Ram Jadonath

Determinants of outcome in patients with sustained ventricular tachyarrhythmias: The Antiarrhythmics Versus Implantable Defibrillators (AVID) Study Registry

BACKGROUND The prognosis of patients with sustained ventricular tachyarrhythmias varies according to clinical characteristics. We sought to identify predictors of survival in a large population of patients with documented sustained ventricular tachyarrhythmias not related to reversible or correctable causes included in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Registry. METHODS AND RESULTS We analyzed the impact of 36 demographic, clinical, and discharge treatment variables on the outcome for 3559 patients. Survival status was assessed with the use of the National Death Index. Multivariate analyses were performed with the use of the Cox proportional hazards model. After a mean follow-up of 17 +/- 12 months, 631 patients died. Actuarial survival was 0.86 (95% confidence interval [CI] 0.85 to 0.88), 0.79 (95% CI 0.78 to 0.81), and 0.72 (95% CI 0.70 to 0.74) at 1, 2, and 3 years. Multivariate predictors of worse survival included older age, severe left ventricular dysfunction, lower systolic blood pressure, history of congestive heart failure, diabetes, smoking or atrial fibrillation, and preexistent pacemaker. The hemodynamic impact of the qualifying arrhythmia was not a predictor of outcome. Defibrillator implantation and hospital discharge while the patient was taking a beta-blocker or an angiotensin-converting enzyme inhibitor were associated with better prognosis. CONCLUSIONS Despite therapeutic advances, the mortality rates of patients with sustained ventricular tachyarrhythmias remain high. Prognosis depends on the severity of underlying heart disease, as reflected by the extent of left ventricular dysfunction and the presence of heart failure. Well-tolerated ventricular tachycardia in patients with structural heart disease does not carry a significantly better prognosis than ventricular tachyarrhythmia with more severe hemodynamic consequences.

Electrical cardioversion of atrial fibrillation or flutter with conscious sedation in the age of cost containment

BACKGROUND The purpose of this study was to compare the safety, efficacy, and cost of conscious sedation administered by electrophysiologists certified in the use of conscious sedation with sedation administered by anesthesiologists during cardioversion of atrial fibrillation or atrial flutter to sinus rhythm. METHODS AND RESULTS Patients with hemodynamically stable persistent atrial fibrillation and flutter were included in this study. Group 1 patients (n = 33) were sedated by an anesthesiologist and group 2 patients (n = 26) were sedated by an electrophysiologist. Anesthesiologists used propofol and electrophysiologists used midazolam and morphine for sedation. A cost analysis based on professional charges and cost of medications was performed for both groups and compared. Hospital charges were similar for both groups and were excluded from the cost analysis. Although time to sedation in group 1 was shorter than that in group 2, sedation was adequate in both groups such that no patient in group 1 and only 1 patient in group 2 recalled being shocked. There were no complications in either group. The cost incurred in group 2 was less than that in group 1. CONCLUSIONS Sedation administered by electrophysiologists for cardioversion of atrial arrhythmias is safe and cost effective. Midazolam and morphine, the sedative agents administered by electrophysiologists, were effective and well tolerated by patients.

Echocardiographic Features of Patients With Heart Failure Who May Benefit From Biventricular Pacing

