Exercise testing in the presence of complete heart block.

A 28-yr-old female presented for preoperative evaluation. The resting ECG revealed sinus arrhythmia with complete heart block with a junctional escape rhythm and a ventricular rate of 43 bpm. The patient was in no apparent distress, and resting blood pressure was 80/50 mm Hg. Physical examination was largely unremarkable, with the exception of a soft, nontender, movable abdominal mass. The patient complained of mild dyspnea with stair climbing, but she was otherwise asymptomatic. Although high-grade atrioventricular (AV) block is considered a relative contraindication for exercise testing, this patient was referred for an exercise ECG stress test to assist in determining whether a electronic pacemaker or other therapy was necessary. A symptom-limited maximal ECG treadmill test was performed using the Bruce protocol. The resting HR before the test was 47 bpm, and resting blood pressure was 70/50 mm Hg. Beginning with the first stage of the test, sinus rhythm with a first-degree AV block was observed. The patient achieved 10.2 METs, with an HRpeak of 122 bpm and a peak blood pressure of 122/70 mm Hg. No ectopy was noted during exercise, no ST segment changes occurred during exercise or recovery, and the patient remained asymptomatic. The test was terminated because of the patient's inability to keep pace with the treadmill. On the basis of these results, no medical therapy or electronic pacemaker was recommended at this time, and the patient was permitted to undergo surgery for uterine fibroid tumors. This case illustrates that although complete heart block is a relative contraindication to exercise testing in some patients, the benefits of testing outweigh the risks.

Repetitive monomorphic ventricular tachycardia associated with exercise--a case report.

The case of a 45-year-old man suffering from a catecholamine-sensitive ventricular tachycardia originating from the right ventricular outflow tract is reported. The authors describe a novel noninvasive treatment strategy for the management of this patient.

Usefulness of P-wave morphology during submaximal treadmill exercise to predict coronary artery disease.

Standard electrocardiographic criteria for exercise testing require near maximal exertion and fail to detect ischemia in the presence of previous infarction or conduction or repolarization abnormalities, in women, or in the presence of certain drugs. Changes in P-wave morphology have been suggested as having diagnostic utility; however, no specific criteria exist, and it is not clear which changes are most useful. This investigation evaluated the ability to detect the presence of coronary artery disease by examining changes in P-wave morphology during exercise. A group of 123 consecutive patients underwent maximum (symptom-limited) exercise nuclear stress tests. The electrocardiograms at rest, 2 minutes of exercise, 50% of maximum exercise time, maximum exercise, and 3 minutes of recovery were analyzed for the duration of the P wave in lead II, the duration of the terminal negative component of the P wave in lead V1, the amplitude of the terminal negative component of the P wave in lead V1, and the duration of the P wave in lead V5. These variables were then analyzed for their relation to the presence of perfusion defects. Of all the P-wave criteria tested, a change in amplitude of the negative component of the P wave in lead V1 from at rest to 50% of maximum exercise time of <0.025 mV was the most predictive of coronary artery disease.

New-onset congestive heart failure secondary to a "huge" right atrial mass--a case report.

Transesophageal echocardiography is a useful adjunct to other diagnostic modalities in uncovering the etiology of congestive heart failure. The authors describe the case of a 75-year-old woman with a 4-week history of progressive congestive heart failure, in whom transesophageal echocardiography played a critical role in the diagnosis of a right atrial mass, accounting for this patient's constellation of symptoms.

Correction of AV-nodal block in a 27-year-old man with severe obstructive sleep apnea--a case report.

A 27-year-old morbidly obese man diagnosed with severe obstructive sleep apnea (OSA) and experiencing significant ventricular asystoles at times exceeding 8 seconds, during polysomnography. The bradyarrhythmias were successfully corrected with the application of a nasal continuous positive airway pressure (CPAP) mask. Follow-up 24-hour ambulatory Holter monitoring without the aid of a nasal CPAP mask and repeat polysomnography with a CPAP mask after several weeks of continuous CPAP therapy during sleep revealed no evidence of ventricular asystole, despite no change in the patient's body mass index. We discuss several mechanisms explaining the findings in this particular patient.

Amiodarone-induced torsade de pointes during bladder irrigation: an unusual presentation--a case report.

The authors present a case of early (within 4 days) development of torsade de pointes (TdP) associated with oral amiodarone therapy. Consistent with other reports this case of TdP occurred in the context of multiple exacerbating factors including hypokalemia and digoxin excess. Transient prolongation of the QT during bladder irrigation prompted the episode of TdP. It is well known that bradycardia exacerbates acquired TdP. The authors speculate that the increased vagal tone during bladder irrigation, a vagal maneuver, in the context of amiodarone therapy resulted in amiodarone-induced proarrhythmia. In the absence of amiodarone therapy, a second bladder irrigation did not induce TdP despite hypokalemia and hypomagnesemia.