S. Serge Barold

Endocardial Biventricular Pacing

Simultaneous righ t and left ventricular pacing was performed in a 73‐year‐old man with coronary artery disease end‐stage congestive heart failure and a DDD pacemaker implanted for sick sinus syndrome. An endocardial LV lead was introduced transseptally after unsuccessful attempts to enter the coronary sinus. This new approach for multisite pacing offers an alternative to epicardial LV from the coronary sinus or by thoracotomy.

Pacer-induced tachycardia associated with an atrial synchronous ventricular inhibited (ASVIP) pulse generator

A 68‐year‐old white male underwent permanent pacemaker implantation with an atrial synchronous ventricular inhibited pulse generator (Medtronic model 2409) because of syncope and abnormal H‐V interval of 70 ms. Paroxysmal bouts of pacemaker associated tachycardia were subsequently recorded on several occasions, initiated and terminated by spontaneous ventricular premature beats. The mechanism for the occurrence of the tachyarrhythmia is discussed in detail and the functional characteristics of the pulse generator are described. Replacement of the unit with a different pacer device prevented further occurrence of the arrhythmia. (PACE, Vol. 5, March‐April, 1982)

Loss of atrial capture during DDD pacing: what is the mechanism?

A 75-year-old man with a past history of myocardial infarction, congestive heart failnre, ventricular tachycardia, and a DDD pacemaker implanted for sick sinus syndrome was hospitalized for recurrent congestive heart failure. He was treated with digoxin, IV diuretics, and large doses of captopril for aggressive unloading therapy. Amiodarone that he had heen taking for several months was continued. On the second day, pacemaker testing revealed a hipolar atrial pacing threshold < 2.5 V at 0.05 ms and a bipolar ventricular pacing threshold < 2.5 V at 0.1 ms. Both outputs were left unchanged at 2.5 V, 0.4 ms. The patient gradually improved, but on the seventh day he developed acute pulmonary edema at which time an ECG was obtained (Fig. 1).

Intermittent VA Conduction Block in Junctional Reentrant Tachycardia: True or False?

A 62-year-old man with a history of drug refractory supraventricular tachycardia (SVT) was referred for catheter ablation. The referring physician had observed that the patient suffered from SVT characterized hy a relatively long RP interval [RP < PR) and easily identifiahle retrograde P waves some of which were occasionally missing. This pattern was confirmed in a 12-lead EGG (Fig. 1) ohtained at the start of an electrophysiological study (EPS). A tentative diagnosis of slow intermediate AV nodal reentrant tachycardia was made on the grounds that VA hlock (missing P waves) excluded the diagnosis of atrial tachycardia or SVT utilizing an accessory pathway.