Adrian H. Shandling

Hyperbaric Oxygen and Thrombolysis in Myocardial Infarction: The ‘HOT MI’ Randomized Multicenter Study

In a previous pilot study, we demonstrated that adjunctive treatment with hyperbaric oxygen (HBO) appears to be feasible and safe in patients with acute myocardial infarction (AMI) and may result in an attenuated rise in creatine phosphokinase (CPK), more rapid resolution of pain and ST changes. This randomized multicenter trial was organized to further assess the safety and feasibility of this treatment in human subjects. Patients with an AMI treated with recombinant tissue plasminogen activator (rTPA) or streptokinase (STK), were randomized to treatment with HBO combined with either rTPA or STK, or rTPA or STK alone. An analysis included 112 patients, 66 of whom had inferior AMIs (p = NS). The remainder of the patients had anterior AMIs. The mean CPK at 12 and 24 h was reduced in the HBO patients by approximately 7.5% (p = NS). Time to pain relief was shorter in the HBO group. There were 2 deaths in the control and 1 in those treated with HBO. The left ventricle ejection fraction (LVEF) on discharge was 51.7% in the HBO group as compared to 48.4% in the controls (p = NS). The LVEF of the controls was 43.4 as compared to 47.6 for those treated, approximately 10% better (no significant difference). Treatment with HBO in combination with thrombolysis appears to be feasible and safe for patients with AMI and may result in an attenuated CPK rise, more rapid resolution of pain and improved ejection fractions. More studies are needed to assess the benefits of this treatment.

Physical Determinants of the Endocardial P Wave

SHANDLING, A.H., ET AL.: Physical Determinants of the Endocardial P Wave. Reliable atrial sensing of intrinsic P wave activity is important to ensure optimal atrial or dual chamber pacemaker function. Various physical factors (e.g., posture, respiration, exercise) may influence P wave characteristics and impair adequate sensing. To investigate this phenomenon, we measured the average of three P wave amplitudes (PWA) and calculated slew rates from telemetered printouts acquired from Pacesetter pacemakers in 32 patients. These measurements were performed in various body positions, with upright exercise and in varying stages of respiration. Results: the mean supine PWA increased on full inspiration (3.56 ± 1.3 mV versus 3.25 ± 1.2 mV during quiet respiration, p < 0.001), and also increased significantly with full expiration. The mean PWA increased on assuming the erect position (3.25 ± 1.2 mV increasing to 3.49 ± 2.3 mV, p < 0.001); in the upright position, the mean erect PWA during quiet respiration was not significantly influenced by the stage of respiration. The mean upright exercise PWA did not differ significantly from the preexercise erect PWA (3.50 f 1.2 with exercise, and 3.47 ± 1.5 before exercise; P = NS). Calculated slew rates were not different lying versus standing. Conclusions: the mean supine PWA increases significantly at the extremes of respiration and on assuming the erect body position; upright exercise results in no appreciable change in the erect PWA. Atrial sensitivity adjustments based on standard supine testing should be adequate for all body positions. (PACE, Vol. 13, December, Part I 1990)

Variation in P Wave Amplitude Immediately After Pacemaker Implantation: Possible Mechanism and Implications for Early Programming

SHANDLING, A.H., et al.: Variation in P Wave Amplitude Immediately After Pacemaker Implantation: Possible Mechanism and Implications for Early Programming The P ivave amplitude (PWA) plays an important role in doterirnning atrial sensing capabilities. To assess early PWA change, we compared lhe unipolar PWA in 43 patients at the time of atrial lead placement, measured by a pacing systems analyzer, to the unipolar PWA recorded at the end of pacemaker surgery, from telemetered airial endocardial electrograms. Individual PWA varied from a decrease of 5.2 mV lo an increase of 2 mV (−63% to 267%). In 33 patients with active fixation leads, the implant PWA was 1.96 ± 0.99mV versus 2.4 ± 1.4 mV after surgery. In 11 patients with passive fixation leads, the implant PWA was 2.8 ± 1.9 mV versus 1.9 ± 0.8 mV after surgery. The PWA change, measured as the difference between the postsurgical and implant PWA was 0.43 ± 0.8mV in active versus −0.86 ± 1.6 mV in the passive fixation lead groups (P < 0.05). Considerable change in individual P wave ampiitude can therefore occur very early after pacemaker implantation. The direction differs significantly between active (predominantly positive) and passive fixation groups (predominantly negative). These data suggest that an adequate margin of safety is important when initially programming atrial sensitivity, particularly when using passive fixation leads.

