Adherence and arrhythmic mortality in the cardiac arrhythmia suppression trial (CAST).

Patient adherence to therapy is essential to assess treatment efficacy, particularly in clinical trials. Active treatment usually is expected to benefit patients. The healthy adherer effect, the association or greater adherence to all health-promoting behaviors, including medication and overall concern for health, explains the improved survival of more adherent patients in both active and placebo medication groups of several clinical trials. The Cardiac Arrhythmia Suppression Trial (CAST), a placebo-controlled double-blind clinical trial of post-myocardial infarction (MI) patients with asymptomatic ventricular arrhythmias, in which active medication (encainide or flecainide) led to increased mortality, provided an opportunity to examine the relationship of adherence to survival from a different perspective. We consider whether adherence to active treatment was related to arrhythmic mortality and whether a healthy adherer effect might counteract the effect of treatment on mortality among patients taking active medication. Adherence (average pill count) at the first follow-up visit did not differ in the active treatment (92.2%, standard deviation (SD) = 11.97, n = 574) and placebo (90.8%, SD = 13.66, n = 579) groups. In a Cox proportional hazard regression model, medication adherence predicted arrhythmic mortality among the active (P < 0.0062) but not the placebo medication group. The effect of adherence on arrhythmic mortality was significant beyond the effects of ejection fraction, race, spouse, smoking status, diuretic medication, and history of MI. A 10% increase in adherence led to more than a threefold increase of risk of arrhythmic death. The design of the CAST, which included a titration phase, may have tended to select relatively adherent patients since only those whose arrhythmias were suppressed with active medication were randomized into the trial. The data do not support a strong healthy adherer effect in the CAST. There was no evidence in this study that a healthy adherer effect counterbalanced the effect of the active medication.

Pericardial effusion in AIDS. Incidence and survival.

BACKGROUND: Although pericardial effusion is known to be common among patients infected with HIV, the incidence of pericardial effusion and its relation to survival have never been described. METHODS AND RESULTS: To evaluate the incidence of pericardial effusion and its relation to mortality in HIV-positive subjects, 601 echocardiograms were performed on 231 subjects recruited over a 5-year period (inception cohort: 59 subjects with asymptomatic HIV, 62 subjects with AIDS-related complex, and 74 subjects with AIDS; 21 HIV-negative healthy gay men; and 15 subjects with non-HIV end-stage medical illness). Echocardiograms were performed every 3 to 6 months (82% had follow-up studies). Sixteen subjects were diagnosed with effusions (prevalence of effusion for AIDS subjects entering the study was 5%). Thirteen subjects developed effusions during follow-up; 12 of these were subjects with AIDS (incidence, 11%/y). The majority of effusions (80%) were small and asymptomatic. The survival of AIDS subjects with effusions was significantly shorter (36% at 6 months) than survival for AIDS subjects without effusions (93% at 6 months). This shortened survival remained significant (relative risk, 2.2, P = .01) after adjustment for lead time bias and was independent of CD4 count and albumin level. CONCLUSIONS: There is a high incidence of pericardial effusion in patients with AIDS, and the presence of an effusion is associated with shortened survival. The development of an effusion in the setting of HIV infection suggests end-stage HIV disease (AIDS).

Invalidation of the resting electrocardiogram obtained via exercise electrode sites as a standard 12-lead recording.

The difficulty in interpreting the standard 12-lead electrocardiogram (ECG) due to the interference from muscle potentials produced by arm and leg motion makes it unsuitable during the exercise treadmill test. Likewise, the exercise lead placement ECG cannot substitute for the standard ECG due to significant errors in the former's diagnostic interpretation. This study compares the ECGs recorded via standard and exercise sites regarding frontal and horizontal plane axes, diagnosis and location of myocardial infarction and estimation of infarct size using the complete 54-criteria and 32-point Selvester QRS scoring system. The altered limb lead locations on the exercise ECG caused the QRS vectors to artifactually appear to be directed more inferiorly, posteriorly and rightward, producing a marked rightward mean frontal plane axis shift of +48 degrees (p less than 0.00001). No false positive or false negative anterior infarct was seen on the exercise lead placement ECG, whereas inferior and posterior infarcts were lost in 69% and 31% of patients, respectively. A false lateral infarct was seen in 19% of patients. Estimation of infarct size differed between the 2 ECG sets, with 11 patients increasing their infarct size by 3 to 9% and 14 others decreasing it by 3 to 15% on the exercise lead placement ECG. This study demonstrates that use of body torso positions for limb leads results in substantial QRS waveform variations that disqualify the exercise lead placement ECG as a "standard" recording. Such ECGs should therefore be labeled as "torso positioned" or "nonstandard" to prevent misuse for clinical and investigative purposes.