Behzad B. Pavri

Cardiac death and stored electrograms in patients with third-generation implantable cardioverter-defibrillators.

OBJECTIVES We sought to utilize terminal stored intracardiac electrograms (EGMs) to study the electrophysiologic events that accompany mortality in patients with third-generation implantable cardioverter-defibrillators (ICDs). BACKGROUND Despite their ability to effectively terminate ventricular tachyarrhythmias, cardiac mortality in patients with ICDs remains high. The mechanisms and modes of death in these patients are not well understood. METHODS We retrospectively analyzed clinical data and stored EGMs from patients enrolled in the clinical trial of the Ventritex Cadence ICD. Of the 1,729 patients 119 died during 6 years of follow-up. The final recorded EGM was reviewed. Postimplant EGMs as well as 50 control EGMs were used to define normal EGM characteristics. RESULTS There were 36 noncardiac deaths (30%) and 83 cardiac deaths (70%). Of the cardiac deaths, 55 (66%) were nonsudden and 28 (34%) were sudden. When cardiac deaths were analyzed, 46 (55%) had no stored EGMs within 1 h of death, implying that the deaths were not directly related to tachyarrhythmias. In 37 cardiac deaths (18 nonsudden, 19 sudden), stored EGMs were present within 1 h of death. In these 37 deaths, the final EGM recorded was wide (>158 ms) in 33 (89%). Wide EGMs were interpreted as ventricular tachycardia in 27 and ventricular fibrillation in 6. In 13 of the 33 patients (39%) with wide EGMs, therapy was not delivered by the ICD, as it incorrectly detected a spontaneous termination of the arrhythmia. EGMs were significantly wider if recorded within 1 h, as compared with those recorded from 1 to 48 h before death (261+/-124 vs. 181+/-93 ms, p=0.04). CONCLUSIONS Only 37 patients (31%) who died after placement of an ICD had a stored EGM within 1 h of the time of death, suggesting that the majority of deaths (69%) were not the immediate result of a tachyarrhythmia. When EGMs were recorded, they were wide in 89% of patients. These wide EGMs most likely represent intracardiac recordings of electromechanical dissociation. Thus, of the 119 deaths, 112 (94%) were not the immediate result of a tachyarrhythmia.

Sustained Bundle Branch Reentry in a Patient with Hypertrophic Cardiomyopathy and Nondilated Left Ventricle

Ventricular tachycardia is a well-known complication in patients withhypertrophic cardiomyopathy. We report the case of a patient withhypertrophic cardiomyo<->pathy with easily inducible monomorphic ventriculartachycardia. Electrophysiology study demonstrated that bundle branch reentrywas the mechanism of the tachycardia. The tachycardia was renderednon-inducible by radiofrequency ablation of the right bundle branch.

Pacing Alternans: An Unusual Pattern of Pacemaker Behavior

PAVRI, B.B., et al.: Pacing Alternans: An Unusual Pattern of Pacemaker Behavior. We report an unusual pattern of pacemaker function related to the “autocapture” feature of a recently released pacemaker model. The electrocardiogram reveals pacing alternans. This report discusses the differential diagnosis and the correct explanation.

Prolonged Quinidine Half-life with Associated Toxicity in a Patient with Hepatic Failure

A markedly prolonged quinidine elimination half‐life due to hepatic failure and resultant quinidine toxicity occurred in a 57‐year‐old man with a history of atrial fibrillation. A prolonged QT interval, development of torsades de pointes, and a serum quinidine concentration of 3.1 μg/ml contributed to a decision favoring permanent pacemaker implantation. The apparent quinidine half‐life ranged from 66–99 hours and was associated with QT prolongation and persistent U waves. On discontinuing quinidine, all signs associated with toxicity resolved as serum quinidine concentrations decreased, which resulted in reversal of the decision to implant a permanent pacemaker. This case reports an extremely long quinidine elimination half‐life and reillustrates the importance of drug pharmacokinetics in patient care.

Dynamic Practical Electrocardiography

No wonder you activities are, reading will be always needed. It is not only to fulfil the duties that you need to finish in deadline time. Reading will encourage your mind and thoughts. Of course, reading will greatly develop your experiences about everything. Reading dynamic practical electrocardiography is also a way as one of the collective books that gives many advantages. The advantages are not only for you, but for the other peoples with those meaningful benefits.

An electrocardiographic masquerade.

A 60-year-old woman underwent successful pulmonary embolectomy for a massive pulmonary embolism. On postoperative day 2, while receiving intravenous dopamine for hypotension, she developed the tachycardia, and a 12-lead ECG was obtained (Fig. 1). Figure 2 shows the 12-lead ECG obtained on the previous day, when she was in sinus rhythm with frequent premature

The Presence of a Q Wave in Lead V5 Excludes Manifest Preexcitation

The degree of preexcitation in patients with the Wolff‐Parkinson‐White syndrome may vary depending on autonomic tone, heart rate, pathway location, and atrioventricular node conduction. When subtle, preexcitation may be difficult to detect with a 12‐lead electrocardiogram (ECG). Furthermore, the pattern of preexcitation may be mimicked in patients with QRS widening and rapid atrioventricular node conduction.

Wide QRS Complex Tachycardia: What is the Mechanism?

A 51-year-old man witb a bistory of a remote anteroseptal myocardia! infarction presented to the emergency room with palpitations and mild ligbtheadedness. He had developed ventricular tacbycardia (VT) 1 year after the infarction and had undergone coronary artery bypass graft surgery witb map-guided subend(x:ardial resection 5 years previously. His ejection fraction was severely decreased. In the emergency room, he was noted to be in a wide complex tachycardia (Fig. IB) that spontaneously terminated with resumption of sinus rhythm (Fig. I A). The patient subsequently underwent electrophysiology study. Figure 2 shows 12 surface leads and intracardiac electrograms from the high right atrium (HRA), the proximal and distal His-bundle regions (HBE-PR, HBEDIS, respectively), cbe left bundle region (ABL-PR), and the right ventricular apex (RVA). Panel A of Figure 2 shows sinus rhytbm., and panel B shows the tachycardia. What is the likely mechanism of this wide QRS complex tachycardia?

QRS Alternans During Tachycardia

A 40-year-old man presented with recurrent palpitations and presyncoi^e. He was taken to the electrophysiology laboratory where the arrhythmia shown in Figure 1 (panel A at paper speed of 25 mm/sec, panel B at 50 min/.sec) was induced. Figure 2 shows the intiacaidiac tracings (displayed at paper speed of 150 mm/sec). Explain the tachycardia mechanism and the QRS altemans seen in the limb leads.

What is the Mechanism of the Arrhythmia

A 37-year-old man complained of frequent episodes of palpitations, often hrought on hy cocaine use. The resting ECG demonstrated normal sinus rhythm with a normal axis and poor R wave progression. During a diagnostic electrophysiologic (BP) study, a wide QRS tachycardia with a cycle length of 274 msec was induced (Fig. I), which spontaneously converted to a narrow complex tachycardia with a cycle length of 548 msec. A spontaneous ventricular premature depolarization (VPD) during the narrow complex tachycardia reproduced the wide complex tachycardia seen previously. What is the mechiuiism of the tachycaniia? What mechiuiism is responsible for the changes observed in QRS morphology?