Sudden Cardiac Death Risk Prediction

Abnormal P‐Wave Morphology Is a Predictor of Atrial Fibrillation Development and Cardiac Death in MADIT II Patients

Several ECG-based approaches have been shown to add value when risk-stratifying patients with congestive heart failure, but little attention has been paid to the prognostic value of abnormal atrial depolarization in this context. The aim of this study was to noninvasively analyze the atrial depolarization phase to identify markers associated with increased risk of mortality, deterioration of heart failure, and development of atrial fibrillation (AF) in a high-risk population with advanced congestive heart failure and a history of acute myocardial infarction. Patients included in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) with sinus rhythm at baseline were studied (n = 802). Unfiltered and band-pass filtered signal-averaged P waves were analyzed to determine orthogonal P-wave morphology (prespecified types 1, 2, and 3/atypical), P-wave duration, and RMS20. The association between P-wave parameters and data on the clinical course and cardiac events during a mean follow-up of 20 months was analyzed. P-wave duration was 139 + or - 23 ms and the RMS20 was 1.9 + or - 1.1 microV. None of these parameters was significantly associated with poor cardiac outcome or AF development. After adjustment for clinical covariates, abnormal P-wave morphology was found to be independently predictive of nonsudden cardiac death (HR 2.66; 95% CI 1.41-5.04, P = 0.0027) and AF development (HR 1.75; 95% CI 1.10-2.79, P = 0.019). Abnormalities in P-wave morphology recorded from orthogonal leads in surface ECG are independently predictive of increased risk of nonsudden cardiac death and AF development in MADIT II patients.

Abstract 2125: P Wave Morphology Is a Predictor of Poor Cardiac Outcome and Death in MADIT II Patients

The objective of the present study was to non-invasively analyse atrial electrophysiology to identify markers associated with increased risk of mortality and deterioration of heart failure in a high-risk population with advanced CHF and a history of acute myocardial infarction. Patients included in MADIT II with sinus rhythm at baseline were studied (n=802). Unfiltered and bandpass filtered signal-averaged P waves were analyzed to determine orthogonal P wave morphology, P wave duration and RMS20. The association between P wave parameters and data on the clinical course and cardiac events during a mean follow-up of 20 months was analyzed. P wave duration was 139±23 ms and the RMS20 was 1.9±1.1 μV. None of these parameters were significantly associated with poor cardiac outcome. Differences in P wave morphology were independently predictive of non-sudden cardiac death (HR 2.66; 95% CI 1.41–5.04, P=0.0027). In addition, in univariate analyses differences in P wave morphology were found to be associated with an increased risk of all-cause mortality (HR 1.35; 95%CI 1.01–1.81, P=0.042) and cardiac death (HR 1.54; 95%CI 1.10 –2.16, P=0.011) (figure ) In the present study the value of analyzing the P wave morphology in patients with previous myocardial infarction and CHF is demonstrated. Changes in P wave morphology were shown to be independently predictive of increased risk of non-sudden cardiac death. Furthermore, statistically significant associations between P wave morphology changes and all-cause mortality, cardiac death and CHF hospitalization was demonstrated.

Association of Blood Pressure and Its Evolving Changes With the Survival of Patients With Heart Failure

