Cardiac rhabdomyoma in an adult patient presenting with ventricular arrhythmia.

Cardiac rhabdomyomas are extremely uncommon in the adult patient. We describe a previously healthy man who presented with ventricular arrhythmias resulting from a right ventricular, cardiac rhabdomyoma. Echocardiography, CT scanning, and MRI are recognized as useful diagnostic modalities for intracardiac lesions. Cardiac catheterization in our patient demonstrated the presence of a tumor blush. This has not previously been reported with cardiac rhabdomyomas. Although lesions may spontaneously regress, surgery is often necessary and frequently resolves the underlying arrhythmia.

Concealed mechanical bradycardia: an indication for permanent pacemaker implantation.

We report a 51-year-old man with severe ischemic cardiomyopathy and heart failure in whom incessant bigeminal ventricular ectopy failed to generate a detectable arterial pressure. This created a mechanical bradycardia despite an adequate electrical heart rate. Dual chamber pacing increased the effective heart rate and allowed discontinuation of an intraaortic balloon pump from which the patient could not otherwise be weaned.

A new method for diagramming pacemaker electrocardiograms.

Advancements in technology have made paced ECG interpretation increasingly difficult. A new method for depicting the complex pacemaker/heart interactions that eliminates the extensive use of symbols and repetitious use of refractory period and rate limit information of previous methods has been devised. The method uses a framework of parallel horizontal lines drawn on grid paper underneath the ECG. The lines are spaced apart by the actual programmed values (lower rate, AV, VA intervals) of the pacemaker in question. This framework allows the simultaneous use of the horizontal and vertical directions for the diagram of pacemaker timing intervals. Also, a single representation of refractory periods, upper rate intervals, and other variables can be labeled vertically and extrapolated horizontally across the entire diagram. Single chamber, dual chamber, and rate-modulated ECGs are readily represented. The diagram is easily plotted on standard ECG paper and flexible enough to represent complex ECGs.

Deleterious effects of long-term single-chamber ventricular pacing in patients with sick sinus syndrome: the hidden benefits of dual-chamber pacing.

Nine hundred fifty patients who received three modes of primary pacemaker systems (581 dual-chamber universal [DDD], 84 atrioventricular-sequential ventricular-inhibited [DVI] and 285 ventricular-inhibited [VVI]) over 12 years were studied retrospectively to determine the effect of pacing mode on patient longevity and the subsequent development of chronic atrial fibrillation or flutter. All patients were followed up continuously for 7 to 8 years. Patients were classified according to indication for permanent pacing (sick sinus syndrome or other indication), age at pacemaker implantation (less than or equal to 70 or greater than 70 years) and history of atrial tachyarrhythmia. Fourteen percent of patients developed atrial fibrillation at some time during the study period. Of those, 4% had a DDD pacemaker, 8% had a DVI pacemaker and 19% had a VVI pacemaker. At 7 years, atrial fibrillation was significantly more frequent in the VVI group than in the DDD and DVI groups. In patients with sick sinus syndrome, the incidence rate was even higher in the VVI group but approximately the same in the DDD and DVI groups. Patients in the VVI and DVI groups who had had previous atrial tachyarrhythmia had a significantly higher incidence of atrial fibrillation at 7 years than did those in the DDD group. During the entire period there were 130 deaths in the study group, including 22% of patients with a DDD pacemaker, 38% of those with a DVI pacemaker and 50% of those with a VVI pacemaker. Patient survival at 7 years was lower in the VVI group than in the DDD or DVI groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term functional integrity of atrial leads.

The effectiveness and reliability of atrial leads has been questioned. We studied retrospectively, all atrial leads implanted at our center (n = 494; 438 Medtronic Model 6957J, 56 Medtronic Model 4512) over a 5-year period ending December 31, 1987, to determine the frequency of atrial lead failure (pacing, sensing, or both) and the median duration of proper pacing and sensing function for each lead model studied. Eighty-eight percent of the polyurethane atrial leads continued to function satisfactorily at 5 years, results somewhat better than those reported heretofore in the literature, as well as our own past results with a variety of different lead types. There were 29 failures of pacing, sensing, or both (6% of implants). The cumulative survival of the atrial leads at 5 years was 88%. Pacing and sensing survival were 91% +/- 2.4% and 88% +/- 2.9%, respectively. We conclude that the choice of pacing mode for a new pacemaker should be based solely on the clinical indication and not on the concern that atrial pacing and sensing will be unreliable.