Jan Poloniecki

Sudden death in hypertrophic cardiomyopathy: identification of high risk patients

OBJECTIVES We sought to identify patients with hypertrophic cardiomyopathy (HCM) at high risk of sudden death (SD). BACKGROUND Relatively low mortality rates in HCM make conventional analysis of multiple clinical risk markers for SD problematic. This study used a referral center registry to investigate a smaller number of generally accepted noninvasive risk markers. METHODS We studied 368 patients (14 to 65 years old, 239 males) with HCM. There were five variables: nonsustained ventricular tachycardia (NSVT), syncope, exercise blood pressure response (BPR), family history of sudden death (FHSD) and left ventricular wall thickness (LVWT). RESULTS During follow-up (3.6+/-2.5 years [range 2 days to 9.6 years]), 36 patients (9.8%) died, 22 of them suddenly. Two patients received heart transplants. The six-year SD-free survival rate was 91% (95% confidence interval [CI] 87% to 95%). In the Cox model, there was a significant pairwise interaction between FHSD and syncope (p = 0.01), and these were subsequently considered together. The multivariate SD risk ratios (with 95% CIs) were 1.8 for BPR (0.7 to 4.4) (p = 0.22); 5.3 for FHSD and syncope (1.9 to 14.9) (p = 0.002); 1.9 for NSVT (0.7 to 5.0) (p = 0.18) and 2.9 for LVWT (1.1 to 7.1) (p = 0.03). Patients with no risk factors (n = 203) had an estimated six-year SD-free survival rate of 95% (95% CI 91% to 99%). The corresponding six-year estimates (with 95% CIs) for one (n = 122), two (n = 36) and three (n = 7) risk factors were 93% (87% to 99%), 82% (67% to 96%) and 36% (0% to 75%), respectively. Patients with two or more risk factors had a lower six-year SD survival rate (95% CI) compared with patients with one or no risk factors (72% [56% to 88%] vs. 94% [91% to 98%]) (p = 0.0001). CONCLUSIONS This study demonstrates that patients with multiple risk factors have a substantially increased risk of SD sufficient to warrant consideration for prophylactic therapy.

Risk stratification for arrhythmic events in postinfarction patients based on heart rate variability, ambulatory electrocardiographic variables and the signal-averaged electrocardiogram

The value of heart rate variability, ambulatory electrocardiographic (ECG) variables and the signal-averaged ECG in the prediction of arrhythmic events (sudden death or life-threatening ventricular arrhythmias) was assessed before hospital discharge in 416 consecutive survivors of acute myocardial infarction. During the follow-up period (range 1 to 1,112 days), there were 24 arrhythmic events and 47 deaths. The initial relation between several prognostic factors and arrhythmic events was explored with use of the Kaplan-Meier product limit estimates of survival function. Impaired heart rate variability less than 20 ms (p less than 0.0000), late potentials (p less than 0.0000), ventricular ectopic beat frequency (p less than 0.0000), repetitive ventricular forms (p less than 0.0000), left ventricular ejection fraction less than 40% (p less than 0.02) and Killip class (p less than 0.02) were identified as significant univariate predictors of arrhythmic events. When these variables were analyzed by using a stepwise Cox regression model, only impaired heart rate variability, followed by late potentials and repetitive ventricular forms remained independent predictors of arrhythmic events. The combination of impaired heart rate variability and late potentials had a sensitivity of 58%, a positive predictive accuracy of 33% and a relative risk of 18.5 for arrhythmic events and was superior to other combinations including those incorporating left ventricular function, exercise ECG, ventricular ectopic beat frequency and repetitive ventricular forms. These results suggest that a simple method of assessment based on heart rate variability and the signal-averaged ECG can select a small subgroup of survivors of myocardial infarction at high risk of future life-threatening arrhythmias and sudden death.

Relation between severity of left-ventricular hypertrophy and prognosis in patients with hypertrophic cardiomyopathy