Objective The association between low blood pressure (BP) levels and increased mortality has been established in several studies of heart failure (HF). Although many drugs administered to these patients decrease BP, the relationship between changes in BP and survival has not been investigated. Nor have previous analyses distinguished among different forms of death. We investigated the influence of baseline BP and changes in BP during a 1-year period on the survival of patients with HF, distinguishing among sudden cardiac death, nonsudden cardiac death, and noncardiac death. We also identified the possible relationship with the baseline values of and changes in other clinical and treatment variables, including pharmacologic treatments. Method and Results A total of 1062 patients with chronic HF included in the Spanish National Registry of Sudden Death (mean age of 64.5 ± 11.8 years, 72% were men, and 21% were in New York Heart Association class III with a mean left ventricular ejection fraction of 36.7% ± 14.2%) were prospectively investigated for a mean of 1.9 ± 0.6 years. A multivariable Cox proportional hazards model adjusting for clinical and therapeutic variables showed an independent association between low baseline systolic blood pressure (SBP) and nonsudden cardiac death (hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.93–0.98), but changes in SBP during the following year did not influence survival, regardless of the baseline SBP level ( P = .55). Contrariwise, baseline diastolic BP was not associated with mortality, but an increase in diastolic BP during the following year showed a borderline independent significant association with lower nonsudden cardiac death (HR 0.90, 95% CI 0.82–1.00). Treatment with angiotensin-converting enzyme inhibitors or beta-blockers at baseline was also associated with lower nonsudden cardiac mortality, as was an increase in left ventricular ejection fraction during the following year (HR 0.69, 95% CI 0.51–0.93; P = .015). Conclusion Among patients with stable HF, low SBP is associated with a greater risk of nonsudden cardiac death. The change in SBP during a 1-year period has no prognostic value. Because the beneficial effects of drugs associated with increased survival (in this study, angiotensin-converting enzyme inhibitors and beta-blockers) thus seem to be independent of their effects on BP, changes in BP should probably not influence the decision to use such drugs or continue their administration.

Risk of sudden versus nonsudden cardiac death in patients with coronary artery disease

Background Patients at high risk of sudden cardiac death, yet at low risk of nonsudden death, might be ideal candidates for antiarrhythmic drugs or devices. Most previous studies of prognostic markers for sudden cardiac death have ignored the competitive risk of nonsudden cardiac death. The goal of the present study was to evaluate the ability of clinical factors to distinguish the risks of sudden and nonsudden cardiac death. Methods We identified all deaths during a 3.3-year follow-up of 30,680 patients discharged alive after admission to the cardiac care unit of a Seattle hospital. Detailed chart reviews were conducted on 1093 subsequent out-of-hospital sudden deaths, 973 nonsudden cardiac deaths, and 442 randomly selected control patients. Results Patients who died in follow-up (suddenly or nonsuddenly) were significantly different for many clinical factors from control patients. In contrast, patients with sudden cardiac death were insignificantly different for most clinical characteristics from patients with nonsudden cardiac death. The mode of death was 20% to 30% less likely to be sudden in women, patients who had angioplasty or bypass surgery, and patients prescribed β-blockers. The mode of death was 20% to 30% more likely to be sudden in patients with heart failure, frequent ventricular ectopy, or a discharge diagnosis of acute myocardial infarction. A multivariable model had only modest predictive capacity for mode of death (c-index of 0.62). Conclusion Standard clinical evaluation is much better at predicting overall risk of death than at predicting the mode of death as sudden or nonsudden. (Am Heart J 2002;144:390-6.)

Prognosis in severe heart failure: Relation to hemodynamic measurements and ventricular ectopic activity

To determine the prognosis of severe heart failure and its relation to the level of ventricular dysfunction and ectopic activity, 77 patients with functional class III or IV heart failure were followed prospectively for 12 ± 11 months (range 5 to 40). Survival was computed using life-table methods and related to clinical, hemodynamic, M-mode echocardiographic and 24 hour Holter monitoring data. Hemodynamic evaluation invariably revealed pump dysfunction. Holter monitoring showed a high incidence of ventricular premature depolarizations which were paired in 62%, multiform in 71%, three or more consecutive in 51% and five or more in 39%. Overall survival was 52% at 1 year and 32% at 2 years. Mortality was highest during the initial 4 months, after which annual mortality averaged 20%. Cardiac mortality was due equally to sudden death and heart failure. Cardiac mortality during the first 4 months was related by univariate analysis to functional class (χ 2 = 11.4, p < 0.001) and to the presence of five or more consecutive ventricular premature depolarizations (χ2 = 3.9, p < 0.05) due to a relation between these variables and nonsudden cardiac death; sudden death was not related to any initial variable. No variable was related to cardiac mortality after 4 months. Multivariate analysis identified only functional class as an independent prognostic variable, functional class IV patients having a 6.8 greater relative risk of nonsudden cardiac death than functional class III patients. Hemodynamic, Holter monitoring and echographic measurements provided no additional prognostic information. It is concluded that severe heart failure is associated with a high mortality from both sudden and nonsudden cardiac death. Cardiac mortality is independently related to functional status but not to the level of pump dysfunction, cardiac size or ventricular ectopic activity.