Frequent recurrent polymorphic ventricular tachycardia during sleep due to managed ventricular pacing.

We report a case of a patient with an implantable cardioverter defibrillator and no prior history of heart block with managed ventricular pacing (MVP) programmed who had frequent recurrent episodes of polymorphic ventricular tachycardia. All of the episodes were initiated by transient atrioventricular block which resulted in short-long-short sequences permitted by MVP. This case illustrates that MVP should be used with caution not only in patients with complete heart block, but also in patients at risk for brief heart block due to such states as hypervagatonia due to sleep apnea.

Heat shock proteins in cardiovascular disease a new therapeutic target.

Cells have the capability of defending themselves from various stressors by activating a genetic program with the production of substances known as heat shock proteins and their regulatory partners, the heat shock transcription factors. In this article, heat shock proteins are discussed, including their roles in pathophysiology and as possible pharmacologic targets to treat disease. Multiple investigations have demonstrated an elevation in heat shock proteins in patients with systemic hypertension, coronary artery disease, carotid atherosclerosis, and myocardial infarction and ischemia. As we further understand how to manipulate their expression, we can explore pharmacologic interventions and gene transfection techniques that can safely be used in humans.

Echocardiographic predictors of ventricular tachycardia.

BACKGROUND: Patients with structural heart disease are prone to ventricular tachycardia (VT) and ventricular fibrillation (VF), which account for the majority of sudden cardiac deaths (SCDs). We sought to examine echocardiographic parameters that can predict VT as documented by implantable cardioverter-defibrillator (ICD) appropriate discharge. We examine echocardiographic parameters other than ejection fraction that may predict VT as recorded via rates of ICD discharge. METHODS: Analysis of 586 patients (469 males; mean age = 68 ± 3 years; mean follow-up time of 11 ± 14 months) was undertaken. Echo parameters assessed included left ventricular (LV) internal end diastolic/systolic dimension (LVIDd, LVIDs), relative wall thickness (RWT), and left atrial (LA) size. RESULTS: The incidence of VT was 0.22 (114 VT episodes per 528 person-years of follow-up time). Median time-to-first VT was 3.8 years. VT was documented in 79 patients (59 first VT incidence, 20 multiple). The echocardiographic parameter associated with first VT was LVIDs >4 cm (P = 0.02). CONCLUSION: The main echocardiographic predictor associated with the first occurrence of VT was LVIDs >4 cm. Patients with an LVIDs >4 cm were 2.5 times more likely to have an episode of VT. Changes in these echocardiographic parameters may warrant aggressive pharmacologic therapy and implantation of an ICD.

Clinical predictors of appropriate implantable-cardioverter defibrillator discharge.

BACKGROUND: The implantable cardioverter-defibrillator (ICD) is the mainstay of treatment for ventricular tachyarrhythmias due to its impact on mortality. ICD discharges may be appropriate or inappropriate, and identification of patients at risk for ICD discharge is essential. We sought to determine the predictors of appropriate ICD discharge. METHODS: We analyzed data from 591 ICD recipients (mean age 67.9 +/- 13.0 years; 474 men; mean follow-up 10.9 +/- 13.8 months). The association between ICD discharges and multiple clinical variables, including age, gender, hypertension, diabetes, coronary artery bypass graft (CABG) surgery, syncope, atrial fibrillation (AF), prior coronary intervention, left ventricular ejection fraction (LVEF), left ventricular end diastolic dimension, left ventricular end systolic dimension (LVESD), and ambient drug therapy was examined. RESULTS: The rates of appropriate or inappropriate discharges, delivered to 155 patients, were 0.49 per follow-up year (F/Y). The median time-to-first appropriate discharge was 3.4 years. Among the discharges delivered, 97(63%) were appropriate and 58(37%) were inappropriate. Risk factors associated with a trend toward earlier appropriate discharges included age