William P. Batsford

Emotional and Physical Precipitants of Ventricular Arrhythmia

Background—Observational studies have suggested that psychological stress increases the incidence of sudden cardiac death. Whether emotional or physical stressors can trigger spontaneous ventricular arrhythmias in patients at risk has not been systematically evaluated. Methods and Results—Patients with implantable cardioverter-defibrillators (ICDs) were given diaries to record levels of defined mood states and physical activity, using a 5-point intensity scale, during 2 periods preceding spontaneously occurring ICD shocks (0 to 15 minutes and 15 minutes to 2 hours) and during control periods 1 week later. ICD-stored electrograms confirmed the rhythm at the time of shock. A total of 107 confirmed ventricular arrhythmias requiring shock were reported by 42 patients (33 men; mean age, 65 years; 78% had coronary artery disease) between August 1996 and September 1999. In the 15 minutes preceding shock, an anger level ≥3 preceded 15% of events compared with 3% of control periods (P <0.04; odds ratio, 1.83; 95% confidence intervals, 1.04 to 3.16) Other mood states (anxiety, worry, sadness, happiness, challenge, feeling in control, or interest) did not differ. Patients were more physically active preceding shock than in control periods. Anger and physical activity were independently associated with the preshock period. Conclusions—Anger and physical activity can trigger ventricular arrhythmias in patients with ICDs. Future investigations of therapies aimed at blocking a response to these stressors may decrease ventricular arrhythmias and shocks in these patients.

Cardiovascular abnormalities accompanying acute spinal cord injury in humans: Incidence, time course and severity

The frequency of cardiovascular abnormalities was evaluated in 71 consecutive patients with acute injury to the spinal cord. Persistent bradycardia was universal in all 31 patients with severe cervical cord injury and less common in milder cervical injury (6 of 17) or thoracolumbar injury (3 of 23) (p less than 0.00001). Marked sinus slowing (71 versus 12 versus 4%, respectively, p less than 0.00001), hypotension (68 versus 0 versus 0%, p less than 0.00001), supraventricular arrhythmias (19 versus 6 versus 0%, p = 0.05) and primary cardiac arrest (16 versus 0 versus 0%, p less than 0.05) were significantly more frequent in the severe cervical injury group. The frequency of bradyarrhythmias peaked on day 4 after injury and gradually declined thereafter. All observed abnormalities resolved spontaneously within 2 to 6 weeks. The primary mechanism underlying these observations appears to involve the acute autonomic imbalance created by the disruption of sympathetic pathways located in the cervical cord. Acute severe injury to the cervical spinal cord is regularly accompanied by arrhythmias and hemodynamic abnormalities not found with thoracolumbar cord trauma. These abnormalities are limited to the first 14 days after injury, a period in which life-threatening disturbances must be anticipated.

Demonstration of Re-entry within the His-Purkinje System in Man

Re-entry within the His-Purkinje system (HPS) was consistently observed in 15/24 consecutive patients in whom retrograde refractory period studies were performed using His bundle electrograms and the ventricular extrastimulus method. Within a narrow range of ventricular coupling intervals (V1V2), V2 retrogradely conducted to the bundle of His (H2) with significant infra-His bundle conduction delay (V2H2 interval). At critical V2H2 delays another beat of ventricular origin (V3) followed V2 and was associated with H2V3 intervals greater than the H-V intervals of sinus beat. It is postulated that V2 retrogradely blocked within the right bundle branch and activated the bundle of His via the left bundle branch after which antegrade conduction occurred along the right bundle branch producing the V3 response. In support of re-entry within the HPS are the following: 1) V3 occurred in a narrow range of V1V2 intervals and critical V2H2 delays, 2) V3 did not occur when V2 retrogradely blocked below the bundle of His, 3) V3 was independent of retrograde A-V nodal delay, 4) V3 rarely occurred in patients with pre-existing complete right bundle branch block pattern. These results reasonably exclude local re-entry near the site of stimulation.

Destabilizing Effects of Mental Stress on Ventricular Arrhythmias in Patients With Implantable Cardioverter-Defibrillators

BACKGROUND The incidence of sudden cardiac death increases in populations who experience disasters such as earthquakes. The physiological link between psychological stress and sudden death is unknown; one mechanism may be the direct effects of sympathetic arousal on arrhythmias. To determine whether mental stress alters the induction, rate, or termination of ventricular arrhythmias, we performed noninvasive programmed stimulation (NIPS) in patients with defibrillators and ventricular tachycardia (VT), which is known to be inducible and terminated by antitachycardia pacing, at rest and during varying states of mental arousal. METHODS AND RESULTS Eighteen patients underwent NIPS in the resting-awake state (nonsedated). Ten underwent repeat testing during mental stress (mental arithmetic and anger recall). Induced VT was faster in 5 patients (P=0.03). VT became more difficult to terminate in 5 patients during mental stress; 4 required a shock (P=0.03). There was no change in ease of induction with mental stress. There was no evidence of ischemia on ECG or continuous ejection fraction monitoring. Eight patients received a shock in the resting-awake state and did not perform mental stress. Four underwent repeat NIPS after sedation; 3 then had induced VT terminated with antitachycardia pacing. All patients with an increase in norepinephrine of >50% had alterations in VT that required shock for termination (P<0.01). CONCLUSIONS Mental stress alters VT cycle length and termination without evidence of ischemia. This suggests that mental stress may lead to sudden death through the facilitation of lethal ventricular arrhythmias.