BACKGROUND A previous study suggested that severe left-ventricular hypertrophy (maximum wall thickness > or = 30 mm) in patients with hypertrophic cardiomyopathy is associated with a risk of sudden cardiac death sufficient to warrant consideration for implantation of a cardioverter defibrillator (ICD). However, the prognostic significance of left-ventricular hypertrophy in relation to other clinical risk factors is poorly characterised. METHODS We studied 630 patients consecutively referred to one hospital in London, UK (mean age 37 years [SD 16]; 382 male; mean follow-up 59 months). Patients underwent two-dimensional and doppler echocardiography, upright exercise testing, and Holter monitoring. FINDINGS 39 patients died suddenly or had an appropriate ICD discharge; nine died from progressive heart failure; 11 from other cardiovascular causes and 23 from non-cardiac causes. There was a trend towards higher probability of sudden death or ICD discharge with increasing wall thickness (p=0.029, relative risk per 5 mm increment 1.31 [95% CI 1.03-1.66]). Of the 39 patients who died suddenly or had an ICD discharge, ten had a wall thickness of 30 mm or more. Patients with wall thickness of 30 mm or more had higher probability of sudden death or ICD discharge than patients with wall thickness less than 30 mm (p=0.049, 2.07 [1.00-4.25]. When considered together, the number of additional risk factors (one to three) was a better predictor of risk of sudden death or ICD discharge than wall thickness (p=0.0001, relative risk per additional factor 2.00 [1.43-2.79] vs p=0.058, 1.26 per 5 mm increment [0.99-1.60]). There was no relation between the pattern of hypertrophy and survival. INTERPRETATION The risk of sudden death associated with a wall thickness of 30 mm or more in patients without other risk factors is insufficient to justify aggressive prophylactic therapy. Most sudden deaths occurred in patients with wall thickness less than 30 mm, so the presence of mild hypertrophy cannot be used to reassure patients that they are at low risk.

Comparison of the predictive characteristics of heart rate variability index and left ventricular ejection fraction for all-cause mortality, arrhythmic events and sudden death after acute myocardial infarction.

Heart rate (HR) variability index and left ventricular ejection fraction (EF) were compared for the prediction of all-cause mortality, arrhythmic events and sudden death in 385 survivors of acute myocardial infarction. For arrhythmic events, where, for a sensitivity of 75%, HR variability index had a specificity of 76%, EF had a specificity of only 45%. An EF of less than or equal to 40% had a sensitivity of 42% and a specificity of 75% for arrhythmic events; for the same sensitivity an HR variability index of 20 U had a specificity of 92%. An EF less than or equal to 40% had a sensitivity of 40% and a specificity of 73% for sudden death; HR variability index had a specificity of 83% for the same sensitivity. For all cause mortality, where, for a sensitivity of 75%, HR variability index had a specificity of 52%, EF had a specificity of 40%. It is concluded that HR variability index appears a better predictor of important postinfarction arrhythmic complications than left ventricular EF, but both indexes perform equally well in predicting all-cause mortality.

Development of a dedicated risk-adjustment scoring system for colorectal surgery (colorectal POSSUM).

The aim of the study was to develop a dedicated colorectal Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (CR‐POSSUM) equation for predicting operative mortality, and to compare its performance with the Portsmouth (P)‐POSSUM model.

Distinction between arrhythmic and nonarrhythmic death after acute myocardial infarction based on heart rate variability, signal-averaged electrocardiogram, ventricular arrhythmias and left ventricular ejection fraction

OBJECTIVES We investigated whether heart rate variability, the signal-averaged electrocardiogram (ECG), ventricular arrhythmias and left ventricular ejection fraction predict the mechanism of cardiac death after myocardial infarction. BACKGROUND Postinfarction risk stratification studies have almost exclusively focused on predicting the risk of arrhythmic death. The factors that identify and distinguish persons at risk for arrhythmic and nonarrhythmic death are poorly known. METHODS Heart rate variability, the signal-averaged ECG, ventricular arrhythmias and left ventricular ejection fraction were assessed in 575 survivors of acute myocardial infarction. The patients were followed up for 2 years; arrhythmic and nonarrhythmic cardiac deaths were used as clinical end points. During the follow-up period, 47 cardiac deaths occurred, 29 (62%) arrhythmic and 18 (38%) nonarrhythmic. RESULTS All risk factors were associated with cardiac mortality in univariate analysis. With the exception of left ventricular ejection fraction, they were also predictors of arrhythmic death. Depressed heart rate variability (p < 0.001), ventricular ectopic beats (p < 0.001) and low ejection fraction (p < 0.001) were related to nonarrhythmic death. In multivariate analysis, depressed heart rate variability (p < 0.001) and runs of ventricular tachycardia (p < 0.05) predicted arrhythmic death. Nonarrhythmic death was associated with depressed heart rate variability (p < 0.001), ventricular ectopic beats (p < 0.001) and low ejection fraction (p < 0.01). By selecting patients with depressed heart rate variability, long filtered QRS duration or ventricular arrhythmias and excluding patients with the lowest ejection fraction, we identified a group in which 75% of deaths were arrhythmic. Similarly, by selecting patients with a low ejection fraction and excluding patients with the lowest heart rate variability, we identified a group in which 75% of deaths were nonarrhythmic. CONCLUSIONS Arrhythmic death was associated predominantly with depressed heart rate variability and ventricular tachycardia runs, and nonarrhythmic death with low ejection fraction, ventricular ectopic beats and depressed heart rate variability. A combination of risk factors identified patient groups in which a majority of deaths were either arrhythmic or nonarrhythmic.

