Shoei K. Huang

Significance of ventricular tachycardia in idiopathic dilated cardiomyopathy: Observations in 35 patients

To evaluate the significance of ventricular tachycardia (VT) in idiopathic dilated cardiomyopathy (IDC), 35 consecutive patients seen between 1976 and 1980 were studied. The criteria for diagnosis of IDC were based on clinical, laboratory, and cardiac catheterization findings. All patients had right and left heart catheterization, left ventriculography, and coronary cineangiography. Long-term ambulatory electrocardiograms (Holter) were obtained in all patients at the time of diagnosis. There were 24 male and 11 female patients aged 22 to 72 years (mean +/- standard deviation [SD]51 +/- 12). Frequent ventricular premature beats (VPB) (30/h) were observed in 29 patients (83%): complex VPB (Lown grades 3, 4, and 5) in 93% and simple VPB in 7%. Twenty-one patients (60%) had nonsustained VT consisting of 3 to 46 beats (8 +/- 5) with rates from 75 to 210/min. No difference between patients with and those without VT was observed in regard to the presenting symptoms, functional classification, electrocardiographic findings, heart size on chest X-ray, and the hemodynamic measurements including cardiac index, left ventricular end-diastolic pressure, and ejection fraction. Patients with VT were older (p less than 0.05). Follow-up observation from 4 to 74 months (34 +/- 17) showed that 2 patients died suddenly (1 with and 1 without previous VT), a third patient died from intractable congestive heart failure, and the fourth from sepsis. It is concluded that (1) the incidence of ventricular arrhythmias in IDC is high, (2) VT is frequent and tends to occur in the nonsustained form, and (3) there is no correlation between VT and the clinical and hemodynamic findings. VT does not appear to predict prognosis during a relatively short follow-up period in patients with IDC.

Clinical, electrocardiographic and follow-up observations in patients having ventricular fibrillation during holter monitoring. Role of quinidine therapy

Ventricular fibrillation occurred during Holter electrocardiographic monitoring in 5 of 3,307 consecutive patients. All five patients had Holter studies for evaluation of antiarrhythmic drug therapy; their ages ranged from 51 to 65 years. No patient had acute myocardial infarction; all had congestive heart failure and severe left ventricular dysfunction. One patient had ischemic and four had nonischemic cardiomyopathy. All patients had recently begun treatment with oral quinidine and had plasma quinidine levels of 1.24 to 5.18 microgram/ml. The Holter monitoring revealed that all had a long Q-T interval and that ventricular fibrillation began during frequent ventricular premature beats and was immediately preceded by ventricular tachycardia of the torsade de pointes type. The coupling interval of the ventricular premature beats initiating torsade de pointes was late (440 to 720 ms) and followed long preceding cycles (840 to 1920 ms). Ventricular fibrillation resolved spontaneously in two patients, but two of the remaining three patients died despite attempted cardiopulmonary resuscitation. It is concluded that (1) left ventricular dysfunction, chronic ventricular arrhythmias and initiation of quinidine therapy were the common findings in these patients; (2) a long Q-T interval, late coupled ventricular premature beats and long preceding cycles facilitate initiation of ventricular fibrillation in quinidine-treated patients; and (3) direct on-line monitoring should be utilized in the management of these patients.

The role of Holter monitoring in patients with recurrent sustained ventricular tachycardia: an electrophysiologic correlation

The significance of spontaneous ventricular premature depolarization (VPD) frequency and severity in patients with sustained ventricular tachycardia undergoing serial electrophysiologic studies (EPS) are unknown. Nineteen patients with sustained ventricular tachycardia were studied with 24-hour Holter recordings prior to control EPS and prior to each drug trial. Successful drug or surgical treatment (with the exception of amiodarone) was based upon noninducibility of ventricular tachycardia in the laboratory. Among the eight noninducible and nonamiodarone medically treated patients, two (25%) had significant VPD reduction and/or Lown class improvement. The remaining six (75%) had no change or worsening of Holter findings, despite noninducibility of sustained VT. Among the six amiodarone-treated patients, five of whom were persistently inducible prior to discharge, four (66%) had improved and two (33%) had worsened Holter findings compared to control. None of the five (100%) surgically managed patients were inducible postoperatively, and three of the five (60%) had no change or worsening of Holter findings. We conclude that (1) EPS are superior to Holter findings in assessing successful management; and (2) Holter findings may be concordant or discordant during EPS serial drug trials or following surgery and therefore cannot predict the success or failure of the intervention.

Short PR interval and narrow QRS complex associated with pheochromocytoma: electrophysiologic observations

A patient with a short (0.10 second) PR interval, narrow QRS complex and palpitation is described. Electrophysiologic studies demonstrated the presence of accelerated atrioventricular (AV) nodal conduction. Subsequently, a pheochromocytoma was found. Surgical removal of the tumor resulted in normalization of the PR interval. These findings suggest that the short PR interval and the accelerated AV nodal conduction were due to the effect of excess catecholamines on the AV conduction system.

Dual AV Nodal Pathways—Vagal Influences on AV Nodal Conduction

This 52‐year‐old male presented with syncope and demonstrated two distinct PR intervals on the electrocar‐diogram. Electrophysiologic studies showed dual A V nodal path ways. Right‐sided carotid sinus massage induced prolonged periods of sinus arrest with no change in AH interval. Left‐sided carotid sinus massage produced long AH intervals (slow pathway conduction) with some slowing of sinus rate. Whenever sinus rhythm with slow pathway conduction was observed (long AH) a 20‐30 mmHg drop systolic pressure was seen. Following implantation of an AV sequential pacemaker, the patient has been asymptomatic.

Normal Electrophysiological Findings in a Patient with Symptomatic Intermittent Advanced Atrioventricular Block

This report describes an otherwise healthy young woman who presented with syncope during episodes of advanced atriovenlricular (A V) block. The His bundle recordings during normal sinus rhythm and atrial and ventricular pacing were normal. Carotid sinus massage produced no abnormality. Subsequently, (he patient received a permanent pacemaker and has been free of symptoms. In termittent advanced A V block has been observed on follow‐up electrocardiograms. This unique case demonstrates a potential limitation of routine electrophysiologic investigation.