Electrocardiographic Predictors of Arrhythmic Death and Total Mortality in the Multicenter Unsustained Tachycardia Trial

Background—Stratifiers of sudden and total mortality risk are needed to optimally target preventive therapies in patients with coronary artery disease and impaired ventricular function. We assessed the prognostic significance of ECG markers of conduction abnormalities and left ventricular hypertrophy in the Multicenter Unsustained Tachycardia Trial (MUSTT). Methods and Results—We analyzed the ECGs of 1638 patients from MUSTT who did not receive antiarrhythmic therapy (antiarrhythmic medication or implantable cardioverter-defibrillator). After adjustment for other significant factors, left bundle-branch block and intraventricular conduction delay were associated with a 50% increase in the risk of both arrhythmic and total mortality. Right bundle-branch block was not associated with arrhythmic or total mortality. Left ventricular hypertrophy was the only ECG predictor of arrhythmic (hazard ratio, 1.35; 95% CI, 1.08 to 1.69) but not total mortality. Conclusions—In patients with coronary artery disease, depressed left ventricular function, and nonsustained ventricular tachycardia, QRS prolongation resulting from left bundle-branch block or intraventricular conduction delay but not right bundle-branch block provided prognostic information about the risk of arrhythmic and total mortality independently of electrophysiological evaluation and ejection fraction. Left ventricular hypertrophy was associated with increased arrhythmic but not total mortality.

Electrophysiologic effects of thrombolytic therapy in patients with a transmural anterior myocardial infarction complicated by left ventricular aneurysm formation

To assess the effects of early thrombolytic therapy on the incidence of clinical and induced ventricular arrhythmias in high risk postmyocardial infarction patients, 32 patients with a transmural anterior myocardial infarction complicated by left ventricular aneurysm formation were prospectively evaluated. Sixteen patients (Group A) received routine care because of contraindication to thrombolytic therapy or other factors and 16 (Group B) received either tissue plasminogen activator or streptokinase within 6 h of the onset of chest pain. The two groups were similar in left ventricular ejection fraction (mean +/- SD, 28 +/- 9% [Group A] versus 30 +/- 8% [Group B]) and occurrence of spontaneous nonsustained ventricular tachycardia, new bundle branch block and congestive heart failure. Group B patients had higher peak creatine kinase MB levels (446 +/- 336 versus 205 +/- 120 IU; p = 0.017) and earlier time to peak creatine kinase values (13.4 +/- 6.6 versus 19.1 +/- 6.1 h; p = 0.006). Twenty patients who had no clinical sustained ventricular arrhythmias underwent electrophysiologic study 13 +/- 6 days after infarction. Ventricular tachycardia was induced during the study in 7 (88%) of 8 Group A patients, but in only 1 (8%) of 12 Group B patients given thrombolytic therapy (p = 0.0008). During a mean follow-up period of 11 +/- 8 months, eight Group A patients (50%) died suddenly or were resuscitated from sustained ventricular tachycardia; all Group B patients are alive and have had no clinical arrhythmic events (p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian variation of sustained ventricular tachycardia in patients with coronary artery disease and implantable cardioverter-defibrillators.

While previous studies using epidemiological data and ambulatory ECG monitoring have shown peak occurrence of sudden death and nonsustained ventricular tachycardia in the morning, none have examined circadian variation of potentially life-threatening ventricular tachycardia (VT), nor has any study observed circadian behavior of any arrhythmias in individuals followed longitudinally. We used the event memory of multiprogrammable implantable cardioverter- defibrillators to evaluate the circadian pattern of sustained VT over time. Methods and ResultsData were reviewed from 32 consecutive patients with coronary artery disease and sustained VT who had received the Ventak PRX (CPI, Inc) cardioverterdefibrillator between May 1991 and August 1993 and had experienced at least one episode of VT terminated by their device. Mean follow-up was 14±7 months. Among the 2558 episodes recorded by the device logs, VT occurrence peaked between 6 AM and noon (P = .007 by ANOVA among four 6-hour time periods). Harmonic regression revealed a morning peak at 9 AM (P < .01). This morning peak occurred in patients with both frequent and infrequent events. Among 21 patients who experienced more than four VT events, 8 (38%) had an AM peak of VT occurrence (>35% of VT between 6 AM and noon). Neither age, ejection fraction, event frequency, presenting arrhythmia, nor drug therapy distinguished patients who displayed the AM VT peak. ConclusionsIn patients with coronary artery disease, sustained VT displays circadian variation with peak frequency in the morning, similar to that for sudden death. Individual patients who display specific patterns of circadian variation over time can be identified using defibrillator logs. Investigation of circadian variation of other phenomena to elucidate mechanisms of VT should focus on these patients.