Atrial fibrillation in hypertrophic cardiomyopathy: a longitudinal study.

The clinical outcome of 52 consecutive patients with hypertrophic cardiomyopathy who developed paroxysmal (less than 1 week) or established (greater than or equal to 1 week) atrial fibrillation between 1960 and 1985 was examined retrospectively and compared with that of a matched group of patients with hypertrophic cardiomyopathy and sinus rhythm. Follow-up study until death or the present ranged from 6 months to 24 years (median 11 years) from diagnosis and from 6 months to 22 years (median 7 years) from the onset of atrial fibrillation. Atrial fibrillation was present in 6 patients at the time of diagnosis, whereas it developed subsequently in 46. The acute onset of arrhythmia was associated with a change in symptoms in 41 (89%) of the 46. After initial treatment of acute atrial fibrillation, sinus rhythm was restored in 29 (63%) of the 46 patients; 43 (93%) of the 46 returned to their original symptom class. Stepwise logistic regression revealed that shorter duration of arrhythmia and amiodarone therapy were the most powerful predictors of return to sinus rhythm. Sinus rhythm was maintained during a median follow-up period of 5.5 years in 22 of the 29 patients in whom it was restored after initial therapy. During follow-up study, 25 of the 52 patients were treated with conventional therapy alone and 7 with amiodarone alone. Amiodarone therapy was associated with maintenance of sinus rhythm, fewer alterations in drug therapy, fewer embolic episodes and fewer attempted direct current cardioversions (during a shorter follow-up period).(ABSTRACT TRUNCATED AT 250 WORDS)

Resternotomy for bleeding after cardiac operation: A marker for increased morbidity and mortality

Over a 2-year period from January 1, 1992, to December 31, 1993, of 2,221 patients undergoing cardiac operations in our unit, 85 (3.8%) were reopened for the control of bleeding (9 patients more than once). The incidence of resternotomy in coronary cases was 2.3%, but resternotomy was more than three times as likely in valve cases (odds ratio, 3.4; 95% confidence interval, 2.1 to 5.4). Previous cardiac operation was more common among resternotomy patients than among the remainder (18% versus 9%, respectively; p = 0.018). An identifiable source of bleeding was found in 57 of the 85 patients (67%), but a concurrent coagulopathy was common (45 patients). Resternotomy patients, as a group, had higher preoperative risk scores (Parsonnet) than did the other patients (p < 0.0001), stayed longer in the intensive care unit (p < 0.0001), and had greater requirements for intraaortic balloon counterpulsation (14% versus 3%) and hemofiltration (9% versus 3%) (p < 0.0001 and p < 0.01, respectively). Nineteen resternotomy patients (22%) died in the hospital, a proportion significantly greater than the risk assigned to this group of patients preoperatively (12.8%) (p = 0.008). In contrast, the observed mortality for the other 2,136 patients (5.5%) was significantly less (8.3%) (p < 0.00006). Multiple forward stepwise logistic-regression analysis confirmed resternotomy for excessive bleeding after cardiac operation to be a significant independent predictor of a prolonged stay in the intensive care unit (p < 0.0001), the need for intraaortic balloon counterpulsation (p < 0.0001), and death (p < 0.0001).

Operative mortality in colorectal cancer: prospective national study

Abstract Objective To develop a mathematical model that will predict the probability of death after surgery for colorectal cancer. Design Descriptive study using routinely collected clinical data. Data source The database of the Association of Coloproctology of Great Britain and Ireland (ACPGBI), encompassing 8077 patients with a new diagnosis of colorectal cancer in 73 hospitals during a 12 month period. Statistical analysis A three level hierarchical logistic regression model was used to identify independent predictors of operative mortality. The model was developed on 60% of the patient population and its validity tested on the remaining 40%. Results Overall postoperative mortality was 7.5% (95% confidence interval 6.9% to 8.1%). Independent predictors of death were age, American Society of Anesthesiology (ASA) grade, Dukess stage, urgency of the operation, and cancer excision. When tested the predictive model showed good discrimination (area under the receiver operating characteristic curve = (0.775) and calibration (comparison of observed with expected mortality across different procedures; Hosmer-Lemeshow statistic = 6.34, 8 df, P = 0.610). Conclusions Clinicians can predict postoperative death by using a simple numerical table derived from the statistical model of the ACPGBI. The model can be used in everyday practice for preoperative counselling of patients and their carers as a part of multidisciplinary care. It may also be used to compare the outcomes between multidisciplinary teams for colorectal cancer.

Meta‐analysis and systematic review of the relationship between volume and outcome in abdominal aortic aneurysm surgery

This study investigated the volume–outcome relationship for abdominal aortic aneurysm (AAA) surgery and quantified critical volume thresholds.