Efficacy of three-channel ambulatory electrocardiographic monitoring for the detection of myocardial ischemia

The recognition of silent myocardial ischemia (SMI) has been demonstrated to have important clinical relevance. Two-channel ambulatory (Holter) electrocardiographic recording is a commonly utilized method for detecting transient electrocardiographic ST segment changes representative of SMI. It has been suggested that the analysis of two channels alone may not adequately detect SMI. We therefore evaluated the diagnostic yield of three channels using a three-channel electrocardiographic monitoring device in 46 consecutive patients (age 61 +/- 9 years) undergoing percutaneous transluminal coronary angioplasty of an isolated single-vessel stenosis. Modified bipolar chest leads V2, V5, and AVF (CM-V2, CM-V5, and CS-AVF) were utilized for analysis. The percent detection of ST segment changes from various combinations of two-lead recordings were compared to the total three leads, and an absolute transient ST segment shift (STSS) of greater than or equal to 1 mm during balloon inflation was considered as evidence of myocardial ischemia. One patient was excluded because of the need for ventricular pacing during balloon inflation. A total of 33 of 45 patients had STSS in all three leads (percent detection = 73%), while 32 (71%) had STSS in the two-lead grouping with the highest diagnostic yield (CM-V2/CM-V5; p = ns). Of the various two-lead combinations studied, leads CM-V2 and CM-V5 provided the best lead set overall for the detection of ischemic STSS. Three-channel ambulatory electrocardiographic recording only marginally improves upon the detection of ischemia when compared with standard (CM-V2/CM-V5 or CM-V5/CS-AVF) two-channel ambulatory electrocardiographic recordings.

Atrial Automatic Tachycardia‐Reversion Pacemakers: Their Economic Viability and Impact on Quality‐of‐Life

Refractory supraventricular tachyarrhythmias may be both difficult and costly to control medically and can interfere with the patients lifestyle. Newer treatment modalities are available for their management, and these require comprehensive assessment. We therefore compared costs and selective indices of patient benefit in a group of 17 patients in whom an atrial antitachycardia (Intermedics Intertach 262–12) pacemaker was placed for refractory supraventricular tachyarrhythmias. Prior medical therapy was compared to subsequent automatic antitachycardia pacemaker treatment. The total medical costs (admissions, emergency room visits, office visits, and medication costs) and the number of hospitalizations and medications were compared prior to implantation (F/U 69.3 ± 61 months) and after implantation (F/U 15.3 ± 7.8 months). A detailed quality‐of‐life questionnaire was also obtained 36.6 ± 11 months after implantation. Results: There were significant per patient differences in total cost before and after implantation: monthly costs were

Utility of the Atrial Endocardial Electrogram Concurrent with Dual‐Chamber Pacing in the Determination of a Pacemaker‐Mediated Arrhythmia

505 ±

Prevalence of patent foramen ovale in patients with acute myocardial infarction and angiographically normal coronary arteries

833 before pacemaker implantation and

Thoracoscopic Microwave Epicardial Ablation: Feasibility for the Treatment of Idiopathic Sinus Node Tachycardia

105 ±

The prevalence of cardiac ectopy in elderly patients with echocardiographically normal hearts is not increased by significant coronary artery disease

117 monthly afterward (P < 0.005). Pacemaker implantation hospitalization costs were

Noninvasive testing of silent myocardial ischemia

19,063 ±