Background: Recent studies suggest that cardiac resynchronization therapy through biventricular pacing (BVP) may be a promising new treatment for patients with advanced congestive heart failure (CHF). This method involves implantation of pacer leads into the right atrium (RA), right ventricle (RV), and coronary sinus (CS) in patients with ventricular dyssynchrony as evidenced by a bundle branch block pattern on electrocardiogram (ECG). Clinical trials are enrolling stable patients with ejection fractions (EF) ≤ 35%, left ventricular end‐diastolic diameters (LVIDd) ≥ 54 mm, and QRS duration ≥140 msec. We compared echocardiography features of these patients (group 1) with other patients with EF ≤ 35%, LVIDd ≥ 54 mm, and QRS < 140 msec (group 2 = presumably no dyssynchrony). Methods: Nine hundred fifty‐one patients with CHF, LVID 54 mm, EF 35% by echocardiography were retrospectively evaluated. One hundred forty‐five patients remained after those with primary valvular disease, prior pacing systems, or chronic atrial arrhythmias were excluded. From this group of 145 patients, a subset of 50 randomly selected patients were further studied (25 patients [7 females, 18 males] from group 1, and 25 patients [7 females, 18 males] from group 2). Mean age group 1 = 75 years old, mean age group 2 = 67 years old. Mean QRS group 1 = 161 msec, mean QRS group 2 = 110 msec. Each group was compared for presence of paradoxical septal motion, atrial and ventricular chamber sizes, LV mass, LVEF, and RV systolic function. Results: Of the initial group of 951 patients, 145 (15%) met inclusion criteria. In the substudy, 20/25 (80%) of group l and 7/25 (28%) of group 2 subjects had paradoxical septal motion on echo (Fishers exact test, P = 0.0005). The t‐tests performed on the other echocardiography variables demonstrated no differences in chamber size, function, or LV mass. Conclusions: Cardiac resynchronization therapy with BVP appears to target a relatively small population of our advanced CHF patients (15% or less). Although increasing QRS duration on ECG is associated with more frequent paradoxical septal motion on echo, it is not entirely predictive. Paradoxical septal motion on echo may therefore be more sensitive at identifying patients who respond to BVP. Further prospective studies are needed. (ECHOCARDIOGRAPHY, Volume 20, April 2003)

Cough‐Induced Heart Block

The patient is a 65-year-old man referred for evaluation of recurrent episodes of syncope, each preceded by coughing. His past medical history is significant for coronary artery disease. His only medications were aspirin and metoprolol (25 mg three times a day). ECG showed normal sinus rhythm with left bundle branch hlock. Echocardiogram demonstrated normal left ventricular function and mild mitral regurgitation. The patient was asked to cough voluntarily while a rhythm strip was recorded, during v̂ ĥich 7 seconds of transient complete heart hlock was recorded [Fig. 1) and the patient lost consciousness. On electrophysiology study, the AH interval was 85 ms and the HV was 80 ms at a sinus cycle length of 620 ms. Atrioventricular (AV) nodal Wenkebach occurred at 340 ms. A DDDR pacemaker was implanted and subsequently cough did not provoke syncope. The

Lead Failure Due to the Subclavian Crush Syndrome in a Patient Implanted with Both Standard and Thin Bipolar Spiral Wound Leads

Subclavian crush syndrome is a well‐described cause of pacemaker lend failure resulting from an entrapment of a lead or leads between the clavicle and the first rib. A new thinner lead (Thin Linetm) was designed to minimize this complication. Our patient de veloped atrial and ventricular lead subclavian crush syndrome with both conventional and thin leads.

A simple electrocardiographic algorithm for detecting ventricular tachycardia.

The purpose of this study wus to determine whether a simple ECG algorithm could be developed for predicting susceptibility to ventricular tachyarrhythmias (VT) as defined by sustained spontaneous or inducible VT. Two different QT dispersion algorithms were determined by the difference between the longest and shortest QT interval measured in three orthogonal leads (I, aVF, V1; QTD3), and at least 11 of 12 leads (QTDl2) from the 12‐lead ECG. These QT dispersion algorithms were investigated (with and without the QRS duration from the 12‐lead EGG) and compared to the signal‐averaged ECG (SAEGG) in order to determine their sensitivity and specificity for detecting VT. Only patients who underwent SAECC and were referred for programmed electrical stimulation were included in this study. A positive SAECG was defined by filtered QRS duration > 114 ms, and/or low amplitude signal duration > 38 ms, and/or root mean square voltage in the last 40 ms of < 20 μV. Sixty patients were enrolled in this study with a mean age of 63 ± 2 years. Eifty‐five percent of the patients had coronary artery disease. A simple ECG algorithm consisting of the sum of QTD3 plus the QBS duration had a sensitivity and specificity of 90% and 63%. respectively, whereas the SAECG had a sensitivity and specificity of 60% and 63%. respectively (P = 0.022). We conclude that a simple EGG algorithm is more sensitive than the SAEGG for predicting VT. This algorithm combines two easily measured variables obtained from the 12‐lead EGG, and can easily be performed without expensive computer equipment.