The electrophysiology of propranolol in man

Abstract The effects of intravenous propranolol (0.1 mg. per kilogram) on the electrophysiologic properties of the A-V conducting system were studied in 16 patients using His-bundle electrograms and the extrastimulus method. The drug was infused at a rate of 1 mg. per minute without significant side effects. Sinus cycle length was slowed in 15 out of 16 patients (average, 128 msec.). AVN conduction time was increased in 13 out of 16 patients (average, 10 msec.) during sinus rhythm and in all patients during atrial pacing. AVN Wenckebach block occurred at slower paced rates in 14 patients. Corrected QT interval was shortened in 9 out of 16 patients (average, 24 msec.). The functional and effective refractory periods (ERP) of the AVN were prolonged in 14 out of 14 patients (average, 29 msec.) and 9 out of 9 patients (average, 24 msec.), respectively. No significant changes were seen in His-Purkinje system (HPS) conduction time, ERP of the atrium, relative refractory period or ERP of the HPS, or ERP of the ventricle in all patients in whom these variables could be muasured. Mean end-study blood level was 13.6 ng. per milliliter. Effects on the AVN explain the efficacy of propranolol in (1) controlling the ventricular rate in atrial fibrillation and flutter and (2) the treatment and prophylaxis of re-entrant supraventricular tachycardias. Its lack of effects on the HPS make its use relatively safe in patients with infra-His conduction disturbances.

Antegrade and retrograde conduction characteristics in three patterns of paroxysmal atrioventricular junctional reentrant tachycardia.

Abstract In 20 patients with PSVT without ventricular pre-excitation, the site of reentry and functional characteristics of Ant. and Ret. pathways were studied. Three distinct patterns of PSVT were observed. In 13 patients (group I) in whom A-V node was the site of reentry, the interval between the Ant. H bundle deflection and the following atrial echo response (H-Ae) measured 30 to 85 msec. and the Ae was partially or completely obscured by ventricular electrogram. The ratio between the H-Ae and the subsequent Ae-H interval ranged 1:3.1–17.3. In a majority of Group I patients (eight out of 13) the Ret. conduction was better than Ant. conduction, as the VACS sustained a 1:1 response at faster paced rates than AVCS. The FRP of the AVCS in Group I was determined by the A-V node in all patients and significantly exceeded the FRP of the VACS; the latter was determined by the HPS in 12 out of 13 patients. In four patients (Group II) a V-A AP silent antegradely was operative during PSVT. The H-Ae in Group II valued 145 to 200 msec. and the Ae clearly followed the ventricular electrogram, the H-Ae: Ae-H being 1:0.5–1.7. The V-A conduction in all Group II patients was better than the A-V conduction. A-V node determined the FRP of the AVCS, whereas AP determined the FRP of the VACS in Group II patients, and the former significantly exceeded the latter. Good correlation existed between PSVT, Ant. and Ret. conduction patterns in Group I and Group II patients. In three patients (Group III) the H-Ae measured 270 to 470 msec. with an H-Ae:Ae-H of 1:0.2–0.4, a relationship quite the opposite of Group I patients. No definite relationship existed between PSVT, Ant. and Ret. conduction patterns in Group III patients. The data in Group III patients were compatible with (1) A-V nodal reentry with reversal of conduction balance compared to Group I, (2) intra-atrial reentry, and (3) enhanced atrail automaticity. It is concluded (1) the site of reentry in patients with PSVT is variable, (2) a fair estimation of reentry site can be made from H-Ae and Ae-H relationship, (3) all patients with PSVT have intact V-A conduction and in most the V-A conduction is better than A-V conduction, and (4) in the majority of patients with PSVT refractoriness of the AVCS exceeds that of the VACS.

Quality‐of‐Life in Patients Receiving Implantable Cardioverter Defibrillators At or Before Age 40

As the use of ICDs increases, more young patients will be eligible to receive these devices. Such patients may have different concerns than older patients who more commonly receive ICDs. We investigated quality‐of‐life issues in patients followed by the Yale electrophysiology service who were ≤ 40 years old (mean = 28) at the time of ICD implant. Mean time since ICD placement was 3.3 years. Each patient received a modified SF‐36 health questionnaire; 16 (88%) of 18 responded. Nine were women; ten were married. The highest education level attained was high school for 6 (37%), and college or beyond for 10 (63%). Ten patients were employed; eight held the same job before and after ICD placement. Four women conceived after ICD implantation; one experienced ICD discharge during pregnancy. All delivered healthy infants. AH patients felt their health was good to excellent, with 6 (38%) reporting an improvement in health since ICD placement. All felt capable of performing the activities of daily living, while 68% engaged freely in moderate physical activities. All patients felt they were average to very attractive. However, 63 % worried about how their clothes fit with the ICD. Three quarters of the patients felt the ICD interfered with social interactions, while 50% were concerned about sexual encounters. Thus, even though these young patients have body image concerns and may limit their activities to some degree, they are productive, active members of society who have benefitted from ICD placement.