Pseudorecurrence of paroxysmal supraventricular tachycardia after radiofrequency catheter ablation

Over an 11-month period (November 1992 to October 1993), 32 radiofrequency catheter ablations were performed for recurrent symptomatic supraventricular tachycardia in 17 patients with atrioventricular (AV) nodal reentry, 13 with AV reentry with an accessory pathway), and 2 with both AV and AV nodal reentry. Each patient underwent both diagnostic and therapeutic electrophysiologic study with radiofrequency catheter ablation in a single session. Twelve of the 32 patients had recurrent symptoms after catheter ablation. A repeat study was performed in 9 of the 12 patients. At 7.7 +/- 0.8 months (range 4 to 11) of follow-up only one patient had had a true symptomatic recurrence. Additional sessions of ablation cured this patient. We conclude that pseudorecurrence of paroxysmal supraventricular tachycardia is a common phenomenon in patients after radiofrequency catheter ablation. Follow-up electrophysiologic study demonstrates and helps differentiate pseudo from true paroxysmal supraventricular tachycardia recurrence.

Planning and Guidance of Cardiac Resynchronization Therapy–Lead Implantation by Evaluating Coronary Venous Anatomy Assessed with Multidetector Computed Tomography

Objectives We sought to evaluate the utility of multidetector computed tomography (MDCT) in preoperative planning of cardiac resynchronization therapy (CRT) device implantation. Background Variation in coronary venous anatomy can affect optimal lead placement and may warrant preimplantation visualization prior to CRT lead placement. Methods Prospective randomized enrollment of 29 patients (17 males; mean age at implant 66.7 ± 12.8 years) was undertaken. Patients were randomized to preimplantation MDCT (GE® 64-detector Lightspeed, n = 16) or no MDCT. Implantation was planned based on three-dimensional coronary venous reconstruction as visualized in the CT group. Measurement of coronary sinus (CS) angulation, CS ostial (os) diameter, right atrial (RA) width, volume, and height was undertaken prior to implant. Intraoperative CS lead implantation times (introduction, cannulation, and left ventricular [LV] lead positioning), procedure time, fluoroscopy time, and venogram contrast volume were measured to determine if there was a difference between patients who underwent preimplant CT scan and those who did not. Results CS os diameter (mean = 13.8 ± 2.9 cm) was inversely correlated with total fluoroscopy time (r = -0.57, P = .008), and total procedure time, but this correlation was not statistically significant (r = - 0.36, P = 0.12). RA width (mean = 52.8 ± 9.9 cm) was associated with a shorter total procedure time (r = −0.44, P = .047) and LV lead positioning time (r = −0.33, P = .012). There were no statistically significant differences between the CT group and the non-CT group with respect to total intraoperative and fluoroscopy times or venogram contrast volumes. Total procedure time was longer in the CT group but the difference was not statistically significant (94 ± 27.2 vs. 74.7 ± 26.6; P = .065). Conclusion Noninvasive visualization of the coronary venous anatomy before CRT implantation can be used as a guide for lead placement. While no significant differences were noted between the two groups with respect to intraoperative variables, CS os diameter and RA width inversely correlated to a shorter procedure time and LV lead positioning time, respectively. Further clinical trials regarding the utility of MDCT to visualize coronary venous anatomy prior to CRT implantation for procedural planning and lead placement guidance are warranted.

Pacemaker ventricular lead microdislodgement following a motor vehicle accident

Pacemaker lead dislodgement can be defined as any lead position change, whether the functionality of the pacemaker is affected or not. Only dislodgements that provoke a malfunction in the pacing system, however, are clinically relevant. Lead dislodgement can be categorized as ‘macro’ or ‘micro’ dislodgement depending upon the presence of radiographic evidence. This case illustrates a case of lead microdislodgement after a low-impact motor vehicle accident. The lead tip was minimally displaced; enough to produce an increase in capture threshold and eventually loss of capture while keeping near normal lead impedance values. Review of the literature shows that ventricular lead dislodgement after a motor vehicle accident is a rare incidence and cause of pacemaker malfunction.

Emotion-Triggered Cardiac Asystole-Inducing Neurocardiogenic Syncope

The pathophysiology of neurocardiogenic syncope (NCS) is multifactorial. Recurrent syncopal episodes can result in injury and can provoke substantial anxiety among patients. Although an abundance of descriptions of various forms of syncope have been reported in the literature, few articles to date address a documented case due to emotional stress or sound. This is a report of a 31‐year‐old woman who fainted after being startled by someone sneezing. Review of the episode on her event recorder revealed a transient cardiac asystole of 10 seconds. We discuss the incidence of NCS and the proposed mechanism by which this syncopal event occurred.